mirror of
https://github.com/torvalds/linux.git
synced 2024-11-23 20:51:44 +00:00
05caf8dbc1
In function get_request_wait, the second call to get_request could be moved to the end of the while loop, because if the first call to get_request fails, the second call will fail without sleep. Signed-off-by: Zhang Yanmin <yanmin.zhang@intel.com> Signed-off-by: Jens Axboe <jens.axboe@oracle.com>
2054 lines
54 KiB
C
2054 lines
54 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/interrupt.h>
|
|
#include <linux/cpu.h>
|
|
#include <linux/blktrace_api.h>
|
|
#include <linux/fault-inject.h>
|
|
|
|
#include "blk.h"
|
|
|
|
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 DEFINE_PER_CPU(struct list_head, blk_cpu_done);
|
|
|
|
static void drive_stat_acct(struct request *rq, int new_io)
|
|
{
|
|
struct hd_struct *part;
|
|
int rw = rq_data_dir(rq);
|
|
|
|
if (!blk_fs_request(rq) || !rq->rq_disk)
|
|
return;
|
|
|
|
part = get_part(rq->rq_disk, rq->sector);
|
|
if (!new_io)
|
|
__all_stat_inc(rq->rq_disk, part, merges[rw], rq->sector);
|
|
else {
|
|
disk_round_stats(rq->rq_disk);
|
|
rq->rq_disk->in_flight++;
|
|
if (part) {
|
|
part_round_stats(part);
|
|
part->in_flight++;
|
|
}
|
|
}
|
|
}
|
|
|
|
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->donelist);
|
|
rq->q = q;
|
|
rq->sector = rq->hard_sector = (sector_t) -1;
|
|
INIT_HLIST_NODE(&rq->hash);
|
|
RB_CLEAR_NODE(&rq->rb_node);
|
|
rq->cmd = rq->__cmd;
|
|
rq->tag = -1;
|
|
rq->ref_count = 1;
|
|
}
|
|
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->bar_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;
|
|
}
|
|
|
|
bio->bi_size -= nbytes;
|
|
bio->bi_sector += (nbytes >> 9);
|
|
if (bio->bi_size == 0)
|
|
bio_endio(bio, error);
|
|
} else {
|
|
|
|
/*
|
|
* Okay, this is the barrier request in progress, just
|
|
* record the error;
|
|
*/
|
|
if (error && !q->orderr)
|
|
q->orderr = 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 %lu/%u\n",
|
|
(unsigned long long)rq->sector,
|
|
rq->nr_sectors,
|
|
rq->current_nr_sectors);
|
|
printk(KERN_INFO " bio %p, biotail %p, buffer %p, data %p, len %u\n",
|
|
rq->bio, rq->biotail,
|
|
rq->buffer, rq->data,
|
|
rq->data_len);
|
|
|
|
if (blk_pc_request(rq)) {
|
|
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 (!test_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags)) {
|
|
__set_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags);
|
|
mod_timer(&q->unplug_timer, jiffies + q->unplug_delay);
|
|
blk_add_trace_generic(q, NULL, 0, BLK_TA_PLUG);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(blk_plug_device);
|
|
|
|
/*
|
|
* 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 (!test_bit(QUEUE_FLAG_PLUGGED, &q->queue_flags))
|
|
return 0;
|
|
|
|
queue_flag_clear(QUEUE_FLAG_PLUGGED, q);
|
|
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))
|
|
return;
|
|
|
|
q->request_fn(q);
|
|
}
|
|
EXPORT_SYMBOL(__generic_unplug_device);
|
|
|
|
/**
|
|
* 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);
|
|
|
|
blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL,
|
|
q->rq.count[READ] + q->rq.count[WRITE]);
|
|
|
|
q->unplug_fn(q);
|
|
}
|
|
|
|
void blk_unplug_timeout(unsigned long data)
|
|
{
|
|
struct request_queue *q = (struct request_queue *)data;
|
|
|
|
blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_TIMER, NULL,
|
|
q->rq.count[READ] + q->rq.count[WRITE]);
|
|
|
|
kblockd_schedule_work(&q->unplug_work);
|
|
}
|
|
|
|
void blk_unplug(struct request_queue *q)
|
|
{
|
|
/*
|
|
* devices don't necessarily have an ->unplug_fn defined
|
|
*/
|
|
if (q->unplug_fn) {
|
|
blk_add_trace_pdu_int(q, BLK_TA_UNPLUG_IO, NULL,
|
|
q->rq.count[READ] + q->rq.count[WRITE]);
|
|
|
|
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);
|
|
|
|
/*
|
|
* one level of recursion is ok and is much faster than kicking
|
|
* the unplug handling
|
|
*/
|
|
if (!test_bit(QUEUE_FLAG_REENTER, &q->queue_flags)) {
|
|
queue_flag_set(QUEUE_FLAG_REENTER, q);
|
|
q->request_fn(q);
|
|
queue_flag_clear(QUEUE_FLAG_REENTER, q);
|
|
} else {
|
|
blk_plug_device(q);
|
|
kblockd_schedule_work(&q->unplug_work);
|
|
}
|
|
}
|
|
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);
|
|
kblockd_flush_work(&q->unplug_work);
|
|
}
|
|
EXPORT_SYMBOL(blk_sync_queue);
|
|
|
|
/**
|
|
* blk_run_queue - run a single device queue
|
|
* @q: The queue to run
|
|
*/
|
|
void __blk_run_queue(struct request_queue *q)
|
|
{
|
|
blk_remove_plug(q);
|
|
|
|
/*
|
|
* Only recurse once to avoid overrunning the stack, let the unplug
|
|
* handling reinvoke the handler shortly if we already got there.
|
|
*/
|
|
if (!elv_queue_empty(q)) {
|
|
if (!test_bit(QUEUE_FLAG_REENTER, &q->queue_flags)) {
|
|
queue_flag_set(QUEUE_FLAG_REENTER, q);
|
|
q->request_fn(q);
|
|
queue_flag_clear(QUEUE_FLAG_REENTER, q);
|
|
} else {
|
|
blk_plug_device(q);
|
|
kblockd_schedule_work(&q->unplug_work);
|
|
}
|
|
}
|
|
}
|
|
EXPORT_SYMBOL(__blk_run_queue);
|
|
|
|
/**
|
|
* blk_run_queue - run a single device queue
|
|
* @q: The queue to run
|
|
*/
|
|
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)
|
|
{
|
|
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;
|
|
|
|
rl->count[READ] = rl->count[WRITE] = 0;
|
|
rl->starved[READ] = rl->starved[WRITE] = 0;
|
|
rl->elvpriv = 0;
|
|
init_waitqueue_head(&rl->wait[READ]);
|
|
init_waitqueue_head(&rl->wait[WRITE]);
|
|
|
|
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;
|
|
err = bdi_init(&q->backing_dev_info);
|
|
if (err) {
|
|
kmem_cache_free(blk_requestq_cachep, q);
|
|
return NULL;
|
|
}
|
|
|
|
init_timer(&q->unplug_timer);
|
|
|
|
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 *q = blk_alloc_queue_node(GFP_KERNEL, node_id);
|
|
|
|
if (!q)
|
|
return NULL;
|
|
|
|
q->node = node_id;
|
|
if (blk_init_free_list(q)) {
|
|
kmem_cache_free(blk_requestq_cachep, q);
|
|
return NULL;
|
|
}
|
|
|
|
/*
|
|
* if caller didn't supply a lock, they get per-queue locking with
|
|
* our embedded lock
|
|
*/
|
|
if (!lock)
|
|
lock = &q->__queue_lock;
|
|
|
|
q->request_fn = rfn;
|
|
q->prep_rq_fn = NULL;
|
|
q->unplug_fn = generic_unplug_device;
|
|
q->queue_flags = (1 << QUEUE_FLAG_CLUSTER);
|
|
q->queue_lock = lock;
|
|
|
|
blk_queue_segment_boundary(q, 0xffffffff);
|
|
|
|
blk_queue_make_request(q, __make_request);
|
|
blk_queue_max_segment_size(q, MAX_SEGMENT_SIZE);
|
|
|
|
blk_queue_max_hw_segments(q, MAX_HW_SEGMENTS);
|
|
blk_queue_max_phys_segments(q, MAX_PHYS_SEGMENTS);
|
|
|
|
q->sg_reserved_size = INT_MAX;
|
|
|
|
/*
|
|
* all done
|
|
*/
|
|
if (!elevator_init(q, NULL)) {
|
|
blk_queue_congestion_threshold(q);
|
|
return q;
|
|
}
|
|
|
|
blk_put_queue(q);
|
|
return NULL;
|
|
}
|
|
EXPORT_SYMBOL(blk_init_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 rw, 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);
|
|
|
|
/*
|
|
* first three bits are identical in rq->cmd_flags and bio->bi_rw,
|
|
* see bio.h and blkdev.h
|
|
*/
|
|
rq->cmd_flags = rw | 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 rw)
|
|
{
|
|
struct request_list *rl = &q->rq;
|
|
|
|
if (rl->count[rw] < queue_congestion_off_threshold(q))
|
|
blk_clear_queue_congested(q, rw);
|
|
|
|
if (rl->count[rw] + 1 <= q->nr_requests) {
|
|
if (waitqueue_active(&rl->wait[rw]))
|
|
wake_up(&rl->wait[rw]);
|
|
|
|
blk_clear_queue_full(q, rw);
|
|
}
|
|
}
|
|
|
|
/*
|
|
* 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 rw, int priv)
|
|
{
|
|
struct request_list *rl = &q->rq;
|
|
|
|
rl->count[rw]--;
|
|
if (priv)
|
|
rl->elvpriv--;
|
|
|
|
__freed_request(q, rw);
|
|
|
|
if (unlikely(rl->starved[rw ^ 1]))
|
|
__freed_request(q, rw ^ 1);
|
|
}
|
|
|
|
#define blkdev_free_rq(list) list_entry((list)->next, struct request, queuelist)
|
|
/*
|
|
* 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 int rw = rw_flags & 0x01;
|
|
int may_queue, priv;
|
|
|
|
may_queue = elv_may_queue(q, rw_flags);
|
|
if (may_queue == ELV_MQUEUE_NO)
|
|
goto rq_starved;
|
|
|
|
if (rl->count[rw]+1 >= queue_congestion_on_threshold(q)) {
|
|
if (rl->count[rw]+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, rw)) {
|
|
ioc_set_batching(q, ioc);
|
|
blk_set_queue_full(q, rw);
|
|
} 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, rw);
|
|
}
|
|
|
|
/*
|
|
* 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[rw] >= (3 * q->nr_requests / 2))
|
|
goto out;
|
|
|
|
rl->count[rw]++;
|
|
rl->starved[rw] = 0;
|
|
|
|
priv = !test_bit(QUEUE_FLAG_ELVSWITCH, &q->queue_flags);
|
|
if (priv)
|
|
rl->elvpriv++;
|
|
|
|
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, rw, 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[rw] == 0))
|
|
rl->starved[rw] = 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--;
|
|
|
|
blk_add_trace_generic(q, bio, rw, BLK_TA_GETRQ);
|
|
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 int rw = rw_flags & 0x01;
|
|
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[rw], &wait,
|
|
TASK_UNINTERRUPTIBLE);
|
|
|
|
blk_add_trace_generic(q, bio, rw, BLK_TA_SLEEPRQ);
|
|
|
|
__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[rw], &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_start_queueing - initiate dispatch of requests to device
|
|
* @q: request queue to kick into gear
|
|
*
|
|
* This is basically a helper to remove the need to know whether a queue
|
|
* is plugged or not if someone just wants to initiate dispatch of requests
|
|
* for this queue.
|
|
*
|
|
* The queue lock must be held with interrupts disabled.
|
|
*/
|
|
void blk_start_queueing(struct request_queue *q)
|
|
{
|
|
if (!blk_queue_plugged(q))
|
|
q->request_fn(q);
|
|
else
|
|
__generic_unplug_device(q);
|
|
}
|
|
EXPORT_SYMBOL(blk_start_queueing);
|
|
|
|
/**
|
|
* 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_add_trace_rq(q, rq, BLK_TA_REQUEUE);
|
|
|
|
if (blk_rq_tagged(rq))
|
|
blk_queue_end_tag(q, rq);
|
|
|
|
elv_requeue_request(q, rq);
|
|
}
|
|
EXPORT_SYMBOL(blk_requeue_request);
|
|
|
|
/**
|
|
* blk_insert_request - insert a special request in to 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_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->cmd_flags |= REQ_SOFTBARRIER;
|
|
|
|
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_start_queueing(q);
|
|
spin_unlock_irqrestore(q->queue_lock, flags);
|
|
}
|
|
EXPORT_SYMBOL(blk_insert_request);
|
|
|
|
/*
|
|
* add-request adds a request to the linked list.
|
|
* queue lock is held and interrupts disabled, as we muck with the
|
|
* request queue list.
|
|
*/
|
|
static inline void add_request(struct request_queue *q, struct request *req)
|
|
{
|
|
drive_stat_acct(req, 1);
|
|
|
|
/*
|
|
* elevator indicated where it wants this request to be
|
|
* inserted at elevator_merge time
|
|
*/
|
|
__elv_add_request(q, req, ELEVATOR_INSERT_SORT, 0);
|
|
}
|
|
|
|
/*
|
|
* disk_round_stats() - Round off the performance stats on a struct
|
|
* disk_stats.
|
|
*
|
|
* 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 disk_round_stats(struct gendisk *disk)
|
|
{
|
|
unsigned long now = jiffies;
|
|
|
|
if (now == disk->stamp)
|
|
return;
|
|
|
|
if (disk->in_flight) {
|
|
__disk_stat_add(disk, time_in_queue,
|
|
disk->in_flight * (now - disk->stamp));
|
|
__disk_stat_add(disk, io_ticks, (now - disk->stamp));
|
|
}
|
|
disk->stamp = now;
|
|
}
|
|
EXPORT_SYMBOL_GPL(disk_round_stats);
|
|
|
|
void part_round_stats(struct hd_struct *part)
|
|
{
|
|
unsigned long now = jiffies;
|
|
|
|
if (now == part->stamp)
|
|
return;
|
|
|
|
if (part->in_flight) {
|
|
__part_stat_add(part, time_in_queue,
|
|
part->in_flight * (now - part->stamp));
|
|
__part_stat_add(part, io_ticks, (now - part->stamp));
|
|
}
|
|
part->stamp = now;
|
|
}
|
|
|
|
/*
|
|
* 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);
|
|
|
|
/*
|
|
* 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 rw = rq_data_dir(req);
|
|
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, rw, priv);
|
|
}
|
|
}
|
|
EXPORT_SYMBOL_GPL(__blk_put_request);
|
|
|
|
void blk_put_request(struct request *req)
|
|
{
|
|
unsigned long flags;
|
|
struct request_queue *q = req->q;
|
|
|
|
/*
|
|
* Gee, IDE calls in w/ NULL q. Fix IDE and remove the
|
|
* following if (q) test.
|
|
*/
|
|
if (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);
|
|
|
|
void init_request_from_bio(struct request *req, struct bio *bio)
|
|
{
|
|
req->cmd_type = REQ_TYPE_FS;
|
|
|
|
/*
|
|
* inherit FAILFAST from bio (for read-ahead, and explicit FAILFAST)
|
|
*/
|
|
if (bio_rw_ahead(bio) || bio_failfast(bio))
|
|
req->cmd_flags |= REQ_FAILFAST;
|
|
|
|
/*
|
|
* REQ_BARRIER implies no merging, but lets make it explicit
|
|
*/
|
|
if (unlikely(bio_barrier(bio)))
|
|
req->cmd_flags |= (REQ_HARDBARRIER | REQ_NOMERGE);
|
|
|
|
if (bio_sync(bio))
|
|
req->cmd_flags |= REQ_RW_SYNC;
|
|
if (bio_rw_meta(bio))
|
|
req->cmd_flags |= REQ_RW_META;
|
|
|
|
req->errors = 0;
|
|
req->hard_sector = req->sector = bio->bi_sector;
|
|
req->ioprio = bio_prio(bio);
|
|
req->start_time = jiffies;
|
|
blk_rq_bio_prep(req->q, req, bio);
|
|
}
|
|
|
|
static int __make_request(struct request_queue *q, struct bio *bio)
|
|
{
|
|
struct request *req;
|
|
int el_ret, nr_sectors, barrier, err;
|
|
const unsigned short prio = bio_prio(bio);
|
|
const int sync = bio_sync(bio);
|
|
int rw_flags;
|
|
|
|
nr_sectors = bio_sectors(bio);
|
|
|
|
/*
|
|
* 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);
|
|
|
|
barrier = bio_barrier(bio);
|
|
if (unlikely(barrier) && (q->next_ordered == QUEUE_ORDERED_NONE)) {
|
|
err = -EOPNOTSUPP;
|
|
goto end_io;
|
|
}
|
|
|
|
spin_lock_irq(q->queue_lock);
|
|
|
|
if (unlikely(barrier) || 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;
|
|
|
|
blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
|
|
|
|
req->biotail->bi_next = bio;
|
|
req->biotail = bio;
|
|
req->nr_sectors = req->hard_nr_sectors += nr_sectors;
|
|
req->ioprio = ioprio_best(req->ioprio, prio);
|
|
drive_stat_acct(req, 0);
|
|
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;
|
|
|
|
blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
|
|
|
|
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->current_nr_sectors = bio_cur_sectors(bio);
|
|
req->hard_cur_sectors = req->current_nr_sectors;
|
|
req->sector = req->hard_sector = bio->bi_sector;
|
|
req->nr_sectors = req->hard_nr_sectors += nr_sectors;
|
|
req->ioprio = ioprio_best(req->ioprio, prio);
|
|
drive_stat_acct(req, 0);
|
|
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_RW_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 (elv_queue_empty(q))
|
|
blk_plug_device(q);
|
|
add_request(q, req);
|
|
out:
|
|
if (sync)
|
|
__generic_unplug_device(q);
|
|
|
|
spin_unlock_irq(q->queue_lock);
|
|
return 0;
|
|
|
|
end_io:
|
|
bio_endio(bio, err);
|
|
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;
|
|
|
|
blk_add_trace_remap(bdev_get_queue(bio->bi_bdev), bio,
|
|
bdev->bd_dev, bio->bi_sector,
|
|
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)
|
|
{
|
|
if ((bio->bi_bdev->bd_disk->flags & GENHD_FL_FAIL) ||
|
|
(bio->bi_bdev->bd_part && bio->bi_bdev->bd_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 (!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);
|
|
end_io:
|
|
bio_endio(bio, err);
|
|
break;
|
|
}
|
|
|
|
if (unlikely(nr_sectors > q->max_hw_sectors)) {
|
|
printk(KERN_ERR "bio too big device %s (%u > %u)\n",
|
|
bdevname(bio->bi_bdev, b),
|
|
bio_sectors(bio),
|
|
q->max_hw_sectors);
|
|
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 (old_sector != -1)
|
|
blk_add_trace_remap(q, bio, old_dev, bio->bi_sector,
|
|
old_sector);
|
|
|
|
blk_add_trace_bio(q, bio, BLK_TA_QUEUE);
|
|
|
|
old_sector = bio->bi_sector;
|
|
old_dev = bio->bi_bdev->bd_dev;
|
|
|
|
if (bio_check_eod(bio, nr_sectors))
|
|
goto end_io;
|
|
if (bio_empty_barrier(bio) && !q->prepare_flush_fn) {
|
|
err = -EOPNOTSUPP;
|
|
goto end_io;
|
|
}
|
|
|
|
ret = q->make_request_fn(q, bio);
|
|
} while (ret);
|
|
}
|
|
|
|
/*
|
|
* 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,tail} to keep a list of requests
|
|
* submited by a make_request_fn function.
|
|
* current->bio_tail 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)
|
|
{
|
|
if (current->bio_tail) {
|
|
/* make_request is active */
|
|
*(current->bio_tail) = bio;
|
|
bio->bi_next = NULL;
|
|
current->bio_tail = &bio->bi_next;
|
|
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 the next (which is NULL) and bio_tail
|
|
* to &bio_list, 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 fixup bio_list and
|
|
* bio_tail or bi_next, 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);
|
|
do {
|
|
current->bio_list = bio->bi_next;
|
|
if (bio->bi_next == NULL)
|
|
current->bio_tail = ¤t->bio_list;
|
|
else
|
|
bio->bi_next = NULL;
|
|
__generic_make_request(bio);
|
|
bio = current->bio_list;
|
|
} while (bio);
|
|
current->bio_tail = 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_empty_barrier(bio)) {
|
|
|
|
BIO_BUG_ON(!bio->bi_size);
|
|
BIO_BUG_ON(!bio->bi_io_vec);
|
|
|
|
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\n",
|
|
current->comm, task_pid_nr(current),
|
|
(rw & WRITE) ? "WRITE" : "READ",
|
|
(unsigned long long)bio->bi_sector,
|
|
bdevname(bio->bi_bdev, b));
|
|
}
|
|
}
|
|
|
|
generic_make_request(bio);
|
|
}
|
|
EXPORT_SYMBOL(submit_bio);
|
|
|
|
/**
|
|
* __end_that_request_first - end I/O on a request
|
|
* @req: 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 @req, and sets it up
|
|
* for the next range of segments (if any) in the cluster.
|
|
*
|
|
* Return:
|
|
* 0 - we are done with this request, call end_that_request_last()
|
|
* 1 - still buffers pending for this request
|
|
**/
|
|
static int __end_that_request_first(struct request *req, int error,
|
|
int nr_bytes)
|
|
{
|
|
int total_bytes, bio_nbytes, next_idx = 0;
|
|
struct bio *bio;
|
|
|
|
blk_add_trace_rq(req->q, req, BLK_TA_COMPLETE);
|
|
|
|
/*
|
|
* for a REQ_BLOCK_PC request, we want to carry any eventual
|
|
* sense key with us all the way through
|
|
*/
|
|
if (!blk_pc_request(req))
|
|
req->errors = 0;
|
|
|
|
if (error && (blk_fs_request(req) && !(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)req->sector);
|
|
}
|
|
|
|
if (blk_fs_request(req) && req->rq_disk) {
|
|
struct hd_struct *part = get_part(req->rq_disk, req->sector);
|
|
const int rw = rq_data_dir(req);
|
|
|
|
all_stat_add(req->rq_disk, part, sectors[rw],
|
|
nr_bytes >> 9, req->sector);
|
|
}
|
|
|
|
total_bytes = bio_nbytes = 0;
|
|
while ((bio = req->bio) != NULL) {
|
|
int nbytes;
|
|
|
|
/*
|
|
* For an empty barrier request, the low level driver must
|
|
* store a potential error location in ->sector. We pass
|
|
* that back up in ->bi_sector.
|
|
*/
|
|
if (blk_empty_barrier(req))
|
|
bio->bi_sector = req->sector;
|
|
|
|
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(bio->bi_idx >= bio->bi_vcnt)) {
|
|
blk_dump_rq_flags(req, "__end_that");
|
|
printk(KERN_ERR "%s: bio idx %d >= vcnt %d\n",
|
|
__func__, bio->bi_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)
|
|
return 0;
|
|
|
|
/*
|
|
* 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;
|
|
}
|
|
|
|
blk_recalc_rq_sectors(req, total_bytes >> 9);
|
|
blk_recalc_rq_segments(req);
|
|
return 1;
|
|
}
|
|
|
|
/*
|
|
* splice the completion data to a local structure and hand off to
|
|
* process_completion_queue() to complete the requests
|
|
*/
|
|
static void blk_done_softirq(struct softirq_action *h)
|
|
{
|
|
struct list_head *cpu_list, local_list;
|
|
|
|
local_irq_disable();
|
|
cpu_list = &__get_cpu_var(blk_cpu_done);
|
|
list_replace_init(cpu_list, &local_list);
|
|
local_irq_enable();
|
|
|
|
while (!list_empty(&local_list)) {
|
|
struct request *rq;
|
|
|
|
rq = list_entry(local_list.next, struct request, donelist);
|
|
list_del_init(&rq->donelist);
|
|
rq->q->softirq_done_fn(rq);
|
|
}
|
|
}
|
|
|
|
static int __cpuinit blk_cpu_notify(struct notifier_block *self,
|
|
unsigned long action, void *hcpu)
|
|
{
|
|
/*
|
|
* If a CPU goes away, splice its entries to the current CPU
|
|
* and trigger a run of the softirq
|
|
*/
|
|
if (action == CPU_DEAD || action == CPU_DEAD_FROZEN) {
|
|
int cpu = (unsigned long) hcpu;
|
|
|
|
local_irq_disable();
|
|
list_splice_init(&per_cpu(blk_cpu_done, cpu),
|
|
&__get_cpu_var(blk_cpu_done));
|
|
raise_softirq_irqoff(BLOCK_SOFTIRQ);
|
|
local_irq_enable();
|
|
}
|
|
|
|
return NOTIFY_OK;
|
|
}
|
|
|
|
|
|
static struct notifier_block blk_cpu_notifier __cpuinitdata = {
|
|
.notifier_call = blk_cpu_notify,
|
|
};
|
|
|
|
/**
|
|
* blk_complete_request - end I/O on a request
|
|
* @req: the request being processed
|
|
*
|
|
* Description:
|
|
* Ends all I/O on a request. It does not handle partial completions,
|
|
* unless the driver actually implements this in its completion callback
|
|
* through requeueing. The actual completion happens out-of-order,
|
|
* through a softirq handler. The user must have registered a completion
|
|
* callback through blk_queue_softirq_done().
|
|
**/
|
|
|
|
void blk_complete_request(struct request *req)
|
|
{
|
|
struct list_head *cpu_list;
|
|
unsigned long flags;
|
|
|
|
BUG_ON(!req->q->softirq_done_fn);
|
|
|
|
local_irq_save(flags);
|
|
|
|
cpu_list = &__get_cpu_var(blk_cpu_done);
|
|
list_add_tail(&req->donelist, cpu_list);
|
|
raise_softirq_irqoff(BLOCK_SOFTIRQ);
|
|
|
|
local_irq_restore(flags);
|
|
}
|
|
EXPORT_SYMBOL(blk_complete_request);
|
|
|
|
/*
|
|
* queue lock must be held
|
|
*/
|
|
static void end_that_request_last(struct request *req, int error)
|
|
{
|
|
struct gendisk *disk = req->rq_disk;
|
|
|
|
if (blk_rq_tagged(req))
|
|
blk_queue_end_tag(req->q, req);
|
|
|
|
if (blk_queued_rq(req))
|
|
blkdev_dequeue_request(req);
|
|
|
|
if (unlikely(laptop_mode) && blk_fs_request(req))
|
|
laptop_io_completion();
|
|
|
|
/*
|
|
* Account IO completion. bar_rq isn't accounted as a normal
|
|
* IO on queueing nor completion. Accounting the containing
|
|
* request is enough.
|
|
*/
|
|
if (disk && blk_fs_request(req) && req != &req->q->bar_rq) {
|
|
unsigned long duration = jiffies - req->start_time;
|
|
const int rw = rq_data_dir(req);
|
|
struct hd_struct *part = get_part(disk, req->sector);
|
|
|
|
__all_stat_inc(disk, part, ios[rw], req->sector);
|
|
__all_stat_add(disk, part, ticks[rw], duration, req->sector);
|
|
disk_round_stats(disk);
|
|
disk->in_flight--;
|
|
if (part) {
|
|
part_round_stats(part);
|
|
part->in_flight--;
|
|
}
|
|
}
|
|
|
|
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);
|
|
}
|
|
}
|
|
|
|
static inline void __end_request(struct request *rq, int uptodate,
|
|
unsigned int nr_bytes)
|
|
{
|
|
int error = 0;
|
|
|
|
if (uptodate <= 0)
|
|
error = uptodate ? uptodate : -EIO;
|
|
|
|
__blk_end_request(rq, error, nr_bytes);
|
|
}
|
|
|
|
/**
|
|
* blk_rq_bytes - Returns bytes left to complete in the entire request
|
|
* @rq: the request being processed
|
|
**/
|
|
unsigned int blk_rq_bytes(struct request *rq)
|
|
{
|
|
if (blk_fs_request(rq))
|
|
return rq->hard_nr_sectors << 9;
|
|
|
|
return rq->data_len;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_rq_bytes);
|
|
|
|
/**
|
|
* blk_rq_cur_bytes - Returns bytes left to complete in the current segment
|
|
* @rq: the request being processed
|
|
**/
|
|
unsigned int blk_rq_cur_bytes(struct request *rq)
|
|
{
|
|
if (blk_fs_request(rq))
|
|
return rq->current_nr_sectors << 9;
|
|
|
|
if (rq->bio)
|
|
return rq->bio->bi_size;
|
|
|
|
return rq->data_len;
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_rq_cur_bytes);
|
|
|
|
/**
|
|
* end_queued_request - end all I/O on a queued request
|
|
* @rq: the request being processed
|
|
* @uptodate: error value or 0/1 uptodate flag
|
|
*
|
|
* Description:
|
|
* Ends all I/O on a request, and removes it from the block layer queues.
|
|
* Not suitable for normal IO completion, unless the driver still has
|
|
* the request attached to the block layer.
|
|
*
|
|
**/
|
|
void end_queued_request(struct request *rq, int uptodate)
|
|
{
|
|
__end_request(rq, uptodate, blk_rq_bytes(rq));
|
|
}
|
|
EXPORT_SYMBOL(end_queued_request);
|
|
|
|
/**
|
|
* end_dequeued_request - end all I/O on a dequeued request
|
|
* @rq: the request being processed
|
|
* @uptodate: error value or 0/1 uptodate flag
|
|
*
|
|
* Description:
|
|
* Ends all I/O on a request. The request must already have been
|
|
* dequeued using blkdev_dequeue_request(), as is normally the case
|
|
* for most drivers.
|
|
*
|
|
**/
|
|
void end_dequeued_request(struct request *rq, int uptodate)
|
|
{
|
|
__end_request(rq, uptodate, blk_rq_bytes(rq));
|
|
}
|
|
EXPORT_SYMBOL(end_dequeued_request);
|
|
|
|
|
|
/**
|
|
* end_request - end I/O on the current segment of the request
|
|
* @req: the request being processed
|
|
* @uptodate: error value or 0/1 uptodate flag
|
|
*
|
|
* Description:
|
|
* Ends I/O on the current segment of a request. If that is the only
|
|
* remaining segment, the request is also completed and freed.
|
|
*
|
|
* This is a remnant of how older block drivers handled IO completions.
|
|
* Modern drivers typically end IO on the full request in one go, unless
|
|
* they have a residual value to account for. For that case this function
|
|
* isn't really useful, unless the residual just happens to be the
|
|
* full current segment. In other words, don't use this function in new
|
|
* code. Either use end_request_completely(), or the
|
|
* end_that_request_chunk() (along with end_that_request_last()) for
|
|
* partial completions.
|
|
*
|
|
**/
|
|
void end_request(struct request *req, int uptodate)
|
|
{
|
|
__end_request(req, uptodate, req->hard_cur_sectors << 9);
|
|
}
|
|
EXPORT_SYMBOL(end_request);
|
|
|
|
/**
|
|
* blk_end_io - Generic end_io function to complete a request.
|
|
* @rq: the request being processed
|
|
* @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
|
|
* @drv_callback: function called between completion of bios in the request
|
|
* and completion of the request.
|
|
* If the callback returns non 0, this helper returns without
|
|
* completion of the request.
|
|
*
|
|
* Description:
|
|
* Ends I/O on a number of bytes attached to @rq and @rq->next_rq.
|
|
* If @rq has leftover, sets it up for the next range of segments.
|
|
*
|
|
* Return:
|
|
* 0 - we are done with this request
|
|
* 1 - this request is not freed yet, it still has pending buffers.
|
|
**/
|
|
static int blk_end_io(struct request *rq, int error, unsigned int nr_bytes,
|
|
unsigned int bidi_bytes,
|
|
int (drv_callback)(struct request *))
|
|
{
|
|
struct request_queue *q = rq->q;
|
|
unsigned long flags = 0UL;
|
|
|
|
if (blk_fs_request(rq) || blk_pc_request(rq)) {
|
|
if (__end_that_request_first(rq, error, nr_bytes))
|
|
return 1;
|
|
|
|
/* Bidi request must be completed as a whole */
|
|
if (blk_bidi_rq(rq) &&
|
|
__end_that_request_first(rq->next_rq, error, bidi_bytes))
|
|
return 1;
|
|
}
|
|
|
|
/* Special feature for tricky drivers */
|
|
if (drv_callback && drv_callback(rq))
|
|
return 1;
|
|
|
|
add_disk_randomness(rq->rq_disk);
|
|
|
|
spin_lock_irqsave(q->queue_lock, flags);
|
|
end_that_request_last(rq, error);
|
|
spin_unlock_irqrestore(q->queue_lock, flags);
|
|
|
|
return 0;
|
|
}
|
|
|
|
/**
|
|
* 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:
|
|
* 0 - we are done with this request
|
|
* 1 - still buffers pending for this request
|
|
**/
|
|
int blk_end_request(struct request *rq, int error, unsigned int nr_bytes)
|
|
{
|
|
return blk_end_io(rq, error, nr_bytes, 0, NULL);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_end_request);
|
|
|
|
/**
|
|
* __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:
|
|
* 0 - we are done with this request
|
|
* 1 - still buffers pending for this request
|
|
**/
|
|
int __blk_end_request(struct request *rq, int error, unsigned int nr_bytes)
|
|
{
|
|
if (blk_fs_request(rq) || blk_pc_request(rq)) {
|
|
if (__end_that_request_first(rq, error, nr_bytes))
|
|
return 1;
|
|
}
|
|
|
|
add_disk_randomness(rq->rq_disk);
|
|
|
|
end_that_request_last(rq, error);
|
|
|
|
return 0;
|
|
}
|
|
EXPORT_SYMBOL_GPL(__blk_end_request);
|
|
|
|
/**
|
|
* blk_end_bidi_request - Helper function for drivers to complete bidi request.
|
|
* @rq: the bidi request being processed
|
|
* @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.
|
|
*
|
|
* Return:
|
|
* 0 - we are done with this request
|
|
* 1 - still buffers pending for this request
|
|
**/
|
|
int blk_end_bidi_request(struct request *rq, int error, unsigned int nr_bytes,
|
|
unsigned int bidi_bytes)
|
|
{
|
|
return blk_end_io(rq, error, nr_bytes, bidi_bytes, NULL);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_end_bidi_request);
|
|
|
|
/**
|
|
* blk_end_request_callback - Special helper function for tricky drivers
|
|
* @rq: the request being processed
|
|
* @error: 0 for success, < 0 for error
|
|
* @nr_bytes: number of bytes to complete
|
|
* @drv_callback: function called between completion of bios in the request
|
|
* and completion of the request.
|
|
* If the callback returns non 0, this helper returns without
|
|
* completion of the request.
|
|
*
|
|
* 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.
|
|
*
|
|
* This special helper function is used only for existing tricky drivers.
|
|
* (e.g. cdrom_newpc_intr() of ide-cd)
|
|
* This interface will be removed when such drivers are rewritten.
|
|
* Don't use this interface in other places anymore.
|
|
*
|
|
* Return:
|
|
* 0 - we are done with this request
|
|
* 1 - this request is not freed yet.
|
|
* this request still has pending buffers or
|
|
* the driver doesn't want to finish this request yet.
|
|
**/
|
|
int blk_end_request_callback(struct request *rq, int error,
|
|
unsigned int nr_bytes,
|
|
int (drv_callback)(struct request *))
|
|
{
|
|
return blk_end_io(rq, error, nr_bytes, 0, drv_callback);
|
|
}
|
|
EXPORT_SYMBOL_GPL(blk_end_request_callback);
|
|
|
|
void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
|
|
struct bio *bio)
|
|
{
|
|
/* first two bits are identical in rq->cmd_flags and bio->bi_rw */
|
|
rq->cmd_flags |= (bio->bi_rw & 3);
|
|
|
|
rq->nr_phys_segments = bio_phys_segments(q, bio);
|
|
rq->nr_hw_segments = bio_hw_segments(q, bio);
|
|
rq->current_nr_sectors = bio_cur_sectors(bio);
|
|
rq->hard_cur_sectors = rq->current_nr_sectors;
|
|
rq->hard_nr_sectors = rq->nr_sectors = bio_sectors(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;
|
|
}
|
|
|
|
int kblockd_schedule_work(struct work_struct *work)
|
|
{
|
|
return queue_work(kblockd_workqueue, work);
|
|
}
|
|
EXPORT_SYMBOL(kblockd_schedule_work);
|
|
|
|
void kblockd_flush_work(struct work_struct *work)
|
|
{
|
|
cancel_work_sync(work);
|
|
}
|
|
EXPORT_SYMBOL(kblockd_flush_work);
|
|
|
|
int __init blk_dev_init(void)
|
|
{
|
|
int i;
|
|
|
|
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);
|
|
|
|
for_each_possible_cpu(i)
|
|
INIT_LIST_HEAD(&per_cpu(blk_cpu_done, i));
|
|
|
|
open_softirq(BLOCK_SOFTIRQ, blk_done_softirq, NULL);
|
|
register_hotcpu_notifier(&blk_cpu_notifier);
|
|
|
|
return 0;
|
|
}
|
|
|