![Oleg Nesterov](/assets/img/avatar_default.png)
task->saved_sigmask and ->restore_sigmask are only used in the ret-from- syscall paths. This means that set_user_sigmask() can save ->blocked in ->saved_sigmask and do set_restore_sigmask() to indicate that ->blocked was modified. This way the callers do not need 2 sigset_t's passed to set/restore and restore_user_sigmask() renamed to restore_saved_sigmask_unless() turns into the trivial helper which just calls restore_saved_sigmask(). Link: http://lkml.kernel.org/r/20190606113206.GA9464@redhat.com Signed-off-by: Oleg Nesterov <oleg@redhat.com> Cc: Deepa Dinamani <deepa.kernel@gmail.com> Cc: Arnd Bergmann <arnd@arndb.de> Cc: Jens Axboe <axboe@kernel.dk> Cc: Davidlohr Bueso <dave@stgolabs.net> Cc: Eric Wong <e@80x24.org> Cc: Jason Baron <jbaron@akamai.com> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Al Viro <viro@ZenIV.linux.org.uk> Cc: Eric W. Biederman <ebiederm@xmission.com> Cc: David Laight <David.Laight@aculab.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
3464 lines
82 KiB
C
3464 lines
82 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/*
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* Shared application/kernel submission and completion ring pairs, for
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* supporting fast/efficient IO.
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*
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* A note on the read/write ordering memory barriers that are matched between
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* the application and kernel side.
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*
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* After the application reads the CQ ring tail, it must use an
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* appropriate smp_rmb() to pair with the smp_wmb() the kernel uses
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* before writing the tail (using smp_load_acquire to read the tail will
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* do). It also needs a smp_mb() before updating CQ head (ordering the
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* entry load(s) with the head store), pairing with an implicit barrier
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* through a control-dependency in io_get_cqring (smp_store_release to
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* store head will do). Failure to do so could lead to reading invalid
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* CQ entries.
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*
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* Likewise, the application must use an appropriate smp_wmb() before
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* writing the SQ tail (ordering SQ entry stores with the tail store),
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* which pairs with smp_load_acquire in io_get_sqring (smp_store_release
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* to store the tail will do). And it needs a barrier ordering the SQ
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* head load before writing new SQ entries (smp_load_acquire to read
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* head will do).
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*
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* When using the SQ poll thread (IORING_SETUP_SQPOLL), the application
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* needs to check the SQ flags for IORING_SQ_NEED_WAKEUP *after*
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* updating the SQ tail; a full memory barrier smp_mb() is needed
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* between.
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*
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* Also see the examples in the liburing library:
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*
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* git://git.kernel.dk/liburing
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*
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* io_uring also uses READ/WRITE_ONCE() for _any_ store or load that happens
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* from data shared between the kernel and application. This is done both
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* for ordering purposes, but also to ensure that once a value is loaded from
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* data that the application could potentially modify, it remains stable.
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*
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* Copyright (C) 2018-2019 Jens Axboe
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* Copyright (c) 2018-2019 Christoph Hellwig
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*/
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#include <linux/kernel.h>
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#include <linux/init.h>
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#include <linux/errno.h>
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#include <linux/syscalls.h>
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#include <linux/compat.h>
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#include <linux/refcount.h>
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#include <linux/uio.h>
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#include <linux/sched/signal.h>
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#include <linux/fs.h>
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#include <linux/file.h>
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#include <linux/fdtable.h>
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#include <linux/mm.h>
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#include <linux/mman.h>
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#include <linux/mmu_context.h>
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#include <linux/percpu.h>
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#include <linux/slab.h>
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#include <linux/workqueue.h>
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#include <linux/kthread.h>
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#include <linux/blkdev.h>
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#include <linux/bvec.h>
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#include <linux/net.h>
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#include <net/sock.h>
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#include <net/af_unix.h>
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#include <net/scm.h>
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#include <linux/anon_inodes.h>
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#include <linux/sched/mm.h>
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#include <linux/uaccess.h>
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#include <linux/nospec.h>
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#include <linux/sizes.h>
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#include <linux/hugetlb.h>
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#include <uapi/linux/io_uring.h>
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#include "internal.h"
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#define IORING_MAX_ENTRIES 4096
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#define IORING_MAX_FIXED_FILES 1024
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struct io_uring {
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u32 head ____cacheline_aligned_in_smp;
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u32 tail ____cacheline_aligned_in_smp;
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};
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/*
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* This data is shared with the application through the mmap at offset
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* IORING_OFF_SQ_RING.
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*
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* The offsets to the member fields are published through struct
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* io_sqring_offsets when calling io_uring_setup.
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*/
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struct io_sq_ring {
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/*
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* Head and tail offsets into the ring; the offsets need to be
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* masked to get valid indices.
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*
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* The kernel controls head and the application controls tail.
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*/
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struct io_uring r;
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/*
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* Bitmask to apply to head and tail offsets (constant, equals
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* ring_entries - 1)
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*/
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u32 ring_mask;
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/* Ring size (constant, power of 2) */
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u32 ring_entries;
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/*
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* Number of invalid entries dropped by the kernel due to
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* invalid index stored in array
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*
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* Written by the kernel, shouldn't be modified by the
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* application (i.e. get number of "new events" by comparing to
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* cached value).
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*
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* After a new SQ head value was read by the application this
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* counter includes all submissions that were dropped reaching
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* the new SQ head (and possibly more).
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*/
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u32 dropped;
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/*
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* Runtime flags
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*
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* Written by the kernel, shouldn't be modified by the
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* application.
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*
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* The application needs a full memory barrier before checking
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* for IORING_SQ_NEED_WAKEUP after updating the sq tail.
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*/
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u32 flags;
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/*
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* Ring buffer of indices into array of io_uring_sqe, which is
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* mmapped by the application using the IORING_OFF_SQES offset.
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*
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* This indirection could e.g. be used to assign fixed
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* io_uring_sqe entries to operations and only submit them to
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* the queue when needed.
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*
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* The kernel modifies neither the indices array nor the entries
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* array.
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*/
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u32 array[];
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};
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/*
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* This data is shared with the application through the mmap at offset
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* IORING_OFF_CQ_RING.
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*
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* The offsets to the member fields are published through struct
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* io_cqring_offsets when calling io_uring_setup.
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*/
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struct io_cq_ring {
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/*
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* Head and tail offsets into the ring; the offsets need to be
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* masked to get valid indices.
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*
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* The application controls head and the kernel tail.
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*/
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struct io_uring r;
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/*
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* Bitmask to apply to head and tail offsets (constant, equals
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* ring_entries - 1)
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*/
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u32 ring_mask;
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/* Ring size (constant, power of 2) */
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u32 ring_entries;
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/*
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* Number of completion events lost because the queue was full;
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* this should be avoided by the application by making sure
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* there are not more requests pending thatn there is space in
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* the completion queue.
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*
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* Written by the kernel, shouldn't be modified by the
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* application (i.e. get number of "new events" by comparing to
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* cached value).
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*
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* As completion events come in out of order this counter is not
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* ordered with any other data.
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*/
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u32 overflow;
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/*
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* Ring buffer of completion events.
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*
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* The kernel writes completion events fresh every time they are
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* produced, so the application is allowed to modify pending
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* entries.
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*/
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struct io_uring_cqe cqes[];
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};
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struct io_mapped_ubuf {
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u64 ubuf;
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size_t len;
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struct bio_vec *bvec;
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unsigned int nr_bvecs;
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};
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struct async_list {
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spinlock_t lock;
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atomic_t cnt;
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struct list_head list;
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struct file *file;
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off_t io_end;
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size_t io_pages;
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};
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struct io_ring_ctx {
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struct {
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struct percpu_ref refs;
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} ____cacheline_aligned_in_smp;
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struct {
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unsigned int flags;
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bool compat;
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bool account_mem;
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/* SQ ring */
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struct io_sq_ring *sq_ring;
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unsigned cached_sq_head;
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unsigned sq_entries;
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unsigned sq_mask;
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unsigned sq_thread_idle;
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struct io_uring_sqe *sq_sqes;
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struct list_head defer_list;
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} ____cacheline_aligned_in_smp;
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/* IO offload */
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struct workqueue_struct *sqo_wq;
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struct task_struct *sqo_thread; /* if using sq thread polling */
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struct mm_struct *sqo_mm;
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wait_queue_head_t sqo_wait;
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struct completion sqo_thread_started;
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struct {
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/* CQ ring */
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struct io_cq_ring *cq_ring;
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unsigned cached_cq_tail;
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unsigned cq_entries;
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unsigned cq_mask;
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struct wait_queue_head cq_wait;
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struct fasync_struct *cq_fasync;
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struct eventfd_ctx *cq_ev_fd;
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} ____cacheline_aligned_in_smp;
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/*
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* If used, fixed file set. Writers must ensure that ->refs is dead,
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* readers must ensure that ->refs is alive as long as the file* is
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* used. Only updated through io_uring_register(2).
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*/
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struct file **user_files;
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unsigned nr_user_files;
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/* if used, fixed mapped user buffers */
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unsigned nr_user_bufs;
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struct io_mapped_ubuf *user_bufs;
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struct user_struct *user;
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struct completion ctx_done;
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struct {
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struct mutex uring_lock;
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wait_queue_head_t wait;
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} ____cacheline_aligned_in_smp;
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struct {
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spinlock_t completion_lock;
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bool poll_multi_file;
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/*
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* ->poll_list is protected by the ctx->uring_lock for
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* io_uring instances that don't use IORING_SETUP_SQPOLL.
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* For SQPOLL, only the single threaded io_sq_thread() will
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* manipulate the list, hence no extra locking is needed there.
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*/
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struct list_head poll_list;
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struct list_head cancel_list;
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} ____cacheline_aligned_in_smp;
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struct async_list pending_async[2];
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#if defined(CONFIG_UNIX)
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struct socket *ring_sock;
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#endif
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};
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struct sqe_submit {
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const struct io_uring_sqe *sqe;
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unsigned short index;
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bool has_user;
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bool needs_lock;
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bool needs_fixed_file;
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};
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/*
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* First field must be the file pointer in all the
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* iocb unions! See also 'struct kiocb' in <linux/fs.h>
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*/
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struct io_poll_iocb {
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struct file *file;
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struct wait_queue_head *head;
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__poll_t events;
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bool done;
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bool canceled;
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struct wait_queue_entry wait;
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};
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/*
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* NOTE! Each of the iocb union members has the file pointer
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* as the first entry in their struct definition. So you can
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* access the file pointer through any of the sub-structs,
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* or directly as just 'ki_filp' in this struct.
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*/
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struct io_kiocb {
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union {
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struct file *file;
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struct kiocb rw;
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struct io_poll_iocb poll;
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};
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struct sqe_submit submit;
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struct io_ring_ctx *ctx;
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struct list_head list;
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struct list_head link_list;
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unsigned int flags;
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refcount_t refs;
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#define REQ_F_NOWAIT 1 /* must not punt to workers */
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#define REQ_F_IOPOLL_COMPLETED 2 /* polled IO has completed */
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#define REQ_F_FIXED_FILE 4 /* ctx owns file */
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#define REQ_F_SEQ_PREV 8 /* sequential with previous */
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#define REQ_F_IO_DRAIN 16 /* drain existing IO first */
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#define REQ_F_IO_DRAINED 32 /* drain done */
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#define REQ_F_LINK 64 /* linked sqes */
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#define REQ_F_FAIL_LINK 128 /* fail rest of links */
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u64 user_data;
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u32 result;
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u32 sequence;
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struct work_struct work;
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};
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#define IO_PLUG_THRESHOLD 2
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#define IO_IOPOLL_BATCH 8
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struct io_submit_state {
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struct blk_plug plug;
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/*
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* io_kiocb alloc cache
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*/
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void *reqs[IO_IOPOLL_BATCH];
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unsigned int free_reqs;
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unsigned int cur_req;
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/*
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* File reference cache
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*/
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struct file *file;
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unsigned int fd;
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unsigned int has_refs;
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unsigned int used_refs;
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unsigned int ios_left;
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};
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static void io_sq_wq_submit_work(struct work_struct *work);
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static struct kmem_cache *req_cachep;
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static const struct file_operations io_uring_fops;
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struct sock *io_uring_get_socket(struct file *file)
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{
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#if defined(CONFIG_UNIX)
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if (file->f_op == &io_uring_fops) {
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struct io_ring_ctx *ctx = file->private_data;
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return ctx->ring_sock->sk;
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}
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#endif
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return NULL;
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}
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EXPORT_SYMBOL(io_uring_get_socket);
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static void io_ring_ctx_ref_free(struct percpu_ref *ref)
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{
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struct io_ring_ctx *ctx = container_of(ref, struct io_ring_ctx, refs);
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complete(&ctx->ctx_done);
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}
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static struct io_ring_ctx *io_ring_ctx_alloc(struct io_uring_params *p)
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{
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struct io_ring_ctx *ctx;
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int i;
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ctx = kzalloc(sizeof(*ctx), GFP_KERNEL);
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if (!ctx)
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return NULL;
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if (percpu_ref_init(&ctx->refs, io_ring_ctx_ref_free,
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PERCPU_REF_ALLOW_REINIT, GFP_KERNEL)) {
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kfree(ctx);
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return NULL;
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}
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ctx->flags = p->flags;
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init_waitqueue_head(&ctx->cq_wait);
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init_completion(&ctx->ctx_done);
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init_completion(&ctx->sqo_thread_started);
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mutex_init(&ctx->uring_lock);
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init_waitqueue_head(&ctx->wait);
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for (i = 0; i < ARRAY_SIZE(ctx->pending_async); i++) {
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spin_lock_init(&ctx->pending_async[i].lock);
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INIT_LIST_HEAD(&ctx->pending_async[i].list);
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atomic_set(&ctx->pending_async[i].cnt, 0);
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}
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spin_lock_init(&ctx->completion_lock);
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INIT_LIST_HEAD(&ctx->poll_list);
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INIT_LIST_HEAD(&ctx->cancel_list);
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INIT_LIST_HEAD(&ctx->defer_list);
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return ctx;
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}
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static inline bool io_sequence_defer(struct io_ring_ctx *ctx,
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struct io_kiocb *req)
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{
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if ((req->flags & (REQ_F_IO_DRAIN|REQ_F_IO_DRAINED)) != REQ_F_IO_DRAIN)
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return false;
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return req->sequence > ctx->cached_cq_tail + ctx->sq_ring->dropped;
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}
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static struct io_kiocb *io_get_deferred_req(struct io_ring_ctx *ctx)
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{
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struct io_kiocb *req;
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if (list_empty(&ctx->defer_list))
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return NULL;
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req = list_first_entry(&ctx->defer_list, struct io_kiocb, list);
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if (!io_sequence_defer(ctx, req)) {
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list_del_init(&req->list);
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return req;
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}
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return NULL;
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}
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static void __io_commit_cqring(struct io_ring_ctx *ctx)
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{
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struct io_cq_ring *ring = ctx->cq_ring;
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if (ctx->cached_cq_tail != READ_ONCE(ring->r.tail)) {
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/* order cqe stores with ring update */
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smp_store_release(&ring->r.tail, ctx->cached_cq_tail);
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if (wq_has_sleeper(&ctx->cq_wait)) {
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wake_up_interruptible(&ctx->cq_wait);
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kill_fasync(&ctx->cq_fasync, SIGIO, POLL_IN);
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}
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}
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}
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static void io_commit_cqring(struct io_ring_ctx *ctx)
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{
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struct io_kiocb *req;
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__io_commit_cqring(ctx);
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while ((req = io_get_deferred_req(ctx)) != NULL) {
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req->flags |= REQ_F_IO_DRAINED;
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queue_work(ctx->sqo_wq, &req->work);
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}
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}
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static struct io_uring_cqe *io_get_cqring(struct io_ring_ctx *ctx)
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{
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struct io_cq_ring *ring = ctx->cq_ring;
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unsigned tail;
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tail = ctx->cached_cq_tail;
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/*
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* writes to the cq entry need to come after reading head; the
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* control dependency is enough as we're using WRITE_ONCE to
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* fill the cq entry
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*/
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if (tail - READ_ONCE(ring->r.head) == ring->ring_entries)
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return NULL;
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ctx->cached_cq_tail++;
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return &ring->cqes[tail & ctx->cq_mask];
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}
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static void io_cqring_fill_event(struct io_ring_ctx *ctx, u64 ki_user_data,
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long res)
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{
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struct io_uring_cqe *cqe;
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/*
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* If we can't get a cq entry, userspace overflowed the
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|
* submission (by quite a lot). Increment the overflow count in
|
|
* the ring.
|
|
*/
|
|
cqe = io_get_cqring(ctx);
|
|
if (cqe) {
|
|
WRITE_ONCE(cqe->user_data, ki_user_data);
|
|
WRITE_ONCE(cqe->res, res);
|
|
WRITE_ONCE(cqe->flags, 0);
|
|
} else {
|
|
unsigned overflow = READ_ONCE(ctx->cq_ring->overflow);
|
|
|
|
WRITE_ONCE(ctx->cq_ring->overflow, overflow + 1);
|
|
}
|
|
}
|
|
|
|
static void io_cqring_ev_posted(struct io_ring_ctx *ctx)
|
|
{
|
|
if (waitqueue_active(&ctx->wait))
|
|
wake_up(&ctx->wait);
|
|
if (waitqueue_active(&ctx->sqo_wait))
|
|
wake_up(&ctx->sqo_wait);
|
|
if (ctx->cq_ev_fd)
|
|
eventfd_signal(ctx->cq_ev_fd, 1);
|
|
}
|
|
|
|
static void io_cqring_add_event(struct io_ring_ctx *ctx, u64 user_data,
|
|
long res)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(&ctx->completion_lock, flags);
|
|
io_cqring_fill_event(ctx, user_data, res);
|
|
io_commit_cqring(ctx);
|
|
spin_unlock_irqrestore(&ctx->completion_lock, flags);
|
|
|
|
io_cqring_ev_posted(ctx);
|
|
}
|
|
|
|
static void io_ring_drop_ctx_refs(struct io_ring_ctx *ctx, unsigned refs)
|
|
{
|
|
percpu_ref_put_many(&ctx->refs, refs);
|
|
|
|
if (waitqueue_active(&ctx->wait))
|
|
wake_up(&ctx->wait);
|
|
}
|
|
|
|
static struct io_kiocb *io_get_req(struct io_ring_ctx *ctx,
|
|
struct io_submit_state *state)
|
|
{
|
|
gfp_t gfp = GFP_KERNEL | __GFP_NOWARN;
|
|
struct io_kiocb *req;
|
|
|
|
if (!percpu_ref_tryget(&ctx->refs))
|
|
return NULL;
|
|
|
|
if (!state) {
|
|
req = kmem_cache_alloc(req_cachep, gfp);
|
|
if (unlikely(!req))
|
|
goto out;
|
|
} else if (!state->free_reqs) {
|
|
size_t sz;
|
|
int ret;
|
|
|
|
sz = min_t(size_t, state->ios_left, ARRAY_SIZE(state->reqs));
|
|
ret = kmem_cache_alloc_bulk(req_cachep, gfp, sz, state->reqs);
|
|
|
|
/*
|
|
* Bulk alloc is all-or-nothing. If we fail to get a batch,
|
|
* retry single alloc to be on the safe side.
|
|
*/
|
|
if (unlikely(ret <= 0)) {
|
|
state->reqs[0] = kmem_cache_alloc(req_cachep, gfp);
|
|
if (!state->reqs[0])
|
|
goto out;
|
|
ret = 1;
|
|
}
|
|
state->free_reqs = ret - 1;
|
|
state->cur_req = 1;
|
|
req = state->reqs[0];
|
|
} else {
|
|
req = state->reqs[state->cur_req];
|
|
state->free_reqs--;
|
|
state->cur_req++;
|
|
}
|
|
|
|
req->file = NULL;
|
|
req->ctx = ctx;
|
|
req->flags = 0;
|
|
/* one is dropped after submission, the other at completion */
|
|
refcount_set(&req->refs, 2);
|
|
req->result = 0;
|
|
return req;
|
|
out:
|
|
io_ring_drop_ctx_refs(ctx, 1);
|
|
return NULL;
|
|
}
|
|
|
|
static void io_free_req_many(struct io_ring_ctx *ctx, void **reqs, int *nr)
|
|
{
|
|
if (*nr) {
|
|
kmem_cache_free_bulk(req_cachep, *nr, reqs);
|
|
io_ring_drop_ctx_refs(ctx, *nr);
|
|
*nr = 0;
|
|
}
|
|
}
|
|
|
|
static void __io_free_req(struct io_kiocb *req)
|
|
{
|
|
if (req->file && !(req->flags & REQ_F_FIXED_FILE))
|
|
fput(req->file);
|
|
io_ring_drop_ctx_refs(req->ctx, 1);
|
|
kmem_cache_free(req_cachep, req);
|
|
}
|
|
|
|
static void io_req_link_next(struct io_kiocb *req)
|
|
{
|
|
struct io_kiocb *nxt;
|
|
|
|
/*
|
|
* The list should never be empty when we are called here. But could
|
|
* potentially happen if the chain is messed up, check to be on the
|
|
* safe side.
|
|
*/
|
|
nxt = list_first_entry_or_null(&req->link_list, struct io_kiocb, list);
|
|
if (nxt) {
|
|
list_del(&nxt->list);
|
|
if (!list_empty(&req->link_list)) {
|
|
INIT_LIST_HEAD(&nxt->link_list);
|
|
list_splice(&req->link_list, &nxt->link_list);
|
|
nxt->flags |= REQ_F_LINK;
|
|
}
|
|
|
|
INIT_WORK(&nxt->work, io_sq_wq_submit_work);
|
|
queue_work(req->ctx->sqo_wq, &nxt->work);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Called if REQ_F_LINK is set, and we fail the head request
|
|
*/
|
|
static void io_fail_links(struct io_kiocb *req)
|
|
{
|
|
struct io_kiocb *link;
|
|
|
|
while (!list_empty(&req->link_list)) {
|
|
link = list_first_entry(&req->link_list, struct io_kiocb, list);
|
|
list_del(&link->list);
|
|
|
|
io_cqring_add_event(req->ctx, link->user_data, -ECANCELED);
|
|
__io_free_req(link);
|
|
}
|
|
}
|
|
|
|
static void io_free_req(struct io_kiocb *req)
|
|
{
|
|
/*
|
|
* If LINK is set, we have dependent requests in this chain. If we
|
|
* didn't fail this request, queue the first one up, moving any other
|
|
* dependencies to the next request. In case of failure, fail the rest
|
|
* of the chain.
|
|
*/
|
|
if (req->flags & REQ_F_LINK) {
|
|
if (req->flags & REQ_F_FAIL_LINK)
|
|
io_fail_links(req);
|
|
else
|
|
io_req_link_next(req);
|
|
}
|
|
|
|
__io_free_req(req);
|
|
}
|
|
|
|
static void io_put_req(struct io_kiocb *req)
|
|
{
|
|
if (refcount_dec_and_test(&req->refs))
|
|
io_free_req(req);
|
|
}
|
|
|
|
/*
|
|
* Find and free completed poll iocbs
|
|
*/
|
|
static void io_iopoll_complete(struct io_ring_ctx *ctx, unsigned int *nr_events,
|
|
struct list_head *done)
|
|
{
|
|
void *reqs[IO_IOPOLL_BATCH];
|
|
struct io_kiocb *req;
|
|
int to_free;
|
|
|
|
to_free = 0;
|
|
while (!list_empty(done)) {
|
|
req = list_first_entry(done, struct io_kiocb, list);
|
|
list_del(&req->list);
|
|
|
|
io_cqring_fill_event(ctx, req->user_data, req->result);
|
|
(*nr_events)++;
|
|
|
|
if (refcount_dec_and_test(&req->refs)) {
|
|
/* If we're not using fixed files, we have to pair the
|
|
* completion part with the file put. Use regular
|
|
* completions for those, only batch free for fixed
|
|
* file and non-linked commands.
|
|
*/
|
|
if ((req->flags & (REQ_F_FIXED_FILE|REQ_F_LINK)) ==
|
|
REQ_F_FIXED_FILE) {
|
|
reqs[to_free++] = req;
|
|
if (to_free == ARRAY_SIZE(reqs))
|
|
io_free_req_many(ctx, reqs, &to_free);
|
|
} else {
|
|
io_free_req(req);
|
|
}
|
|
}
|
|
}
|
|
|
|
io_commit_cqring(ctx);
|
|
io_free_req_many(ctx, reqs, &to_free);
|
|
}
|
|
|
|
static int io_do_iopoll(struct io_ring_ctx *ctx, unsigned int *nr_events,
|
|
long min)
|
|
{
|
|
struct io_kiocb *req, *tmp;
|
|
LIST_HEAD(done);
|
|
bool spin;
|
|
int ret;
|
|
|
|
/*
|
|
* Only spin for completions if we don't have multiple devices hanging
|
|
* off our complete list, and we're under the requested amount.
|
|
*/
|
|
spin = !ctx->poll_multi_file && *nr_events < min;
|
|
|
|
ret = 0;
|
|
list_for_each_entry_safe(req, tmp, &ctx->poll_list, list) {
|
|
struct kiocb *kiocb = &req->rw;
|
|
|
|
/*
|
|
* Move completed entries to our local list. If we find a
|
|
* request that requires polling, break out and complete
|
|
* the done list first, if we have entries there.
|
|
*/
|
|
if (req->flags & REQ_F_IOPOLL_COMPLETED) {
|
|
list_move_tail(&req->list, &done);
|
|
continue;
|
|
}
|
|
if (!list_empty(&done))
|
|
break;
|
|
|
|
ret = kiocb->ki_filp->f_op->iopoll(kiocb, spin);
|
|
if (ret < 0)
|
|
break;
|
|
|
|
if (ret && spin)
|
|
spin = false;
|
|
ret = 0;
|
|
}
|
|
|
|
if (!list_empty(&done))
|
|
io_iopoll_complete(ctx, nr_events, &done);
|
|
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Poll for a mininum of 'min' events. Note that if min == 0 we consider that a
|
|
* non-spinning poll check - we'll still enter the driver poll loop, but only
|
|
* as a non-spinning completion check.
|
|
*/
|
|
static int io_iopoll_getevents(struct io_ring_ctx *ctx, unsigned int *nr_events,
|
|
long min)
|
|
{
|
|
while (!list_empty(&ctx->poll_list)) {
|
|
int ret;
|
|
|
|
ret = io_do_iopoll(ctx, nr_events, min);
|
|
if (ret < 0)
|
|
return ret;
|
|
if (!min || *nr_events >= min)
|
|
return 0;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* We can't just wait for polled events to come to us, we have to actively
|
|
* find and complete them.
|
|
*/
|
|
static void io_iopoll_reap_events(struct io_ring_ctx *ctx)
|
|
{
|
|
if (!(ctx->flags & IORING_SETUP_IOPOLL))
|
|
return;
|
|
|
|
mutex_lock(&ctx->uring_lock);
|
|
while (!list_empty(&ctx->poll_list)) {
|
|
unsigned int nr_events = 0;
|
|
|
|
io_iopoll_getevents(ctx, &nr_events, 1);
|
|
}
|
|
mutex_unlock(&ctx->uring_lock);
|
|
}
|
|
|
|
static int io_iopoll_check(struct io_ring_ctx *ctx, unsigned *nr_events,
|
|
long min)
|
|
{
|
|
int ret = 0;
|
|
|
|
do {
|
|
int tmin = 0;
|
|
|
|
if (*nr_events < min)
|
|
tmin = min - *nr_events;
|
|
|
|
ret = io_iopoll_getevents(ctx, nr_events, tmin);
|
|
if (ret <= 0)
|
|
break;
|
|
ret = 0;
|
|
} while (min && !*nr_events && !need_resched());
|
|
|
|
return ret;
|
|
}
|
|
|
|
static void kiocb_end_write(struct kiocb *kiocb)
|
|
{
|
|
if (kiocb->ki_flags & IOCB_WRITE) {
|
|
struct inode *inode = file_inode(kiocb->ki_filp);
|
|
|
|
/*
|
|
* Tell lockdep we inherited freeze protection from submission
|
|
* thread.
|
|
*/
|
|
if (S_ISREG(inode->i_mode))
|
|
__sb_writers_acquired(inode->i_sb, SB_FREEZE_WRITE);
|
|
file_end_write(kiocb->ki_filp);
|
|
}
|
|
}
|
|
|
|
static void io_complete_rw(struct kiocb *kiocb, long res, long res2)
|
|
{
|
|
struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw);
|
|
|
|
kiocb_end_write(kiocb);
|
|
|
|
if ((req->flags & REQ_F_LINK) && res != req->result)
|
|
req->flags |= REQ_F_FAIL_LINK;
|
|
io_cqring_add_event(req->ctx, req->user_data, res);
|
|
io_put_req(req);
|
|
}
|
|
|
|
static void io_complete_rw_iopoll(struct kiocb *kiocb, long res, long res2)
|
|
{
|
|
struct io_kiocb *req = container_of(kiocb, struct io_kiocb, rw);
|
|
|
|
kiocb_end_write(kiocb);
|
|
|
|
if ((req->flags & REQ_F_LINK) && res != req->result)
|
|
req->flags |= REQ_F_FAIL_LINK;
|
|
req->result = res;
|
|
if (res != -EAGAIN)
|
|
req->flags |= REQ_F_IOPOLL_COMPLETED;
|
|
}
|
|
|
|
/*
|
|
* After the iocb has been issued, it's safe to be found on the poll list.
|
|
* Adding the kiocb to the list AFTER submission ensures that we don't
|
|
* find it from a io_iopoll_getevents() thread before the issuer is done
|
|
* accessing the kiocb cookie.
|
|
*/
|
|
static void io_iopoll_req_issued(struct io_kiocb *req)
|
|
{
|
|
struct io_ring_ctx *ctx = req->ctx;
|
|
|
|
/*
|
|
* Track whether we have multiple files in our lists. This will impact
|
|
* how we do polling eventually, not spinning if we're on potentially
|
|
* different devices.
|
|
*/
|
|
if (list_empty(&ctx->poll_list)) {
|
|
ctx->poll_multi_file = false;
|
|
} else if (!ctx->poll_multi_file) {
|
|
struct io_kiocb *list_req;
|
|
|
|
list_req = list_first_entry(&ctx->poll_list, struct io_kiocb,
|
|
list);
|
|
if (list_req->rw.ki_filp != req->rw.ki_filp)
|
|
ctx->poll_multi_file = true;
|
|
}
|
|
|
|
/*
|
|
* For fast devices, IO may have already completed. If it has, add
|
|
* it to the front so we find it first.
|
|
*/
|
|
if (req->flags & REQ_F_IOPOLL_COMPLETED)
|
|
list_add(&req->list, &ctx->poll_list);
|
|
else
|
|
list_add_tail(&req->list, &ctx->poll_list);
|
|
}
|
|
|
|
static void io_file_put(struct io_submit_state *state)
|
|
{
|
|
if (state->file) {
|
|
int diff = state->has_refs - state->used_refs;
|
|
|
|
if (diff)
|
|
fput_many(state->file, diff);
|
|
state->file = NULL;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Get as many references to a file as we have IOs left in this submission,
|
|
* assuming most submissions are for one file, or at least that each file
|
|
* has more than one submission.
|
|
*/
|
|
static struct file *io_file_get(struct io_submit_state *state, int fd)
|
|
{
|
|
if (!state)
|
|
return fget(fd);
|
|
|
|
if (state->file) {
|
|
if (state->fd == fd) {
|
|
state->used_refs++;
|
|
state->ios_left--;
|
|
return state->file;
|
|
}
|
|
io_file_put(state);
|
|
}
|
|
state->file = fget_many(fd, state->ios_left);
|
|
if (!state->file)
|
|
return NULL;
|
|
|
|
state->fd = fd;
|
|
state->has_refs = state->ios_left;
|
|
state->used_refs = 1;
|
|
state->ios_left--;
|
|
return state->file;
|
|
}
|
|
|
|
/*
|
|
* If we tracked the file through the SCM inflight mechanism, we could support
|
|
* any file. For now, just ensure that anything potentially problematic is done
|
|
* inline.
|
|
*/
|
|
static bool io_file_supports_async(struct file *file)
|
|
{
|
|
umode_t mode = file_inode(file)->i_mode;
|
|
|
|
if (S_ISBLK(mode) || S_ISCHR(mode))
|
|
return true;
|
|
if (S_ISREG(mode) && file->f_op != &io_uring_fops)
|
|
return true;
|
|
|
|
return false;
|
|
}
|
|
|
|
static int io_prep_rw(struct io_kiocb *req, const struct sqe_submit *s,
|
|
bool force_nonblock)
|
|
{
|
|
const struct io_uring_sqe *sqe = s->sqe;
|
|
struct io_ring_ctx *ctx = req->ctx;
|
|
struct kiocb *kiocb = &req->rw;
|
|
unsigned ioprio;
|
|
int ret;
|
|
|
|
if (!req->file)
|
|
return -EBADF;
|
|
|
|
if (force_nonblock && !io_file_supports_async(req->file))
|
|
force_nonblock = false;
|
|
|
|
kiocb->ki_pos = READ_ONCE(sqe->off);
|
|
kiocb->ki_flags = iocb_flags(kiocb->ki_filp);
|
|
kiocb->ki_hint = ki_hint_validate(file_write_hint(kiocb->ki_filp));
|
|
|
|
ioprio = READ_ONCE(sqe->ioprio);
|
|
if (ioprio) {
|
|
ret = ioprio_check_cap(ioprio);
|
|
if (ret)
|
|
return ret;
|
|
|
|
kiocb->ki_ioprio = ioprio;
|
|
} else
|
|
kiocb->ki_ioprio = get_current_ioprio();
|
|
|
|
ret = kiocb_set_rw_flags(kiocb, READ_ONCE(sqe->rw_flags));
|
|
if (unlikely(ret))
|
|
return ret;
|
|
|
|
/* don't allow async punt if RWF_NOWAIT was requested */
|
|
if (kiocb->ki_flags & IOCB_NOWAIT)
|
|
req->flags |= REQ_F_NOWAIT;
|
|
|
|
if (force_nonblock)
|
|
kiocb->ki_flags |= IOCB_NOWAIT;
|
|
|
|
if (ctx->flags & IORING_SETUP_IOPOLL) {
|
|
if (!(kiocb->ki_flags & IOCB_DIRECT) ||
|
|
!kiocb->ki_filp->f_op->iopoll)
|
|
return -EOPNOTSUPP;
|
|
|
|
kiocb->ki_flags |= IOCB_HIPRI;
|
|
kiocb->ki_complete = io_complete_rw_iopoll;
|
|
} else {
|
|
if (kiocb->ki_flags & IOCB_HIPRI)
|
|
return -EINVAL;
|
|
kiocb->ki_complete = io_complete_rw;
|
|
}
|
|
return 0;
|
|
}
|
|
|
|
static inline void io_rw_done(struct kiocb *kiocb, ssize_t ret)
|
|
{
|
|
switch (ret) {
|
|
case -EIOCBQUEUED:
|
|
break;
|
|
case -ERESTARTSYS:
|
|
case -ERESTARTNOINTR:
|
|
case -ERESTARTNOHAND:
|
|
case -ERESTART_RESTARTBLOCK:
|
|
/*
|
|
* We can't just restart the syscall, since previously
|
|
* submitted sqes may already be in progress. Just fail this
|
|
* IO with EINTR.
|
|
*/
|
|
ret = -EINTR;
|
|
/* fall through */
|
|
default:
|
|
kiocb->ki_complete(kiocb, ret, 0);
|
|
}
|
|
}
|
|
|
|
static int io_import_fixed(struct io_ring_ctx *ctx, int rw,
|
|
const struct io_uring_sqe *sqe,
|
|
struct iov_iter *iter)
|
|
{
|
|
size_t len = READ_ONCE(sqe->len);
|
|
struct io_mapped_ubuf *imu;
|
|
unsigned index, buf_index;
|
|
size_t offset;
|
|
u64 buf_addr;
|
|
|
|
/* attempt to use fixed buffers without having provided iovecs */
|
|
if (unlikely(!ctx->user_bufs))
|
|
return -EFAULT;
|
|
|
|
buf_index = READ_ONCE(sqe->buf_index);
|
|
if (unlikely(buf_index >= ctx->nr_user_bufs))
|
|
return -EFAULT;
|
|
|
|
index = array_index_nospec(buf_index, ctx->nr_user_bufs);
|
|
imu = &ctx->user_bufs[index];
|
|
buf_addr = READ_ONCE(sqe->addr);
|
|
|
|
/* overflow */
|
|
if (buf_addr + len < buf_addr)
|
|
return -EFAULT;
|
|
/* not inside the mapped region */
|
|
if (buf_addr < imu->ubuf || buf_addr + len > imu->ubuf + imu->len)
|
|
return -EFAULT;
|
|
|
|
/*
|
|
* May not be a start of buffer, set size appropriately
|
|
* and advance us to the beginning.
|
|
*/
|
|
offset = buf_addr - imu->ubuf;
|
|
iov_iter_bvec(iter, rw, imu->bvec, imu->nr_bvecs, offset + len);
|
|
if (offset)
|
|
iov_iter_advance(iter, offset);
|
|
return 0;
|
|
}
|
|
|
|
static ssize_t io_import_iovec(struct io_ring_ctx *ctx, int rw,
|
|
const struct sqe_submit *s, struct iovec **iovec,
|
|
struct iov_iter *iter)
|
|
{
|
|
const struct io_uring_sqe *sqe = s->sqe;
|
|
void __user *buf = u64_to_user_ptr(READ_ONCE(sqe->addr));
|
|
size_t sqe_len = READ_ONCE(sqe->len);
|
|
u8 opcode;
|
|
|
|
/*
|
|
* We're reading ->opcode for the second time, but the first read
|
|
* doesn't care whether it's _FIXED or not, so it doesn't matter
|
|
* whether ->opcode changes concurrently. The first read does care
|
|
* about whether it is a READ or a WRITE, so we don't trust this read
|
|
* for that purpose and instead let the caller pass in the read/write
|
|
* flag.
|
|
*/
|
|
opcode = READ_ONCE(sqe->opcode);
|
|
if (opcode == IORING_OP_READ_FIXED ||
|
|
opcode == IORING_OP_WRITE_FIXED) {
|
|
ssize_t ret = io_import_fixed(ctx, rw, sqe, iter);
|
|
*iovec = NULL;
|
|
return ret;
|
|
}
|
|
|
|
if (!s->has_user)
|
|
return -EFAULT;
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
if (ctx->compat)
|
|
return compat_import_iovec(rw, buf, sqe_len, UIO_FASTIOV,
|
|
iovec, iter);
|
|
#endif
|
|
|
|
return import_iovec(rw, buf, sqe_len, UIO_FASTIOV, iovec, iter);
|
|
}
|
|
|
|
/*
|
|
* Make a note of the last file/offset/direction we punted to async
|
|
* context. We'll use this information to see if we can piggy back a
|
|
* sequential request onto the previous one, if it's still hasn't been
|
|
* completed by the async worker.
|
|
*/
|
|
static void io_async_list_note(int rw, struct io_kiocb *req, size_t len)
|
|
{
|
|
struct async_list *async_list = &req->ctx->pending_async[rw];
|
|
struct kiocb *kiocb = &req->rw;
|
|
struct file *filp = kiocb->ki_filp;
|
|
off_t io_end = kiocb->ki_pos + len;
|
|
|
|
if (filp == async_list->file && kiocb->ki_pos == async_list->io_end) {
|
|
unsigned long max_pages;
|
|
|
|
/* Use 8x RA size as a decent limiter for both reads/writes */
|
|
max_pages = filp->f_ra.ra_pages;
|
|
if (!max_pages)
|
|
max_pages = VM_READAHEAD_PAGES;
|
|
max_pages *= 8;
|
|
|
|
/* If max pages are exceeded, reset the state */
|
|
len >>= PAGE_SHIFT;
|
|
if (async_list->io_pages + len <= max_pages) {
|
|
req->flags |= REQ_F_SEQ_PREV;
|
|
async_list->io_pages += len;
|
|
} else {
|
|
io_end = 0;
|
|
async_list->io_pages = 0;
|
|
}
|
|
}
|
|
|
|
/* New file? Reset state. */
|
|
if (async_list->file != filp) {
|
|
async_list->io_pages = 0;
|
|
async_list->file = filp;
|
|
}
|
|
async_list->io_end = io_end;
|
|
}
|
|
|
|
static int io_read(struct io_kiocb *req, const struct sqe_submit *s,
|
|
bool force_nonblock)
|
|
{
|
|
struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
|
|
struct kiocb *kiocb = &req->rw;
|
|
struct iov_iter iter;
|
|
struct file *file;
|
|
size_t iov_count;
|
|
ssize_t read_size, ret;
|
|
|
|
ret = io_prep_rw(req, s, force_nonblock);
|
|
if (ret)
|
|
return ret;
|
|
file = kiocb->ki_filp;
|
|
|
|
if (unlikely(!(file->f_mode & FMODE_READ)))
|
|
return -EBADF;
|
|
if (unlikely(!file->f_op->read_iter))
|
|
return -EINVAL;
|
|
|
|
ret = io_import_iovec(req->ctx, READ, s, &iovec, &iter);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
read_size = ret;
|
|
if (req->flags & REQ_F_LINK)
|
|
req->result = read_size;
|
|
|
|
iov_count = iov_iter_count(&iter);
|
|
ret = rw_verify_area(READ, file, &kiocb->ki_pos, iov_count);
|
|
if (!ret) {
|
|
ssize_t ret2;
|
|
|
|
ret2 = call_read_iter(file, kiocb, &iter);
|
|
/*
|
|
* In case of a short read, punt to async. This can happen
|
|
* if we have data partially cached. Alternatively we can
|
|
* return the short read, in which case the application will
|
|
* need to issue another SQE and wait for it. That SQE will
|
|
* need async punt anyway, so it's more efficient to do it
|
|
* here.
|
|
*/
|
|
if (force_nonblock && ret2 > 0 && ret2 < read_size)
|
|
ret2 = -EAGAIN;
|
|
/* Catch -EAGAIN return for forced non-blocking submission */
|
|
if (!force_nonblock || ret2 != -EAGAIN) {
|
|
io_rw_done(kiocb, ret2);
|
|
} else {
|
|
/*
|
|
* If ->needs_lock is true, we're already in async
|
|
* context.
|
|
*/
|
|
if (!s->needs_lock)
|
|
io_async_list_note(READ, req, iov_count);
|
|
ret = -EAGAIN;
|
|
}
|
|
}
|
|
kfree(iovec);
|
|
return ret;
|
|
}
|
|
|
|
static int io_write(struct io_kiocb *req, const struct sqe_submit *s,
|
|
bool force_nonblock)
|
|
{
|
|
struct iovec inline_vecs[UIO_FASTIOV], *iovec = inline_vecs;
|
|
struct kiocb *kiocb = &req->rw;
|
|
struct iov_iter iter;
|
|
struct file *file;
|
|
size_t iov_count;
|
|
ssize_t ret;
|
|
|
|
ret = io_prep_rw(req, s, force_nonblock);
|
|
if (ret)
|
|
return ret;
|
|
|
|
file = kiocb->ki_filp;
|
|
if (unlikely(!(file->f_mode & FMODE_WRITE)))
|
|
return -EBADF;
|
|
if (unlikely(!file->f_op->write_iter))
|
|
return -EINVAL;
|
|
|
|
ret = io_import_iovec(req->ctx, WRITE, s, &iovec, &iter);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
if (req->flags & REQ_F_LINK)
|
|
req->result = ret;
|
|
|
|
iov_count = iov_iter_count(&iter);
|
|
|
|
ret = -EAGAIN;
|
|
if (force_nonblock && !(kiocb->ki_flags & IOCB_DIRECT)) {
|
|
/* If ->needs_lock is true, we're already in async context. */
|
|
if (!s->needs_lock)
|
|
io_async_list_note(WRITE, req, iov_count);
|
|
goto out_free;
|
|
}
|
|
|
|
ret = rw_verify_area(WRITE, file, &kiocb->ki_pos, iov_count);
|
|
if (!ret) {
|
|
ssize_t ret2;
|
|
|
|
/*
|
|
* Open-code file_start_write here to grab freeze protection,
|
|
* which will be released by another thread in
|
|
* io_complete_rw(). Fool lockdep by telling it the lock got
|
|
* released so that it doesn't complain about the held lock when
|
|
* we return to userspace.
|
|
*/
|
|
if (S_ISREG(file_inode(file)->i_mode)) {
|
|
__sb_start_write(file_inode(file)->i_sb,
|
|
SB_FREEZE_WRITE, true);
|
|
__sb_writers_release(file_inode(file)->i_sb,
|
|
SB_FREEZE_WRITE);
|
|
}
|
|
kiocb->ki_flags |= IOCB_WRITE;
|
|
|
|
ret2 = call_write_iter(file, kiocb, &iter);
|
|
if (!force_nonblock || ret2 != -EAGAIN) {
|
|
io_rw_done(kiocb, ret2);
|
|
} else {
|
|
/*
|
|
* If ->needs_lock is true, we're already in async
|
|
* context.
|
|
*/
|
|
if (!s->needs_lock)
|
|
io_async_list_note(WRITE, req, iov_count);
|
|
ret = -EAGAIN;
|
|
}
|
|
}
|
|
out_free:
|
|
kfree(iovec);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* IORING_OP_NOP just posts a completion event, nothing else.
|
|
*/
|
|
static int io_nop(struct io_kiocb *req, u64 user_data)
|
|
{
|
|
struct io_ring_ctx *ctx = req->ctx;
|
|
long err = 0;
|
|
|
|
if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
|
|
return -EINVAL;
|
|
|
|
io_cqring_add_event(ctx, user_data, err);
|
|
io_put_req(req);
|
|
return 0;
|
|
}
|
|
|
|
static int io_prep_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe)
|
|
{
|
|
struct io_ring_ctx *ctx = req->ctx;
|
|
|
|
if (!req->file)
|
|
return -EBADF;
|
|
|
|
if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
|
|
return -EINVAL;
|
|
if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index))
|
|
return -EINVAL;
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int io_fsync(struct io_kiocb *req, const struct io_uring_sqe *sqe,
|
|
bool force_nonblock)
|
|
{
|
|
loff_t sqe_off = READ_ONCE(sqe->off);
|
|
loff_t sqe_len = READ_ONCE(sqe->len);
|
|
loff_t end = sqe_off + sqe_len;
|
|
unsigned fsync_flags;
|
|
int ret;
|
|
|
|
fsync_flags = READ_ONCE(sqe->fsync_flags);
|
|
if (unlikely(fsync_flags & ~IORING_FSYNC_DATASYNC))
|
|
return -EINVAL;
|
|
|
|
ret = io_prep_fsync(req, sqe);
|
|
if (ret)
|
|
return ret;
|
|
|
|
/* fsync always requires a blocking context */
|
|
if (force_nonblock)
|
|
return -EAGAIN;
|
|
|
|
ret = vfs_fsync_range(req->rw.ki_filp, sqe_off,
|
|
end > 0 ? end : LLONG_MAX,
|
|
fsync_flags & IORING_FSYNC_DATASYNC);
|
|
|
|
if (ret < 0 && (req->flags & REQ_F_LINK))
|
|
req->flags |= REQ_F_FAIL_LINK;
|
|
io_cqring_add_event(req->ctx, sqe->user_data, ret);
|
|
io_put_req(req);
|
|
return 0;
|
|
}
|
|
|
|
static int io_prep_sfr(struct io_kiocb *req, const struct io_uring_sqe *sqe)
|
|
{
|
|
struct io_ring_ctx *ctx = req->ctx;
|
|
int ret = 0;
|
|
|
|
if (!req->file)
|
|
return -EBADF;
|
|
|
|
if (unlikely(ctx->flags & IORING_SETUP_IOPOLL))
|
|
return -EINVAL;
|
|
if (unlikely(sqe->addr || sqe->ioprio || sqe->buf_index))
|
|
return -EINVAL;
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int io_sync_file_range(struct io_kiocb *req,
|
|
const struct io_uring_sqe *sqe,
|
|
bool force_nonblock)
|
|
{
|
|
loff_t sqe_off;
|
|
loff_t sqe_len;
|
|
unsigned flags;
|
|
int ret;
|
|
|
|
ret = io_prep_sfr(req, sqe);
|
|
if (ret)
|
|
return ret;
|
|
|
|
/* sync_file_range always requires a blocking context */
|
|
if (force_nonblock)
|
|
return -EAGAIN;
|
|
|
|
sqe_off = READ_ONCE(sqe->off);
|
|
sqe_len = READ_ONCE(sqe->len);
|
|
flags = READ_ONCE(sqe->sync_range_flags);
|
|
|
|
ret = sync_file_range(req->rw.ki_filp, sqe_off, sqe_len, flags);
|
|
|
|
if (ret < 0 && (req->flags & REQ_F_LINK))
|
|
req->flags |= REQ_F_FAIL_LINK;
|
|
io_cqring_add_event(req->ctx, sqe->user_data, ret);
|
|
io_put_req(req);
|
|
return 0;
|
|
}
|
|
|
|
#if defined(CONFIG_NET)
|
|
static int io_send_recvmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe,
|
|
bool force_nonblock,
|
|
long (*fn)(struct socket *, struct user_msghdr __user *,
|
|
unsigned int))
|
|
{
|
|
struct socket *sock;
|
|
int ret;
|
|
|
|
if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
|
|
return -EINVAL;
|
|
|
|
sock = sock_from_file(req->file, &ret);
|
|
if (sock) {
|
|
struct user_msghdr __user *msg;
|
|
unsigned flags;
|
|
|
|
flags = READ_ONCE(sqe->msg_flags);
|
|
if (flags & MSG_DONTWAIT)
|
|
req->flags |= REQ_F_NOWAIT;
|
|
else if (force_nonblock)
|
|
flags |= MSG_DONTWAIT;
|
|
|
|
msg = (struct user_msghdr __user *) (unsigned long)
|
|
READ_ONCE(sqe->addr);
|
|
|
|
ret = fn(sock, msg, flags);
|
|
if (force_nonblock && ret == -EAGAIN)
|
|
return ret;
|
|
}
|
|
|
|
io_cqring_add_event(req->ctx, sqe->user_data, ret);
|
|
io_put_req(req);
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
static int io_sendmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe,
|
|
bool force_nonblock)
|
|
{
|
|
#if defined(CONFIG_NET)
|
|
return io_send_recvmsg(req, sqe, force_nonblock, __sys_sendmsg_sock);
|
|
#else
|
|
return -EOPNOTSUPP;
|
|
#endif
|
|
}
|
|
|
|
static int io_recvmsg(struct io_kiocb *req, const struct io_uring_sqe *sqe,
|
|
bool force_nonblock)
|
|
{
|
|
#if defined(CONFIG_NET)
|
|
return io_send_recvmsg(req, sqe, force_nonblock, __sys_recvmsg_sock);
|
|
#else
|
|
return -EOPNOTSUPP;
|
|
#endif
|
|
}
|
|
|
|
static void io_poll_remove_one(struct io_kiocb *req)
|
|
{
|
|
struct io_poll_iocb *poll = &req->poll;
|
|
|
|
spin_lock(&poll->head->lock);
|
|
WRITE_ONCE(poll->canceled, true);
|
|
if (!list_empty(&poll->wait.entry)) {
|
|
list_del_init(&poll->wait.entry);
|
|
queue_work(req->ctx->sqo_wq, &req->work);
|
|
}
|
|
spin_unlock(&poll->head->lock);
|
|
|
|
list_del_init(&req->list);
|
|
}
|
|
|
|
static void io_poll_remove_all(struct io_ring_ctx *ctx)
|
|
{
|
|
struct io_kiocb *req;
|
|
|
|
spin_lock_irq(&ctx->completion_lock);
|
|
while (!list_empty(&ctx->cancel_list)) {
|
|
req = list_first_entry(&ctx->cancel_list, struct io_kiocb,list);
|
|
io_poll_remove_one(req);
|
|
}
|
|
spin_unlock_irq(&ctx->completion_lock);
|
|
}
|
|
|
|
/*
|
|
* Find a running poll command that matches one specified in sqe->addr,
|
|
* and remove it if found.
|
|
*/
|
|
static int io_poll_remove(struct io_kiocb *req, const struct io_uring_sqe *sqe)
|
|
{
|
|
struct io_ring_ctx *ctx = req->ctx;
|
|
struct io_kiocb *poll_req, *next;
|
|
int ret = -ENOENT;
|
|
|
|
if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
|
|
return -EINVAL;
|
|
if (sqe->ioprio || sqe->off || sqe->len || sqe->buf_index ||
|
|
sqe->poll_events)
|
|
return -EINVAL;
|
|
|
|
spin_lock_irq(&ctx->completion_lock);
|
|
list_for_each_entry_safe(poll_req, next, &ctx->cancel_list, list) {
|
|
if (READ_ONCE(sqe->addr) == poll_req->user_data) {
|
|
io_poll_remove_one(poll_req);
|
|
ret = 0;
|
|
break;
|
|
}
|
|
}
|
|
spin_unlock_irq(&ctx->completion_lock);
|
|
|
|
io_cqring_add_event(req->ctx, sqe->user_data, ret);
|
|
io_put_req(req);
|
|
return 0;
|
|
}
|
|
|
|
static void io_poll_complete(struct io_ring_ctx *ctx, struct io_kiocb *req,
|
|
__poll_t mask)
|
|
{
|
|
req->poll.done = true;
|
|
io_cqring_fill_event(ctx, req->user_data, mangle_poll(mask));
|
|
io_commit_cqring(ctx);
|
|
}
|
|
|
|
static void io_poll_complete_work(struct work_struct *work)
|
|
{
|
|
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
|
|
struct io_poll_iocb *poll = &req->poll;
|
|
struct poll_table_struct pt = { ._key = poll->events };
|
|
struct io_ring_ctx *ctx = req->ctx;
|
|
__poll_t mask = 0;
|
|
|
|
if (!READ_ONCE(poll->canceled))
|
|
mask = vfs_poll(poll->file, &pt) & poll->events;
|
|
|
|
/*
|
|
* Note that ->ki_cancel callers also delete iocb from active_reqs after
|
|
* calling ->ki_cancel. We need the ctx_lock roundtrip here to
|
|
* synchronize with them. In the cancellation case the list_del_init
|
|
* itself is not actually needed, but harmless so we keep it in to
|
|
* avoid further branches in the fast path.
|
|
*/
|
|
spin_lock_irq(&ctx->completion_lock);
|
|
if (!mask && !READ_ONCE(poll->canceled)) {
|
|
add_wait_queue(poll->head, &poll->wait);
|
|
spin_unlock_irq(&ctx->completion_lock);
|
|
return;
|
|
}
|
|
list_del_init(&req->list);
|
|
io_poll_complete(ctx, req, mask);
|
|
spin_unlock_irq(&ctx->completion_lock);
|
|
|
|
io_cqring_ev_posted(ctx);
|
|
io_put_req(req);
|
|
}
|
|
|
|
static int io_poll_wake(struct wait_queue_entry *wait, unsigned mode, int sync,
|
|
void *key)
|
|
{
|
|
struct io_poll_iocb *poll = container_of(wait, struct io_poll_iocb,
|
|
wait);
|
|
struct io_kiocb *req = container_of(poll, struct io_kiocb, poll);
|
|
struct io_ring_ctx *ctx = req->ctx;
|
|
__poll_t mask = key_to_poll(key);
|
|
unsigned long flags;
|
|
|
|
/* for instances that support it check for an event match first: */
|
|
if (mask && !(mask & poll->events))
|
|
return 0;
|
|
|
|
list_del_init(&poll->wait.entry);
|
|
|
|
if (mask && spin_trylock_irqsave(&ctx->completion_lock, flags)) {
|
|
list_del(&req->list);
|
|
io_poll_complete(ctx, req, mask);
|
|
spin_unlock_irqrestore(&ctx->completion_lock, flags);
|
|
|
|
io_cqring_ev_posted(ctx);
|
|
io_put_req(req);
|
|
} else {
|
|
queue_work(ctx->sqo_wq, &req->work);
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
struct io_poll_table {
|
|
struct poll_table_struct pt;
|
|
struct io_kiocb *req;
|
|
int error;
|
|
};
|
|
|
|
static void io_poll_queue_proc(struct file *file, struct wait_queue_head *head,
|
|
struct poll_table_struct *p)
|
|
{
|
|
struct io_poll_table *pt = container_of(p, struct io_poll_table, pt);
|
|
|
|
if (unlikely(pt->req->poll.head)) {
|
|
pt->error = -EINVAL;
|
|
return;
|
|
}
|
|
|
|
pt->error = 0;
|
|
pt->req->poll.head = head;
|
|
add_wait_queue(head, &pt->req->poll.wait);
|
|
}
|
|
|
|
static int io_poll_add(struct io_kiocb *req, const struct io_uring_sqe *sqe)
|
|
{
|
|
struct io_poll_iocb *poll = &req->poll;
|
|
struct io_ring_ctx *ctx = req->ctx;
|
|
struct io_poll_table ipt;
|
|
bool cancel = false;
|
|
__poll_t mask;
|
|
u16 events;
|
|
|
|
if (unlikely(req->ctx->flags & IORING_SETUP_IOPOLL))
|
|
return -EINVAL;
|
|
if (sqe->addr || sqe->ioprio || sqe->off || sqe->len || sqe->buf_index)
|
|
return -EINVAL;
|
|
if (!poll->file)
|
|
return -EBADF;
|
|
|
|
INIT_WORK(&req->work, io_poll_complete_work);
|
|
events = READ_ONCE(sqe->poll_events);
|
|
poll->events = demangle_poll(events) | EPOLLERR | EPOLLHUP;
|
|
|
|
poll->head = NULL;
|
|
poll->done = false;
|
|
poll->canceled = false;
|
|
|
|
ipt.pt._qproc = io_poll_queue_proc;
|
|
ipt.pt._key = poll->events;
|
|
ipt.req = req;
|
|
ipt.error = -EINVAL; /* same as no support for IOCB_CMD_POLL */
|
|
|
|
/* initialized the list so that we can do list_empty checks */
|
|
INIT_LIST_HEAD(&poll->wait.entry);
|
|
init_waitqueue_func_entry(&poll->wait, io_poll_wake);
|
|
|
|
mask = vfs_poll(poll->file, &ipt.pt) & poll->events;
|
|
|
|
spin_lock_irq(&ctx->completion_lock);
|
|
if (likely(poll->head)) {
|
|
spin_lock(&poll->head->lock);
|
|
if (unlikely(list_empty(&poll->wait.entry))) {
|
|
if (ipt.error)
|
|
cancel = true;
|
|
ipt.error = 0;
|
|
mask = 0;
|
|
}
|
|
if (mask || ipt.error)
|
|
list_del_init(&poll->wait.entry);
|
|
else if (cancel)
|
|
WRITE_ONCE(poll->canceled, true);
|
|
else if (!poll->done) /* actually waiting for an event */
|
|
list_add_tail(&req->list, &ctx->cancel_list);
|
|
spin_unlock(&poll->head->lock);
|
|
}
|
|
if (mask) { /* no async, we'd stolen it */
|
|
ipt.error = 0;
|
|
io_poll_complete(ctx, req, mask);
|
|
}
|
|
spin_unlock_irq(&ctx->completion_lock);
|
|
|
|
if (mask) {
|
|
io_cqring_ev_posted(ctx);
|
|
io_put_req(req);
|
|
}
|
|
return ipt.error;
|
|
}
|
|
|
|
static int io_req_defer(struct io_ring_ctx *ctx, struct io_kiocb *req,
|
|
const struct io_uring_sqe *sqe)
|
|
{
|
|
struct io_uring_sqe *sqe_copy;
|
|
|
|
if (!io_sequence_defer(ctx, req) && list_empty(&ctx->defer_list))
|
|
return 0;
|
|
|
|
sqe_copy = kmalloc(sizeof(*sqe_copy), GFP_KERNEL);
|
|
if (!sqe_copy)
|
|
return -EAGAIN;
|
|
|
|
spin_lock_irq(&ctx->completion_lock);
|
|
if (!io_sequence_defer(ctx, req) && list_empty(&ctx->defer_list)) {
|
|
spin_unlock_irq(&ctx->completion_lock);
|
|
kfree(sqe_copy);
|
|
return 0;
|
|
}
|
|
|
|
memcpy(sqe_copy, sqe, sizeof(*sqe_copy));
|
|
req->submit.sqe = sqe_copy;
|
|
|
|
INIT_WORK(&req->work, io_sq_wq_submit_work);
|
|
list_add_tail(&req->list, &ctx->defer_list);
|
|
spin_unlock_irq(&ctx->completion_lock);
|
|
return -EIOCBQUEUED;
|
|
}
|
|
|
|
static int __io_submit_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
|
|
const struct sqe_submit *s, bool force_nonblock)
|
|
{
|
|
int ret, opcode;
|
|
|
|
req->user_data = READ_ONCE(s->sqe->user_data);
|
|
|
|
if (unlikely(s->index >= ctx->sq_entries))
|
|
return -EINVAL;
|
|
|
|
opcode = READ_ONCE(s->sqe->opcode);
|
|
switch (opcode) {
|
|
case IORING_OP_NOP:
|
|
ret = io_nop(req, req->user_data);
|
|
break;
|
|
case IORING_OP_READV:
|
|
if (unlikely(s->sqe->buf_index))
|
|
return -EINVAL;
|
|
ret = io_read(req, s, force_nonblock);
|
|
break;
|
|
case IORING_OP_WRITEV:
|
|
if (unlikely(s->sqe->buf_index))
|
|
return -EINVAL;
|
|
ret = io_write(req, s, force_nonblock);
|
|
break;
|
|
case IORING_OP_READ_FIXED:
|
|
ret = io_read(req, s, force_nonblock);
|
|
break;
|
|
case IORING_OP_WRITE_FIXED:
|
|
ret = io_write(req, s, force_nonblock);
|
|
break;
|
|
case IORING_OP_FSYNC:
|
|
ret = io_fsync(req, s->sqe, force_nonblock);
|
|
break;
|
|
case IORING_OP_POLL_ADD:
|
|
ret = io_poll_add(req, s->sqe);
|
|
break;
|
|
case IORING_OP_POLL_REMOVE:
|
|
ret = io_poll_remove(req, s->sqe);
|
|
break;
|
|
case IORING_OP_SYNC_FILE_RANGE:
|
|
ret = io_sync_file_range(req, s->sqe, force_nonblock);
|
|
break;
|
|
case IORING_OP_SENDMSG:
|
|
ret = io_sendmsg(req, s->sqe, force_nonblock);
|
|
break;
|
|
case IORING_OP_RECVMSG:
|
|
ret = io_recvmsg(req, s->sqe, force_nonblock);
|
|
break;
|
|
default:
|
|
ret = -EINVAL;
|
|
break;
|
|
}
|
|
|
|
if (ret)
|
|
return ret;
|
|
|
|
if (ctx->flags & IORING_SETUP_IOPOLL) {
|
|
if (req->result == -EAGAIN)
|
|
return -EAGAIN;
|
|
|
|
/* workqueue context doesn't hold uring_lock, grab it now */
|
|
if (s->needs_lock)
|
|
mutex_lock(&ctx->uring_lock);
|
|
io_iopoll_req_issued(req);
|
|
if (s->needs_lock)
|
|
mutex_unlock(&ctx->uring_lock);
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static struct async_list *io_async_list_from_sqe(struct io_ring_ctx *ctx,
|
|
const struct io_uring_sqe *sqe)
|
|
{
|
|
switch (sqe->opcode) {
|
|
case IORING_OP_READV:
|
|
case IORING_OP_READ_FIXED:
|
|
return &ctx->pending_async[READ];
|
|
case IORING_OP_WRITEV:
|
|
case IORING_OP_WRITE_FIXED:
|
|
return &ctx->pending_async[WRITE];
|
|
default:
|
|
return NULL;
|
|
}
|
|
}
|
|
|
|
static inline bool io_sqe_needs_user(const struct io_uring_sqe *sqe)
|
|
{
|
|
u8 opcode = READ_ONCE(sqe->opcode);
|
|
|
|
return !(opcode == IORING_OP_READ_FIXED ||
|
|
opcode == IORING_OP_WRITE_FIXED);
|
|
}
|
|
|
|
static void io_sq_wq_submit_work(struct work_struct *work)
|
|
{
|
|
struct io_kiocb *req = container_of(work, struct io_kiocb, work);
|
|
struct io_ring_ctx *ctx = req->ctx;
|
|
struct mm_struct *cur_mm = NULL;
|
|
struct async_list *async_list;
|
|
LIST_HEAD(req_list);
|
|
mm_segment_t old_fs;
|
|
int ret;
|
|
|
|
async_list = io_async_list_from_sqe(ctx, req->submit.sqe);
|
|
restart:
|
|
do {
|
|
struct sqe_submit *s = &req->submit;
|
|
const struct io_uring_sqe *sqe = s->sqe;
|
|
|
|
/* Ensure we clear previously set non-block flag */
|
|
req->rw.ki_flags &= ~IOCB_NOWAIT;
|
|
|
|
ret = 0;
|
|
if (io_sqe_needs_user(sqe) && !cur_mm) {
|
|
if (!mmget_not_zero(ctx->sqo_mm)) {
|
|
ret = -EFAULT;
|
|
} else {
|
|
cur_mm = ctx->sqo_mm;
|
|
use_mm(cur_mm);
|
|
old_fs = get_fs();
|
|
set_fs(USER_DS);
|
|
}
|
|
}
|
|
|
|
if (!ret) {
|
|
s->has_user = cur_mm != NULL;
|
|
s->needs_lock = true;
|
|
do {
|
|
ret = __io_submit_sqe(ctx, req, s, false);
|
|
/*
|
|
* We can get EAGAIN for polled IO even though
|
|
* we're forcing a sync submission from here,
|
|
* since we can't wait for request slots on the
|
|
* block side.
|
|
*/
|
|
if (ret != -EAGAIN)
|
|
break;
|
|
cond_resched();
|
|
} while (1);
|
|
}
|
|
|
|
/* drop submission reference */
|
|
io_put_req(req);
|
|
|
|
if (ret) {
|
|
io_cqring_add_event(ctx, sqe->user_data, ret);
|
|
io_put_req(req);
|
|
}
|
|
|
|
/* async context always use a copy of the sqe */
|
|
kfree(sqe);
|
|
|
|
if (!async_list)
|
|
break;
|
|
if (!list_empty(&req_list)) {
|
|
req = list_first_entry(&req_list, struct io_kiocb,
|
|
list);
|
|
list_del(&req->list);
|
|
continue;
|
|
}
|
|
if (list_empty(&async_list->list))
|
|
break;
|
|
|
|
req = NULL;
|
|
spin_lock(&async_list->lock);
|
|
if (list_empty(&async_list->list)) {
|
|
spin_unlock(&async_list->lock);
|
|
break;
|
|
}
|
|
list_splice_init(&async_list->list, &req_list);
|
|
spin_unlock(&async_list->lock);
|
|
|
|
req = list_first_entry(&req_list, struct io_kiocb, list);
|
|
list_del(&req->list);
|
|
} while (req);
|
|
|
|
/*
|
|
* Rare case of racing with a submitter. If we find the count has
|
|
* dropped to zero AND we have pending work items, then restart
|
|
* the processing. This is a tiny race window.
|
|
*/
|
|
if (async_list) {
|
|
ret = atomic_dec_return(&async_list->cnt);
|
|
while (!ret && !list_empty(&async_list->list)) {
|
|
spin_lock(&async_list->lock);
|
|
atomic_inc(&async_list->cnt);
|
|
list_splice_init(&async_list->list, &req_list);
|
|
spin_unlock(&async_list->lock);
|
|
|
|
if (!list_empty(&req_list)) {
|
|
req = list_first_entry(&req_list,
|
|
struct io_kiocb, list);
|
|
list_del(&req->list);
|
|
goto restart;
|
|
}
|
|
ret = atomic_dec_return(&async_list->cnt);
|
|
}
|
|
}
|
|
|
|
if (cur_mm) {
|
|
set_fs(old_fs);
|
|
unuse_mm(cur_mm);
|
|
mmput(cur_mm);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* See if we can piggy back onto previously submitted work, that is still
|
|
* running. We currently only allow this if the new request is sequential
|
|
* to the previous one we punted.
|
|
*/
|
|
static bool io_add_to_prev_work(struct async_list *list, struct io_kiocb *req)
|
|
{
|
|
bool ret = false;
|
|
|
|
if (!list)
|
|
return false;
|
|
if (!(req->flags & REQ_F_SEQ_PREV))
|
|
return false;
|
|
if (!atomic_read(&list->cnt))
|
|
return false;
|
|
|
|
ret = true;
|
|
spin_lock(&list->lock);
|
|
list_add_tail(&req->list, &list->list);
|
|
if (!atomic_read(&list->cnt)) {
|
|
list_del_init(&req->list);
|
|
ret = false;
|
|
}
|
|
spin_unlock(&list->lock);
|
|
return ret;
|
|
}
|
|
|
|
static bool io_op_needs_file(const struct io_uring_sqe *sqe)
|
|
{
|
|
int op = READ_ONCE(sqe->opcode);
|
|
|
|
switch (op) {
|
|
case IORING_OP_NOP:
|
|
case IORING_OP_POLL_REMOVE:
|
|
return false;
|
|
default:
|
|
return true;
|
|
}
|
|
}
|
|
|
|
static int io_req_set_file(struct io_ring_ctx *ctx, const struct sqe_submit *s,
|
|
struct io_submit_state *state, struct io_kiocb *req)
|
|
{
|
|
unsigned flags;
|
|
int fd;
|
|
|
|
flags = READ_ONCE(s->sqe->flags);
|
|
fd = READ_ONCE(s->sqe->fd);
|
|
|
|
if (flags & IOSQE_IO_DRAIN) {
|
|
req->flags |= REQ_F_IO_DRAIN;
|
|
req->sequence = ctx->cached_sq_head - 1;
|
|
}
|
|
|
|
if (!io_op_needs_file(s->sqe))
|
|
return 0;
|
|
|
|
if (flags & IOSQE_FIXED_FILE) {
|
|
if (unlikely(!ctx->user_files ||
|
|
(unsigned) fd >= ctx->nr_user_files))
|
|
return -EBADF;
|
|
req->file = ctx->user_files[fd];
|
|
req->flags |= REQ_F_FIXED_FILE;
|
|
} else {
|
|
if (s->needs_fixed_file)
|
|
return -EBADF;
|
|
req->file = io_file_get(state, fd);
|
|
if (unlikely(!req->file))
|
|
return -EBADF;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int io_queue_sqe(struct io_ring_ctx *ctx, struct io_kiocb *req,
|
|
struct sqe_submit *s)
|
|
{
|
|
int ret;
|
|
|
|
ret = __io_submit_sqe(ctx, req, s, true);
|
|
if (ret == -EAGAIN && !(req->flags & REQ_F_NOWAIT)) {
|
|
struct io_uring_sqe *sqe_copy;
|
|
|
|
sqe_copy = kmalloc(sizeof(*sqe_copy), GFP_KERNEL);
|
|
if (sqe_copy) {
|
|
struct async_list *list;
|
|
|
|
memcpy(sqe_copy, s->sqe, sizeof(*sqe_copy));
|
|
s->sqe = sqe_copy;
|
|
|
|
memcpy(&req->submit, s, sizeof(*s));
|
|
list = io_async_list_from_sqe(ctx, s->sqe);
|
|
if (!io_add_to_prev_work(list, req)) {
|
|
if (list)
|
|
atomic_inc(&list->cnt);
|
|
INIT_WORK(&req->work, io_sq_wq_submit_work);
|
|
queue_work(ctx->sqo_wq, &req->work);
|
|
}
|
|
|
|
/*
|
|
* Queued up for async execution, worker will release
|
|
* submit reference when the iocb is actually submitted.
|
|
*/
|
|
return 0;
|
|
}
|
|
}
|
|
|
|
/* drop submission reference */
|
|
io_put_req(req);
|
|
|
|
/* and drop final reference, if we failed */
|
|
if (ret) {
|
|
io_cqring_add_event(ctx, req->user_data, ret);
|
|
if (req->flags & REQ_F_LINK)
|
|
req->flags |= REQ_F_FAIL_LINK;
|
|
io_put_req(req);
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
|
|
#define SQE_VALID_FLAGS (IOSQE_FIXED_FILE|IOSQE_IO_DRAIN|IOSQE_IO_LINK)
|
|
|
|
static void io_submit_sqe(struct io_ring_ctx *ctx, struct sqe_submit *s,
|
|
struct io_submit_state *state, struct io_kiocb **link)
|
|
{
|
|
struct io_uring_sqe *sqe_copy;
|
|
struct io_kiocb *req;
|
|
int ret;
|
|
|
|
/* enforce forwards compatibility on users */
|
|
if (unlikely(s->sqe->flags & ~SQE_VALID_FLAGS)) {
|
|
ret = -EINVAL;
|
|
goto err;
|
|
}
|
|
|
|
req = io_get_req(ctx, state);
|
|
if (unlikely(!req)) {
|
|
ret = -EAGAIN;
|
|
goto err;
|
|
}
|
|
|
|
ret = io_req_set_file(ctx, s, state, req);
|
|
if (unlikely(ret)) {
|
|
err_req:
|
|
io_free_req(req);
|
|
err:
|
|
io_cqring_add_event(ctx, s->sqe->user_data, ret);
|
|
return;
|
|
}
|
|
|
|
ret = io_req_defer(ctx, req, s->sqe);
|
|
if (ret) {
|
|
if (ret != -EIOCBQUEUED)
|
|
goto err_req;
|
|
return;
|
|
}
|
|
|
|
/*
|
|
* If we already have a head request, queue this one for async
|
|
* submittal once the head completes. If we don't have a head but
|
|
* IOSQE_IO_LINK is set in the sqe, start a new head. This one will be
|
|
* submitted sync once the chain is complete. If none of those
|
|
* conditions are true (normal request), then just queue it.
|
|
*/
|
|
if (*link) {
|
|
struct io_kiocb *prev = *link;
|
|
|
|
sqe_copy = kmemdup(s->sqe, sizeof(*sqe_copy), GFP_KERNEL);
|
|
if (!sqe_copy) {
|
|
ret = -EAGAIN;
|
|
goto err_req;
|
|
}
|
|
|
|
s->sqe = sqe_copy;
|
|
memcpy(&req->submit, s, sizeof(*s));
|
|
list_add_tail(&req->list, &prev->link_list);
|
|
} else if (s->sqe->flags & IOSQE_IO_LINK) {
|
|
req->flags |= REQ_F_LINK;
|
|
|
|
memcpy(&req->submit, s, sizeof(*s));
|
|
INIT_LIST_HEAD(&req->link_list);
|
|
*link = req;
|
|
} else {
|
|
io_queue_sqe(ctx, req, s);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Batched submission is done, ensure local IO is flushed out.
|
|
*/
|
|
static void io_submit_state_end(struct io_submit_state *state)
|
|
{
|
|
blk_finish_plug(&state->plug);
|
|
io_file_put(state);
|
|
if (state->free_reqs)
|
|
kmem_cache_free_bulk(req_cachep, state->free_reqs,
|
|
&state->reqs[state->cur_req]);
|
|
}
|
|
|
|
/*
|
|
* Start submission side cache.
|
|
*/
|
|
static void io_submit_state_start(struct io_submit_state *state,
|
|
struct io_ring_ctx *ctx, unsigned max_ios)
|
|
{
|
|
blk_start_plug(&state->plug);
|
|
state->free_reqs = 0;
|
|
state->file = NULL;
|
|
state->ios_left = max_ios;
|
|
}
|
|
|
|
static void io_commit_sqring(struct io_ring_ctx *ctx)
|
|
{
|
|
struct io_sq_ring *ring = ctx->sq_ring;
|
|
|
|
if (ctx->cached_sq_head != READ_ONCE(ring->r.head)) {
|
|
/*
|
|
* Ensure any loads from the SQEs are done at this point,
|
|
* since once we write the new head, the application could
|
|
* write new data to them.
|
|
*/
|
|
smp_store_release(&ring->r.head, ctx->cached_sq_head);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* Fetch an sqe, if one is available. Note that s->sqe will point to memory
|
|
* that is mapped by userspace. This means that care needs to be taken to
|
|
* ensure that reads are stable, as we cannot rely on userspace always
|
|
* being a good citizen. If members of the sqe are validated and then later
|
|
* used, it's important that those reads are done through READ_ONCE() to
|
|
* prevent a re-load down the line.
|
|
*/
|
|
static bool io_get_sqring(struct io_ring_ctx *ctx, struct sqe_submit *s)
|
|
{
|
|
struct io_sq_ring *ring = ctx->sq_ring;
|
|
unsigned head;
|
|
|
|
/*
|
|
* The cached sq head (or cq tail) serves two purposes:
|
|
*
|
|
* 1) allows us to batch the cost of updating the user visible
|
|
* head updates.
|
|
* 2) allows the kernel side to track the head on its own, even
|
|
* though the application is the one updating it.
|
|
*/
|
|
head = ctx->cached_sq_head;
|
|
/* make sure SQ entry isn't read before tail */
|
|
if (head == smp_load_acquire(&ring->r.tail))
|
|
return false;
|
|
|
|
head = READ_ONCE(ring->array[head & ctx->sq_mask]);
|
|
if (head < ctx->sq_entries) {
|
|
s->index = head;
|
|
s->sqe = &ctx->sq_sqes[head];
|
|
ctx->cached_sq_head++;
|
|
return true;
|
|
}
|
|
|
|
/* drop invalid entries */
|
|
ctx->cached_sq_head++;
|
|
ring->dropped++;
|
|
return false;
|
|
}
|
|
|
|
static int io_submit_sqes(struct io_ring_ctx *ctx, struct sqe_submit *sqes,
|
|
unsigned int nr, bool has_user, bool mm_fault)
|
|
{
|
|
struct io_submit_state state, *statep = NULL;
|
|
struct io_kiocb *link = NULL;
|
|
bool prev_was_link = false;
|
|
int i, submitted = 0;
|
|
|
|
if (nr > IO_PLUG_THRESHOLD) {
|
|
io_submit_state_start(&state, ctx, nr);
|
|
statep = &state;
|
|
}
|
|
|
|
for (i = 0; i < nr; i++) {
|
|
/*
|
|
* If previous wasn't linked and we have a linked command,
|
|
* that's the end of the chain. Submit the previous link.
|
|
*/
|
|
if (!prev_was_link && link) {
|
|
io_queue_sqe(ctx, link, &link->submit);
|
|
link = NULL;
|
|
}
|
|
prev_was_link = (sqes[i].sqe->flags & IOSQE_IO_LINK) != 0;
|
|
|
|
if (unlikely(mm_fault)) {
|
|
io_cqring_add_event(ctx, sqes[i].sqe->user_data,
|
|
-EFAULT);
|
|
} else {
|
|
sqes[i].has_user = has_user;
|
|
sqes[i].needs_lock = true;
|
|
sqes[i].needs_fixed_file = true;
|
|
io_submit_sqe(ctx, &sqes[i], statep, &link);
|
|
submitted++;
|
|
}
|
|
}
|
|
|
|
if (link)
|
|
io_queue_sqe(ctx, link, &link->submit);
|
|
if (statep)
|
|
io_submit_state_end(&state);
|
|
|
|
return submitted;
|
|
}
|
|
|
|
static int io_sq_thread(void *data)
|
|
{
|
|
struct sqe_submit sqes[IO_IOPOLL_BATCH];
|
|
struct io_ring_ctx *ctx = data;
|
|
struct mm_struct *cur_mm = NULL;
|
|
mm_segment_t old_fs;
|
|
DEFINE_WAIT(wait);
|
|
unsigned inflight;
|
|
unsigned long timeout;
|
|
|
|
complete(&ctx->sqo_thread_started);
|
|
|
|
old_fs = get_fs();
|
|
set_fs(USER_DS);
|
|
|
|
timeout = inflight = 0;
|
|
while (!kthread_should_park()) {
|
|
bool all_fixed, mm_fault = false;
|
|
int i;
|
|
|
|
if (inflight) {
|
|
unsigned nr_events = 0;
|
|
|
|
if (ctx->flags & IORING_SETUP_IOPOLL) {
|
|
/*
|
|
* We disallow the app entering submit/complete
|
|
* with polling, but we still need to lock the
|
|
* ring to prevent racing with polled issue
|
|
* that got punted to a workqueue.
|
|
*/
|
|
mutex_lock(&ctx->uring_lock);
|
|
io_iopoll_check(ctx, &nr_events, 0);
|
|
mutex_unlock(&ctx->uring_lock);
|
|
} else {
|
|
/*
|
|
* Normal IO, just pretend everything completed.
|
|
* We don't have to poll completions for that.
|
|
*/
|
|
nr_events = inflight;
|
|
}
|
|
|
|
inflight -= nr_events;
|
|
if (!inflight)
|
|
timeout = jiffies + ctx->sq_thread_idle;
|
|
}
|
|
|
|
if (!io_get_sqring(ctx, &sqes[0])) {
|
|
/*
|
|
* We're polling. If we're within the defined idle
|
|
* period, then let us spin without work before going
|
|
* to sleep.
|
|
*/
|
|
if (inflight || !time_after(jiffies, timeout)) {
|
|
cpu_relax();
|
|
continue;
|
|
}
|
|
|
|
/*
|
|
* Drop cur_mm before scheduling, we can't hold it for
|
|
* long periods (or over schedule()). Do this before
|
|
* adding ourselves to the waitqueue, as the unuse/drop
|
|
* may sleep.
|
|
*/
|
|
if (cur_mm) {
|
|
unuse_mm(cur_mm);
|
|
mmput(cur_mm);
|
|
cur_mm = NULL;
|
|
}
|
|
|
|
prepare_to_wait(&ctx->sqo_wait, &wait,
|
|
TASK_INTERRUPTIBLE);
|
|
|
|
/* Tell userspace we may need a wakeup call */
|
|
ctx->sq_ring->flags |= IORING_SQ_NEED_WAKEUP;
|
|
/* make sure to read SQ tail after writing flags */
|
|
smp_mb();
|
|
|
|
if (!io_get_sqring(ctx, &sqes[0])) {
|
|
if (kthread_should_park()) {
|
|
finish_wait(&ctx->sqo_wait, &wait);
|
|
break;
|
|
}
|
|
if (signal_pending(current))
|
|
flush_signals(current);
|
|
schedule();
|
|
finish_wait(&ctx->sqo_wait, &wait);
|
|
|
|
ctx->sq_ring->flags &= ~IORING_SQ_NEED_WAKEUP;
|
|
continue;
|
|
}
|
|
finish_wait(&ctx->sqo_wait, &wait);
|
|
|
|
ctx->sq_ring->flags &= ~IORING_SQ_NEED_WAKEUP;
|
|
}
|
|
|
|
i = 0;
|
|
all_fixed = true;
|
|
do {
|
|
if (all_fixed && io_sqe_needs_user(sqes[i].sqe))
|
|
all_fixed = false;
|
|
|
|
i++;
|
|
if (i == ARRAY_SIZE(sqes))
|
|
break;
|
|
} while (io_get_sqring(ctx, &sqes[i]));
|
|
|
|
/* Unless all new commands are FIXED regions, grab mm */
|
|
if (!all_fixed && !cur_mm) {
|
|
mm_fault = !mmget_not_zero(ctx->sqo_mm);
|
|
if (!mm_fault) {
|
|
use_mm(ctx->sqo_mm);
|
|
cur_mm = ctx->sqo_mm;
|
|
}
|
|
}
|
|
|
|
inflight += io_submit_sqes(ctx, sqes, i, cur_mm != NULL,
|
|
mm_fault);
|
|
|
|
/* Commit SQ ring head once we've consumed all SQEs */
|
|
io_commit_sqring(ctx);
|
|
}
|
|
|
|
set_fs(old_fs);
|
|
if (cur_mm) {
|
|
unuse_mm(cur_mm);
|
|
mmput(cur_mm);
|
|
}
|
|
|
|
kthread_parkme();
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int io_ring_submit(struct io_ring_ctx *ctx, unsigned int to_submit)
|
|
{
|
|
struct io_submit_state state, *statep = NULL;
|
|
struct io_kiocb *link = NULL;
|
|
bool prev_was_link = false;
|
|
int i, submit = 0;
|
|
|
|
if (to_submit > IO_PLUG_THRESHOLD) {
|
|
io_submit_state_start(&state, ctx, to_submit);
|
|
statep = &state;
|
|
}
|
|
|
|
for (i = 0; i < to_submit; i++) {
|
|
struct sqe_submit s;
|
|
|
|
if (!io_get_sqring(ctx, &s))
|
|
break;
|
|
|
|
/*
|
|
* If previous wasn't linked and we have a linked command,
|
|
* that's the end of the chain. Submit the previous link.
|
|
*/
|
|
if (!prev_was_link && link) {
|
|
io_queue_sqe(ctx, link, &link->submit);
|
|
link = NULL;
|
|
}
|
|
prev_was_link = (s.sqe->flags & IOSQE_IO_LINK) != 0;
|
|
|
|
s.has_user = true;
|
|
s.needs_lock = false;
|
|
s.needs_fixed_file = false;
|
|
submit++;
|
|
io_submit_sqe(ctx, &s, statep, &link);
|
|
}
|
|
io_commit_sqring(ctx);
|
|
|
|
if (link)
|
|
io_queue_sqe(ctx, link, &link->submit);
|
|
if (statep)
|
|
io_submit_state_end(statep);
|
|
|
|
return submit;
|
|
}
|
|
|
|
static unsigned io_cqring_events(struct io_cq_ring *ring)
|
|
{
|
|
/* See comment at the top of this file */
|
|
smp_rmb();
|
|
return READ_ONCE(ring->r.tail) - READ_ONCE(ring->r.head);
|
|
}
|
|
|
|
/*
|
|
* Wait until events become available, if we don't already have some. The
|
|
* application must reap them itself, as they reside on the shared cq ring.
|
|
*/
|
|
static int io_cqring_wait(struct io_ring_ctx *ctx, int min_events,
|
|
const sigset_t __user *sig, size_t sigsz)
|
|
{
|
|
struct io_cq_ring *ring = ctx->cq_ring;
|
|
int ret;
|
|
|
|
if (io_cqring_events(ring) >= min_events)
|
|
return 0;
|
|
|
|
if (sig) {
|
|
#ifdef CONFIG_COMPAT
|
|
if (in_compat_syscall())
|
|
ret = set_compat_user_sigmask((const compat_sigset_t __user *)sig,
|
|
sigsz);
|
|
else
|
|
#endif
|
|
ret = set_user_sigmask(sig, sigsz);
|
|
|
|
if (ret)
|
|
return ret;
|
|
}
|
|
|
|
ret = wait_event_interruptible(ctx->wait, io_cqring_events(ring) >= min_events);
|
|
restore_saved_sigmask_unless(ret == -ERESTARTSYS);
|
|
if (ret == -ERESTARTSYS)
|
|
ret = -EINTR;
|
|
|
|
return READ_ONCE(ring->r.head) == READ_ONCE(ring->r.tail) ? ret : 0;
|
|
}
|
|
|
|
static void __io_sqe_files_unregister(struct io_ring_ctx *ctx)
|
|
{
|
|
#if defined(CONFIG_UNIX)
|
|
if (ctx->ring_sock) {
|
|
struct sock *sock = ctx->ring_sock->sk;
|
|
struct sk_buff *skb;
|
|
|
|
while ((skb = skb_dequeue(&sock->sk_receive_queue)) != NULL)
|
|
kfree_skb(skb);
|
|
}
|
|
#else
|
|
int i;
|
|
|
|
for (i = 0; i < ctx->nr_user_files; i++)
|
|
fput(ctx->user_files[i]);
|
|
#endif
|
|
}
|
|
|
|
static int io_sqe_files_unregister(struct io_ring_ctx *ctx)
|
|
{
|
|
if (!ctx->user_files)
|
|
return -ENXIO;
|
|
|
|
__io_sqe_files_unregister(ctx);
|
|
kfree(ctx->user_files);
|
|
ctx->user_files = NULL;
|
|
ctx->nr_user_files = 0;
|
|
return 0;
|
|
}
|
|
|
|
static void io_sq_thread_stop(struct io_ring_ctx *ctx)
|
|
{
|
|
if (ctx->sqo_thread) {
|
|
wait_for_completion(&ctx->sqo_thread_started);
|
|
/*
|
|
* The park is a bit of a work-around, without it we get
|
|
* warning spews on shutdown with SQPOLL set and affinity
|
|
* set to a single CPU.
|
|
*/
|
|
kthread_park(ctx->sqo_thread);
|
|
kthread_stop(ctx->sqo_thread);
|
|
ctx->sqo_thread = NULL;
|
|
}
|
|
}
|
|
|
|
static void io_finish_async(struct io_ring_ctx *ctx)
|
|
{
|
|
io_sq_thread_stop(ctx);
|
|
|
|
if (ctx->sqo_wq) {
|
|
destroy_workqueue(ctx->sqo_wq);
|
|
ctx->sqo_wq = NULL;
|
|
}
|
|
}
|
|
|
|
#if defined(CONFIG_UNIX)
|
|
static void io_destruct_skb(struct sk_buff *skb)
|
|
{
|
|
struct io_ring_ctx *ctx = skb->sk->sk_user_data;
|
|
|
|
io_finish_async(ctx);
|
|
unix_destruct_scm(skb);
|
|
}
|
|
|
|
/*
|
|
* Ensure the UNIX gc is aware of our file set, so we are certain that
|
|
* the io_uring can be safely unregistered on process exit, even if we have
|
|
* loops in the file referencing.
|
|
*/
|
|
static int __io_sqe_files_scm(struct io_ring_ctx *ctx, int nr, int offset)
|
|
{
|
|
struct sock *sk = ctx->ring_sock->sk;
|
|
struct scm_fp_list *fpl;
|
|
struct sk_buff *skb;
|
|
int i;
|
|
|
|
if (!capable(CAP_SYS_RESOURCE) && !capable(CAP_SYS_ADMIN)) {
|
|
unsigned long inflight = ctx->user->unix_inflight + nr;
|
|
|
|
if (inflight > task_rlimit(current, RLIMIT_NOFILE))
|
|
return -EMFILE;
|
|
}
|
|
|
|
fpl = kzalloc(sizeof(*fpl), GFP_KERNEL);
|
|
if (!fpl)
|
|
return -ENOMEM;
|
|
|
|
skb = alloc_skb(0, GFP_KERNEL);
|
|
if (!skb) {
|
|
kfree(fpl);
|
|
return -ENOMEM;
|
|
}
|
|
|
|
skb->sk = sk;
|
|
skb->destructor = io_destruct_skb;
|
|
|
|
fpl->user = get_uid(ctx->user);
|
|
for (i = 0; i < nr; i++) {
|
|
fpl->fp[i] = get_file(ctx->user_files[i + offset]);
|
|
unix_inflight(fpl->user, fpl->fp[i]);
|
|
}
|
|
|
|
fpl->max = fpl->count = nr;
|
|
UNIXCB(skb).fp = fpl;
|
|
refcount_add(skb->truesize, &sk->sk_wmem_alloc);
|
|
skb_queue_head(&sk->sk_receive_queue, skb);
|
|
|
|
for (i = 0; i < nr; i++)
|
|
fput(fpl->fp[i]);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* If UNIX sockets are enabled, fd passing can cause a reference cycle which
|
|
* causes regular reference counting to break down. We rely on the UNIX
|
|
* garbage collection to take care of this problem for us.
|
|
*/
|
|
static int io_sqe_files_scm(struct io_ring_ctx *ctx)
|
|
{
|
|
unsigned left, total;
|
|
int ret = 0;
|
|
|
|
total = 0;
|
|
left = ctx->nr_user_files;
|
|
while (left) {
|
|
unsigned this_files = min_t(unsigned, left, SCM_MAX_FD);
|
|
|
|
ret = __io_sqe_files_scm(ctx, this_files, total);
|
|
if (ret)
|
|
break;
|
|
left -= this_files;
|
|
total += this_files;
|
|
}
|
|
|
|
if (!ret)
|
|
return 0;
|
|
|
|
while (total < ctx->nr_user_files) {
|
|
fput(ctx->user_files[total]);
|
|
total++;
|
|
}
|
|
|
|
return ret;
|
|
}
|
|
#else
|
|
static int io_sqe_files_scm(struct io_ring_ctx *ctx)
|
|
{
|
|
return 0;
|
|
}
|
|
#endif
|
|
|
|
static int io_sqe_files_register(struct io_ring_ctx *ctx, void __user *arg,
|
|
unsigned nr_args)
|
|
{
|
|
__s32 __user *fds = (__s32 __user *) arg;
|
|
int fd, ret = 0;
|
|
unsigned i;
|
|
|
|
if (ctx->user_files)
|
|
return -EBUSY;
|
|
if (!nr_args)
|
|
return -EINVAL;
|
|
if (nr_args > IORING_MAX_FIXED_FILES)
|
|
return -EMFILE;
|
|
|
|
ctx->user_files = kcalloc(nr_args, sizeof(struct file *), GFP_KERNEL);
|
|
if (!ctx->user_files)
|
|
return -ENOMEM;
|
|
|
|
for (i = 0; i < nr_args; i++) {
|
|
ret = -EFAULT;
|
|
if (copy_from_user(&fd, &fds[i], sizeof(fd)))
|
|
break;
|
|
|
|
ctx->user_files[i] = fget(fd);
|
|
|
|
ret = -EBADF;
|
|
if (!ctx->user_files[i])
|
|
break;
|
|
/*
|
|
* Don't allow io_uring instances to be registered. If UNIX
|
|
* isn't enabled, then this causes a reference cycle and this
|
|
* instance can never get freed. If UNIX is enabled we'll
|
|
* handle it just fine, but there's still no point in allowing
|
|
* a ring fd as it doesn't support regular read/write anyway.
|
|
*/
|
|
if (ctx->user_files[i]->f_op == &io_uring_fops) {
|
|
fput(ctx->user_files[i]);
|
|
break;
|
|
}
|
|
ctx->nr_user_files++;
|
|
ret = 0;
|
|
}
|
|
|
|
if (ret) {
|
|
for (i = 0; i < ctx->nr_user_files; i++)
|
|
fput(ctx->user_files[i]);
|
|
|
|
kfree(ctx->user_files);
|
|
ctx->user_files = NULL;
|
|
ctx->nr_user_files = 0;
|
|
return ret;
|
|
}
|
|
|
|
ret = io_sqe_files_scm(ctx);
|
|
if (ret)
|
|
io_sqe_files_unregister(ctx);
|
|
|
|
return ret;
|
|
}
|
|
|
|
static int io_sq_offload_start(struct io_ring_ctx *ctx,
|
|
struct io_uring_params *p)
|
|
{
|
|
int ret;
|
|
|
|
init_waitqueue_head(&ctx->sqo_wait);
|
|
mmgrab(current->mm);
|
|
ctx->sqo_mm = current->mm;
|
|
|
|
if (ctx->flags & IORING_SETUP_SQPOLL) {
|
|
ret = -EPERM;
|
|
if (!capable(CAP_SYS_ADMIN))
|
|
goto err;
|
|
|
|
ctx->sq_thread_idle = msecs_to_jiffies(p->sq_thread_idle);
|
|
if (!ctx->sq_thread_idle)
|
|
ctx->sq_thread_idle = HZ;
|
|
|
|
if (p->flags & IORING_SETUP_SQ_AFF) {
|
|
int cpu = p->sq_thread_cpu;
|
|
|
|
ret = -EINVAL;
|
|
if (cpu >= nr_cpu_ids)
|
|
goto err;
|
|
if (!cpu_online(cpu))
|
|
goto err;
|
|
|
|
ctx->sqo_thread = kthread_create_on_cpu(io_sq_thread,
|
|
ctx, cpu,
|
|
"io_uring-sq");
|
|
} else {
|
|
ctx->sqo_thread = kthread_create(io_sq_thread, ctx,
|
|
"io_uring-sq");
|
|
}
|
|
if (IS_ERR(ctx->sqo_thread)) {
|
|
ret = PTR_ERR(ctx->sqo_thread);
|
|
ctx->sqo_thread = NULL;
|
|
goto err;
|
|
}
|
|
wake_up_process(ctx->sqo_thread);
|
|
} else if (p->flags & IORING_SETUP_SQ_AFF) {
|
|
/* Can't have SQ_AFF without SQPOLL */
|
|
ret = -EINVAL;
|
|
goto err;
|
|
}
|
|
|
|
/* Do QD, or 2 * CPUS, whatever is smallest */
|
|
ctx->sqo_wq = alloc_workqueue("io_ring-wq", WQ_UNBOUND | WQ_FREEZABLE,
|
|
min(ctx->sq_entries - 1, 2 * num_online_cpus()));
|
|
if (!ctx->sqo_wq) {
|
|
ret = -ENOMEM;
|
|
goto err;
|
|
}
|
|
|
|
return 0;
|
|
err:
|
|
io_sq_thread_stop(ctx);
|
|
mmdrop(ctx->sqo_mm);
|
|
ctx->sqo_mm = NULL;
|
|
return ret;
|
|
}
|
|
|
|
static void io_unaccount_mem(struct user_struct *user, unsigned long nr_pages)
|
|
{
|
|
atomic_long_sub(nr_pages, &user->locked_vm);
|
|
}
|
|
|
|
static int io_account_mem(struct user_struct *user, unsigned long nr_pages)
|
|
{
|
|
unsigned long page_limit, cur_pages, new_pages;
|
|
|
|
/* Don't allow more pages than we can safely lock */
|
|
page_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
|
|
|
|
do {
|
|
cur_pages = atomic_long_read(&user->locked_vm);
|
|
new_pages = cur_pages + nr_pages;
|
|
if (new_pages > page_limit)
|
|
return -ENOMEM;
|
|
} while (atomic_long_cmpxchg(&user->locked_vm, cur_pages,
|
|
new_pages) != cur_pages);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static void io_mem_free(void *ptr)
|
|
{
|
|
struct page *page;
|
|
|
|
if (!ptr)
|
|
return;
|
|
|
|
page = virt_to_head_page(ptr);
|
|
if (put_page_testzero(page))
|
|
free_compound_page(page);
|
|
}
|
|
|
|
static void *io_mem_alloc(size_t size)
|
|
{
|
|
gfp_t gfp_flags = GFP_KERNEL | __GFP_ZERO | __GFP_NOWARN | __GFP_COMP |
|
|
__GFP_NORETRY;
|
|
|
|
return (void *) __get_free_pages(gfp_flags, get_order(size));
|
|
}
|
|
|
|
static unsigned long ring_pages(unsigned sq_entries, unsigned cq_entries)
|
|
{
|
|
struct io_sq_ring *sq_ring;
|
|
struct io_cq_ring *cq_ring;
|
|
size_t bytes;
|
|
|
|
bytes = struct_size(sq_ring, array, sq_entries);
|
|
bytes += array_size(sizeof(struct io_uring_sqe), sq_entries);
|
|
bytes += struct_size(cq_ring, cqes, cq_entries);
|
|
|
|
return (bytes + PAGE_SIZE - 1) / PAGE_SIZE;
|
|
}
|
|
|
|
static int io_sqe_buffer_unregister(struct io_ring_ctx *ctx)
|
|
{
|
|
int i, j;
|
|
|
|
if (!ctx->user_bufs)
|
|
return -ENXIO;
|
|
|
|
for (i = 0; i < ctx->nr_user_bufs; i++) {
|
|
struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
|
|
|
|
for (j = 0; j < imu->nr_bvecs; j++)
|
|
put_page(imu->bvec[j].bv_page);
|
|
|
|
if (ctx->account_mem)
|
|
io_unaccount_mem(ctx->user, imu->nr_bvecs);
|
|
kvfree(imu->bvec);
|
|
imu->nr_bvecs = 0;
|
|
}
|
|
|
|
kfree(ctx->user_bufs);
|
|
ctx->user_bufs = NULL;
|
|
ctx->nr_user_bufs = 0;
|
|
return 0;
|
|
}
|
|
|
|
static int io_copy_iov(struct io_ring_ctx *ctx, struct iovec *dst,
|
|
void __user *arg, unsigned index)
|
|
{
|
|
struct iovec __user *src;
|
|
|
|
#ifdef CONFIG_COMPAT
|
|
if (ctx->compat) {
|
|
struct compat_iovec __user *ciovs;
|
|
struct compat_iovec ciov;
|
|
|
|
ciovs = (struct compat_iovec __user *) arg;
|
|
if (copy_from_user(&ciov, &ciovs[index], sizeof(ciov)))
|
|
return -EFAULT;
|
|
|
|
dst->iov_base = (void __user *) (unsigned long) ciov.iov_base;
|
|
dst->iov_len = ciov.iov_len;
|
|
return 0;
|
|
}
|
|
#endif
|
|
src = (struct iovec __user *) arg;
|
|
if (copy_from_user(dst, &src[index], sizeof(*dst)))
|
|
return -EFAULT;
|
|
return 0;
|
|
}
|
|
|
|
static int io_sqe_buffer_register(struct io_ring_ctx *ctx, void __user *arg,
|
|
unsigned nr_args)
|
|
{
|
|
struct vm_area_struct **vmas = NULL;
|
|
struct page **pages = NULL;
|
|
int i, j, got_pages = 0;
|
|
int ret = -EINVAL;
|
|
|
|
if (ctx->user_bufs)
|
|
return -EBUSY;
|
|
if (!nr_args || nr_args > UIO_MAXIOV)
|
|
return -EINVAL;
|
|
|
|
ctx->user_bufs = kcalloc(nr_args, sizeof(struct io_mapped_ubuf),
|
|
GFP_KERNEL);
|
|
if (!ctx->user_bufs)
|
|
return -ENOMEM;
|
|
|
|
for (i = 0; i < nr_args; i++) {
|
|
struct io_mapped_ubuf *imu = &ctx->user_bufs[i];
|
|
unsigned long off, start, end, ubuf;
|
|
int pret, nr_pages;
|
|
struct iovec iov;
|
|
size_t size;
|
|
|
|
ret = io_copy_iov(ctx, &iov, arg, i);
|
|
if (ret)
|
|
goto err;
|
|
|
|
/*
|
|
* Don't impose further limits on the size and buffer
|
|
* constraints here, we'll -EINVAL later when IO is
|
|
* submitted if they are wrong.
|
|
*/
|
|
ret = -EFAULT;
|
|
if (!iov.iov_base || !iov.iov_len)
|
|
goto err;
|
|
|
|
/* arbitrary limit, but we need something */
|
|
if (iov.iov_len > SZ_1G)
|
|
goto err;
|
|
|
|
ubuf = (unsigned long) iov.iov_base;
|
|
end = (ubuf + iov.iov_len + PAGE_SIZE - 1) >> PAGE_SHIFT;
|
|
start = ubuf >> PAGE_SHIFT;
|
|
nr_pages = end - start;
|
|
|
|
if (ctx->account_mem) {
|
|
ret = io_account_mem(ctx->user, nr_pages);
|
|
if (ret)
|
|
goto err;
|
|
}
|
|
|
|
ret = 0;
|
|
if (!pages || nr_pages > got_pages) {
|
|
kfree(vmas);
|
|
kfree(pages);
|
|
pages = kvmalloc_array(nr_pages, sizeof(struct page *),
|
|
GFP_KERNEL);
|
|
vmas = kvmalloc_array(nr_pages,
|
|
sizeof(struct vm_area_struct *),
|
|
GFP_KERNEL);
|
|
if (!pages || !vmas) {
|
|
ret = -ENOMEM;
|
|
if (ctx->account_mem)
|
|
io_unaccount_mem(ctx->user, nr_pages);
|
|
goto err;
|
|
}
|
|
got_pages = nr_pages;
|
|
}
|
|
|
|
imu->bvec = kvmalloc_array(nr_pages, sizeof(struct bio_vec),
|
|
GFP_KERNEL);
|
|
ret = -ENOMEM;
|
|
if (!imu->bvec) {
|
|
if (ctx->account_mem)
|
|
io_unaccount_mem(ctx->user, nr_pages);
|
|
goto err;
|
|
}
|
|
|
|
ret = 0;
|
|
down_read(¤t->mm->mmap_sem);
|
|
pret = get_user_pages(ubuf, nr_pages,
|
|
FOLL_WRITE | FOLL_LONGTERM,
|
|
pages, vmas);
|
|
if (pret == nr_pages) {
|
|
/* don't support file backed memory */
|
|
for (j = 0; j < nr_pages; j++) {
|
|
struct vm_area_struct *vma = vmas[j];
|
|
|
|
if (vma->vm_file &&
|
|
!is_file_hugepages(vma->vm_file)) {
|
|
ret = -EOPNOTSUPP;
|
|
break;
|
|
}
|
|
}
|
|
} else {
|
|
ret = pret < 0 ? pret : -EFAULT;
|
|
}
|
|
up_read(¤t->mm->mmap_sem);
|
|
if (ret) {
|
|
/*
|
|
* if we did partial map, or found file backed vmas,
|
|
* release any pages we did get
|
|
*/
|
|
if (pret > 0) {
|
|
for (j = 0; j < pret; j++)
|
|
put_page(pages[j]);
|
|
}
|
|
if (ctx->account_mem)
|
|
io_unaccount_mem(ctx->user, nr_pages);
|
|
kvfree(imu->bvec);
|
|
goto err;
|
|
}
|
|
|
|
off = ubuf & ~PAGE_MASK;
|
|
size = iov.iov_len;
|
|
for (j = 0; j < nr_pages; j++) {
|
|
size_t vec_len;
|
|
|
|
vec_len = min_t(size_t, size, PAGE_SIZE - off);
|
|
imu->bvec[j].bv_page = pages[j];
|
|
imu->bvec[j].bv_len = vec_len;
|
|
imu->bvec[j].bv_offset = off;
|
|
off = 0;
|
|
size -= vec_len;
|
|
}
|
|
/* store original address for later verification */
|
|
imu->ubuf = ubuf;
|
|
imu->len = iov.iov_len;
|
|
imu->nr_bvecs = nr_pages;
|
|
|
|
ctx->nr_user_bufs++;
|
|
}
|
|
kvfree(pages);
|
|
kvfree(vmas);
|
|
return 0;
|
|
err:
|
|
kvfree(pages);
|
|
kvfree(vmas);
|
|
io_sqe_buffer_unregister(ctx);
|
|
return ret;
|
|
}
|
|
|
|
static int io_eventfd_register(struct io_ring_ctx *ctx, void __user *arg)
|
|
{
|
|
__s32 __user *fds = arg;
|
|
int fd;
|
|
|
|
if (ctx->cq_ev_fd)
|
|
return -EBUSY;
|
|
|
|
if (copy_from_user(&fd, fds, sizeof(*fds)))
|
|
return -EFAULT;
|
|
|
|
ctx->cq_ev_fd = eventfd_ctx_fdget(fd);
|
|
if (IS_ERR(ctx->cq_ev_fd)) {
|
|
int ret = PTR_ERR(ctx->cq_ev_fd);
|
|
ctx->cq_ev_fd = NULL;
|
|
return ret;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int io_eventfd_unregister(struct io_ring_ctx *ctx)
|
|
{
|
|
if (ctx->cq_ev_fd) {
|
|
eventfd_ctx_put(ctx->cq_ev_fd);
|
|
ctx->cq_ev_fd = NULL;
|
|
return 0;
|
|
}
|
|
|
|
return -ENXIO;
|
|
}
|
|
|
|
static void io_ring_ctx_free(struct io_ring_ctx *ctx)
|
|
{
|
|
io_finish_async(ctx);
|
|
if (ctx->sqo_mm)
|
|
mmdrop(ctx->sqo_mm);
|
|
|
|
io_iopoll_reap_events(ctx);
|
|
io_sqe_buffer_unregister(ctx);
|
|
io_sqe_files_unregister(ctx);
|
|
io_eventfd_unregister(ctx);
|
|
|
|
#if defined(CONFIG_UNIX)
|
|
if (ctx->ring_sock) {
|
|
ctx->ring_sock->file = NULL; /* so that iput() is called */
|
|
sock_release(ctx->ring_sock);
|
|
}
|
|
#endif
|
|
|
|
io_mem_free(ctx->sq_ring);
|
|
io_mem_free(ctx->sq_sqes);
|
|
io_mem_free(ctx->cq_ring);
|
|
|
|
percpu_ref_exit(&ctx->refs);
|
|
if (ctx->account_mem)
|
|
io_unaccount_mem(ctx->user,
|
|
ring_pages(ctx->sq_entries, ctx->cq_entries));
|
|
free_uid(ctx->user);
|
|
kfree(ctx);
|
|
}
|
|
|
|
static __poll_t io_uring_poll(struct file *file, poll_table *wait)
|
|
{
|
|
struct io_ring_ctx *ctx = file->private_data;
|
|
__poll_t mask = 0;
|
|
|
|
poll_wait(file, &ctx->cq_wait, wait);
|
|
/*
|
|
* synchronizes with barrier from wq_has_sleeper call in
|
|
* io_commit_cqring
|
|
*/
|
|
smp_rmb();
|
|
if (READ_ONCE(ctx->sq_ring->r.tail) - ctx->cached_sq_head !=
|
|
ctx->sq_ring->ring_entries)
|
|
mask |= EPOLLOUT | EPOLLWRNORM;
|
|
if (READ_ONCE(ctx->cq_ring->r.head) != ctx->cached_cq_tail)
|
|
mask |= EPOLLIN | EPOLLRDNORM;
|
|
|
|
return mask;
|
|
}
|
|
|
|
static int io_uring_fasync(int fd, struct file *file, int on)
|
|
{
|
|
struct io_ring_ctx *ctx = file->private_data;
|
|
|
|
return fasync_helper(fd, file, on, &ctx->cq_fasync);
|
|
}
|
|
|
|
static void io_ring_ctx_wait_and_kill(struct io_ring_ctx *ctx)
|
|
{
|
|
mutex_lock(&ctx->uring_lock);
|
|
percpu_ref_kill(&ctx->refs);
|
|
mutex_unlock(&ctx->uring_lock);
|
|
|
|
io_poll_remove_all(ctx);
|
|
io_iopoll_reap_events(ctx);
|
|
wait_for_completion(&ctx->ctx_done);
|
|
io_ring_ctx_free(ctx);
|
|
}
|
|
|
|
static int io_uring_release(struct inode *inode, struct file *file)
|
|
{
|
|
struct io_ring_ctx *ctx = file->private_data;
|
|
|
|
file->private_data = NULL;
|
|
io_ring_ctx_wait_and_kill(ctx);
|
|
return 0;
|
|
}
|
|
|
|
static int io_uring_mmap(struct file *file, struct vm_area_struct *vma)
|
|
{
|
|
loff_t offset = (loff_t) vma->vm_pgoff << PAGE_SHIFT;
|
|
unsigned long sz = vma->vm_end - vma->vm_start;
|
|
struct io_ring_ctx *ctx = file->private_data;
|
|
unsigned long pfn;
|
|
struct page *page;
|
|
void *ptr;
|
|
|
|
switch (offset) {
|
|
case IORING_OFF_SQ_RING:
|
|
ptr = ctx->sq_ring;
|
|
break;
|
|
case IORING_OFF_SQES:
|
|
ptr = ctx->sq_sqes;
|
|
break;
|
|
case IORING_OFF_CQ_RING:
|
|
ptr = ctx->cq_ring;
|
|
break;
|
|
default:
|
|
return -EINVAL;
|
|
}
|
|
|
|
page = virt_to_head_page(ptr);
|
|
if (sz > (PAGE_SIZE << compound_order(page)))
|
|
return -EINVAL;
|
|
|
|
pfn = virt_to_phys(ptr) >> PAGE_SHIFT;
|
|
return remap_pfn_range(vma, vma->vm_start, pfn, sz, vma->vm_page_prot);
|
|
}
|
|
|
|
SYSCALL_DEFINE6(io_uring_enter, unsigned int, fd, u32, to_submit,
|
|
u32, min_complete, u32, flags, const sigset_t __user *, sig,
|
|
size_t, sigsz)
|
|
{
|
|
struct io_ring_ctx *ctx;
|
|
long ret = -EBADF;
|
|
int submitted = 0;
|
|
struct fd f;
|
|
|
|
if (flags & ~(IORING_ENTER_GETEVENTS | IORING_ENTER_SQ_WAKEUP))
|
|
return -EINVAL;
|
|
|
|
f = fdget(fd);
|
|
if (!f.file)
|
|
return -EBADF;
|
|
|
|
ret = -EOPNOTSUPP;
|
|
if (f.file->f_op != &io_uring_fops)
|
|
goto out_fput;
|
|
|
|
ret = -ENXIO;
|
|
ctx = f.file->private_data;
|
|
if (!percpu_ref_tryget(&ctx->refs))
|
|
goto out_fput;
|
|
|
|
/*
|
|
* For SQ polling, the thread will do all submissions and completions.
|
|
* Just return the requested submit count, and wake the thread if
|
|
* we were asked to.
|
|
*/
|
|
if (ctx->flags & IORING_SETUP_SQPOLL) {
|
|
if (flags & IORING_ENTER_SQ_WAKEUP)
|
|
wake_up(&ctx->sqo_wait);
|
|
submitted = to_submit;
|
|
goto out_ctx;
|
|
}
|
|
|
|
ret = 0;
|
|
if (to_submit) {
|
|
to_submit = min(to_submit, ctx->sq_entries);
|
|
|
|
mutex_lock(&ctx->uring_lock);
|
|
submitted = io_ring_submit(ctx, to_submit);
|
|
mutex_unlock(&ctx->uring_lock);
|
|
}
|
|
if (flags & IORING_ENTER_GETEVENTS) {
|
|
unsigned nr_events = 0;
|
|
|
|
min_complete = min(min_complete, ctx->cq_entries);
|
|
|
|
if (ctx->flags & IORING_SETUP_IOPOLL) {
|
|
mutex_lock(&ctx->uring_lock);
|
|
ret = io_iopoll_check(ctx, &nr_events, min_complete);
|
|
mutex_unlock(&ctx->uring_lock);
|
|
} else {
|
|
ret = io_cqring_wait(ctx, min_complete, sig, sigsz);
|
|
}
|
|
}
|
|
|
|
out_ctx:
|
|
io_ring_drop_ctx_refs(ctx, 1);
|
|
out_fput:
|
|
fdput(f);
|
|
return submitted ? submitted : ret;
|
|
}
|
|
|
|
static const struct file_operations io_uring_fops = {
|
|
.release = io_uring_release,
|
|
.mmap = io_uring_mmap,
|
|
.poll = io_uring_poll,
|
|
.fasync = io_uring_fasync,
|
|
};
|
|
|
|
static int io_allocate_scq_urings(struct io_ring_ctx *ctx,
|
|
struct io_uring_params *p)
|
|
{
|
|
struct io_sq_ring *sq_ring;
|
|
struct io_cq_ring *cq_ring;
|
|
size_t size;
|
|
|
|
sq_ring = io_mem_alloc(struct_size(sq_ring, array, p->sq_entries));
|
|
if (!sq_ring)
|
|
return -ENOMEM;
|
|
|
|
ctx->sq_ring = sq_ring;
|
|
sq_ring->ring_mask = p->sq_entries - 1;
|
|
sq_ring->ring_entries = p->sq_entries;
|
|
ctx->sq_mask = sq_ring->ring_mask;
|
|
ctx->sq_entries = sq_ring->ring_entries;
|
|
|
|
size = array_size(sizeof(struct io_uring_sqe), p->sq_entries);
|
|
if (size == SIZE_MAX)
|
|
return -EOVERFLOW;
|
|
|
|
ctx->sq_sqes = io_mem_alloc(size);
|
|
if (!ctx->sq_sqes)
|
|
return -ENOMEM;
|
|
|
|
cq_ring = io_mem_alloc(struct_size(cq_ring, cqes, p->cq_entries));
|
|
if (!cq_ring)
|
|
return -ENOMEM;
|
|
|
|
ctx->cq_ring = cq_ring;
|
|
cq_ring->ring_mask = p->cq_entries - 1;
|
|
cq_ring->ring_entries = p->cq_entries;
|
|
ctx->cq_mask = cq_ring->ring_mask;
|
|
ctx->cq_entries = cq_ring->ring_entries;
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* Allocate an anonymous fd, this is what constitutes the application
|
|
* visible backing of an io_uring instance. The application mmaps this
|
|
* fd to gain access to the SQ/CQ ring details. If UNIX sockets are enabled,
|
|
* we have to tie this fd to a socket for file garbage collection purposes.
|
|
*/
|
|
static int io_uring_get_fd(struct io_ring_ctx *ctx)
|
|
{
|
|
struct file *file;
|
|
int ret;
|
|
|
|
#if defined(CONFIG_UNIX)
|
|
ret = sock_create_kern(&init_net, PF_UNIX, SOCK_RAW, IPPROTO_IP,
|
|
&ctx->ring_sock);
|
|
if (ret)
|
|
return ret;
|
|
#endif
|
|
|
|
ret = get_unused_fd_flags(O_RDWR | O_CLOEXEC);
|
|
if (ret < 0)
|
|
goto err;
|
|
|
|
file = anon_inode_getfile("[io_uring]", &io_uring_fops, ctx,
|
|
O_RDWR | O_CLOEXEC);
|
|
if (IS_ERR(file)) {
|
|
put_unused_fd(ret);
|
|
ret = PTR_ERR(file);
|
|
goto err;
|
|
}
|
|
|
|
#if defined(CONFIG_UNIX)
|
|
ctx->ring_sock->file = file;
|
|
ctx->ring_sock->sk->sk_user_data = ctx;
|
|
#endif
|
|
fd_install(ret, file);
|
|
return ret;
|
|
err:
|
|
#if defined(CONFIG_UNIX)
|
|
sock_release(ctx->ring_sock);
|
|
ctx->ring_sock = NULL;
|
|
#endif
|
|
return ret;
|
|
}
|
|
|
|
static int io_uring_create(unsigned entries, struct io_uring_params *p)
|
|
{
|
|
struct user_struct *user = NULL;
|
|
struct io_ring_ctx *ctx;
|
|
bool account_mem;
|
|
int ret;
|
|
|
|
if (!entries || entries > IORING_MAX_ENTRIES)
|
|
return -EINVAL;
|
|
|
|
/*
|
|
* Use twice as many entries for the CQ ring. It's possible for the
|
|
* application to drive a higher depth than the size of the SQ ring,
|
|
* since the sqes are only used at submission time. This allows for
|
|
* some flexibility in overcommitting a bit.
|
|
*/
|
|
p->sq_entries = roundup_pow_of_two(entries);
|
|
p->cq_entries = 2 * p->sq_entries;
|
|
|
|
user = get_uid(current_user());
|
|
account_mem = !capable(CAP_IPC_LOCK);
|
|
|
|
if (account_mem) {
|
|
ret = io_account_mem(user,
|
|
ring_pages(p->sq_entries, p->cq_entries));
|
|
if (ret) {
|
|
free_uid(user);
|
|
return ret;
|
|
}
|
|
}
|
|
|
|
ctx = io_ring_ctx_alloc(p);
|
|
if (!ctx) {
|
|
if (account_mem)
|
|
io_unaccount_mem(user, ring_pages(p->sq_entries,
|
|
p->cq_entries));
|
|
free_uid(user);
|
|
return -ENOMEM;
|
|
}
|
|
ctx->compat = in_compat_syscall();
|
|
ctx->account_mem = account_mem;
|
|
ctx->user = user;
|
|
|
|
ret = io_allocate_scq_urings(ctx, p);
|
|
if (ret)
|
|
goto err;
|
|
|
|
ret = io_sq_offload_start(ctx, p);
|
|
if (ret)
|
|
goto err;
|
|
|
|
ret = io_uring_get_fd(ctx);
|
|
if (ret < 0)
|
|
goto err;
|
|
|
|
memset(&p->sq_off, 0, sizeof(p->sq_off));
|
|
p->sq_off.head = offsetof(struct io_sq_ring, r.head);
|
|
p->sq_off.tail = offsetof(struct io_sq_ring, r.tail);
|
|
p->sq_off.ring_mask = offsetof(struct io_sq_ring, ring_mask);
|
|
p->sq_off.ring_entries = offsetof(struct io_sq_ring, ring_entries);
|
|
p->sq_off.flags = offsetof(struct io_sq_ring, flags);
|
|
p->sq_off.dropped = offsetof(struct io_sq_ring, dropped);
|
|
p->sq_off.array = offsetof(struct io_sq_ring, array);
|
|
|
|
memset(&p->cq_off, 0, sizeof(p->cq_off));
|
|
p->cq_off.head = offsetof(struct io_cq_ring, r.head);
|
|
p->cq_off.tail = offsetof(struct io_cq_ring, r.tail);
|
|
p->cq_off.ring_mask = offsetof(struct io_cq_ring, ring_mask);
|
|
p->cq_off.ring_entries = offsetof(struct io_cq_ring, ring_entries);
|
|
p->cq_off.overflow = offsetof(struct io_cq_ring, overflow);
|
|
p->cq_off.cqes = offsetof(struct io_cq_ring, cqes);
|
|
return ret;
|
|
err:
|
|
io_ring_ctx_wait_and_kill(ctx);
|
|
return ret;
|
|
}
|
|
|
|
/*
|
|
* Sets up an aio uring context, and returns the fd. Applications asks for a
|
|
* ring size, we return the actual sq/cq ring sizes (among other things) in the
|
|
* params structure passed in.
|
|
*/
|
|
static long io_uring_setup(u32 entries, struct io_uring_params __user *params)
|
|
{
|
|
struct io_uring_params p;
|
|
long ret;
|
|
int i;
|
|
|
|
if (copy_from_user(&p, params, sizeof(p)))
|
|
return -EFAULT;
|
|
for (i = 0; i < ARRAY_SIZE(p.resv); i++) {
|
|
if (p.resv[i])
|
|
return -EINVAL;
|
|
}
|
|
|
|
if (p.flags & ~(IORING_SETUP_IOPOLL | IORING_SETUP_SQPOLL |
|
|
IORING_SETUP_SQ_AFF))
|
|
return -EINVAL;
|
|
|
|
ret = io_uring_create(entries, &p);
|
|
if (ret < 0)
|
|
return ret;
|
|
|
|
if (copy_to_user(params, &p, sizeof(p)))
|
|
return -EFAULT;
|
|
|
|
return ret;
|
|
}
|
|
|
|
SYSCALL_DEFINE2(io_uring_setup, u32, entries,
|
|
struct io_uring_params __user *, params)
|
|
{
|
|
return io_uring_setup(entries, params);
|
|
}
|
|
|
|
static int __io_uring_register(struct io_ring_ctx *ctx, unsigned opcode,
|
|
void __user *arg, unsigned nr_args)
|
|
__releases(ctx->uring_lock)
|
|
__acquires(ctx->uring_lock)
|
|
{
|
|
int ret;
|
|
|
|
/*
|
|
* We're inside the ring mutex, if the ref is already dying, then
|
|
* someone else killed the ctx or is already going through
|
|
* io_uring_register().
|
|
*/
|
|
if (percpu_ref_is_dying(&ctx->refs))
|
|
return -ENXIO;
|
|
|
|
percpu_ref_kill(&ctx->refs);
|
|
|
|
/*
|
|
* Drop uring mutex before waiting for references to exit. If another
|
|
* thread is currently inside io_uring_enter() it might need to grab
|
|
* the uring_lock to make progress. If we hold it here across the drain
|
|
* wait, then we can deadlock. It's safe to drop the mutex here, since
|
|
* no new references will come in after we've killed the percpu ref.
|
|
*/
|
|
mutex_unlock(&ctx->uring_lock);
|
|
wait_for_completion(&ctx->ctx_done);
|
|
mutex_lock(&ctx->uring_lock);
|
|
|
|
switch (opcode) {
|
|
case IORING_REGISTER_BUFFERS:
|
|
ret = io_sqe_buffer_register(ctx, arg, nr_args);
|
|
break;
|
|
case IORING_UNREGISTER_BUFFERS:
|
|
ret = -EINVAL;
|
|
if (arg || nr_args)
|
|
break;
|
|
ret = io_sqe_buffer_unregister(ctx);
|
|
break;
|
|
case IORING_REGISTER_FILES:
|
|
ret = io_sqe_files_register(ctx, arg, nr_args);
|
|
break;
|
|
case IORING_UNREGISTER_FILES:
|
|
ret = -EINVAL;
|
|
if (arg || nr_args)
|
|
break;
|
|
ret = io_sqe_files_unregister(ctx);
|
|
break;
|
|
case IORING_REGISTER_EVENTFD:
|
|
ret = -EINVAL;
|
|
if (nr_args != 1)
|
|
break;
|
|
ret = io_eventfd_register(ctx, arg);
|
|
break;
|
|
case IORING_UNREGISTER_EVENTFD:
|
|
ret = -EINVAL;
|
|
if (arg || nr_args)
|
|
break;
|
|
ret = io_eventfd_unregister(ctx);
|
|
break;
|
|
default:
|
|
ret = -EINVAL;
|
|
break;
|
|
}
|
|
|
|
/* bring the ctx back to life */
|
|
reinit_completion(&ctx->ctx_done);
|
|
percpu_ref_reinit(&ctx->refs);
|
|
return ret;
|
|
}
|
|
|
|
SYSCALL_DEFINE4(io_uring_register, unsigned int, fd, unsigned int, opcode,
|
|
void __user *, arg, unsigned int, nr_args)
|
|
{
|
|
struct io_ring_ctx *ctx;
|
|
long ret = -EBADF;
|
|
struct fd f;
|
|
|
|
f = fdget(fd);
|
|
if (!f.file)
|
|
return -EBADF;
|
|
|
|
ret = -EOPNOTSUPP;
|
|
if (f.file->f_op != &io_uring_fops)
|
|
goto out_fput;
|
|
|
|
ctx = f.file->private_data;
|
|
|
|
mutex_lock(&ctx->uring_lock);
|
|
ret = __io_uring_register(ctx, opcode, arg, nr_args);
|
|
mutex_unlock(&ctx->uring_lock);
|
|
out_fput:
|
|
fdput(f);
|
|
return ret;
|
|
}
|
|
|
|
static int __init io_uring_init(void)
|
|
{
|
|
req_cachep = KMEM_CACHE(io_kiocb, SLAB_HWCACHE_ALIGN | SLAB_PANIC);
|
|
return 0;
|
|
};
|
|
__initcall(io_uring_init);
|