![Linus Torvalds](/assets/img/avatar_default.png)
* 'for-next' of git://git.kernel.org/pub/scm/linux/kernel/git/jikos/trivial: (39 commits) Update broken web addresses in arch directory. Update broken web addresses in the kernel. Revert "drivers/usb: Remove unnecessary return's from void functions" for musb gadget Revert "Fix typo: configuation => configuration" partially ida: document IDA_BITMAP_LONGS calculation ext2: fix a typo on comment in ext2/inode.c drivers/scsi: Remove unnecessary casts of private_data drivers/s390: Remove unnecessary casts of private_data net/sunrpc/rpc_pipe.c: Remove unnecessary casts of private_data drivers/infiniband: Remove unnecessary casts of private_data drivers/gpu/drm: Remove unnecessary casts of private_data kernel/pm_qos_params.c: Remove unnecessary casts of private_data fs/ecryptfs: Remove unnecessary casts of private_data fs/seq_file.c: Remove unnecessary casts of private_data arm: uengine.c: remove C99 comments arm: scoop.c: remove C99 comments Fix typo configue => configure in comments Fix typo: configuation => configuration Fix typo interrest[ing|ed] => interest[ing|ed] Fix various typos of valid in comments ... Fix up trivial conflicts in: drivers/char/ipmi/ipmi_si_intf.c drivers/usb/gadget/rndis.c net/irda/irnet/irnet_ppp.c
2636 lines
70 KiB
C
2636 lines
70 KiB
C
/*
|
|
* Copyright (C) 1991, 1992 Linus Torvalds
|
|
* Copyright (C) 1994, Karl Keyte: Added support for disk statistics
|
|
* Elevator latency, (C) 2000 Andrea Arcangeli <andrea@suse.de> SuSE
|
|
* Queue request tables / lock, selectable elevator, Jens Axboe <axboe@suse.de>
|
|
* kernel-doc documentation started by NeilBrown <neilb@cse.unsw.edu.au>
|
|
* - July2000
|
|
* bio rewrite, highmem i/o, etc, Jens Axboe <axboe@suse.de> - may 2001
|
|
*/
|
|
|
|
/*
|
|
* This handles all read/write requests to block devices
|
|
*/
|
|
#include <linux/kernel.h>
|
|
#include <linux/module.h>
|
|
#include <linux/backing-dev.h>
|
|
#include <linux/bio.h>
|
|
#include <linux/blkdev.h>
|
|
#include <linux/highmem.h>
|
|
#include <linux/mm.h>
|
|
#include <linux/kernel_stat.h>
|
|
#include <linux/string.h>
|
|
#include <linux/init.h>
|
|
#include <linux/completion.h>
|
|
#include <linux/slab.h>
|
|
#include <linux/swap.h>
|
|
#include <linux/writeback.h>
|
|
#include <linux/task_io_accounting_ops.h>
|
|
#include <linux/fault-inject.h>
|
|
|
|
#define CREATE_TRACE_POINTS
|
|
#include <trace/events/block.h>
|
|
|
|
#include "blk.h"
|
|
|
|
EXPORT_TRACEPOINT_SYMBOL_GPL(block_remap);
|
|
EXPORT_TRACEPOINT_SYMBOL_GPL(block_rq_remap);
|
|
EXPORT_TRACEPOINT_SYMBOL_GPL(block_bio_complete);
|
|
|
|
static int __make_request(struct request_queue *q, struct bio *bio);
|
|
|
|
/*
|
|
* For the allocated request tables
|
|
*/
|
|
static struct kmem_cache *request_cachep;
|
|
|
|
/*
|
|
* For queue allocation
|
|
*/
|
|
struct kmem_cache *blk_requestq_cachep;
|
|
|
|
/*
|
|
* Controlling structure to kblockd
|
|
*/
|
|
static struct workqueue_struct *kblockd_workqueue;
|
|
|
|
static void drive_stat_acct(struct request *rq, int new_io)
|
|
{
|
|
struct hd_struct *part;
|
|
int rw = rq_data_dir(rq);
|
|
int cpu;
|
|
|
|
if (!blk_do_io_stat(rq))
|
|
return;
|
|
|
|
cpu = part_stat_lock();
|
|
|
|
if (!new_io) {
|
|
part = rq->part;
|
|
part_stat_inc(cpu, part, merges[rw]);
|
|
} else {
|
|
part = disk_map_sector_rcu(rq->rq_disk, blk_rq_pos(rq));
|
|
part_round_stats(cpu, part);
|
|
part_inc_in_flight(part, rw);
|
|
rq->part = part;
|
|
}
|
|
|
|
part_stat_unlock();
|
|
}
|
|
|
|
void blk_queue_congestion_threshold(struct request_queue *q)
|
|
{
|
|
int nr;
|
|
|
|
nr = q->nr_requests - (q->nr_requests / 8) + 1;
|
|
if (nr > q->nr_requests)
|
|
nr = q->nr_requests;
|
|
q->nr_congestion_on = nr;
|
|
|
|
nr = q->nr_requests - (q->nr_requests / 8) - (q->nr_requests / 16) - 1;
|
|
if (nr < 1)
|
|
nr = 1;
|
|
q->nr_congestion_off = nr;
|
|
}
|
|
|
|
/**
|
|
* blk_get_backing_dev_info - get the address of a queue's backing_dev_info
|
|
* @bdev: device
|
|
*
|
|
* Locates the passed device's request queue and returns the address of its
|
|
* backing_dev_info
|
|
*
|
|
* Will return NULL if the request queue cannot be located.
|
|
*/
|
|
struct backing_dev_info *blk_get_backing_dev_info(struct block_device *bdev)
|
|
{
|
|
struct backing_dev_info *ret = NULL;
|
|
struct request_queue *q = bdev_get_queue(bdev);
|
|
|
|
if (q)
|
|
ret = &q->backing_dev_info;
|
|
return ret;
|
|
}
|
|
EXPORT_SYMBOL(blk_get_backing_dev_info);
|
|
|
|
void blk_rq_init(struct request_queue *q, struct request *rq)
|
|
{
|
|
memset(rq, 0, sizeof(*rq));
|
|
|
|
INIT_LIST_HEAD(&rq->queuelist);
|
|
INIT_LIST_HEAD(&rq->timeout_list);
|
|
rq->cpu = -1;
|
|
rq->q = q;
|
|
rq->__sector = (sector_t) -1;
|
|
INIT_HLIST_NODE(&rq->hash);
|
|
RB_CLEAR_NODE(&rq->rb_node);
|
|
rq->cmd = rq->__cmd;
|
|
rq->cmd_len = BLK_MAX_CDB;
|
|
rq->tag = -1;
|
|
rq->ref_count = 1;
|
|
rq->start_time = jiffies;
|
|
set_start_time_ns(rq);
|
|
rq->part = NULL;
|
|
}
|
|
EXPORT_SYMBOL(blk_rq_init);
|
|
|
|
static void req_bio_endio(struct request *rq, struct bio *bio,
|
|
unsigned int nbytes, int error)
|
|
{
|
|
struct request_queue *q = rq->q;
|
|
|
|
if (&q->flush_rq != rq) {
|
|
if (error)
|
|
clear_bit(BIO_UPTODATE, &bio->bi_flags);
|
|
else if (!test_bit(BIO_UPTODATE, &bio->bi_flags))
|
|
error = -EIO;
|
|
|
|
if (unlikely(nbytes > bio->bi_size)) {
|
|
printk(KERN_ERR "%s: want %u bytes done, %u left\n",
|
|
__func__, nbytes, bio->bi_size);
|
|
nbytes = bio->bi_size;
|
|
}
|
|
|
|
if (unlikely(rq->cmd_flags & REQ_QUIET))
|
|
set_bit(BIO_QUIET, &bio->bi_flags);
|
|
|
|
bio->bi_size -= nbytes;
|
|
bio->bi_sector += (nbytes >> 9);
|
|
|
|
if (bio_integrity(bio))
|
|
bio_integrity_advance(bio, nbytes);
|
|
|
|
if (bio->bi_size == 0)
|
|
bio_endio(bio, error);
|
|
} else {
|
|
/*
|
|
* Okay, this is the sequenced flush request in
|
|
* progress, just record the error;
|
|
*/
|
|
if (error && !q->flush_err)
|
|
q->flush_err = error;
|
|
}
|
|
}
|
|
|
|
void blk_dump_rq_flags(struct request *rq, char *msg)
|
|
{
|
|
int bit;
|
|
|
|
printk(KERN_INFO "%s: dev %s: type=%x, flags=%x\n", msg,
|
|
rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->cmd_type,
|
|
rq->cmd_flags);
|
|
|
|
printk(KERN_INFO " sector %llu, nr/cnr %u/%u\n",
|
|
(unsigned long long)blk_rq_pos(rq),
|
|
blk_rq_sectors(rq), blk_rq_cur_sectors(rq));
|
|
printk(KERN_INFO " bio %p, biotail %p, buffer %p, len %u\n",
|
|
rq->bio, rq->biotail, rq->buffer, blk_rq_bytes(rq));
|
|
|
|
if (rq->cmd_type == REQ_TYPE_BLOCK_PC) {
|
|
printk(KERN_INFO " cdb: ");
|
|
for (bit = 0; bit < BLK_MAX_CDB; bit++)
|
|
printk("%02x ", rq->cmd[bit]);
|
|
printk("\n");
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(blk_dump_rq_flags);
|
|
|
|
/*
|
|
* "plug" the device if there are no outstanding requests: this will
|
|
* force the transfer to start only after we have put all the requests
|
|
* on the list.
|
|
*
|
|
* This is called with interrupts off and no requests on the queue and
|
|
* with the queue lock held.
|
|
*/
|
|
void blk_plug_device(struct request_queue *q)
|
|
{
|
|
WARN_ON(!irqs_disabled());
|
|
|
|
/*
|
|
* don't plug a stopped queue, it must be paired with blk_start_queue()
|
|
* which will restart the queueing
|
|
*/
|
|
if (blk_queue_stopped(q))
|
|
return;
|
|
|
|
if (!queue_flag_test_and_set(QUEUE_FLAG_PLUGGED, q)) {
|
|
mod_timer(&q->unplug_timer, jiffies + q->unplug_delay);
|
|
trace_block_plug(q);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(blk_plug_device);
|
|
|
|
/**
|
|
* blk_plug_device_unlocked - plug a device without queue lock held
|
|
* @q: The &struct request_queue to plug
|
|
*
|
|
* Description:
|
|
* Like @blk_plug_device(), but grabs the queue lock and disables
|
|
* interrupts.
|
|
**/
|
|
void blk_plug_device_unlocked(struct request_queue *q)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(q->queue_lock, flags);
|
|
blk_plug_device(q);
|
|
spin_unlock_irqrestore(q->queue_lock, flags);
|
|
}
|
|
EXPORT_SYMBOL(blk_plug_device_unlocked);
|
|
|
|
/*
|
|
* remove the queue from the plugged list, if present. called with
|
|
* queue lock held and interrupts disabled.
|
|
*/
|
|
int blk_remove_plug(struct request_queue *q)
|
|
{
|
|
WARN_ON(!irqs_disabled());
|
|
|
|
if (!queue_flag_test_and_clear(QUEUE_FLAG_PLUGGED, q))
|
|
return 0;
|
|
|
|
del_timer(&q->unplug_timer);
|
|
return 1;
|
|
}
|
|
EXPORT_SYMBOL(blk_remove_plug);
|
|
|
|
/*
|
|
* remove the plug and let it rip..
|
|
*/
|
|
void __generic_unplug_device(struct request_queue *q)
|
|
{
|
|
if (unlikely(blk_queue_stopped(q)))
|
|
return;
|
|
if (!blk_remove_plug(q) && !blk_queue_nonrot(q))
|
|
return;
|
|
|
|
q->request_fn(q);
|
|
}
|
|
|
|
/**
|
|
* generic_unplug_device - fire a request queue
|
|
* @q: The &struct request_queue in question
|
|
*
|
|
* Description:
|
|
* Linux uses plugging to build bigger requests queues before letting
|
|
* the device have at them. If a queue is plugged, the I/O scheduler
|
|
* is still adding and merging requests on the queue. Once the queue
|
|
* gets unplugged, the request_fn defined for the queue is invoked and
|
|
* transfers started.
|
|
**/
|
|
void generic_unplug_device(struct request_queue *q)
|
|
{
|
|
if (blk_queue_plugged(q)) {
|
|
spin_lock_irq(q->queue_lock);
|
|
__generic_unplug_device(q);
|
|
spin_unlock_irq(q->queue_lock);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(generic_unplug_device);
|
|
|
|
static void blk_backing_dev_unplug(struct backing_dev_info *bdi,
|
|
struct page *page)
|
|
{
|
|
struct request_queue *q = bdi->unplug_io_data;
|
|
|
|
blk_unplug(q);
|
|
}
|
|
|
|
void blk_unplug_work(struct work_struct *work)
|
|
{
|
|
struct request_queue *q =
|
|
container_of(work, struct request_queue, unplug_work);
|
|
|
|
trace_block_unplug_io(q);
|
|
q->unplug_fn(q);
|
|
}
|
|
|
|
void blk_unplug_timeout(unsigned long data)
|
|
{
|
|
struct request_queue *q = (struct request_queue *)data;
|
|
|
|
trace_block_unplug_timer(q);
|
|
kblockd_schedule_work(q, &q->unplug_work);
|
|
}
|
|
|
|
void blk_unplug(struct request_queue *q)
|
|
{
|
|
/*
|
|
* devices don't necessarily have an ->unplug_fn defined
|
|
*/
|
|
if (q->unplug_fn) {
|
|
trace_block_unplug_io(q);
|
|
q->unplug_fn(q);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(blk_unplug);
|
|
|
|
/**
|
|
* blk_start_queue - restart a previously stopped queue
|
|
* @q: The &struct request_queue in question
|
|
*
|
|
* Description:
|
|
* blk_start_queue() will clear the stop flag on the queue, and call
|
|
* the request_fn for the queue if it was in a stopped state when
|
|
* entered. Also see blk_stop_queue(). Queue lock must be held.
|
|
**/
|
|
void blk_start_queue(struct request_queue *q)
|
|
{
|
|
WARN_ON(!irqs_disabled());
|
|
|
|
queue_flag_clear(QUEUE_FLAG_STOPPED, q);
|
|
__blk_run_queue(q);
|
|
}
|
|
EXPORT_SYMBOL(blk_start_queue);
|
|
|
|
/**
|
|
* blk_stop_queue - stop a queue
|
|
* @q: The &struct request_queue in question
|
|
*
|
|
* Description:
|
|
* The Linux block layer assumes that a block driver will consume all
|
|
* entries on the request queue when the request_fn strategy is called.
|
|
* Often this will not happen, because of hardware limitations (queue
|
|
* depth settings). If a device driver gets a 'queue full' response,
|
|
* or if it simply chooses not to queue more I/O at one point, it can
|
|
* call this function to prevent the request_fn from being called until
|
|
* the driver has signalled it's ready to go again. This happens by calling
|
|
* blk_start_queue() to restart queue operations. Queue lock must be held.
|
|
**/
|
|
void blk_stop_queue(struct request_queue *q)
|
|
{
|
|
blk_remove_plug(q);
|
|
queue_flag_set(QUEUE_FLAG_STOPPED, q);
|
|
}
|
|
EXPORT_SYMBOL(blk_stop_queue);
|
|
|
|
/**
|
|
* blk_sync_queue - cancel any pending callbacks on a queue
|
|
* @q: the queue
|
|
*
|
|
* Description:
|
|
* The block layer may perform asynchronous callback activity
|
|
* on a queue, such as calling the unplug function after a timeout.
|
|
* A block device may call blk_sync_queue to ensure that any
|
|
* such activity is cancelled, thus allowing it to release resources
|
|
* that the callbacks might use. The caller must already have made sure
|
|
* that its ->make_request_fn will not re-add plugging prior to calling
|
|
* this function.
|
|
*
|
|
*/
|
|
void blk_sync_queue(struct request_queue *q)
|
|
{
|
|
del_timer_sync(&q->unplug_timer);
|
|
del_timer_sync(&q->timeout);
|
|
cancel_work_sync(&q->unplug_work);
|
|
throtl_shutdown_timer_wq(q);
|
|
}
|
|
EXPORT_SYMBOL(blk_sync_queue);
|
|
|
|
/**
|
|
* __blk_run_queue - run a single device queue
|
|
* @q: The queue to run
|
|
*
|
|
* Description:
|
|
* See @blk_run_queue. This variant must be called with the queue lock
|
|
* held and interrupts disabled.
|
|
*
|
|
*/
|
|
void __blk_run_queue(struct request_queue *q)
|
|
{
|
|
blk_remove_plug(q);
|
|
|
|
if (unlikely(blk_queue_stopped(q)))
|
|
return;
|
|
|
|
if (elv_queue_empty(q))
|
|
return;
|
|
|
|
/*
|
|
* Only recurse once to avoid overrunning the stack, let the unplug
|
|
* handling reinvoke the handler shortly if we already got there.
|
|
*/
|
|
if (!queue_flag_test_and_set(QUEUE_FLAG_REENTER, q)) {
|
|
q->request_fn(q);
|
|
queue_flag_clear(QUEUE_FLAG_REENTER, q);
|
|
} else {
|
|
queue_flag_set(QUEUE_FLAG_PLUGGED, q);
|
|
kblockd_schedule_work(q, &q->unplug_work);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(__blk_run_queue);
|
|
|
|
/**
|
|
* blk_run_queue - run a single device queue
|
|
* @q: The queue to run
|
|
*
|
|
* Description:
|
|
* Invoke request handling on this queue, if it has pending work to do.
|
|
* May be used to restart queueing when a request has completed.
|
|
*/
|
|
void blk_run_queue(struct request_queue *q)
|
|
{
|
|
unsigned long flags;
|
|
|
|
spin_lock_irqsave(q->queue_lock, flags);
|
|
__blk_run_queue(q);
|
|
spin_unlock_irqrestore(q->queue_lock, flags);
|
|
}
|
|
EXPORT_SYMBOL(blk_run_queue);
|
|
|
|
void blk_put_queue(struct request_queue *q)
|
|
{
|
|
kobject_put(&q->kobj);
|
|
}
|
|
|
|
void blk_cleanup_queue(struct request_queue *q)
|
|
{
|
|
/*
|
|
* We know we have process context here, so we can be a little
|
|
* cautious and ensure that pending block actions on this device
|
|
* are done before moving on. Going into this function, we should
|
|
* not have processes doing IO to this device.
|
|
*/
|
|
blk_sync_queue(q);
|
|
|
|
del_timer_sync(&q->backing_dev_info.laptop_mode_wb_timer);
|
|
mutex_lock(&q->sysfs_lock);
|
|
queue_flag_set_unlocked(QUEUE_FLAG_DEAD, q);
|
|
mutex_unlock(&q->sysfs_lock);
|
|
|
|
if (q->elevator)
|
|
elevator_exit(q->elevator);
|
|
|
|
blk_put_queue(q);
|
|
}
|
|
EXPORT_SYMBOL(blk_cleanup_queue);
|
|
|
|
static int blk_init_free_list(struct request_queue *q)
|
|
{
|
|
struct request_list *rl = &q->rq;
|
|
|
|
if (unlikely(rl->rq_pool))
|
|
return 0;
|
|
|
|
rl->count[BLK_RW_SYNC] = rl->count[BLK_RW_ASYNC] = 0;
|
|
rl->starved[BLK_RW_SYNC] = rl->starved[BLK_RW_ASYNC] = 0;
|
|
rl->elvpriv = 0;
|
|
init_waitqueue_head(&rl->wait[BLK_RW_SYNC]);
|
|
init_waitqueue_head(&rl->wait[BLK_RW_ASYNC]);
|
|
|
|
rl->rq_pool = mempool_create_node(BLKDEV_MIN_RQ, mempool_alloc_slab,
|
|
mempool_free_slab, request_cachep, q->node);
|
|
|
|
if (!rl->rq_pool)
|
|
return -ENOMEM;
|
|
|
|
return 0;
|
|
}
|
|
|
|
struct request_queue *blk_alloc_queue(gfp_t gfp_mask)
|
|
{
|
|
return blk_alloc_queue_node(gfp_mask, -1);
|
|
}
|
|
EXPORT_SYMBOL(blk_alloc_queue);
|
|
|
|
struct request_queue *blk_alloc_queue_node(gfp_t gfp_mask, int node_id)
|
|
{
|
|
struct request_queue *q;
|
|
int err;
|
|
|
|
q = kmem_cache_alloc_node(blk_requestq_cachep,
|
|
gfp_mask | __GFP_ZERO, node_id);
|
|
if (!q)
|
|
return NULL;
|
|
|
|
q->backing_dev_info.unplug_io_fn = blk_backing_dev_unplug;
|
|
q->backing_dev_info.unplug_io_data = q;
|
|
q->backing_dev_info.ra_pages =
|
|
(VM_MAX_READAHEAD * 1024) / PAGE_CACHE_SIZE;
|
|
q->backing_dev_info.state = 0;
|
|
q->backing_dev_info.capabilities = BDI_CAP_MAP_COPY;
|
|
q->backing_dev_info.name = "block";
|
|
|
|
err = bdi_init(&q->backing_dev_info);
|
|
if (err) {
|
|
kmem_cache_free(blk_requestq_cachep, q);
|
|
return NULL;
|
|
}
|
|
|
|
if (blk_throtl_init(q)) {
|
|
kmem_cache_free(blk_requestq_cachep, q);
|
|
return NULL;
|
|
}
|
|
|
|
setup_timer(&q->backing_dev_info.laptop_mode_wb_timer,
|
|
laptop_mode_timer_fn, (unsigned long) q);
|
|
init_timer(&q->unplug_timer);
|
|
setup_timer(&q->timeout, blk_rq_timed_out_timer, (unsigned long) q);
|
|
INIT_LIST_HEAD(&q->timeout_list);
|
|
INIT_LIST_HEAD(&q->pending_flushes);
|
|
INIT_WORK(&q->unplug_work, blk_unplug_work);
|
|
|
|
kobject_init(&q->kobj, &blk_queue_ktype);
|
|
|
|
mutex_init(&q->sysfs_lock);
|
|
spin_lock_init(&q->__queue_lock);
|
|
|
|
return q;
|
|
}
|
|
EXPORT_SYMBOL(blk_alloc_queue_node);
|
|
|
|
/**
|
|
* blk_init_queue - prepare a request queue for use with a block device
|
|
* @rfn: The function to be called to process requests that have been
|
|
* placed on the queue.
|
|
* @lock: Request queue spin lock
|
|
*
|
|
* Description:
|
|
* If a block device wishes to use the standard request handling procedures,
|
|
* which sorts requests and coalesces adjacent requests, then it must
|
|
* call blk_init_queue(). The function @rfn will be called when there
|
|
* are requests on the queue that need to be processed. If the device
|
|
* supports plugging, then @rfn may not be called immediately when requests
|
|
* are available on the queue, but may be called at some time later instead.
|
|
* Plugged queues are generally unplugged when a buffer belonging to one
|
|
* of the requests on the queue is needed, or due to memory pressure.
|
|
*
|
|
* @rfn is not required, or even expected, to remove all requests off the
|
|
* queue, but only as many as it can handle at a time. If it does leave
|
|
* requests on the queue, it is responsible for arranging that the requests
|
|
* get dealt with eventually.
|
|
*
|
|
* The queue spin lock must be held while manipulating the requests on the
|
|
* request queue; this lock will be taken also from interrupt context, so irq
|
|
* disabling is needed for it.
|
|
*
|
|
* Function returns a pointer to the initialized request queue, or %NULL if
|
|
* it didn't succeed.
|
|
*
|
|
* Note:
|
|
* blk_init_queue() must be paired with a blk_cleanup_queue() call
|
|
* when the block device is deactivated (such as at module unload).
|
|
**/
|
|
|
|
struct request_queue *blk_init_queue(request_fn_proc *rfn, spinlock_t *lock)
|
|
{
|
|
return blk_init_queue_node(rfn, lock, -1);
|
|
}
|
|
EXPORT_SYMBOL(blk_init_queue);
|
|
|
|
struct request_queue *
|
|
blk_init_queue_node(request_fn_proc *rfn, spinlock_t *lock, int node_id)
|
|
{
|
|
struct request_queue *uninit_q, *q;
|
|
|
|
uninit_q = blk_alloc_queue_node(GFP_KERNEL, node_id);
|
|
if (!uninit_q)
|
|
return NULL;
|
|
|
|
q = blk_init_allocated_queue_node(uninit_q, rfn, lock, node_id);
|
|
if (!q)
|
|
blk_cleanup_queue(uninit_q);
|
|
|
|
return q;
|
|
}
|
|
EXPORT_SYMBOL(blk_init_queue_node);
|
|
|
|
struct request_queue *
|
|
blk_init_allocated_queue(struct request_queue *q, request_fn_proc *rfn,
|
|
spinlock_t *lock)
|
|
{
|
|
return blk_init_allocated_queue_node(q, rfn, lock, -1);
|
|
}
|
|
EXPORT_SYMBOL(blk_init_allocated_queue);
|
|
|
|
struct request_queue *
|
|
blk_init_allocated_queue_node(struct request_queue *q, request_fn_proc *rfn,
|
|
spinlock_t *lock, int node_id)
|
|
{
|
|
if (!q)
|
|
return NULL;
|
|
|
|
q->node = node_id;
|
|
if (blk_init_free_list(q))
|
|
return NULL;
|
|
|
|
q->request_fn = rfn;
|
|
q->prep_rq_fn = NULL;
|
|
q->unprep_rq_fn = NULL;
|
|
q->unplug_fn = generic_unplug_device;
|
|
q->queue_flags = QUEUE_FLAG_DEFAULT;
|
|
q->queue_lock = lock;
|
|
|
|
/*
|
|
* This also sets hw/phys segments, boundary and size
|
|
*/
|
|
blk_queue_make_request(q, __make_request);
|
|
|
|
q->sg_reserved_size = INT_MAX;
|
|
|
|
/*
|
|
* all done
|
|
*/
|
|
if (!elevator_init(q, NULL)) {
|
|
blk_queue_congestion_threshold(q);
|
|
return q;
|
|
}
|
|
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL(blk_init_allocated_queue_node);
|
|
|
|
int blk_get_queue(struct request_queue *q)
|
|
{
|
|
if (likely(!test_bit(QUEUE_FLAG_DEAD, &q->queue_flags))) {
|
|
kobject_get(&q->kobj);
|
|
return 0;
|
|
}
|
|
|
|
return 1;
|
|
}
|
|
|
|
static inline void blk_free_request(struct request_queue *q, struct request *rq)
|
|
{
|
|
if (rq->cmd_flags & REQ_ELVPRIV)
|
|
elv_put_request(q, rq);
|
|
mempool_free(rq, q->rq.rq_pool);
|
|
}
|
|
|
|
static struct request *
|
|
blk_alloc_request(struct request_queue *q, int flags, int priv, gfp_t gfp_mask)
|
|
{
|
|
struct request *rq = mempool_alloc(q->rq.rq_pool, gfp_mask);
|
|
|
|
if (!rq)
|
|
return NULL;
|
|
|
|
blk_rq_init(q, rq);
|
|
|
|
rq->cmd_flags = flags | REQ_ALLOCED;
|
|
|
|
if (priv) {
|
|
if (unlikely(elv_set_request(q, rq, gfp_mask))) {
|
|
mempool_free(rq, q->rq.rq_pool);
|
|
return NULL;
|
|
}
|
|
rq->cmd_flags |= REQ_ELVPRIV;
|
|
}
|
|
|
|
return rq;
|
|
}
|
|
|
|
/*
|
|
* ioc_batching returns true if the ioc is a valid batching request and
|
|
* should be given priority access to a request.
|
|
*/
|
|
static inline int ioc_batching(struct request_queue *q, struct io_context *ioc)
|
|
{
|
|
if (!ioc)
|
|
return 0;
|
|
|
|
/*
|
|
* Make sure the process is able to allocate at least 1 request
|
|
* even if the batch times out, otherwise we could theoretically
|
|
* lose wakeups.
|
|
*/
|
|
return ioc->nr_batch_requests == q->nr_batching ||
|
|
(ioc->nr_batch_requests > 0
|
|
&& time_before(jiffies, ioc->last_waited + BLK_BATCH_TIME));
|
|
}
|
|
|
|
/*
|
|
* ioc_set_batching sets ioc to be a new "batcher" if it is not one. This
|
|
* will cause the process to be a "batcher" on all queues in the system. This
|
|
* is the behaviour we want though - once it gets a wakeup it should be given
|
|
* a nice run.
|
|
*/
|
|
static void ioc_set_batching(struct request_queue *q, struct io_context *ioc)
|
|
{
|
|
if (!ioc || ioc_batching(q, ioc))
|
|
return;
|
|
|
|
ioc->nr_batch_requests = q->nr_batching;
|
|
ioc->last_waited = jiffies;
|
|
}
|
|
|
|
static void __freed_request(struct request_queue *q, int sync)
|
|
{
|
|
struct request_list *rl = &q->rq;
|
|
|
|
if (rl->count[sync] < queue_congestion_off_threshold(q))
|
|
blk_clear_queue_congested(q, sync);
|
|
|
|
if (rl->count[sync] + 1 <= q->nr_requests) {
|
|
if (waitqueue_active(&rl->wait[sync]))
|
|
wake_up(&rl->wait[sync]);
|
|
|
|
blk_clear_queue_full(q, sync);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* A request has just been released. Account for it, update the full and
|
|
* congestion status, wake up any waiters. Called under q->queue_lock.
|
|
*/
|
|
static void freed_request(struct request_queue *q, int sync, int priv)
|
|
{
|
|
struct request_list *rl = &q->rq;
|
|
|
|
rl->count[sync]--;
|
|
if (priv)
|
|
rl->elvpriv--;
|
|
|
|
__freed_request(q, sync);
|
|
|
|
if (unlikely(rl->starved[sync ^ 1]))
|
|
__freed_request(q, sync ^ 1);
|
|
}
|
|
|
|
/*
|
|
* Get a free request, queue_lock must be held.
|
|
* Returns NULL on failure, with queue_lock held.
|
|
* Returns !NULL on success, with queue_lock *not held*.
|
|
*/
|
|
static struct request *get_request(struct request_queue *q, int rw_flags,
|
|
struct bio *bio, gfp_t gfp_mask)
|
|
{
|
|
struct request *rq = NULL;
|
|
struct request_list *rl = &q->rq;
|
|
struct io_context *ioc = NULL;
|
|
const bool is_sync = rw_is_sync(rw_flags) != 0;
|
|
int may_queue, priv;
|
|
|
|
may_queue = elv_may_queue(q, rw_flags);
|
|
if (may_queue == ELV_MQUEUE_NO)
|
|
goto rq_starved;
|
|
|
|
if (rl->count[is_sync]+1 >= queue_congestion_on_threshold(q)) {
|
|
if (rl->count[is_sync]+1 >= q->nr_requests) {
|
|
ioc = current_io_context(GFP_ATOMIC, q->node);
|
|
/*
|
|
* The queue will fill after this allocation, so set
|
|
* it as full, and mark this process as "batching".
|
|
* This process will be allowed to complete a batch of
|
|
* requests, others will be blocked.
|
|
*/
|
|
if (!blk_queue_full(q, is_sync)) {
|
|
ioc_set_batching(q, ioc);
|
|
blk_set_queue_full(q, is_sync);
|
|
} else {
|
|
if (may_queue != ELV_MQUEUE_MUST
|
|
&& !ioc_batching(q, ioc)) {
|
|
/*
|
|
* The queue is full and the allocating
|
|
* process is not a "batcher", and not
|
|
* exempted by the IO scheduler
|
|
*/
|
|
goto out;
|
|
}
|
|
}
|
|
}
|
|
blk_set_queue_congested(q, is_sync);
|
|
}
|
|
|
|
/*
|
|
* Only allow batching queuers to allocate up to 50% over the defined
|
|
* limit of requests, otherwise we could have thousands of requests
|
|
* allocated with any setting of ->nr_requests
|
|
*/
|
|
if (rl->count[is_sync] >= (3 * q->nr_requests / 2))
|
|
goto out;
|
|
|
|
rl->count[is_sync]++;
|
|
rl->starved[is_sync] = 0;
|
|
|
|
priv = !test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags);
|
|
if (priv) {
|
|
rl->elvpriv++;
|
|
|
|
/*
|
|
* Don't do stats for non-priv requests
|
|
*/
|
|
if (blk_queue_io_stat(q))
|
|
rw_flags |= REQ_IO_STAT;
|
|
}
|
|
|
|
spin_unlock_irq(q->queue_lock);
|
|
|
|
rq = blk_alloc_request(q, rw_flags, priv, gfp_mask);
|
|
if (unlikely(!rq)) {
|
|
/*
|
|
* Allocation failed presumably due to memory. Undo anything
|
|
* we might have messed up.
|
|
*
|
|
* Allocating task should really be put onto the front of the
|
|
* wait queue, but this is pretty rare.
|
|
*/
|
|
spin_lock_irq(q->queue_lock);
|
|
freed_request(q, is_sync, priv);
|
|
|
|
/*
|
|
* in the very unlikely event that allocation failed and no
|
|
* requests for this direction was pending, mark us starved
|
|
* so that freeing of a request in the other direction will
|
|
* notice us. another possible fix would be to split the
|
|
* rq mempool into READ and WRITE
|
|
*/
|
|
rq_starved:
|
|
if (unlikely(rl->count[is_sync] == 0))
|
|
rl->starved[is_sync] = 1;
|
|
|
|
goto out;
|
|
}
|
|
|
|
/*
|
|
* ioc may be NULL here, and ioc_batching will be false. That's
|
|
* OK, if the queue is under the request limit then requests need
|
|
* not count toward the nr_batch_requests limit. There will always
|
|
* be some limit enforced by BLK_BATCH_TIME.
|
|
*/
|
|
if (ioc_batching(q, ioc))
|
|
ioc->nr_batch_requests--;
|
|
|
|
trace_block_getrq(q, bio, rw_flags & 1);
|
|
out:
|
|
return rq;
|
|
}
|
|
|
|
/*
|
|
* No available requests for this queue, unplug the device and wait for some
|
|
* requests to become available.
|
|
*
|
|
* Called with q->queue_lock held, and returns with it unlocked.
|
|
*/
|
|
static struct request *get_request_wait(struct request_queue *q, int rw_flags,
|
|
struct bio *bio)
|
|
{
|
|
const bool is_sync = rw_is_sync(rw_flags) != 0;
|
|
struct request *rq;
|
|
|
|
rq = get_request(q, rw_flags, bio, GFP_NOIO);
|
|
while (!rq) {
|
|
DEFINE_WAIT(wait);
|
|
struct io_context *ioc;
|
|
struct request_list *rl = &q->rq;
|
|
|
|
prepare_to_wait_exclusive(&rl->wait[is_sync], &wait,
|
|
TASK_UNINTERRUPTIBLE);
|
|
|
|
trace_block_sleeprq(q, bio, rw_flags & 1);
|
|
|
|
__generic_unplug_device(q);
|
|
spin_unlock_irq(q->queue_lock);
|
|
io_schedule();
|
|
|
|
/*
|
|
* After sleeping, we become a "batching" process and
|
|
* will be able to allocate at least one request, and
|
|
* up to a big batch of them for a small period time.
|
|
* See ioc_batching, ioc_set_batching
|
|
*/
|
|
ioc = current_io_context(GFP_NOIO, q->node);
|
|
ioc_set_batching(q, ioc);
|
|
|
|
spin_lock_irq(q->queue_lock);
|
|
finish_wait(&rl->wait[is_sync], &wait);
|
|
|
|
rq = get_request(q, rw_flags, bio, GFP_NOIO);
|
|
};
|
|
|
|
return rq;
|
|
}
|
|
|
|
struct request *blk_get_request(struct request_queue *q, int rw, gfp_t gfp_mask)
|
|
{
|
|
struct request *rq;
|
|
|
|
BUG_ON(rw != READ && rw != WRITE);
|
|
|
|
spin_lock_irq(q->queue_lock);
|
|
if (gfp_mask & __GFP_WAIT) {
|
|
rq = get_request_wait(q, rw, NULL);
|
|
} else {
|
|
rq = get_request(q, rw, NULL, gfp_mask);
|
|
if (!rq)
|
|
spin_unlock_irq(q->queue_lock);
|
|
}
|
|
/* q->queue_lock is unlocked at this point */
|
|
|
|
return rq;
|
|
}
|
|
EXPORT_SYMBOL(blk_get_request);
|
|
|
|
/**
|
|
* blk_make_request - given a bio, allocate a corresponding struct request.
|
|
* @q: target request queue
|
|
* @bio: The bio describing the memory mappings that will be submitted for IO.
|
|
* It may be a chained-bio properly constructed by block/bio layer.
|
|
* @gfp_mask: gfp flags to be used for memory allocation
|
|
*
|
|
* blk_make_request is the parallel of generic_make_request for BLOCK_PC
|
|
* type commands. Where the struct request needs to be farther initialized by
|
|
* the caller. It is passed a &struct bio, which describes the memory info of
|
|
* the I/O transfer.
|
|
*
|
|
* The caller of blk_make_request must make sure that bi_io_vec
|
|
* are set to describe the memory buffers. That bio_data_dir() will return
|
|
* the needed direction of the request. (And all bio's in the passed bio-chain
|
|
* are properly set accordingly)
|
|
*
|
|
* If called under none-sleepable conditions, mapped bio buffers must not
|
|
* need bouncing, by calling the appropriate masked or flagged allocator,
|
|
* suitable for the target device. Otherwise the call to blk_queue_bounce will
|
|
* BUG.
|
|
*
|
|
* WARNING: When allocating/cloning a bio-chain, careful consideration should be
|
|
* given to how you allocate bios. In particular, you cannot use __GFP_WAIT for
|
|
* anything but the first bio in the chain. Otherwise you risk waiting for IO
|
|
* completion of a bio that hasn't been submitted yet, thus resulting in a
|
|
* deadlock. Alternatively bios should be allocated using bio_kmalloc() instead
|
|
* of bio_alloc(), as that avoids the mempool deadlock.
|
|
* If possible a big IO should be split into smaller parts when allocation
|
|
* fails. Partial allocation should not be an error, or you risk a live-lock.
|
|
*/
|
|
struct request *blk_make_request(struct request_queue *q, struct bio *bio,
|
|
gfp_t gfp_mask)
|
|
{
|
|
struct request *rq = blk_get_request(q, bio_data_dir(bio), gfp_mask);
|
|
|
|
if (unlikely(!rq))
|
|
return ERR_PTR(-ENOMEM);
|
|
|
|
for_each_bio(bio) {
|
|
struct bio *bounce_bio = bio;
|
|
int ret;
|
|
|
|
blk_queue_bounce(q, &bounce_bio);
|
|
ret = blk_rq_append_bio(q, rq, bounce_bio);
|
|
if (unlikely(ret)) {
|
|
blk_put_request(rq);
|
|
return ERR_PTR(ret);
|
|
}
|
|
}
|
|
|
|
return rq;
|
|
}
|
|
EXPORT_SYMBOL(blk_make_request);
|
|
|
|
/**
|
|
* blk_requeue_request - put a request back on queue
|
|
* @q: request queue where request should be inserted
|
|
* @rq: request to be inserted
|
|
*
|
|
* Description:
|
|
* Drivers often keep queueing requests until the hardware cannot accept
|
|
* more, when that condition happens we need to put the request back
|
|
* on the queue. Must be called with queue lock held.
|
|
*/
|
|
void blk_requeue_request(struct request_queue *q, struct request *rq)
|
|
{
|
|
blk_delete_timer(rq);
|
|
blk_clear_rq_complete(rq);
|
|
trace_block_rq_requeue(q, rq);
|
|
|
|
if (blk_rq_tagged(rq))
|
|
blk_queue_end_tag(q, rq);
|
|
|
|
BUG_ON(blk_queued_rq(rq));
|
|
|
|
elv_requeue_request(q, rq);
|
|
}
|
|
EXPORT_SYMBOL(blk_requeue_request);
|
|
|
|
/**
|
|
* blk_insert_request - insert a special request into a request queue
|
|
* @q: request queue where request should be inserted
|
|
* @rq: request to be inserted
|
|
* @at_head: insert request at head or tail of queue
|
|
* @data: private data
|
|
*
|
|
* Description:
|
|
* Many block devices need to execute commands asynchronously, so they don't
|
|
* block the whole kernel from preemption during request execution. This is
|
|
* accomplished normally by inserting aritficial requests tagged as
|
|
* REQ_TYPE_SPECIAL in to the corresponding request queue, and letting them
|
|
* be scheduled for actual execution by the request queue.
|
|
*
|
|
* We have the option of inserting the head or the tail of the queue.
|
|
* Typically we use the tail for new ioctls and so forth. We use the head
|
|
* of the queue for things like a QUEUE_FULL message from a device, or a
|
|
* host that is unable to accept a particular command.
|
|
*/
|
|
void blk_insert_request(struct request_queue *q, struct request *rq,
|
|
int at_head, void *data)
|
|
{
|
|
int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
|
|
unsigned long flags;
|
|
|
|
/*
|
|
* tell I/O scheduler that this isn't a regular read/write (ie it
|
|
* must not attempt merges on this) and that it acts as a soft
|
|
* barrier
|
|
*/
|
|
rq->cmd_type = REQ_TYPE_SPECIAL;
|
|
|
|
rq->special = data;
|
|
|
|
spin_lock_irqsave(q->queue_lock, flags);
|
|
|
|
/*
|
|
* If command is tagged, release the tag
|
|
*/
|
|
if (blk_rq_tagged(rq))
|
|
blk_queue_end_tag(q, rq);
|
|
|
|
drive_stat_acct(rq, 1);
|
|
__elv_add_request(q, rq, where, 0);
|
|
__blk_run_queue(q);
|
|
spin_unlock_irqrestore(q->queue_lock, flags);
|
|
}
|
|
EXPORT_SYMBOL(blk_insert_request);
|
|
|
|
static void part_round_stats_single(int cpu, struct hd_struct *part,
|
|
unsigned long now)
|
|
{
|
|
if (now == part->stamp)
|
|
return;
|
|
|
|
if (part_in_flight(part)) {
|
|
__part_stat_add(cpu, part, time_in_queue,
|
|
part_in_flight(part) * (now - part->stamp));
|
|
__part_stat_add(cpu, part, io_ticks, (now - part->stamp));
|
|
}
|
|
part->stamp = now;
|
|
}
|
|
|
|
/**
|
|
* part_round_stats() - Round off the performance stats on a struct disk_stats.
|
|
* @cpu: cpu number for stats access
|
|
* @part: target partition
|
|
*
|
|
* The average IO queue length and utilisation statistics are maintained
|
|
* by observing the current state of the queue length and the amount of
|
|
* time it has been in this state for.
|
|
*
|
|
* Normally, that accounting is done on IO completion, but that can result
|
|
* in more than a second's worth of IO being accounted for within any one
|
|
* second, leading to >100% utilisation. To deal with that, we call this
|
|
* function to do a round-off before returning the results when reading
|
|
* /proc/diskstats. This accounts immediately for all queue usage up to
|
|
* the current jiffies and restarts the counters again.
|
|
*/
|
|
void part_round_stats(int cpu, struct hd_struct *part)
|
|
{
|
|
unsigned long now = jiffies;
|
|
|
|
if (part->partno)
|
|
part_round_stats_single(cpu, &part_to_disk(part)->part0, now);
|
|
part_round_stats_single(cpu, part, now);
|
|
}
|
|
EXPORT_SYMBOL_GPL(part_round_stats);
|
|
|
|
/*
|
|
* queue lock must be held
|
|
*/
|
|
void __blk_put_request(struct request_queue *q, struct request *req)
|
|
{
|
|
if (unlikely(!q))
|
|
return;
|
|
if (unlikely(--req->ref_count))
|
|
return;
|
|
|
|
elv_completed_request(q, req);
|
|
|
|
/* this is a bio leak */
|
|
WARN_ON(req->bio != NULL);
|
|
|
|
/*
|
|
* Request may not have originated from ll_rw_blk. if not,
|
|
* it didn't come out of our reserved rq pools
|
|
*/
|
|
if (req->cmd_flags & REQ_ALLOCED) {
|
|
int is_sync = rq_is_sync(req) != 0;
|
|
int priv = req->cmd_flags & REQ_ELVPRIV;
|
|
|
|
BUG_ON(!list_empty(&req->queuelist));
|
|
BUG_ON(!hlist_unhashed(&req->hash));
|
|
|
|
blk_free_request(q, req);
|
|
freed_request(q, is_sync, priv);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(__blk_put_request);
|
|
|
|
void blk_put_request(struct request *req)
|
|
{
|
|
unsigned long flags;
|
|
struct request_queue *q = req->q;
|
|
|
|
spin_lock_irqsave(q->queue_lock, flags);
|
|
__blk_put_request(q, req);
|
|
spin_unlock_irqrestore(q->queue_lock, flags);
|
|
}
|
|
EXPORT_SYMBOL(blk_put_request);
|
|
|
|
/**
|
|
* blk_add_request_payload - add a payload to a request
|
|
* @rq: request to update
|
|
* @page: page backing the payload
|
|
* @len: length of the payload.
|
|
*
|
|
* This allows to later add a payload to an already submitted request by
|
|
* a block driver. The driver needs to take care of freeing the payload
|
|
* itself.
|
|
*
|
|
* Note that this is a quite horrible hack and nothing but handling of
|
|
* discard requests should ever use it.
|
|
*/
|
|
void blk_add_request_payload(struct request *rq, struct page *page,
|
|
unsigned int len)
|
|
{
|
|
struct bio *bio = rq->bio;
|
|
|
|
bio->bi_io_vec->bv_page = page;
|
|
bio->bi_io_vec->bv_offset = 0;
|
|
bio->bi_io_vec->bv_len = len;
|
|
|
|
bio->bi_size = len;
|
|
bio->bi_vcnt = 1;
|
|
bio->bi_phys_segments = 1;
|
|
|
|
rq->__data_len = rq->resid_len = len;
|
|
rq->nr_phys_segments = 1;
|
|
rq->buffer = bio_data(bio);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_add_request_payload);
|
|
|
|
void init_request_from_bio(struct request *req, struct bio *bio)
|
|
{
|
|
req->cpu = bio->bi_comp_cpu;
|
|
req->cmd_type = REQ_TYPE_FS;
|
|
|
|
req->cmd_flags |= bio->bi_rw & REQ_COMMON_MASK;
|
|
if (bio->bi_rw & REQ_RAHEAD)
|
|
req->cmd_flags |= REQ_FAILFAST_MASK;
|
|
|
|
req->errors = 0;
|
|
req->__sector = bio->bi_sector;
|
|
req->ioprio = bio_prio(bio);
|
|
blk_rq_bio_prep(req->q, req, bio);
|
|
}
|
|
|
|
/*
|
|
* Only disabling plugging for non-rotational devices if it does tagging
|
|
* as well, otherwise we do need the proper merging
|
|
*/
|
|
static inline bool queue_should_plug(struct request_queue *q)
|
|
{
|
|
return !(blk_queue_nonrot(q) && blk_queue_tagged(q));
|
|
}
|
|
|
|
static int __make_request(struct request_queue *q, struct bio *bio)
|
|
{
|
|
struct request *req;
|
|
int el_ret;
|
|
unsigned int bytes = bio->bi_size;
|
|
const unsigned short prio = bio_prio(bio);
|
|
const bool sync = !!(bio->bi_rw & REQ_SYNC);
|
|
const bool unplug = !!(bio->bi_rw & REQ_UNPLUG);
|
|
const unsigned long ff = bio->bi_rw & REQ_FAILFAST_MASK;
|
|
int where = ELEVATOR_INSERT_SORT;
|
|
int rw_flags;
|
|
|
|
/* REQ_HARDBARRIER is no more */
|
|
if (WARN_ONCE(bio->bi_rw & REQ_HARDBARRIER,
|
|
"block: HARDBARRIER is deprecated, use FLUSH/FUA instead\n")) {
|
|
bio_endio(bio, -EOPNOTSUPP);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* low level driver can indicate that it wants pages above a
|
|
* certain limit bounced to low memory (ie for highmem, or even
|
|
* ISA dma in theory)
|
|
*/
|
|
blk_queue_bounce(q, &bio);
|
|
|
|
spin_lock_irq(q->queue_lock);
|
|
|
|
if (bio->bi_rw & (REQ_FLUSH | REQ_FUA)) {
|
|
where = ELEVATOR_INSERT_FRONT;
|
|
goto get_rq;
|
|
}
|
|
|
|
if (elv_queue_empty(q))
|
|
goto get_rq;
|
|
|
|
el_ret = elv_merge(q, &req, bio);
|
|
switch (el_ret) {
|
|
case ELEVATOR_BACK_MERGE:
|
|
BUG_ON(!rq_mergeable(req));
|
|
|
|
if (!ll_back_merge_fn(q, req, bio))
|
|
break;
|
|
|
|
trace_block_bio_backmerge(q, bio);
|
|
|
|
if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff)
|
|
blk_rq_set_mixed_merge(req);
|
|
|
|
req->biotail->bi_next = bio;
|
|
req->biotail = bio;
|
|
req->__data_len += bytes;
|
|
req->ioprio = ioprio_best(req->ioprio, prio);
|
|
if (!blk_rq_cpu_valid(req))
|
|
req->cpu = bio->bi_comp_cpu;
|
|
drive_stat_acct(req, 0);
|
|
elv_bio_merged(q, req, bio);
|
|
if (!attempt_back_merge(q, req))
|
|
elv_merged_request(q, req, el_ret);
|
|
goto out;
|
|
|
|
case ELEVATOR_FRONT_MERGE:
|
|
BUG_ON(!rq_mergeable(req));
|
|
|
|
if (!ll_front_merge_fn(q, req, bio))
|
|
break;
|
|
|
|
trace_block_bio_frontmerge(q, bio);
|
|
|
|
if ((req->cmd_flags & REQ_FAILFAST_MASK) != ff) {
|
|
blk_rq_set_mixed_merge(req);
|
|
req->cmd_flags &= ~REQ_FAILFAST_MASK;
|
|
req->cmd_flags |= ff;
|
|
}
|
|
|
|
bio->bi_next = req->bio;
|
|
req->bio = bio;
|
|
|
|
/*
|
|
* may not be valid. if the low level driver said
|
|
* it didn't need a bounce buffer then it better
|
|
* not touch req->buffer either...
|
|
*/
|
|
req->buffer = bio_data(bio);
|
|
req->__sector = bio->bi_sector;
|
|
req->__data_len += bytes;
|
|
req->ioprio = ioprio_best(req->ioprio, prio);
|
|
if (!blk_rq_cpu_valid(req))
|
|
req->cpu = bio->bi_comp_cpu;
|
|
drive_stat_acct(req, 0);
|
|
elv_bio_merged(q, req, bio);
|
|
if (!attempt_front_merge(q, req))
|
|
elv_merged_request(q, req, el_ret);
|
|
goto out;
|
|
|
|
/* ELV_NO_MERGE: elevator says don't/can't merge. */
|
|
default:
|
|
;
|
|
}
|
|
|
|
get_rq:
|
|
/*
|
|
* This sync check and mask will be re-done in init_request_from_bio(),
|
|
* but we need to set it earlier to expose the sync flag to the
|
|
* rq allocator and io schedulers.
|
|
*/
|
|
rw_flags = bio_data_dir(bio);
|
|
if (sync)
|
|
rw_flags |= REQ_SYNC;
|
|
|
|
/*
|
|
* Grab a free request. This is might sleep but can not fail.
|
|
* Returns with the queue unlocked.
|
|
*/
|
|
req = get_request_wait(q, rw_flags, bio);
|
|
|
|
/*
|
|
* After dropping the lock and possibly sleeping here, our request
|
|
* may now be mergeable after it had proven unmergeable (above).
|
|
* We don't worry about that case for efficiency. It won't happen
|
|
* often, and the elevators are able to handle it.
|
|
*/
|
|
init_request_from_bio(req, bio);
|
|
|
|
spin_lock_irq(q->queue_lock);
|
|
if (test_bit(QUEUE_FLAG_SAME_COMP, &q->queue_flags) ||
|
|
bio_flagged(bio, BIO_CPU_AFFINE))
|
|
req->cpu = blk_cpu_to_group(smp_processor_id());
|
|
if (queue_should_plug(q) && elv_queue_empty(q))
|
|
blk_plug_device(q);
|
|
|
|
/* insert the request into the elevator */
|
|
drive_stat_acct(req, 1);
|
|
__elv_add_request(q, req, where, 0);
|
|
out:
|
|
if (unplug || !queue_should_plug(q))
|
|
__generic_unplug_device(q);
|
|
spin_unlock_irq(q->queue_lock);
|
|
return 0;
|
|
}
|
|
|
|
/*
|
|
* If bio->bi_dev is a partition, remap the location
|
|
*/
|
|
static inline void blk_partition_remap(struct bio *bio)
|
|
{
|
|
struct block_device *bdev = bio->bi_bdev;
|
|
|
|
if (bio_sectors(bio) && bdev != bdev->bd_contains) {
|
|
struct hd_struct *p = bdev->bd_part;
|
|
|
|
bio->bi_sector += p->start_sect;
|
|
bio->bi_bdev = bdev->bd_contains;
|
|
|
|
trace_block_remap(bdev_get_queue(bio->bi_bdev), bio,
|
|
bdev->bd_dev,
|
|
bio->bi_sector - p->start_sect);
|
|
}
|
|
}
|
|
|
|
static void handle_bad_sector(struct bio *bio)
|
|
{
|
|
char b[BDEVNAME_SIZE];
|
|
|
|
printk(KERN_INFO "attempt to access beyond end of device\n");
|
|
printk(KERN_INFO "%s: rw=%ld, want=%Lu, limit=%Lu\n",
|
|
bdevname(bio->bi_bdev, b),
|
|
bio->bi_rw,
|
|
(unsigned long long)bio->bi_sector + bio_sectors(bio),
|
|
(long long)(bio->bi_bdev->bd_inode->i_size >> 9));
|
|
|
|
set_bit(BIO_EOF, &bio->bi_flags);
|
|
}
|
|
|
|
#ifdef CONFIG_FAIL_MAKE_REQUEST
|
|
|
|
static DECLARE_FAULT_ATTR(fail_make_request);
|
|
|
|
static int __init setup_fail_make_request(char *str)
|
|
{
|
|
return setup_fault_attr(&fail_make_request, str);
|
|
}
|
|
__setup("fail_make_request=", setup_fail_make_request);
|
|
|
|
static int should_fail_request(struct bio *bio)
|
|
{
|
|
struct hd_struct *part = bio->bi_bdev->bd_part;
|
|
|
|
if (part_to_disk(part)->part0.make_it_fail || part->make_it_fail)
|
|
return should_fail(&fail_make_request, bio->bi_size);
|
|
|
|
return 0;
|
|
}
|
|
|
|
static int __init fail_make_request_debugfs(void)
|
|
{
|
|
return init_fault_attr_dentries(&fail_make_request,
|
|
"fail_make_request");
|
|
}
|
|
|
|
late_initcall(fail_make_request_debugfs);
|
|
|
|
#else /* CONFIG_FAIL_MAKE_REQUEST */
|
|
|
|
static inline int should_fail_request(struct bio *bio)
|
|
{
|
|
return 0;
|
|
}
|
|
|
|
#endif /* CONFIG_FAIL_MAKE_REQUEST */
|
|
|
|
/*
|
|
* Check whether this bio extends beyond the end of the device.
|
|
*/
|
|
static inline int bio_check_eod(struct bio *bio, unsigned int nr_sectors)
|
|
{
|
|
sector_t maxsector;
|
|
|
|
if (!nr_sectors)
|
|
return 0;
|
|
|
|
/* Test device or partition size, when known. */
|
|
maxsector = bio->bi_bdev->bd_inode->i_size >> 9;
|
|
if (maxsector) {
|
|
sector_t sector = bio->bi_sector;
|
|
|
|
if (maxsector < nr_sectors || maxsector - nr_sectors < sector) {
|
|
/*
|
|
* This may well happen - the kernel calls bread()
|
|
* without checking the size of the device, e.g., when
|
|
* mounting a device.
|
|
*/
|
|
handle_bad_sector(bio);
|
|
return 1;
|
|
}
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* generic_make_request - hand a buffer to its device driver for I/O
|
|
* @bio: The bio describing the location in memory and on the device.
|
|
*
|
|
* generic_make_request() is used to make I/O requests of block
|
|
* devices. It is passed a &struct bio, which describes the I/O that needs
|
|
* to be done.
|
|
*
|
|
* generic_make_request() does not return any status. The
|
|
* success/failure status of the request, along with notification of
|
|
* completion, is delivered asynchronously through the bio->bi_end_io
|
|
* function described (one day) else where.
|
|
*
|
|
* The caller of generic_make_request must make sure that bi_io_vec
|
|
* are set to describe the memory buffer, and that bi_dev and bi_sector are
|
|
* set to describe the device address, and the
|
|
* bi_end_io and optionally bi_private are set to describe how
|
|
* completion notification should be signaled.
|
|
*
|
|
* generic_make_request and the drivers it calls may use bi_next if this
|
|
* bio happens to be merged with someone else, and may change bi_dev and
|
|
* bi_sector for remaps as it sees fit. So the values of these fields
|
|
* should NOT be depended on after the call to generic_make_request.
|
|
*/
|
|
static inline void __generic_make_request(struct bio *bio)
|
|
{
|
|
struct request_queue *q;
|
|
sector_t old_sector;
|
|
int ret, nr_sectors = bio_sectors(bio);
|
|
dev_t old_dev;
|
|
int err = -EIO;
|
|
|
|
might_sleep();
|
|
|
|
if (bio_check_eod(bio, nr_sectors))
|
|
goto end_io;
|
|
|
|
/*
|
|
* Resolve the mapping until finished. (drivers are
|
|
* still free to implement/resolve their own stacking
|
|
* by explicitly returning 0)
|
|
*
|
|
* NOTE: we don't repeat the blk_size check for each new device.
|
|
* Stacking drivers are expected to know what they are doing.
|
|
*/
|
|
old_sector = -1;
|
|
old_dev = 0;
|
|
do {
|
|
char b[BDEVNAME_SIZE];
|
|
|
|
q = bdev_get_queue(bio->bi_bdev);
|
|
if (unlikely(!q)) {
|
|
printk(KERN_ERR
|
|
"generic_make_request: Trying to access "
|
|
"nonexistent block-device %s (%Lu)\n",
|
|
bdevname(bio->bi_bdev, b),
|
|
(long long) bio->bi_sector);
|
|
goto end_io;
|
|
}
|
|
|
|
if (unlikely(!(bio->bi_rw & REQ_DISCARD) &&
|
|
nr_sectors > queue_max_hw_sectors(q))) {
|
|
printk(KERN_ERR "bio too big device %s (%u > %u)\n",
|
|
bdevname(bio->bi_bdev, b),
|
|
bio_sectors(bio),
|
|
queue_max_hw_sectors(q));
|
|
goto end_io;
|
|
}
|
|
|
|
if (unlikely(test_bit(QUEUE_FLAG_DEAD, &q->queue_flags)))
|
|
goto end_io;
|
|
|
|
if (should_fail_request(bio))
|
|
goto end_io;
|
|
|
|
/*
|
|
* If this device has partitions, remap block n
|
|
* of partition p to block n+start(p) of the disk.
|
|
*/
|
|
blk_partition_remap(bio);
|
|
|
|
if (bio_integrity_enabled(bio) && bio_integrity_prep(bio))
|
|
goto end_io;
|
|
|
|
if (old_sector != -1)
|
|
trace_block_remap(q, bio, old_dev, old_sector);
|
|
|
|
old_sector = bio->bi_sector;
|
|
old_dev = bio->bi_bdev->bd_dev;
|
|
|
|
if (bio_check_eod(bio, nr_sectors))
|
|
goto end_io;
|
|
|
|
/*
|
|
* Filter flush bio's early so that make_request based
|
|
* drivers without flush support don't have to worry
|
|
* about them.
|
|
*/
|
|
if ((bio->bi_rw & (REQ_FLUSH | REQ_FUA)) && !q->flush_flags) {
|
|
bio->bi_rw &= ~(REQ_FLUSH | REQ_FUA);
|
|
if (!nr_sectors) {
|
|
err = 0;
|
|
goto end_io;
|
|
}
|
|
}
|
|
|
|
if ((bio->bi_rw & REQ_DISCARD) &&
|
|
(!blk_queue_discard(q) ||
|
|
((bio->bi_rw & REQ_SECURE) &&
|
|
!blk_queue_secdiscard(q)))) {
|
|
err = -EOPNOTSUPP;
|
|
goto end_io;
|
|
}
|
|
|
|
blk_throtl_bio(q, &bio);
|
|
|
|
/*
|
|
* If bio = NULL, bio has been throttled and will be submitted
|
|
* later.
|
|
*/
|
|
if (!bio)
|
|
break;
|
|
|
|
trace_block_bio_queue(q, bio);
|
|
|
|
ret = q->make_request_fn(q, bio);
|
|
} while (ret);
|
|
|
|
return;
|
|
|
|
end_io:
|
|
bio_endio(bio, err);
|
|
}
|
|
|
|
/*
|
|
* We only want one ->make_request_fn to be active at a time,
|
|
* else stack usage with stacked devices could be a problem.
|
|
* So use current->bio_list to keep a list of requests
|
|
* submited by a make_request_fn function.
|
|
* current->bio_list is also used as a flag to say if
|
|
* generic_make_request is currently active in this task or not.
|
|
* If it is NULL, then no make_request is active. If it is non-NULL,
|
|
* then a make_request is active, and new requests should be added
|
|
* at the tail
|
|
*/
|
|
void generic_make_request(struct bio *bio)
|
|
{
|
|
struct bio_list bio_list_on_stack;
|
|
|
|
if (current->bio_list) {
|
|
/* make_request is active */
|
|
bio_list_add(current->bio_list, bio);
|
|
return;
|
|
}
|
|
/* following loop may be a bit non-obvious, and so deserves some
|
|
* explanation.
|
|
* Before entering the loop, bio->bi_next is NULL (as all callers
|
|
* ensure that) so we have a list with a single bio.
|
|
* We pretend that we have just taken it off a longer list, so
|
|
* we assign bio_list to a pointer to the bio_list_on_stack,
|
|
* thus initialising the bio_list of new bios to be
|
|
* added. __generic_make_request may indeed add some more bios
|
|
* through a recursive call to generic_make_request. If it
|
|
* did, we find a non-NULL value in bio_list and re-enter the loop
|
|
* from the top. In this case we really did just take the bio
|
|
* of the top of the list (no pretending) and so remove it from
|
|
* bio_list, and call into __generic_make_request again.
|
|
*
|
|
* The loop was structured like this to make only one call to
|
|
* __generic_make_request (which is important as it is large and
|
|
* inlined) and to keep the structure simple.
|
|
*/
|
|
BUG_ON(bio->bi_next);
|
|
bio_list_init(&bio_list_on_stack);
|
|
current->bio_list = &bio_list_on_stack;
|
|
do {
|
|
__generic_make_request(bio);
|
|
bio = bio_list_pop(current->bio_list);
|
|
} while (bio);
|
|
current->bio_list = NULL; /* deactivate */
|
|
}
|
|
EXPORT_SYMBOL(generic_make_request);
|
|
|
|
/**
|
|
* submit_bio - submit a bio to the block device layer for I/O
|
|
* @rw: whether to %READ or %WRITE, or maybe to %READA (read ahead)
|
|
* @bio: The &struct bio which describes the I/O
|
|
*
|
|
* submit_bio() is very similar in purpose to generic_make_request(), and
|
|
* uses that function to do most of the work. Both are fairly rough
|
|
* interfaces; @bio must be presetup and ready for I/O.
|
|
*
|
|
*/
|
|
void submit_bio(int rw, struct bio *bio)
|
|
{
|
|
int count = bio_sectors(bio);
|
|
|
|
bio->bi_rw |= rw;
|
|
|
|
/*
|
|
* If it's a regular read/write or a barrier with data attached,
|
|
* go through the normal accounting stuff before submission.
|
|
*/
|
|
if (bio_has_data(bio) && !(rw & REQ_DISCARD)) {
|
|
if (rw & WRITE) {
|
|
count_vm_events(PGPGOUT, count);
|
|
} else {
|
|
task_io_account_read(bio->bi_size);
|
|
count_vm_events(PGPGIN, count);
|
|
}
|
|
|
|
if (unlikely(block_dump)) {
|
|
char b[BDEVNAME_SIZE];
|
|
printk(KERN_DEBUG "%s(%d): %s block %Lu on %s (%u sectors)\n",
|
|
current->comm, task_pid_nr(current),
|
|
(rw & WRITE) ? "WRITE" : "READ",
|
|
(unsigned long long)bio->bi_sector,
|
|
bdevname(bio->bi_bdev, b),
|
|
count);
|
|
}
|
|
}
|
|
|
|
generic_make_request(bio);
|
|
}
|
|
EXPORT_SYMBOL(submit_bio);
|
|
|
|
/**
|
|
* blk_rq_check_limits - Helper function to check a request for the queue limit
|
|
* @q: the queue
|
|
* @rq: the request being checked
|
|
*
|
|
* Description:
|
|
* @rq may have been made based on weaker limitations of upper-level queues
|
|
* in request stacking drivers, and it may violate the limitation of @q.
|
|
* Since the block layer and the underlying device driver trust @rq
|
|
* after it is inserted to @q, it should be checked against @q before
|
|
* the insertion using this generic function.
|
|
*
|
|
* This function should also be useful for request stacking drivers
|
|
* in some cases below, so export this function.
|
|
* Request stacking drivers like request-based dm may change the queue
|
|
* limits while requests are in the queue (e.g. dm's table swapping).
|
|
* Such request stacking drivers should check those requests agaist
|
|
* the new queue limits again when they dispatch those requests,
|
|
* although such checkings are also done against the old queue limits
|
|
* when submitting requests.
|
|
*/
|
|
int blk_rq_check_limits(struct request_queue *q, struct request *rq)
|
|
{
|
|
if (rq->cmd_flags & REQ_DISCARD)
|
|
return 0;
|
|
|
|
if (blk_rq_sectors(rq) > queue_max_sectors(q) ||
|
|
blk_rq_bytes(rq) > queue_max_hw_sectors(q) << 9) {
|
|
printk(KERN_ERR "%s: over max size limit.\n", __func__);
|
|
return -EIO;
|
|
}
|
|
|
|
/*
|
|
* queue's settings related to segment counting like q->bounce_pfn
|
|
* may differ from that of other stacking queues.
|
|
* Recalculate it to check the request correctly on this queue's
|
|
* limitation.
|
|
*/
|
|
blk_recalc_rq_segments(rq);
|
|
if (rq->nr_phys_segments > queue_max_segments(q)) {
|
|
printk(KERN_ERR "%s: over max segments limit.\n", __func__);
|
|
return -EIO;
|
|
}
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_rq_check_limits);
|
|
|
|
/**
|
|
* blk_insert_cloned_request - Helper for stacking drivers to submit a request
|
|
* @q: the queue to submit the request
|
|
* @rq: the request being queued
|
|
*/
|
|
int blk_insert_cloned_request(struct request_queue *q, struct request *rq)
|
|
{
|
|
unsigned long flags;
|
|
|
|
if (blk_rq_check_limits(q, rq))
|
|
return -EIO;
|
|
|
|
#ifdef CONFIG_FAIL_MAKE_REQUEST
|
|
if (rq->rq_disk && rq->rq_disk->part0.make_it_fail &&
|
|
should_fail(&fail_make_request, blk_rq_bytes(rq)))
|
|
return -EIO;
|
|
#endif
|
|
|
|
spin_lock_irqsave(q->queue_lock, flags);
|
|
|
|
/*
|
|
* Submitting request must be dequeued before calling this function
|
|
* because it will be linked to another request_queue
|
|
*/
|
|
BUG_ON(blk_queued_rq(rq));
|
|
|
|
drive_stat_acct(rq, 1);
|
|
__elv_add_request(q, rq, ELEVATOR_INSERT_BACK, 0);
|
|
|
|
spin_unlock_irqrestore(q->queue_lock, flags);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_insert_cloned_request);
|
|
|
|
/**
|
|
* blk_rq_err_bytes - determine number of bytes till the next failure boundary
|
|
* @rq: request to examine
|
|
*
|
|
* Description:
|
|
* A request could be merge of IOs which require different failure
|
|
* handling. This function determines the number of bytes which
|
|
* can be failed from the beginning of the request without
|
|
* crossing into area which need to be retried further.
|
|
*
|
|
* Return:
|
|
* The number of bytes to fail.
|
|
*
|
|
* Context:
|
|
* queue_lock must be held.
|
|
*/
|
|
unsigned int blk_rq_err_bytes(const struct request *rq)
|
|
{
|
|
unsigned int ff = rq->cmd_flags & REQ_FAILFAST_MASK;
|
|
unsigned int bytes = 0;
|
|
struct bio *bio;
|
|
|
|
if (!(rq->cmd_flags & REQ_MIXED_MERGE))
|
|
return blk_rq_bytes(rq);
|
|
|
|
/*
|
|
* Currently the only 'mixing' which can happen is between
|
|
* different fastfail types. We can safely fail portions
|
|
* which have all the failfast bits that the first one has -
|
|
* the ones which are at least as eager to fail as the first
|
|
* one.
|
|
*/
|
|
for (bio = rq->bio; bio; bio = bio->bi_next) {
|
|
if ((bio->bi_rw & ff) != ff)
|
|
break;
|
|
bytes += bio->bi_size;
|
|
}
|
|
|
|
/* this could lead to infinite loop */
|
|
BUG_ON(blk_rq_bytes(rq) && !bytes);
|
|
return bytes;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_rq_err_bytes);
|
|
|
|
static void blk_account_io_completion(struct request *req, unsigned int bytes)
|
|
{
|
|
if (blk_do_io_stat(req)) {
|
|
const int rw = rq_data_dir(req);
|
|
struct hd_struct *part;
|
|
int cpu;
|
|
|
|
cpu = part_stat_lock();
|
|
part = req->part;
|
|
part_stat_add(cpu, part, sectors[rw], bytes >> 9);
|
|
part_stat_unlock();
|
|
}
|
|
}
|
|
|
|
static void blk_account_io_done(struct request *req)
|
|
{
|
|
/*
|
|
* Account IO completion. flush_rq isn't accounted as a
|
|
* normal IO on queueing nor completion. Accounting the
|
|
* containing request is enough.
|
|
*/
|
|
if (blk_do_io_stat(req) && req != &req->q->flush_rq) {
|
|
unsigned long duration = jiffies - req->start_time;
|
|
const int rw = rq_data_dir(req);
|
|
struct hd_struct *part;
|
|
int cpu;
|
|
|
|
cpu = part_stat_lock();
|
|
part = req->part;
|
|
|
|
part_stat_inc(cpu, part, ios[rw]);
|
|
part_stat_add(cpu, part, ticks[rw], duration);
|
|
part_round_stats(cpu, part);
|
|
part_dec_in_flight(part, rw);
|
|
|
|
part_stat_unlock();
|
|
}
|
|
}
|
|
|
|
/**
|
|
* blk_peek_request - peek at the top of a request queue
|
|
* @q: request queue to peek at
|
|
*
|
|
* Description:
|
|
* Return the request at the top of @q. The returned request
|
|
* should be started using blk_start_request() before LLD starts
|
|
* processing it.
|
|
*
|
|
* Return:
|
|
* Pointer to the request at the top of @q if available. Null
|
|
* otherwise.
|
|
*
|
|
* Context:
|
|
* queue_lock must be held.
|
|
*/
|
|
struct request *blk_peek_request(struct request_queue *q)
|
|
{
|
|
struct request *rq;
|
|
int ret;
|
|
|
|
while ((rq = __elv_next_request(q)) != NULL) {
|
|
if (!(rq->cmd_flags & REQ_STARTED)) {
|
|
/*
|
|
* This is the first time the device driver
|
|
* sees this request (possibly after
|
|
* requeueing). Notify IO scheduler.
|
|
*/
|
|
if (rq->cmd_flags & REQ_SORTED)
|
|
elv_activate_rq(q, rq);
|
|
|
|
/*
|
|
* just mark as started even if we don't start
|
|
* it, a request that has been delayed should
|
|
* not be passed by new incoming requests
|
|
*/
|
|
rq->cmd_flags |= REQ_STARTED;
|
|
trace_block_rq_issue(q, rq);
|
|
}
|
|
|
|
if (!q->boundary_rq || q->boundary_rq == rq) {
|
|
q->end_sector = rq_end_sector(rq);
|
|
q->boundary_rq = NULL;
|
|
}
|
|
|
|
if (rq->cmd_flags & REQ_DONTPREP)
|
|
break;
|
|
|
|
if (q->dma_drain_size && blk_rq_bytes(rq)) {
|
|
/*
|
|
* make sure space for the drain appears we
|
|
* know we can do this because max_hw_segments
|
|
* has been adjusted to be one fewer than the
|
|
* device can handle
|
|
*/
|
|
rq->nr_phys_segments++;
|
|
}
|
|
|
|
if (!q->prep_rq_fn)
|
|
break;
|
|
|
|
ret = q->prep_rq_fn(q, rq);
|
|
if (ret == BLKPREP_OK) {
|
|
break;
|
|
} else if (ret == BLKPREP_DEFER) {
|
|
/*
|
|
* the request may have been (partially) prepped.
|
|
* we need to keep this request in the front to
|
|
* avoid resource deadlock. REQ_STARTED will
|
|
* prevent other fs requests from passing this one.
|
|
*/
|
|
if (q->dma_drain_size && blk_rq_bytes(rq) &&
|
|
!(rq->cmd_flags & REQ_DONTPREP)) {
|
|
/*
|
|
* remove the space for the drain we added
|
|
* so that we don't add it again
|
|
*/
|
|
--rq->nr_phys_segments;
|
|
}
|
|
|
|
rq = NULL;
|
|
break;
|
|
} else if (ret == BLKPREP_KILL) {
|
|
rq->cmd_flags |= REQ_QUIET;
|
|
/*
|
|
* Mark this request as started so we don't trigger
|
|
* any debug logic in the end I/O path.
|
|
*/
|
|
blk_start_request(rq);
|
|
__blk_end_request_all(rq, -EIO);
|
|
} else {
|
|
printk(KERN_ERR "%s: bad return=%d\n", __func__, ret);
|
|
break;
|
|
}
|
|
}
|
|
|
|
return rq;
|
|
}
|
|
EXPORT_SYMBOL(blk_peek_request);
|
|
|
|
void blk_dequeue_request(struct request *rq)
|
|
{
|
|
struct request_queue *q = rq->q;
|
|
|
|
BUG_ON(list_empty(&rq->queuelist));
|
|
BUG_ON(ELV_ON_HASH(rq));
|
|
|
|
list_del_init(&rq->queuelist);
|
|
|
|
/*
|
|
* the time frame between a request being removed from the lists
|
|
* and to it is freed is accounted as io that is in progress at
|
|
* the driver side.
|
|
*/
|
|
if (blk_account_rq(rq)) {
|
|
q->in_flight[rq_is_sync(rq)]++;
|
|
set_io_start_time_ns(rq);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* blk_start_request - start request processing on the driver
|
|
* @req: request to dequeue
|
|
*
|
|
* Description:
|
|
* Dequeue @req and start timeout timer on it. This hands off the
|
|
* request to the driver.
|
|
*
|
|
* Block internal functions which don't want to start timer should
|
|
* call blk_dequeue_request().
|
|
*
|
|
* Context:
|
|
* queue_lock must be held.
|
|
*/
|
|
void blk_start_request(struct request *req)
|
|
{
|
|
blk_dequeue_request(req);
|
|
|
|
/*
|
|
* We are now handing the request to the hardware, initialize
|
|
* resid_len to full count and add the timeout handler.
|
|
*/
|
|
req->resid_len = blk_rq_bytes(req);
|
|
if (unlikely(blk_bidi_rq(req)))
|
|
req->next_rq->resid_len = blk_rq_bytes(req->next_rq);
|
|
|
|
blk_add_timer(req);
|
|
}
|
|
EXPORT_SYMBOL(blk_start_request);
|
|
|
|
/**
|
|
* blk_fetch_request - fetch a request from a request queue
|
|
* @q: request queue to fetch a request from
|
|
*
|
|
* Description:
|
|
* Return the request at the top of @q. The request is started on
|
|
* return and LLD can start processing it immediately.
|
|
*
|
|
* Return:
|
|
* Pointer to the request at the top of @q if available. Null
|
|
* otherwise.
|
|
*
|
|
* Context:
|
|
* queue_lock must be held.
|
|
*/
|
|
struct request *blk_fetch_request(struct request_queue *q)
|
|
{
|
|
struct request *rq;
|
|
|
|
rq = blk_peek_request(q);
|
|
if (rq)
|
|
blk_start_request(rq);
|
|
return rq;
|
|
}
|
|
EXPORT_SYMBOL(blk_fetch_request);
|
|
|
|
/**
|
|
* blk_update_request - Special helper function for request stacking drivers
|
|
* @req: the request being processed
|
|
* @error: %0 for success, < %0 for error
|
|
* @nr_bytes: number of bytes to complete @req
|
|
*
|
|
* Description:
|
|
* Ends I/O on a number of bytes attached to @req, but doesn't complete
|
|
* the request structure even if @req doesn't have leftover.
|
|
* If @req has leftover, sets it up for the next range of segments.
|
|
*
|
|
* This special helper function is only for request stacking drivers
|
|
* (e.g. request-based dm) so that they can handle partial completion.
|
|
* Actual device drivers should use blk_end_request instead.
|
|
*
|
|
* Passing the result of blk_rq_bytes() as @nr_bytes guarantees
|
|
* %false return from this function.
|
|
*
|
|
* Return:
|
|
* %false - this request doesn't have any more data
|
|
* %true - this request has more data
|
|
**/
|
|
bool blk_update_request(struct request *req, int error, unsigned int nr_bytes)
|
|
{
|
|
int total_bytes, bio_nbytes, next_idx = 0;
|
|
struct bio *bio;
|
|
|
|
if (!req->bio)
|
|
return false;
|
|
|
|
trace_block_rq_complete(req->q, req);
|
|
|
|
/*
|
|
* For fs requests, rq is just carrier of independent bio's
|
|
* and each partial completion should be handled separately.
|
|
* Reset per-request error on each partial completion.
|
|
*
|
|
* TODO: tj: This is too subtle. It would be better to let
|
|
* low level drivers do what they see fit.
|
|
*/
|
|
if (req->cmd_type == REQ_TYPE_FS)
|
|
req->errors = 0;
|
|
|
|
if (error && req->cmd_type == REQ_TYPE_FS &&
|
|
!(req->cmd_flags & REQ_QUIET)) {
|
|
printk(KERN_ERR "end_request: I/O error, dev %s, sector %llu\n",
|
|
req->rq_disk ? req->rq_disk->disk_name : "?",
|
|
(unsigned long long)blk_rq_pos(req));
|
|
}
|
|
|
|
blk_account_io_completion(req, nr_bytes);
|
|
|
|
total_bytes = bio_nbytes = 0;
|
|
while ((bio = req->bio) != NULL) {
|
|
int nbytes;
|
|
|
|
if (nr_bytes >= bio->bi_size) {
|
|
req->bio = bio->bi_next;
|
|
nbytes = bio->bi_size;
|
|
req_bio_endio(req, bio, nbytes, error);
|
|
next_idx = 0;
|
|
bio_nbytes = 0;
|
|
} else {
|
|
int idx = bio->bi_idx + next_idx;
|
|
|
|
if (unlikely(idx >= bio->bi_vcnt)) {
|
|
blk_dump_rq_flags(req, "__end_that");
|
|
printk(KERN_ERR "%s: bio idx %d >= vcnt %d\n",
|
|
__func__, idx, bio->bi_vcnt);
|
|
break;
|
|
}
|
|
|
|
nbytes = bio_iovec_idx(bio, idx)->bv_len;
|
|
BIO_BUG_ON(nbytes > bio->bi_size);
|
|
|
|
/*
|
|
* not a complete bvec done
|
|
*/
|
|
if (unlikely(nbytes > nr_bytes)) {
|
|
bio_nbytes += nr_bytes;
|
|
total_bytes += nr_bytes;
|
|
break;
|
|
}
|
|
|
|
/*
|
|
* advance to the next vector
|
|
*/
|
|
next_idx++;
|
|
bio_nbytes += nbytes;
|
|
}
|
|
|
|
total_bytes += nbytes;
|
|
nr_bytes -= nbytes;
|
|
|
|
bio = req->bio;
|
|
if (bio) {
|
|
/*
|
|
* end more in this run, or just return 'not-done'
|
|
*/
|
|
if (unlikely(nr_bytes <= 0))
|
|
break;
|
|
}
|
|
}
|
|
|
|
/*
|
|
* completely done
|
|
*/
|
|
if (!req->bio) {
|
|
/*
|
|
* Reset counters so that the request stacking driver
|
|
* can find how many bytes remain in the request
|
|
* later.
|
|
*/
|
|
req->__data_len = 0;
|
|
return false;
|
|
}
|
|
|
|
/*
|
|
* if the request wasn't completed, update state
|
|
*/
|
|
if (bio_nbytes) {
|
|
req_bio_endio(req, bio, bio_nbytes, error);
|
|
bio->bi_idx += next_idx;
|
|
bio_iovec(bio)->bv_offset += nr_bytes;
|
|
bio_iovec(bio)->bv_len -= nr_bytes;
|
|
}
|
|
|
|
req->__data_len -= total_bytes;
|
|
req->buffer = bio_data(req->bio);
|
|
|
|
/* update sector only for requests with clear definition of sector */
|
|
if (req->cmd_type == REQ_TYPE_FS || (req->cmd_flags & REQ_DISCARD))
|
|
req->__sector += total_bytes >> 9;
|
|
|
|
/* mixed attributes always follow the first bio */
|
|
if (req->cmd_flags & REQ_MIXED_MERGE) {
|
|
req->cmd_flags &= ~REQ_FAILFAST_MASK;
|
|
req->cmd_flags |= req->bio->bi_rw & REQ_FAILFAST_MASK;
|
|
}
|
|
|
|
/*
|
|
* If total number of sectors is less than the first segment
|
|
* size, something has gone terribly wrong.
|
|
*/
|
|
if (blk_rq_bytes(req) < blk_rq_cur_bytes(req)) {
|
|
printk(KERN_ERR "blk: request botched\n");
|
|
req->__data_len = blk_rq_cur_bytes(req);
|
|
}
|
|
|
|
/* recalculate the number of segments */
|
|
blk_recalc_rq_segments(req);
|
|
|
|
return true;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_update_request);
|
|
|
|
static bool blk_update_bidi_request(struct request *rq, int error,
|
|
unsigned int nr_bytes,
|
|
unsigned int bidi_bytes)
|
|
{
|
|
if (blk_update_request(rq, error, nr_bytes))
|
|
return true;
|
|
|
|
/* Bidi request must be completed as a whole */
|
|
if (unlikely(blk_bidi_rq(rq)) &&
|
|
blk_update_request(rq->next_rq, error, bidi_bytes))
|
|
return true;
|
|
|
|
if (blk_queue_add_random(rq->q))
|
|
add_disk_randomness(rq->rq_disk);
|
|
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* blk_unprep_request - unprepare a request
|
|
* @req: the request
|
|
*
|
|
* This function makes a request ready for complete resubmission (or
|
|
* completion). It happens only after all error handling is complete,
|
|
* so represents the appropriate moment to deallocate any resources
|
|
* that were allocated to the request in the prep_rq_fn. The queue
|
|
* lock is held when calling this.
|
|
*/
|
|
void blk_unprep_request(struct request *req)
|
|
{
|
|
struct request_queue *q = req->q;
|
|
|
|
req->cmd_flags &= ~REQ_DONTPREP;
|
|
if (q->unprep_rq_fn)
|
|
q->unprep_rq_fn(q, req);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_unprep_request);
|
|
|
|
/*
|
|
* queue lock must be held
|
|
*/
|
|
static void blk_finish_request(struct request *req, int error)
|
|
{
|
|
if (blk_rq_tagged(req))
|
|
blk_queue_end_tag(req->q, req);
|
|
|
|
BUG_ON(blk_queued_rq(req));
|
|
|
|
if (unlikely(laptop_mode) && req->cmd_type == REQ_TYPE_FS)
|
|
laptop_io_completion(&req->q->backing_dev_info);
|
|
|
|
blk_delete_timer(req);
|
|
|
|
if (req->cmd_flags & REQ_DONTPREP)
|
|
blk_unprep_request(req);
|
|
|
|
|
|
blk_account_io_done(req);
|
|
|
|
if (req->end_io)
|
|
req->end_io(req, error);
|
|
else {
|
|
if (blk_bidi_rq(req))
|
|
__blk_put_request(req->next_rq->q, req->next_rq);
|
|
|
|
__blk_put_request(req->q, req);
|
|
}
|
|
}
|
|
|
|
/**
|
|
* blk_end_bidi_request - Complete a bidi request
|
|
* @rq: the request to complete
|
|
* @error: %0 for success, < %0 for error
|
|
* @nr_bytes: number of bytes to complete @rq
|
|
* @bidi_bytes: number of bytes to complete @rq->next_rq
|
|
*
|
|
* Description:
|
|
* Ends I/O on a number of bytes attached to @rq and @rq->next_rq.
|
|
* Drivers that supports bidi can safely call this member for any
|
|
* type of request, bidi or uni. In the later case @bidi_bytes is
|
|
* just ignored.
|
|
*
|
|
* Return:
|
|
* %false - we are done with this request
|
|
* %true - still buffers pending for this request
|
|
**/
|
|
static bool blk_end_bidi_request(struct request *rq, int error,
|
|
unsigned int nr_bytes, unsigned int bidi_bytes)
|
|
{
|
|
struct request_queue *q = rq->q;
|
|
unsigned long flags;
|
|
|
|
if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes))
|
|
return true;
|
|
|
|
spin_lock_irqsave(q->queue_lock, flags);
|
|
blk_finish_request(rq, error);
|
|
spin_unlock_irqrestore(q->queue_lock, flags);
|
|
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* __blk_end_bidi_request - Complete a bidi request with queue lock held
|
|
* @rq: the request to complete
|
|
* @error: %0 for success, < %0 for error
|
|
* @nr_bytes: number of bytes to complete @rq
|
|
* @bidi_bytes: number of bytes to complete @rq->next_rq
|
|
*
|
|
* Description:
|
|
* Identical to blk_end_bidi_request() except that queue lock is
|
|
* assumed to be locked on entry and remains so on return.
|
|
*
|
|
* Return:
|
|
* %false - we are done with this request
|
|
* %true - still buffers pending for this request
|
|
**/
|
|
static bool __blk_end_bidi_request(struct request *rq, int error,
|
|
unsigned int nr_bytes, unsigned int bidi_bytes)
|
|
{
|
|
if (blk_update_bidi_request(rq, error, nr_bytes, bidi_bytes))
|
|
return true;
|
|
|
|
blk_finish_request(rq, error);
|
|
|
|
return false;
|
|
}
|
|
|
|
/**
|
|
* blk_end_request - Helper function for drivers to complete the request.
|
|
* @rq: the request being processed
|
|
* @error: %0 for success, < %0 for error
|
|
* @nr_bytes: number of bytes to complete
|
|
*
|
|
* Description:
|
|
* Ends I/O on a number of bytes attached to @rq.
|
|
* If @rq has leftover, sets it up for the next range of segments.
|
|
*
|
|
* Return:
|
|
* %false - we are done with this request
|
|
* %true - still buffers pending for this request
|
|
**/
|
|
bool blk_end_request(struct request *rq, int error, unsigned int nr_bytes)
|
|
{
|
|
return blk_end_bidi_request(rq, error, nr_bytes, 0);
|
|
}
|
|
EXPORT_SYMBOL(blk_end_request);
|
|
|
|
/**
|
|
* blk_end_request_all - Helper function for drives to finish the request.
|
|
* @rq: the request to finish
|
|
* @error: %0 for success, < %0 for error
|
|
*
|
|
* Description:
|
|
* Completely finish @rq.
|
|
*/
|
|
void blk_end_request_all(struct request *rq, int error)
|
|
{
|
|
bool pending;
|
|
unsigned int bidi_bytes = 0;
|
|
|
|
if (unlikely(blk_bidi_rq(rq)))
|
|
bidi_bytes = blk_rq_bytes(rq->next_rq);
|
|
|
|
pending = blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes);
|
|
BUG_ON(pending);
|
|
}
|
|
EXPORT_SYMBOL(blk_end_request_all);
|
|
|
|
/**
|
|
* blk_end_request_cur - Helper function to finish the current request chunk.
|
|
* @rq: the request to finish the current chunk for
|
|
* @error: %0 for success, < %0 for error
|
|
*
|
|
* Description:
|
|
* Complete the current consecutively mapped chunk from @rq.
|
|
*
|
|
* Return:
|
|
* %false - we are done with this request
|
|
* %true - still buffers pending for this request
|
|
*/
|
|
bool blk_end_request_cur(struct request *rq, int error)
|
|
{
|
|
return blk_end_request(rq, error, blk_rq_cur_bytes(rq));
|
|
}
|
|
EXPORT_SYMBOL(blk_end_request_cur);
|
|
|
|
/**
|
|
* blk_end_request_err - Finish a request till the next failure boundary.
|
|
* @rq: the request to finish till the next failure boundary for
|
|
* @error: must be negative errno
|
|
*
|
|
* Description:
|
|
* Complete @rq till the next failure boundary.
|
|
*
|
|
* Return:
|
|
* %false - we are done with this request
|
|
* %true - still buffers pending for this request
|
|
*/
|
|
bool blk_end_request_err(struct request *rq, int error)
|
|
{
|
|
WARN_ON(error >= 0);
|
|
return blk_end_request(rq, error, blk_rq_err_bytes(rq));
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_end_request_err);
|
|
|
|
/**
|
|
* __blk_end_request - Helper function for drivers to complete the request.
|
|
* @rq: the request being processed
|
|
* @error: %0 for success, < %0 for error
|
|
* @nr_bytes: number of bytes to complete
|
|
*
|
|
* Description:
|
|
* Must be called with queue lock held unlike blk_end_request().
|
|
*
|
|
* Return:
|
|
* %false - we are done with this request
|
|
* %true - still buffers pending for this request
|
|
**/
|
|
bool __blk_end_request(struct request *rq, int error, unsigned int nr_bytes)
|
|
{
|
|
return __blk_end_bidi_request(rq, error, nr_bytes, 0);
|
|
}
|
|
EXPORT_SYMBOL(__blk_end_request);
|
|
|
|
/**
|
|
* __blk_end_request_all - Helper function for drives to finish the request.
|
|
* @rq: the request to finish
|
|
* @error: %0 for success, < %0 for error
|
|
*
|
|
* Description:
|
|
* Completely finish @rq. Must be called with queue lock held.
|
|
*/
|
|
void __blk_end_request_all(struct request *rq, int error)
|
|
{
|
|
bool pending;
|
|
unsigned int bidi_bytes = 0;
|
|
|
|
if (unlikely(blk_bidi_rq(rq)))
|
|
bidi_bytes = blk_rq_bytes(rq->next_rq);
|
|
|
|
pending = __blk_end_bidi_request(rq, error, blk_rq_bytes(rq), bidi_bytes);
|
|
BUG_ON(pending);
|
|
}
|
|
EXPORT_SYMBOL(__blk_end_request_all);
|
|
|
|
/**
|
|
* __blk_end_request_cur - Helper function to finish the current request chunk.
|
|
* @rq: the request to finish the current chunk for
|
|
* @error: %0 for success, < %0 for error
|
|
*
|
|
* Description:
|
|
* Complete the current consecutively mapped chunk from @rq. Must
|
|
* be called with queue lock held.
|
|
*
|
|
* Return:
|
|
* %false - we are done with this request
|
|
* %true - still buffers pending for this request
|
|
*/
|
|
bool __blk_end_request_cur(struct request *rq, int error)
|
|
{
|
|
return __blk_end_request(rq, error, blk_rq_cur_bytes(rq));
|
|
}
|
|
EXPORT_SYMBOL(__blk_end_request_cur);
|
|
|
|
/**
|
|
* __blk_end_request_err - Finish a request till the next failure boundary.
|
|
* @rq: the request to finish till the next failure boundary for
|
|
* @error: must be negative errno
|
|
*
|
|
* Description:
|
|
* Complete @rq till the next failure boundary. Must be called
|
|
* with queue lock held.
|
|
*
|
|
* Return:
|
|
* %false - we are done with this request
|
|
* %true - still buffers pending for this request
|
|
*/
|
|
bool __blk_end_request_err(struct request *rq, int error)
|
|
{
|
|
WARN_ON(error >= 0);
|
|
return __blk_end_request(rq, error, blk_rq_err_bytes(rq));
|
|
}
|
|
EXPORT_SYMBOL_GPL(__blk_end_request_err);
|
|
|
|
void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
|
|
struct bio *bio)
|
|
{
|
|
/* Bit 0 (R/W) is identical in rq->cmd_flags and bio->bi_rw */
|
|
rq->cmd_flags |= bio->bi_rw & REQ_WRITE;
|
|
|
|
if (bio_has_data(bio)) {
|
|
rq->nr_phys_segments = bio_phys_segments(q, bio);
|
|
rq->buffer = bio_data(bio);
|
|
}
|
|
rq->__data_len = bio->bi_size;
|
|
rq->bio = rq->biotail = bio;
|
|
|
|
if (bio->bi_bdev)
|
|
rq->rq_disk = bio->bi_bdev->bd_disk;
|
|
}
|
|
|
|
#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
|
|
/**
|
|
* rq_flush_dcache_pages - Helper function to flush all pages in a request
|
|
* @rq: the request to be flushed
|
|
*
|
|
* Description:
|
|
* Flush all pages in @rq.
|
|
*/
|
|
void rq_flush_dcache_pages(struct request *rq)
|
|
{
|
|
struct req_iterator iter;
|
|
struct bio_vec *bvec;
|
|
|
|
rq_for_each_segment(bvec, rq, iter)
|
|
flush_dcache_page(bvec->bv_page);
|
|
}
|
|
EXPORT_SYMBOL_GPL(rq_flush_dcache_pages);
|
|
#endif
|
|
|
|
/**
|
|
* blk_lld_busy - Check if underlying low-level drivers of a device are busy
|
|
* @q : the queue of the device being checked
|
|
*
|
|
* Description:
|
|
* Check if underlying low-level drivers of a device are busy.
|
|
* If the drivers want to export their busy state, they must set own
|
|
* exporting function using blk_queue_lld_busy() first.
|
|
*
|
|
* Basically, this function is used only by request stacking drivers
|
|
* to stop dispatching requests to underlying devices when underlying
|
|
* devices are busy. This behavior helps more I/O merging on the queue
|
|
* of the request stacking driver and prevents I/O throughput regression
|
|
* on burst I/O load.
|
|
*
|
|
* Return:
|
|
* 0 - Not busy (The request stacking driver should dispatch request)
|
|
* 1 - Busy (The request stacking driver should stop dispatching request)
|
|
*/
|
|
int blk_lld_busy(struct request_queue *q)
|
|
{
|
|
if (q->lld_busy_fn)
|
|
return q->lld_busy_fn(q);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_lld_busy);
|
|
|
|
/**
|
|
* blk_rq_unprep_clone - Helper function to free all bios in a cloned request
|
|
* @rq: the clone request to be cleaned up
|
|
*
|
|
* Description:
|
|
* Free all bios in @rq for a cloned request.
|
|
*/
|
|
void blk_rq_unprep_clone(struct request *rq)
|
|
{
|
|
struct bio *bio;
|
|
|
|
while ((bio = rq->bio) != NULL) {
|
|
rq->bio = bio->bi_next;
|
|
|
|
bio_put(bio);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_rq_unprep_clone);
|
|
|
|
/*
|
|
* Copy attributes of the original request to the clone request.
|
|
* The actual data parts (e.g. ->cmd, ->buffer, ->sense) are not copied.
|
|
*/
|
|
static void __blk_rq_prep_clone(struct request *dst, struct request *src)
|
|
{
|
|
dst->cpu = src->cpu;
|
|
dst->cmd_flags = (src->cmd_flags & REQ_CLONE_MASK) | REQ_NOMERGE;
|
|
dst->cmd_type = src->cmd_type;
|
|
dst->__sector = blk_rq_pos(src);
|
|
dst->__data_len = blk_rq_bytes(src);
|
|
dst->nr_phys_segments = src->nr_phys_segments;
|
|
dst->ioprio = src->ioprio;
|
|
dst->extra_len = src->extra_len;
|
|
}
|
|
|
|
/**
|
|
* blk_rq_prep_clone - Helper function to setup clone request
|
|
* @rq: the request to be setup
|
|
* @rq_src: original request to be cloned
|
|
* @bs: bio_set that bios for clone are allocated from
|
|
* @gfp_mask: memory allocation mask for bio
|
|
* @bio_ctr: setup function to be called for each clone bio.
|
|
* Returns %0 for success, non %0 for failure.
|
|
* @data: private data to be passed to @bio_ctr
|
|
*
|
|
* Description:
|
|
* Clones bios in @rq_src to @rq, and copies attributes of @rq_src to @rq.
|
|
* The actual data parts of @rq_src (e.g. ->cmd, ->buffer, ->sense)
|
|
* are not copied, and copying such parts is the caller's responsibility.
|
|
* Also, pages which the original bios are pointing to are not copied
|
|
* and the cloned bios just point same pages.
|
|
* So cloned bios must be completed before original bios, which means
|
|
* the caller must complete @rq before @rq_src.
|
|
*/
|
|
int blk_rq_prep_clone(struct request *rq, struct request *rq_src,
|
|
struct bio_set *bs, gfp_t gfp_mask,
|
|
int (*bio_ctr)(struct bio *, struct bio *, void *),
|
|
void *data)
|
|
{
|
|
struct bio *bio, *bio_src;
|
|
|
|
if (!bs)
|
|
bs = fs_bio_set;
|
|
|
|
blk_rq_init(NULL, rq);
|
|
|
|
__rq_for_each_bio(bio_src, rq_src) {
|
|
bio = bio_alloc_bioset(gfp_mask, bio_src->bi_max_vecs, bs);
|
|
if (!bio)
|
|
goto free_and_out;
|
|
|
|
__bio_clone(bio, bio_src);
|
|
|
|
if (bio_integrity(bio_src) &&
|
|
bio_integrity_clone(bio, bio_src, gfp_mask, bs))
|
|
goto free_and_out;
|
|
|
|
if (bio_ctr && bio_ctr(bio, bio_src, data))
|
|
goto free_and_out;
|
|
|
|
if (rq->bio) {
|
|
rq->biotail->bi_next = bio;
|
|
rq->biotail = bio;
|
|
} else
|
|
rq->bio = rq->biotail = bio;
|
|
}
|
|
|
|
__blk_rq_prep_clone(rq, rq_src);
|
|
|
|
return 0;
|
|
|
|
free_and_out:
|
|
if (bio)
|
|
bio_free(bio, bs);
|
|
blk_rq_unprep_clone(rq);
|
|
|
|
return -ENOMEM;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_rq_prep_clone);
|
|
|
|
int kblockd_schedule_work(struct request_queue *q, struct work_struct *work)
|
|
{
|
|
return queue_work(kblockd_workqueue, work);
|
|
}
|
|
EXPORT_SYMBOL(kblockd_schedule_work);
|
|
|
|
int kblockd_schedule_delayed_work(struct request_queue *q,
|
|
struct delayed_work *dwork, unsigned long delay)
|
|
{
|
|
return queue_delayed_work(kblockd_workqueue, dwork, delay);
|
|
}
|
|
EXPORT_SYMBOL(kblockd_schedule_delayed_work);
|
|
|
|
int __init blk_dev_init(void)
|
|
{
|
|
BUILD_BUG_ON(__REQ_NR_BITS > 8 *
|
|
sizeof(((struct request *)0)->cmd_flags));
|
|
|
|
kblockd_workqueue = create_workqueue("kblockd");
|
|
if (!kblockd_workqueue)
|
|
panic("Failed to create kblockd\n");
|
|
|
|
request_cachep = kmem_cache_create("blkdev_requests",
|
|
sizeof(struct request), 0, SLAB_PANIC, NULL);
|
|
|
|
blk_requestq_cachep = kmem_cache_create("blkdev_queue",
|
|
sizeof(struct request_queue), 0, SLAB_PANIC, NULL);
|
|
|
|
return 0;
|
|
}
|