bec68faaf3
Originally, io_event() was documented to return the io_event if cancellation succeeded - the io_event wouldn't be delivered via the ring buffer like it normally would. But this isn't what the implementation was actually doing; the only driver implementing cancellation, the usb gadget code, never returned an io_event in its cancel function. And aio_complete() was recently changed to no longer suppress event delivery if the kiocb had been cancelled. This gets rid of the unused io_event argument to kiocb_cancel() and kiocb->ki_cancel(), and changes io_cancel() to return -EINPROGRESS if kiocb->ki_cancel() returned success. Also tweak the refcounting in kiocb_cancel() to make more sense. Signed-off-by: Kent Overstreet <koverstreet@google.com> Cc: Zach Brown <zab@redhat.com> Cc: Felipe Balbi <balbi@ti.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Mark Fasheh <mfasheh@suse.com> Cc: Joel Becker <jlbec@evilplan.org> Cc: Rusty Russell <rusty@rustcorp.com.au> Cc: Jens Axboe <axboe@kernel.dk> Cc: Asai Thambi S P <asamymuthupa@micron.com> Cc: Selvan Mani <smani@micron.com> Cc: Sam Bradshaw <sbradshaw@micron.com> Cc: Jeff Moyer <jmoyer@redhat.com> Cc: Al Viro <viro@zeniv.linux.org.uk> Cc: Benjamin LaHaise <bcrl@kvack.org> Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
117 lines
3.3 KiB
C
117 lines
3.3 KiB
C
#ifndef __LINUX__AIO_H
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#define __LINUX__AIO_H
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#include <linux/list.h>
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#include <linux/workqueue.h>
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#include <linux/aio_abi.h>
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#include <linux/uio.h>
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#include <linux/rcupdate.h>
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#include <linux/atomic.h>
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struct kioctx;
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struct kiocb;
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#define KIOCB_KEY 0
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/*
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* We use ki_cancel == KIOCB_CANCELLED to indicate that a kiocb has been either
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* cancelled or completed (this makes a certain amount of sense because
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* successful cancellation - io_cancel() - does deliver the completion to
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* userspace).
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*
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* And since most things don't implement kiocb cancellation and we'd really like
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* kiocb completion to be lockless when possible, we use ki_cancel to
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* synchronize cancellation and completion - we only set it to KIOCB_CANCELLED
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* with xchg() or cmpxchg(), see batch_complete_aio() and kiocb_cancel().
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*/
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#define KIOCB_CANCELLED ((void *) (~0ULL))
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typedef int (kiocb_cancel_fn)(struct kiocb *);
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struct kiocb {
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atomic_t ki_users;
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struct file *ki_filp;
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struct kioctx *ki_ctx; /* NULL for sync ops */
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kiocb_cancel_fn *ki_cancel;
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void (*ki_dtor)(struct kiocb *);
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union {
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void __user *user;
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struct task_struct *tsk;
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} ki_obj;
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__u64 ki_user_data; /* user's data for completion */
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loff_t ki_pos;
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void *private;
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/* State that we remember to be able to restart/retry */
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unsigned short ki_opcode;
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size_t ki_nbytes; /* copy of iocb->aio_nbytes */
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char __user *ki_buf; /* remaining iocb->aio_buf */
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size_t ki_left; /* remaining bytes */
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struct iovec ki_inline_vec; /* inline vector */
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struct iovec *ki_iovec;
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unsigned long ki_nr_segs;
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unsigned long ki_cur_seg;
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struct list_head ki_list; /* the aio core uses this
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* for cancellation */
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/*
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* If the aio_resfd field of the userspace iocb is not zero,
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* this is the underlying eventfd context to deliver events to.
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*/
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struct eventfd_ctx *ki_eventfd;
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};
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static inline bool is_sync_kiocb(struct kiocb *kiocb)
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{
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return kiocb->ki_ctx == NULL;
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}
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static inline void init_sync_kiocb(struct kiocb *kiocb, struct file *filp)
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{
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*kiocb = (struct kiocb) {
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.ki_users = ATOMIC_INIT(1),
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.ki_ctx = NULL,
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.ki_filp = filp,
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.ki_obj.tsk = current,
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};
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}
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/* prototypes */
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#ifdef CONFIG_AIO
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extern ssize_t wait_on_sync_kiocb(struct kiocb *iocb);
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extern void aio_put_req(struct kiocb *iocb);
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extern void aio_complete(struct kiocb *iocb, long res, long res2);
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struct mm_struct;
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extern void exit_aio(struct mm_struct *mm);
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extern long do_io_submit(aio_context_t ctx_id, long nr,
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struct iocb __user *__user *iocbpp, bool compat);
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void kiocb_set_cancel_fn(struct kiocb *req, kiocb_cancel_fn *cancel);
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#else
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static inline ssize_t wait_on_sync_kiocb(struct kiocb *iocb) { return 0; }
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static inline void aio_put_req(struct kiocb *iocb) { }
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static inline void aio_complete(struct kiocb *iocb, long res, long res2) { }
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struct mm_struct;
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static inline void exit_aio(struct mm_struct *mm) { }
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static inline long do_io_submit(aio_context_t ctx_id, long nr,
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struct iocb __user * __user *iocbpp,
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bool compat) { return 0; }
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static inline void kiocb_set_cancel_fn(struct kiocb *req,
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kiocb_cancel_fn *cancel) { }
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#endif /* CONFIG_AIO */
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static inline struct kiocb *list_kiocb(struct list_head *h)
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{
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return list_entry(h, struct kiocb, ki_list);
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}
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/* for sysctl: */
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extern unsigned long aio_nr;
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extern unsigned long aio_max_nr;
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#endif /* __LINUX__AIO_H */
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