* 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
+ * 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
*/
#include <linux/kernel_stat.h>
#include <linux/string.h>
#include <linux/init.h>
-#include <linux/bootmem.h> /* for max_pfn/max_low_pfn */
#include <linux/completion.h>
#include <linux/slab.h>
#include <linux/swap.h>
#include <linux/cpu.h>
#include <linux/blktrace_api.h>
#include <linux/fault-inject.h>
-#include <linux/scatterlist.h>
#include "blk.h"
-/*
- * for max sense size
- */
-#include <scsi/scsi_cmnd.h>
-
-static void blk_unplug_work(struct work_struct *work);
-static void blk_unplug_timeout(unsigned long data);
-static void drive_stat_acct(struct request *rq, int new_io);
-static void init_request_from_bio(struct request *req, struct bio *bio);
static int __make_request(struct request_queue *q, struct bio *bio);
-static struct io_context *current_io_context(gfp_t gfp_flags, int node);
-static void blk_recalc_rq_segments(struct request *rq);
-static void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
- struct bio *bio);
/*
* For the allocated request tables
/*
* For queue allocation
*/
-struct kmem_cache *blk_requestq_cachep = NULL;
-
-/*
- * For io context allocations
- */
-static struct kmem_cache *iocontext_cachep;
+struct kmem_cache *blk_requestq_cachep;
/*
* Controlling structure to kblockd
*/
static struct workqueue_struct *kblockd_workqueue;
-unsigned long blk_max_low_pfn, blk_max_pfn;
-
-EXPORT_SYMBOL(blk_max_low_pfn);
-EXPORT_SYMBOL(blk_max_pfn);
-
static DEFINE_PER_CPU(struct list_head, blk_cpu_done);
-/* Amount of time in which a process may batch requests */
-#define BLK_BATCH_TIME (HZ/50UL)
+static void drive_stat_acct(struct request *rq, int new_io)
+{
+ int rw = rq_data_dir(rq);
-/* Number of requests a "batching" process may submit */
-#define BLK_BATCH_REQ 32
+ if (!blk_fs_request(rq) || !rq->rq_disk)
+ return;
+
+ if (!new_io) {
+ __disk_stat_inc(rq->rq_disk, merges[rw]);
+ } else {
+ disk_round_stats(rq->rq_disk);
+ rq->rq_disk->in_flight++;
+ }
+}
void blk_queue_congestion_threshold(struct request_queue *q)
{
}
EXPORT_SYMBOL(blk_get_backing_dev_info);
-/**
- * blk_queue_prep_rq - set a prepare_request function for queue
- * @q: queue
- * @pfn: prepare_request function
- *
- * It's possible for a queue to register a prepare_request callback which
- * is invoked before the request is handed to the request_fn. The goal of
- * the function is to prepare a request for I/O, it can be used to build a
- * cdb from the request data for instance.
- *
- */
-void blk_queue_prep_rq(struct request_queue *q, prep_rq_fn *pfn)
-{
- q->prep_rq_fn = pfn;
-}
-
-EXPORT_SYMBOL(blk_queue_prep_rq);
-
-/**
- * blk_queue_merge_bvec - set a merge_bvec function for queue
- * @q: queue
- * @mbfn: merge_bvec_fn
- *
- * Usually queues have static limitations on the max sectors or segments that
- * we can put in a request. Stacking drivers may have some settings that
- * are dynamic, and thus we have to query the queue whether it is ok to
- * add a new bio_vec to a bio at a given offset or not. If the block device
- * has such limitations, it needs to register a merge_bvec_fn to control
- * the size of bio's sent to it. Note that a block device *must* allow a
- * single page to be added to an empty bio. The block device driver may want
- * to use the bio_split() function to deal with these bio's. By default
- * no merge_bvec_fn is defined for a queue, and only the fixed limits are
- * honored.
+/*
+ * We can't just memset() the structure, since the allocation path
+ * already stored some information in the request.
*/
-void blk_queue_merge_bvec(struct request_queue *q, merge_bvec_fn *mbfn)
-{
- q->merge_bvec_fn = mbfn;
-}
-
-EXPORT_SYMBOL(blk_queue_merge_bvec);
-
-void blk_queue_softirq_done(struct request_queue *q, softirq_done_fn *fn)
-{
- q->softirq_done_fn = fn;
-}
-
-EXPORT_SYMBOL(blk_queue_softirq_done);
-
-/**
- * blk_queue_make_request - define an alternate make_request function for a device
- * @q: the request queue for the device to be affected
- * @mfn: the alternate make_request function
- *
- * Description:
- * The normal way for &struct bios to be passed to a device
- * driver is for them to be collected into requests on a request
- * queue, and then to allow the device driver to select requests
- * off that queue when it is ready. This works well for many block
- * devices. However some block devices (typically virtual devices
- * such as md or lvm) do not benefit from the processing on the
- * request queue, and are served best by having the requests passed
- * directly to them. This can be achieved by providing a function
- * to blk_queue_make_request().
- *
- * Caveat:
- * The driver that does this *must* be able to deal appropriately
- * with buffers in "highmemory". This can be accomplished by either calling
- * __bio_kmap_atomic() to get a temporary kernel mapping, or by calling
- * blk_queue_bounce() to create a buffer in normal memory.
- **/
-void blk_queue_make_request(struct request_queue * q, make_request_fn * mfn)
-{
- /*
- * set defaults
- */
- q->nr_requests = BLKDEV_MAX_RQ;
- blk_queue_max_phys_segments(q, MAX_PHYS_SEGMENTS);
- blk_queue_max_hw_segments(q, MAX_HW_SEGMENTS);
- q->make_request_fn = mfn;
- 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;
- blk_queue_max_sectors(q, SAFE_MAX_SECTORS);
- blk_queue_hardsect_size(q, 512);
- blk_queue_dma_alignment(q, 511);
- blk_queue_congestion_threshold(q);
- q->nr_batching = BLK_BATCH_REQ;
-
- q->unplug_thresh = 4; /* hmm */
- q->unplug_delay = (3 * HZ) / 1000; /* 3 milliseconds */
- if (q->unplug_delay == 0)
- q->unplug_delay = 1;
-
- INIT_WORK(&q->unplug_work, blk_unplug_work);
-
- q->unplug_timer.function = blk_unplug_timeout;
- q->unplug_timer.data = (unsigned long)q;
-
- /*
- * by default assume old behaviour and bounce for any highmem page
- */
- blk_queue_bounce_limit(q, BLK_BOUNCE_HIGH);
-}
-
-EXPORT_SYMBOL(blk_queue_make_request);
-
-static void rq_init(struct request_queue *q, struct request *rq)
+void rq_init(struct request_queue *q, struct request *rq)
{
INIT_LIST_HEAD(&rq->queuelist);
INIT_LIST_HEAD(&rq->donelist);
-
- rq->errors = 0;
+ rq->q = q;
+ rq->sector = rq->hard_sector = (sector_t) -1;
+ rq->nr_sectors = rq->hard_nr_sectors = 0;
+ rq->current_nr_sectors = rq->hard_cur_sectors = 0;
rq->bio = rq->biotail = NULL;
INIT_HLIST_NODE(&rq->hash);
RB_CLEAR_NODE(&rq->rb_node);
+ rq->rq_disk = NULL;
+ rq->nr_phys_segments = 0;
+ rq->nr_hw_segments = 0;
rq->ioprio = 0;
+ rq->special = NULL;
rq->buffer = NULL;
+ rq->tag = -1;
+ rq->errors = 0;
rq->ref_count = 1;
- rq->q = q;
- rq->special = NULL;
+ rq->cmd_len = 0;
+ memset(rq->cmd, 0, sizeof(rq->cmd));
rq->data_len = 0;
+ rq->sense_len = 0;
rq->data = NULL;
- rq->nr_phys_segments = 0;
rq->sense = NULL;
rq->end_io = NULL;
rq->end_io_data = NULL;
- rq->completion_data = NULL;
- rq->next_rq = NULL;
-}
-
-/**
- * blk_queue_ordered - does this queue support ordered writes
- * @q: the request queue
- * @ordered: one of QUEUE_ORDERED_*
- * @prepare_flush_fn: rq setup helper for cache flush ordered writes
- *
- * Description:
- * For journalled file systems, doing ordered writes on a commit
- * block instead of explicitly doing wait_on_buffer (which is bad
- * for performance) can be a big win. Block drivers supporting this
- * feature should call this function and indicate so.
- *
- **/
-int blk_queue_ordered(struct request_queue *q, unsigned ordered,
- prepare_flush_fn *prepare_flush_fn)
-{
- if (ordered & (QUEUE_ORDERED_PREFLUSH | QUEUE_ORDERED_POSTFLUSH) &&
- prepare_flush_fn == NULL) {
- printk(KERN_ERR "blk_queue_ordered: prepare_flush_fn required\n");
- return -EINVAL;
- }
-
- if (ordered != QUEUE_ORDERED_NONE &&
- ordered != QUEUE_ORDERED_DRAIN &&
- ordered != QUEUE_ORDERED_DRAIN_FLUSH &&
- ordered != QUEUE_ORDERED_DRAIN_FUA &&
- ordered != QUEUE_ORDERED_TAG &&
- ordered != QUEUE_ORDERED_TAG_FLUSH &&
- ordered != QUEUE_ORDERED_TAG_FUA) {
- printk(KERN_ERR "blk_queue_ordered: bad value %d\n", ordered);
- return -EINVAL;
- }
-
- q->ordered = ordered;
- q->next_ordered = ordered;
- q->prepare_flush_fn = prepare_flush_fn;
-
- return 0;
-}
-
-EXPORT_SYMBOL(blk_queue_ordered);
-
-/*
- * Cache flushing for ordered writes handling
- */
-inline unsigned blk_ordered_cur_seq(struct request_queue *q)
-{
- if (!q->ordseq)
- return 0;
- return 1 << ffz(q->ordseq);
-}
-
-unsigned blk_ordered_req_seq(struct request *rq)
-{
- struct request_queue *q = rq->q;
-
- BUG_ON(q->ordseq == 0);
-
- if (rq == &q->pre_flush_rq)
- return QUEUE_ORDSEQ_PREFLUSH;
- if (rq == &q->bar_rq)
- return QUEUE_ORDSEQ_BAR;
- if (rq == &q->post_flush_rq)
- return QUEUE_ORDSEQ_POSTFLUSH;
-
- /*
- * !fs requests don't need to follow barrier ordering. Always
- * put them at the front. This fixes the following deadlock.
- *
- * http://thread.gmane.org/gmane.linux.kernel/537473
- */
- if (!blk_fs_request(rq))
- return QUEUE_ORDSEQ_DRAIN;
-
- if ((rq->cmd_flags & REQ_ORDERED_COLOR) ==
- (q->orig_bar_rq->cmd_flags & REQ_ORDERED_COLOR))
- return QUEUE_ORDSEQ_DRAIN;
- else
- return QUEUE_ORDSEQ_DONE;
-}
-
-void blk_ordered_complete_seq(struct request_queue *q, unsigned seq, int error)
-{
- struct request *rq;
-
- if (error && !q->orderr)
- q->orderr = error;
-
- BUG_ON(q->ordseq & seq);
- q->ordseq |= seq;
-
- if (blk_ordered_cur_seq(q) != QUEUE_ORDSEQ_DONE)
- return;
-
- /*
- * Okay, sequence complete.
- */
- q->ordseq = 0;
- rq = q->orig_bar_rq;
-
- if (__blk_end_request(rq, q->orderr, blk_rq_bytes(rq)))
- BUG();
-}
-
-static void pre_flush_end_io(struct request *rq, int error)
-{
- elv_completed_request(rq->q, rq);
- blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_PREFLUSH, error);
-}
-
-static void bar_end_io(struct request *rq, int error)
-{
- elv_completed_request(rq->q, rq);
- blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_BAR, error);
-}
-
-static void post_flush_end_io(struct request *rq, int error)
-{
- elv_completed_request(rq->q, rq);
- blk_ordered_complete_seq(rq->q, QUEUE_ORDSEQ_POSTFLUSH, error);
-}
-
-static void queue_flush(struct request_queue *q, unsigned which)
-{
- struct request *rq;
- rq_end_io_fn *end_io;
-
- if (which == QUEUE_ORDERED_PREFLUSH) {
- rq = &q->pre_flush_rq;
- end_io = pre_flush_end_io;
- } else {
- rq = &q->post_flush_rq;
- end_io = post_flush_end_io;
- }
-
- rq->cmd_flags = REQ_HARDBARRIER;
- rq_init(q, rq);
- rq->elevator_private = NULL;
- rq->elevator_private2 = NULL;
- rq->rq_disk = q->bar_rq.rq_disk;
- rq->end_io = end_io;
- q->prepare_flush_fn(q, rq);
-
- elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
-}
-
-static inline struct request *start_ordered(struct request_queue *q,
- struct request *rq)
-{
- q->orderr = 0;
- q->ordered = q->next_ordered;
- q->ordseq |= QUEUE_ORDSEQ_STARTED;
-
- /*
- * Prep proxy barrier request.
- */
- blkdev_dequeue_request(rq);
- q->orig_bar_rq = rq;
- rq = &q->bar_rq;
- rq->cmd_flags = 0;
- rq_init(q, rq);
- if (bio_data_dir(q->orig_bar_rq->bio) == WRITE)
- rq->cmd_flags |= REQ_RW;
- if (q->ordered & QUEUE_ORDERED_FUA)
- rq->cmd_flags |= REQ_FUA;
- rq->elevator_private = NULL;
- rq->elevator_private2 = NULL;
- init_request_from_bio(rq, q->orig_bar_rq->bio);
- rq->end_io = bar_end_io;
-
- /*
- * Queue ordered sequence. As we stack them at the head, we
- * need to queue in reverse order. Note that we rely on that
- * no fs request uses ELEVATOR_INSERT_FRONT and thus no fs
- * request gets inbetween ordered sequence. If this request is
- * an empty barrier, we don't need to do a postflush ever since
- * there will be no data written between the pre and post flush.
- * Hence a single flush will suffice.
- */
- if ((q->ordered & QUEUE_ORDERED_POSTFLUSH) && !blk_empty_barrier(rq))
- queue_flush(q, QUEUE_ORDERED_POSTFLUSH);
- else
- q->ordseq |= QUEUE_ORDSEQ_POSTFLUSH;
-
- elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
-
- if (q->ordered & QUEUE_ORDERED_PREFLUSH) {
- queue_flush(q, QUEUE_ORDERED_PREFLUSH);
- rq = &q->pre_flush_rq;
- } else
- q->ordseq |= QUEUE_ORDSEQ_PREFLUSH;
-
- if ((q->ordered & QUEUE_ORDERED_TAG) || q->in_flight == 0)
- q->ordseq |= QUEUE_ORDSEQ_DRAIN;
- else
- rq = NULL;
-
- return rq;
-}
-
-int blk_do_ordered(struct request_queue *q, struct request **rqp)
-{
- struct request *rq = *rqp;
- const int is_barrier = blk_fs_request(rq) && blk_barrier_rq(rq);
-
- if (!q->ordseq) {
- if (!is_barrier)
- return 1;
-
- if (q->next_ordered != QUEUE_ORDERED_NONE) {
- *rqp = start_ordered(q, rq);
- return 1;
- } else {
- /*
- * This can happen when the queue switches to
- * ORDERED_NONE while this request is on it.
- */
- blkdev_dequeue_request(rq);
- if (__blk_end_request(rq, -EOPNOTSUPP,
- blk_rq_bytes(rq)))
- BUG();
- *rqp = NULL;
- return 0;
- }
- }
-
- /*
- * Ordered sequence in progress
- */
-
- /* Special requests are not subject to ordering rules. */
- if (!blk_fs_request(rq) &&
- rq != &q->pre_flush_rq && rq != &q->post_flush_rq)
- return 1;
-
- if (q->ordered & QUEUE_ORDERED_TAG) {
- /* Ordered by tag. Blocking the next barrier is enough. */
- if (is_barrier && rq != &q->bar_rq)
- *rqp = NULL;
- } else {
- /* Ordered by draining. Wait for turn. */
- WARN_ON(blk_ordered_req_seq(rq) < blk_ordered_cur_seq(q));
- if (blk_ordered_req_seq(rq) > blk_ordered_cur_seq(q))
- *rqp = NULL;
- }
-
- return 1;
-}
-
-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("%s: want %u bytes done, only %u left\n",
- __FUNCTION__, 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;
- }
-}
-
-/**
- * blk_queue_bounce_limit - set bounce buffer limit for queue
- * @q: the request queue for the device
- * @dma_addr: bus address limit
- *
- * Description:
- * Different hardware can have different requirements as to what pages
- * it can do I/O directly to. A low level driver can call
- * blk_queue_bounce_limit to have lower memory pages allocated as bounce
- * buffers for doing I/O to pages residing above @page.
- **/
-void blk_queue_bounce_limit(struct request_queue *q, u64 dma_addr)
-{
- unsigned long bounce_pfn = dma_addr >> PAGE_SHIFT;
- int dma = 0;
-
- q->bounce_gfp = GFP_NOIO;
-#if BITS_PER_LONG == 64
- /* Assume anything <= 4GB can be handled by IOMMU.
- Actually some IOMMUs can handle everything, but I don't
- know of a way to test this here. */
- if (bounce_pfn < (min_t(u64,0xffffffff,BLK_BOUNCE_HIGH) >> PAGE_SHIFT))
- dma = 1;
- q->bounce_pfn = max_low_pfn;
-#else
- if (bounce_pfn < blk_max_low_pfn)
- dma = 1;
- q->bounce_pfn = bounce_pfn;
-#endif
- if (dma) {
- init_emergency_isa_pool();
- q->bounce_gfp = GFP_NOIO | GFP_DMA;
- q->bounce_pfn = bounce_pfn;
- }
-}
-
-EXPORT_SYMBOL(blk_queue_bounce_limit);
-
-/**
- * blk_queue_max_sectors - set max sectors for a request for this queue
- * @q: the request queue for the device
- * @max_sectors: max sectors in the usual 512b unit
- *
- * Description:
- * Enables a low level driver to set an upper limit on the size of
- * received requests.
- **/
-void blk_queue_max_sectors(struct request_queue *q, unsigned int max_sectors)
-{
- if ((max_sectors << 9) < PAGE_CACHE_SIZE) {
- max_sectors = 1 << (PAGE_CACHE_SHIFT - 9);
- printk("%s: set to minimum %d\n", __FUNCTION__, max_sectors);
- }
-
- if (BLK_DEF_MAX_SECTORS > max_sectors)
- q->max_hw_sectors = q->max_sectors = max_sectors;
- else {
- q->max_sectors = BLK_DEF_MAX_SECTORS;
- q->max_hw_sectors = max_sectors;
- }
-}
-
-EXPORT_SYMBOL(blk_queue_max_sectors);
-
-/**
- * blk_queue_max_phys_segments - set max phys segments for a request for this queue
- * @q: the request queue for the device
- * @max_segments: max number of segments
- *
- * Description:
- * Enables a low level driver to set an upper limit on the number of
- * physical data segments in a request. This would be the largest sized
- * scatter list the driver could handle.
- **/
-void blk_queue_max_phys_segments(struct request_queue *q,
- unsigned short max_segments)
-{
- if (!max_segments) {
- max_segments = 1;
- printk("%s: set to minimum %d\n", __FUNCTION__, max_segments);
- }
-
- q->max_phys_segments = max_segments;
-}
-
-EXPORT_SYMBOL(blk_queue_max_phys_segments);
-
-/**
- * blk_queue_max_hw_segments - set max hw segments for a request for this queue
- * @q: the request queue for the device
- * @max_segments: max number of segments
- *
- * Description:
- * Enables a low level driver to set an upper limit on the number of
- * hw data segments in a request. This would be the largest number of
- * address/length pairs the host adapter can actually give as once
- * to the device.
- **/
-void blk_queue_max_hw_segments(struct request_queue *q,
- unsigned short max_segments)
-{
- if (!max_segments) {
- max_segments = 1;
- printk("%s: set to minimum %d\n", __FUNCTION__, max_segments);
- }
-
- q->max_hw_segments = max_segments;
-}
-
-EXPORT_SYMBOL(blk_queue_max_hw_segments);
-
-/**
- * blk_queue_max_segment_size - set max segment size for blk_rq_map_sg
- * @q: the request queue for the device
- * @max_size: max size of segment in bytes
- *
- * Description:
- * Enables a low level driver to set an upper limit on the size of a
- * coalesced segment
- **/
-void blk_queue_max_segment_size(struct request_queue *q, unsigned int max_size)
-{
- if (max_size < PAGE_CACHE_SIZE) {
- max_size = PAGE_CACHE_SIZE;
- printk("%s: set to minimum %d\n", __FUNCTION__, max_size);
- }
-
- q->max_segment_size = max_size;
-}
-
-EXPORT_SYMBOL(blk_queue_max_segment_size);
-
-/**
- * blk_queue_hardsect_size - set hardware sector size for the queue
- * @q: the request queue for the device
- * @size: the hardware sector size, in bytes
- *
- * Description:
- * This should typically be set to the lowest possible sector size
- * that the hardware can operate on (possible without reverting to
- * even internal read-modify-write operations). Usually the default
- * of 512 covers most hardware.
- **/
-void blk_queue_hardsect_size(struct request_queue *q, unsigned short size)
-{
- q->hardsect_size = size;
-}
-
-EXPORT_SYMBOL(blk_queue_hardsect_size);
-
-/*
- * Returns the minimum that is _not_ zero, unless both are zero.
- */
-#define min_not_zero(l, r) (l == 0) ? r : ((r == 0) ? l : min(l, r))
-
-/**
- * blk_queue_stack_limits - inherit underlying queue limits for stacked drivers
- * @t: the stacking driver (top)
- * @b: the underlying device (bottom)
- **/
-void blk_queue_stack_limits(struct request_queue *t, struct request_queue *b)
-{
- /* zero is "infinity" */
- t->max_sectors = min_not_zero(t->max_sectors,b->max_sectors);
- t->max_hw_sectors = min_not_zero(t->max_hw_sectors,b->max_hw_sectors);
-
- t->max_phys_segments = min(t->max_phys_segments,b->max_phys_segments);
- t->max_hw_segments = min(t->max_hw_segments,b->max_hw_segments);
- t->max_segment_size = min(t->max_segment_size,b->max_segment_size);
- t->hardsect_size = max(t->hardsect_size,b->hardsect_size);
- if (!test_bit(QUEUE_FLAG_CLUSTER, &b->queue_flags))
- clear_bit(QUEUE_FLAG_CLUSTER, &t->queue_flags);
-}
-
-EXPORT_SYMBOL(blk_queue_stack_limits);
-
-/**
- * blk_queue_dma_drain - Set up a drain buffer for excess dma.
- *
- * @q: the request queue for the device
- * @buf: physically contiguous buffer
- * @size: size of the buffer in bytes
- *
- * Some devices have excess DMA problems and can't simply discard (or
- * zero fill) the unwanted piece of the transfer. They have to have a
- * real area of memory to transfer it into. The use case for this is
- * ATAPI devices in DMA mode. If the packet command causes a transfer
- * bigger than the transfer size some HBAs will lock up if there
- * aren't DMA elements to contain the excess transfer. What this API
- * does is adjust the queue so that the buf is always appended
- * silently to the scatterlist.
- *
- * Note: This routine adjusts max_hw_segments to make room for
- * appending the drain buffer. If you call
- * blk_queue_max_hw_segments() or blk_queue_max_phys_segments() after
- * calling this routine, you must set the limit to one fewer than your
- * device can support otherwise there won't be room for the drain
- * buffer.
- */
-int blk_queue_dma_drain(struct request_queue *q, void *buf,
- unsigned int size)
-{
- if (q->max_hw_segments < 2 || q->max_phys_segments < 2)
- return -EINVAL;
- /* make room for appending the drain */
- --q->max_hw_segments;
- --q->max_phys_segments;
- q->dma_drain_buffer = buf;
- q->dma_drain_size = size;
-
- return 0;
-}
-
-EXPORT_SYMBOL_GPL(blk_queue_dma_drain);
-
-/**
- * blk_queue_segment_boundary - set boundary rules for segment merging
- * @q: the request queue for the device
- * @mask: the memory boundary mask
- **/
-void blk_queue_segment_boundary(struct request_queue *q, unsigned long mask)
-{
- if (mask < PAGE_CACHE_SIZE - 1) {
- mask = PAGE_CACHE_SIZE - 1;
- printk("%s: set to minimum %lx\n", __FUNCTION__, mask);
- }
-
- q->seg_boundary_mask = mask;
-}
-
-EXPORT_SYMBOL(blk_queue_segment_boundary);
-
-/**
- * blk_queue_dma_alignment - set dma length and memory alignment
- * @q: the request queue for the device
- * @mask: alignment mask
- *
- * description:
- * set required memory and length aligment for direct dma transactions.
- * this is used when buiding direct io requests for the queue.
- *
- **/
-void blk_queue_dma_alignment(struct request_queue *q, int mask)
-{
- q->dma_alignment = mask;
-}
-
-EXPORT_SYMBOL(blk_queue_dma_alignment);
-
-/**
- * blk_queue_update_dma_alignment - update dma length and memory alignment
- * @q: the request queue for the device
- * @mask: alignment mask
- *
- * description:
- * update required memory and length aligment for direct dma transactions.
- * If the requested alignment is larger than the current alignment, then
- * the current queue alignment is updated to the new value, otherwise it
- * is left alone. The design of this is to allow multiple objects
- * (driver, device, transport etc) to set their respective
- * alignments without having them interfere.
- *
- **/
-void blk_queue_update_dma_alignment(struct request_queue *q, int mask)
-{
- BUG_ON(mask > PAGE_SIZE);
-
- if (mask > q->dma_alignment)
- q->dma_alignment = mask;
-}
-
-EXPORT_SYMBOL(blk_queue_update_dma_alignment);
-
-void blk_dump_rq_flags(struct request *rq, char *msg)
-{
- int bit;
-
- printk("%s: dev %s: type=%x, flags=%x\n", msg,
- rq->rq_disk ? rq->rq_disk->disk_name : "?", rq->cmd_type,
- rq->cmd_flags);
-
- printk("\nsector %llu, nr/cnr %lu/%u\n", (unsigned long long)rq->sector,
- rq->nr_sectors,
- rq->current_nr_sectors);
- printk("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("cdb: ");
- for (bit = 0; bit < sizeof(rq->cmd); bit++)
- printk("%02x ", rq->cmd[bit]);
- printk("\n");
- }
-}
-
-EXPORT_SYMBOL(blk_dump_rq_flags);
-
-void blk_recount_segments(struct request_queue *q, struct bio *bio)
-{
- struct request rq;
- struct bio *nxt = bio->bi_next;
- rq.q = q;
- rq.bio = rq.biotail = bio;
- bio->bi_next = NULL;
- blk_recalc_rq_segments(&rq);
- bio->bi_next = nxt;
- bio->bi_phys_segments = rq.nr_phys_segments;
- bio->bi_hw_segments = rq.nr_hw_segments;
- bio->bi_flags |= (1 << BIO_SEG_VALID);
-}
-EXPORT_SYMBOL(blk_recount_segments);
-
-static void blk_recalc_rq_segments(struct request *rq)
-{
- int nr_phys_segs;
- int nr_hw_segs;
- unsigned int phys_size;
- unsigned int hw_size;
- struct bio_vec *bv, *bvprv = NULL;
- int seg_size;
- int hw_seg_size;
- int cluster;
- struct req_iterator iter;
- int high, highprv = 1;
- struct request_queue *q = rq->q;
-
- if (!rq->bio)
- return;
-
- cluster = q->queue_flags & (1 << QUEUE_FLAG_CLUSTER);
- hw_seg_size = seg_size = 0;
- phys_size = hw_size = nr_phys_segs = nr_hw_segs = 0;
- rq_for_each_segment(bv, rq, iter) {
- /*
- * the trick here is making sure that a high page is never
- * considered part of another segment, since that might
- * change with the bounce page.
- */
- high = page_to_pfn(bv->bv_page) > q->bounce_pfn;
- if (high || highprv)
- goto new_hw_segment;
- if (cluster) {
- if (seg_size + bv->bv_len > q->max_segment_size)
- goto new_segment;
- if (!BIOVEC_PHYS_MERGEABLE(bvprv, bv))
- goto new_segment;
- if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bv))
- goto new_segment;
- if (BIOVEC_VIRT_OVERSIZE(hw_seg_size + bv->bv_len))
- goto new_hw_segment;
-
- seg_size += bv->bv_len;
- hw_seg_size += bv->bv_len;
- bvprv = bv;
- continue;
- }
-new_segment:
- if (BIOVEC_VIRT_MERGEABLE(bvprv, bv) &&
- !BIOVEC_VIRT_OVERSIZE(hw_seg_size + bv->bv_len))
- hw_seg_size += bv->bv_len;
- else {
-new_hw_segment:
- if (nr_hw_segs == 1 &&
- hw_seg_size > rq->bio->bi_hw_front_size)
- rq->bio->bi_hw_front_size = hw_seg_size;
- hw_seg_size = BIOVEC_VIRT_START_SIZE(bv) + bv->bv_len;
- nr_hw_segs++;
- }
-
- nr_phys_segs++;
- bvprv = bv;
- seg_size = bv->bv_len;
- highprv = high;
- }
-
- if (nr_hw_segs == 1 &&
- hw_seg_size > rq->bio->bi_hw_front_size)
- rq->bio->bi_hw_front_size = hw_seg_size;
- if (hw_seg_size > rq->biotail->bi_hw_back_size)
- rq->biotail->bi_hw_back_size = hw_seg_size;
- rq->nr_phys_segments = nr_phys_segs;
- rq->nr_hw_segments = nr_hw_segs;
-}
-
-static int blk_phys_contig_segment(struct request_queue *q, struct bio *bio,
- struct bio *nxt)
-{
- if (!(q->queue_flags & (1 << QUEUE_FLAG_CLUSTER)))
- return 0;
-
- if (!BIOVEC_PHYS_MERGEABLE(__BVEC_END(bio), __BVEC_START(nxt)))
- return 0;
- if (bio->bi_size + nxt->bi_size > q->max_segment_size)
- return 0;
-
- /*
- * bio and nxt are contigous in memory, check if the queue allows
- * these two to be merged into one
- */
- if (BIO_SEG_BOUNDARY(q, bio, nxt))
- return 1;
-
- return 0;
-}
-
-static int blk_hw_contig_segment(struct request_queue *q, struct bio *bio,
- struct bio *nxt)
-{
- if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
- blk_recount_segments(q, bio);
- if (unlikely(!bio_flagged(nxt, BIO_SEG_VALID)))
- blk_recount_segments(q, nxt);
- if (!BIOVEC_VIRT_MERGEABLE(__BVEC_END(bio), __BVEC_START(nxt)) ||
- BIOVEC_VIRT_OVERSIZE(bio->bi_hw_back_size + nxt->bi_hw_front_size))
- return 0;
- if (bio->bi_hw_back_size + nxt->bi_hw_front_size > q->max_segment_size)
- return 0;
-
- return 1;
-}
-
-/*
- * map a request to scatterlist, return number of sg entries setup. Caller
- * must make sure sg can hold rq->nr_phys_segments entries
- */
-int blk_rq_map_sg(struct request_queue *q, struct request *rq,
- struct scatterlist *sglist)
-{
- struct bio_vec *bvec, *bvprv;
- struct req_iterator iter;
- struct scatterlist *sg;
- int nsegs, cluster;
-
- nsegs = 0;
- cluster = q->queue_flags & (1 << QUEUE_FLAG_CLUSTER);
-
- /*
- * for each bio in rq
- */
- bvprv = NULL;
- sg = NULL;
- rq_for_each_segment(bvec, rq, iter) {
- int nbytes = bvec->bv_len;
-
- if (bvprv && cluster) {
- if (sg->length + nbytes > q->max_segment_size)
- goto new_segment;
-
- if (!BIOVEC_PHYS_MERGEABLE(bvprv, bvec))
- goto new_segment;
- if (!BIOVEC_SEG_BOUNDARY(q, bvprv, bvec))
- goto new_segment;
-
- sg->length += nbytes;
- } else {
-new_segment:
- if (!sg)
- sg = sglist;
- else {
- /*
- * If the driver previously mapped a shorter
- * list, we could see a termination bit
- * prematurely unless it fully inits the sg
- * table on each mapping. We KNOW that there
- * must be more entries here or the driver
- * would be buggy, so force clear the
- * termination bit to avoid doing a full
- * sg_init_table() in drivers for each command.
- */
- sg->page_link &= ~0x02;
- sg = sg_next(sg);
- }
-
- sg_set_page(sg, bvec->bv_page, nbytes, bvec->bv_offset);
- nsegs++;
- }
- bvprv = bvec;
- } /* segments in rq */
-
- if (q->dma_drain_size) {
- sg->page_link &= ~0x02;
- sg = sg_next(sg);
- sg_set_page(sg, virt_to_page(q->dma_drain_buffer),
- q->dma_drain_size,
- ((unsigned long)q->dma_drain_buffer) &
- (PAGE_SIZE - 1));
- nsegs++;
- }
-
- if (sg)
- sg_mark_end(sg);
-
- return nsegs;
-}
-
-EXPORT_SYMBOL(blk_rq_map_sg);
-
-/*
- * the standard queue merge functions, can be overridden with device
- * specific ones if so desired
- */
-
-static inline int ll_new_mergeable(struct request_queue *q,
- struct request *req,
- struct bio *bio)
-{
- int nr_phys_segs = bio_phys_segments(q, bio);
-
- if (req->nr_phys_segments + nr_phys_segs > q->max_phys_segments) {
- req->cmd_flags |= REQ_NOMERGE;
- if (req == q->last_merge)
- q->last_merge = NULL;
- return 0;
- }
-
- /*
- * A hw segment is just getting larger, bump just the phys
- * counter.
- */
- req->nr_phys_segments += nr_phys_segs;
- return 1;
-}
-
-static inline int ll_new_hw_segment(struct request_queue *q,
- struct request *req,
- struct bio *bio)
-{
- int nr_hw_segs = bio_hw_segments(q, bio);
- int nr_phys_segs = bio_phys_segments(q, bio);
-
- if (req->nr_hw_segments + nr_hw_segs > q->max_hw_segments
- || req->nr_phys_segments + nr_phys_segs > q->max_phys_segments) {
- req->cmd_flags |= REQ_NOMERGE;
- if (req == q->last_merge)
- q->last_merge = NULL;
- return 0;
- }
-
- /*
- * This will form the start of a new hw segment. Bump both
- * counters.
- */
- req->nr_hw_segments += nr_hw_segs;
- req->nr_phys_segments += nr_phys_segs;
- return 1;
+ rq->next_rq = NULL;
}
-static int ll_back_merge_fn(struct request_queue *q, struct request *req,
- struct bio *bio)
+static void req_bio_endio(struct request *rq, struct bio *bio,
+ unsigned int nbytes, int error)
{
- unsigned short max_sectors;
- int len;
+ struct request_queue *q = rq->q;
- if (unlikely(blk_pc_request(req)))
- max_sectors = q->max_hw_sectors;
- else
- max_sectors = q->max_sectors;
+ 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 (req->nr_sectors + bio_sectors(bio) > max_sectors) {
- req->cmd_flags |= REQ_NOMERGE;
- if (req == q->last_merge)
- q->last_merge = NULL;
- return 0;
- }
- if (unlikely(!bio_flagged(req->biotail, BIO_SEG_VALID)))
- blk_recount_segments(q, req->biotail);
- if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
- blk_recount_segments(q, bio);
- len = req->biotail->bi_hw_back_size + bio->bi_hw_front_size;
- if (BIOVEC_VIRT_MERGEABLE(__BVEC_END(req->biotail), __BVEC_START(bio)) &&
- !BIOVEC_VIRT_OVERSIZE(len)) {
- int mergeable = ll_new_mergeable(q, req, bio);
-
- if (mergeable) {
- if (req->nr_hw_segments == 1)
- req->bio->bi_hw_front_size = len;
- if (bio->bi_hw_segments == 1)
- bio->bi_hw_back_size = len;
+ if (unlikely(nbytes > bio->bi_size)) {
+ printk(KERN_ERR "%s: want %u bytes done, %u left\n",
+ __FUNCTION__, nbytes, bio->bi_size);
+ nbytes = bio->bi_size;
}
- return mergeable;
- }
-
- return ll_new_hw_segment(q, req, bio);
-}
-
-static int ll_front_merge_fn(struct request_queue *q, struct request *req,
- struct bio *bio)
-{
- unsigned short max_sectors;
- int len;
-
- if (unlikely(blk_pc_request(req)))
- max_sectors = q->max_hw_sectors;
- else
- max_sectors = q->max_sectors;
+ bio->bi_size -= nbytes;
+ bio->bi_sector += (nbytes >> 9);
+ if (bio->bi_size == 0)
+ bio_endio(bio, error);
+ } else {
- if (req->nr_sectors + bio_sectors(bio) > max_sectors) {
- req->cmd_flags |= REQ_NOMERGE;
- if (req == q->last_merge)
- q->last_merge = NULL;
- return 0;
- }
- len = bio->bi_hw_back_size + req->bio->bi_hw_front_size;
- if (unlikely(!bio_flagged(bio, BIO_SEG_VALID)))
- blk_recount_segments(q, bio);
- if (unlikely(!bio_flagged(req->bio, BIO_SEG_VALID)))
- blk_recount_segments(q, req->bio);
- if (BIOVEC_VIRT_MERGEABLE(__BVEC_END(bio), __BVEC_START(req->bio)) &&
- !BIOVEC_VIRT_OVERSIZE(len)) {
- int mergeable = ll_new_mergeable(q, req, bio);
-
- if (mergeable) {
- if (bio->bi_hw_segments == 1)
- bio->bi_hw_front_size = len;
- if (req->nr_hw_segments == 1)
- req->biotail->bi_hw_back_size = len;
- }
- return mergeable;
+ /*
+ * Okay, this is the barrier request in progress, just
+ * record the error;
+ */
+ if (error && !q->orderr)
+ q->orderr = error;
}
-
- return ll_new_hw_segment(q, req, bio);
}
-static int ll_merge_requests_fn(struct request_queue *q, struct request *req,
- struct request *next)
+void blk_dump_rq_flags(struct request *rq, char *msg)
{
- int total_phys_segments;
- int total_hw_segments;
-
- /*
- * First check if the either of the requests are re-queued
- * requests. Can't merge them if they are.
- */
- if (req->special || next->special)
- return 0;
-
- /*
- * Will it become too large?
- */
- if ((req->nr_sectors + next->nr_sectors) > q->max_sectors)
- return 0;
+ int bit;
- total_phys_segments = req->nr_phys_segments + next->nr_phys_segments;
- if (blk_phys_contig_segment(q, req->biotail, next->bio))
- total_phys_segments--;
+ 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);
- if (total_phys_segments > q->max_phys_segments)
- return 0;
+ 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);
- total_hw_segments = req->nr_hw_segments + next->nr_hw_segments;
- if (blk_hw_contig_segment(q, req->biotail, next->bio)) {
- int len = req->biotail->bi_hw_back_size + next->bio->bi_hw_front_size;
- /*
- * propagate the combined length to the end of the requests
- */
- if (req->nr_hw_segments == 1)
- req->bio->bi_hw_front_size = len;
- if (next->nr_hw_segments == 1)
- next->biotail->bi_hw_back_size = len;
- total_hw_segments--;
+ if (blk_pc_request(rq)) {
+ printk(KERN_INFO " cdb: ");
+ for (bit = 0; bit < sizeof(rq->cmd); bit++)
+ printk("%02x ", rq->cmd[bit]);
+ printk("\n");
}
-
- if (total_hw_segments > q->max_hw_segments)
- return 0;
-
- /* Merge is OK... */
- req->nr_phys_segments = total_phys_segments;
- req->nr_hw_segments = total_hw_segments;
- return 1;
}
+EXPORT_SYMBOL(blk_dump_rq_flags);
/*
* "plug" the device if there are no outstanding requests: this will
blk_add_trace_generic(q, NULL, 0, BLK_TA_PLUG);
}
}
-
EXPORT_SYMBOL(blk_plug_device);
/*
del_timer(&q->unplug_timer);
return 1;
}
-
EXPORT_SYMBOL(blk_remove_plug);
/*
blk_unplug(q);
}
-static void blk_unplug_work(struct work_struct *work)
+void blk_unplug_work(struct work_struct *work)
{
struct request_queue *q =
container_of(work, struct request_queue, unplug_work);
q->unplug_fn(q);
}
-static void blk_unplug_timeout(unsigned long data)
+void blk_unplug_timeout(unsigned long data)
{
struct request_queue *q = (struct request_queue *)data;
kblockd_schedule_work(&q->unplug_work);
}
}
-
EXPORT_SYMBOL(blk_start_queue);
/**
}
EXPORT_SYMBOL(blk_put_queue);
-void blk_cleanup_queue(struct request_queue * q)
+void blk_cleanup_queue(struct request_queue *q)
{
mutex_lock(&q->sysfs_lock);
set_bit(QUEUE_FLAG_DEAD, &q->queue_flags);
blk_put_queue(q);
}
-
EXPORT_SYMBOL(blk_cleanup_queue);
static int blk_init_free_list(struct request_queue *q)
return 1;
}
-
EXPORT_SYMBOL(blk_get_queue);
static inline void blk_free_request(struct request_queue *q, struct request *rq)
*/
if (ioc_batching(q, ioc))
ioc->nr_batch_requests--;
-
+
rq_init(q, rq);
blk_add_trace_generic(q, bio, rw, BLK_TA_GETRQ);
/**
* 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);
-
-static int __blk_rq_unmap_user(struct bio *bio)
-{
- int ret = 0;
-
- if (bio) {
- if (bio_flagged(bio, BIO_USER_MAPPED))
- bio_unmap_user(bio);
- else
- ret = bio_uncopy_user(bio);
- }
-
- return ret;
-}
-
-int blk_rq_append_bio(struct request_queue *q, struct request *rq,
- struct bio *bio)
-{
- if (!rq->bio)
- blk_rq_bio_prep(q, rq, bio);
- else if (!ll_back_merge_fn(q, rq, bio))
- return -EINVAL;
- else {
- rq->biotail->bi_next = bio;
- rq->biotail = bio;
-
- rq->data_len += bio->bi_size;
- }
- return 0;
-}
-EXPORT_SYMBOL(blk_rq_append_bio);
-
-static int __blk_rq_map_user(struct request_queue *q, struct request *rq,
- void __user *ubuf, unsigned int len)
-{
- unsigned long uaddr;
- struct bio *bio, *orig_bio;
- int reading, ret;
-
- reading = rq_data_dir(rq) == READ;
-
- /*
- * if alignment requirement is satisfied, map in user pages for
- * direct dma. else, set up kernel bounce buffers
- */
- uaddr = (unsigned long) ubuf;
- if (!(uaddr & queue_dma_alignment(q)) && !(len & queue_dma_alignment(q)))
- bio = bio_map_user(q, NULL, uaddr, len, reading);
- else
- bio = bio_copy_user(q, uaddr, len, reading);
-
- if (IS_ERR(bio))
- return PTR_ERR(bio);
-
- orig_bio = bio;
- blk_queue_bounce(q, &bio);
-
- /*
- * We link the bounce buffer in and could have to traverse it
- * later so we have to get a ref to prevent it from being freed
- */
- bio_get(bio);
-
- ret = blk_rq_append_bio(q, rq, bio);
- if (!ret)
- return bio->bi_size;
-
- /* if it was boucned we must call the end io function */
- bio_endio(bio, 0);
- __blk_rq_unmap_user(orig_bio);
- bio_put(bio);
- return ret;
-}
-
-/**
- * blk_rq_map_user - map user data to a request, for REQ_BLOCK_PC usage
- * @q: request queue where request should be inserted
- * @rq: request structure to fill
- * @ubuf: the user buffer
- * @len: length of user data
- *
- * Description:
- * Data will be mapped directly for zero copy io, if possible. Otherwise
- * a kernel bounce buffer is used.
- *
- * A matching blk_rq_unmap_user() must be issued at the end of io, while
- * still in process context.
- *
- * Note: The mapped bio may need to be bounced through blk_queue_bounce()
- * before being submitted to the device, as pages mapped may be out of
- * reach. It's the callers responsibility to make sure this happens. The
- * original bio must be passed back in to blk_rq_unmap_user() for proper
- * unmapping.
- */
-int blk_rq_map_user(struct request_queue *q, struct request *rq,
- void __user *ubuf, unsigned long len)
-{
- unsigned long bytes_read = 0;
- struct bio *bio = NULL;
- int ret;
-
- if (len > (q->max_hw_sectors << 9))
- return -EINVAL;
- if (!len || !ubuf)
- return -EINVAL;
-
- while (bytes_read != len) {
- unsigned long map_len, end, start;
-
- map_len = min_t(unsigned long, len - bytes_read, BIO_MAX_SIZE);
- end = ((unsigned long)ubuf + map_len + PAGE_SIZE - 1)
- >> PAGE_SHIFT;
- start = (unsigned long)ubuf >> PAGE_SHIFT;
-
- /*
- * A bad offset could cause us to require BIO_MAX_PAGES + 1
- * pages. If this happens we just lower the requested
- * mapping len by a page so that we can fit
- */
- if (end - start > BIO_MAX_PAGES)
- map_len -= PAGE_SIZE;
-
- ret = __blk_rq_map_user(q, rq, ubuf, map_len);
- if (ret < 0)
- goto unmap_rq;
- if (!bio)
- bio = rq->bio;
- bytes_read += ret;
- ubuf += ret;
- }
-
- rq->buffer = rq->data = NULL;
- return 0;
-unmap_rq:
- blk_rq_unmap_user(bio);
- return ret;
-}
-
-EXPORT_SYMBOL(blk_rq_map_user);
-
-/**
- * blk_rq_map_user_iov - map user data to a request, for REQ_BLOCK_PC usage
- * @q: request queue where request should be inserted
- * @rq: request to map data to
- * @iov: pointer to the iovec
- * @iov_count: number of elements in the iovec
- * @len: I/O byte count
- *
- * Description:
- * Data will be mapped directly for zero copy io, if possible. Otherwise
- * a kernel bounce buffer is used.
- *
- * A matching blk_rq_unmap_user() must be issued at the end of io, while
- * still in process context.
- *
- * Note: The mapped bio may need to be bounced through blk_queue_bounce()
- * before being submitted to the device, as pages mapped may be out of
- * reach. It's the callers responsibility to make sure this happens. The
- * original bio must be passed back in to blk_rq_unmap_user() for proper
- * unmapping.
- */
-int blk_rq_map_user_iov(struct request_queue *q, struct request *rq,
- struct sg_iovec *iov, int iov_count, unsigned int len)
-{
- struct bio *bio;
-
- if (!iov || iov_count <= 0)
- return -EINVAL;
-
- /* we don't allow misaligned data like bio_map_user() does. If the
- * user is using sg, they're expected to know the alignment constraints
- * and respect them accordingly */
- bio = bio_map_user_iov(q, NULL, iov, iov_count, rq_data_dir(rq)== READ);
- if (IS_ERR(bio))
- return PTR_ERR(bio);
-
- if (bio->bi_size != len) {
- bio_endio(bio, 0);
- bio_unmap_user(bio);
- return -EINVAL;
- }
-
- bio_get(bio);
- blk_rq_bio_prep(q, rq, bio);
- rq->buffer = rq->data = NULL;
- return 0;
-}
-
-EXPORT_SYMBOL(blk_rq_map_user_iov);
-
-/**
- * blk_rq_unmap_user - unmap a request with user data
- * @bio: start of bio list
- *
- * Description:
- * Unmap a rq previously mapped by blk_rq_map_user(). The caller must
- * supply the original rq->bio from the blk_rq_map_user() return, since
- * the io completion may have changed rq->bio.
- */
-int blk_rq_unmap_user(struct bio *bio)
-{
- struct bio *mapped_bio;
- int ret = 0, ret2;
-
- while (bio) {
- mapped_bio = bio;
- if (unlikely(bio_flagged(bio, BIO_BOUNCED)))
- mapped_bio = bio->bi_private;
-
- ret2 = __blk_rq_unmap_user(mapped_bio);
- if (ret2 && !ret)
- ret = ret2;
-
- mapped_bio = bio;
- bio = bio->bi_next;
- bio_put(mapped_bio);
- }
-
- return ret;
-}
-
-EXPORT_SYMBOL(blk_rq_unmap_user);
-
-/**
- * blk_rq_map_kern - map kernel data to a request, for REQ_BLOCK_PC usage
- * @q: request queue where request should be inserted
- * @rq: request to fill
- * @kbuf: the kernel buffer
- * @len: length of user data
- * @gfp_mask: memory allocation flags
- */
-int blk_rq_map_kern(struct request_queue *q, struct request *rq, void *kbuf,
- unsigned int len, gfp_t gfp_mask)
-{
- struct bio *bio;
-
- if (len > (q->max_hw_sectors << 9))
- return -EINVAL;
- if (!len || !kbuf)
- return -EINVAL;
-
- bio = bio_map_kern(q, kbuf, len, gfp_mask);
- if (IS_ERR(bio))
- return PTR_ERR(bio);
-
- if (rq_data_dir(rq) == WRITE)
- bio->bi_rw |= (1 << BIO_RW);
-
- blk_rq_bio_prep(q, rq, bio);
- blk_queue_bounce(q, &rq->bio);
- rq->buffer = rq->data = NULL;
- return 0;
-}
-
-EXPORT_SYMBOL(blk_rq_map_kern);
-
-/**
- * blk_execute_rq_nowait - insert a request into queue for execution
- * @q: queue to insert the request in
- * @bd_disk: matching gendisk
- * @rq: request to insert
- * @at_head: insert request at head or tail of queue
- * @done: I/O completion handler
+ * @q: request queue to kick into gear
*
- * Description:
- * Insert a fully prepared request at the back of the io scheduler queue
- * for execution. Don't wait for completion.
+ * 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_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
- struct request *rq, int at_head,
- rq_end_io_fn *done)
+void blk_start_queueing(struct request_queue *q)
{
- int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
-
- rq->rq_disk = bd_disk;
- rq->cmd_flags |= REQ_NOMERGE;
- rq->end_io = done;
- WARN_ON(irqs_disabled());
- spin_lock_irq(q->queue_lock);
- __elv_add_request(q, rq, where, 1);
- __generic_unplug_device(q);
- spin_unlock_irq(q->queue_lock);
+ if (!blk_queue_plugged(q))
+ q->request_fn(q);
+ else
+ __generic_unplug_device(q);
}
-EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
+EXPORT_SYMBOL(blk_start_queueing);
/**
- * blk_execute_rq - insert a request into queue for execution
- * @q: queue to insert the request in
- * @bd_disk: matching gendisk
- * @rq: request to insert
- * @at_head: insert request at head or tail of queue
+ * blk_requeue_request - put a request back on queue
+ * @q: request queue where request should be inserted
+ * @rq: request to be inserted
*
* Description:
- * Insert a fully prepared request at the back of the io scheduler queue
- * for execution and wait for completion.
+ * 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.
*/
-int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk,
- struct request *rq, int at_head)
+void blk_requeue_request(struct request_queue *q, struct request *rq)
{
- DECLARE_COMPLETION_ONSTACK(wait);
- char sense[SCSI_SENSE_BUFFERSIZE];
- int err = 0;
-
- /*
- * we need an extra reference to the request, so we can look at
- * it after io completion
- */
- rq->ref_count++;
-
- if (!rq->sense) {
- memset(sense, 0, sizeof(sense));
- rq->sense = sense;
- rq->sense_len = 0;
- }
-
- rq->end_io_data = &wait;
- blk_execute_rq_nowait(q, bd_disk, rq, at_head, blk_end_sync_rq);
- wait_for_completion(&wait);
-
- if (rq->errors)
- err = -EIO;
-
- return err;
-}
-
-EXPORT_SYMBOL(blk_execute_rq);
+ blk_add_trace_rq(q, rq, BLK_TA_REQUEUE);
-static void bio_end_empty_barrier(struct bio *bio, int err)
-{
- if (err)
- clear_bit(BIO_UPTODATE, &bio->bi_flags);
+ if (blk_rq_tagged(rq))
+ blk_queue_end_tag(q, rq);
- complete(bio->bi_private);
+ elv_requeue_request(q, rq);
}
+EXPORT_SYMBOL(blk_requeue_request);
/**
- * blkdev_issue_flush - queue a flush
- * @bdev: blockdev to issue flush for
- * @error_sector: error sector
+ * 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:
- * Issue a flush for the block device in question. Caller can supply
- * room for storing the error offset in case of a flush error, if they
- * wish to. Caller must run wait_for_completion() on its own.
+ * 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.
*/
-int blkdev_issue_flush(struct block_device *bdev, sector_t *error_sector)
+void blk_insert_request(struct request_queue *q, struct request *rq,
+ int at_head, void *data)
{
- DECLARE_COMPLETION_ONSTACK(wait);
- struct request_queue *q;
- struct bio *bio;
- int ret;
-
- if (bdev->bd_disk == NULL)
- return -ENXIO;
-
- q = bdev_get_queue(bdev);
- if (!q)
- return -ENXIO;
-
- bio = bio_alloc(GFP_KERNEL, 0);
- if (!bio)
- return -ENOMEM;
-
- bio->bi_end_io = bio_end_empty_barrier;
- bio->bi_private = &wait;
- bio->bi_bdev = bdev;
- submit_bio(1 << BIO_RW_BARRIER, bio);
-
- wait_for_completion(&wait);
+ int where = at_head ? ELEVATOR_INSERT_FRONT : ELEVATOR_INSERT_BACK;
+ unsigned long flags;
/*
- * The driver must store the error location in ->bi_sector, if
- * it supports it. For non-stacked drivers, this should be copied
- * from rq->sector.
+ * 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
*/
- if (error_sector)
- *error_sector = bio->bi_sector;
-
- ret = 0;
- if (!bio_flagged(bio, BIO_UPTODATE))
- ret = -EIO;
-
- bio_put(bio);
- return ret;
-}
+ rq->cmd_type = REQ_TYPE_SPECIAL;
+ rq->cmd_flags |= REQ_SOFTBARRIER;
-EXPORT_SYMBOL(blkdev_issue_flush);
+ rq->special = data;
-static void drive_stat_acct(struct request *rq, int new_io)
-{
- int rw = rq_data_dir(rq);
+ spin_lock_irqsave(q->queue_lock, flags);
- if (!blk_fs_request(rq) || !rq->rq_disk)
- return;
+ /*
+ * If command is tagged, release the tag
+ */
+ if (blk_rq_tagged(rq))
+ blk_queue_end_tag(q, rq);
- if (!new_io) {
- __disk_stat_inc(rq->rq_disk, merges[rw]);
- } else {
- disk_round_stats(rq->rq_disk);
- rq->rq_disk->in_flight++;
- }
+ 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)
+static inline void add_request(struct request_queue *q, struct request *req)
{
drive_stat_acct(req, 1);
*/
__elv_add_request(q, req, ELEVATOR_INSERT_SORT, 0);
}
-
+
/*
* disk_round_stats() - Round off the performance stats on a struct
* disk_stats.
}
disk->stamp = now;
}
-
EXPORT_SYMBOL_GPL(disk_round_stats);
/*
freed_request(q, rw, priv);
}
}
-
EXPORT_SYMBOL_GPL(__blk_put_request);
void blk_put_request(struct request *req)
spin_unlock_irqrestore(q->queue_lock, flags);
}
}
-
EXPORT_SYMBOL(blk_put_request);
-/**
- * blk_end_sync_rq - executes a completion event on a request
- * @rq: request to complete
- * @error: end io status of the request
- */
-void blk_end_sync_rq(struct request *rq, int error)
-{
- struct completion *waiting = rq->end_io_data;
-
- rq->end_io_data = NULL;
- __blk_put_request(rq->q, rq);
-
- /*
- * complete last, if this is a stack request the process (and thus
- * the rq pointer) could be invalid right after this complete()
- */
- complete(waiting);
-}
-EXPORT_SYMBOL(blk_end_sync_rq);
-
-/*
- * Has to be called with the request spinlock acquired
- */
-static int attempt_merge(struct request_queue *q, struct request *req,
- struct request *next)
-{
- if (!rq_mergeable(req) || !rq_mergeable(next))
- return 0;
-
- /*
- * not contiguous
- */
- if (req->sector + req->nr_sectors != next->sector)
- return 0;
-
- if (rq_data_dir(req) != rq_data_dir(next)
- || req->rq_disk != next->rq_disk
- || next->special)
- return 0;
-
- /*
- * If we are allowed to merge, then append bio list
- * from next to rq and release next. merge_requests_fn
- * will have updated segment counts, update sector
- * counts here.
- */
- if (!ll_merge_requests_fn(q, req, next))
- return 0;
-
- /*
- * At this point we have either done a back merge
- * or front merge. We need the smaller start_time of
- * the merged requests to be the current request
- * for accounting purposes.
- */
- if (time_after(req->start_time, next->start_time))
- req->start_time = next->start_time;
-
- req->biotail->bi_next = next->bio;
- req->biotail = next->biotail;
-
- req->nr_sectors = req->hard_nr_sectors += next->hard_nr_sectors;
-
- elv_merge_requests(q, req, next);
-
- if (req->rq_disk) {
- disk_round_stats(req->rq_disk);
- req->rq_disk->in_flight--;
- }
-
- req->ioprio = ioprio_best(req->ioprio, next->ioprio);
-
- __blk_put_request(q, next);
- return 1;
-}
-
-static inline int attempt_back_merge(struct request_queue *q,
- struct request *rq)
-{
- struct request *next = elv_latter_request(q, rq);
-
- if (next)
- return attempt_merge(q, rq, next);
-
- return 0;
-}
-
-static inline int attempt_front_merge(struct request_queue *q,
- struct request *rq)
-{
- struct request *prev = elv_former_request(q, rq);
-
- if (prev)
- return attempt_merge(q, prev, rq);
-
- return 0;
-}
-
-static void init_request_from_bio(struct request *req, struct bio *bio)
+void init_request_from_bio(struct request *req, struct bio *bio)
{
req->cmd_type = REQ_TYPE_FS;
el_ret = elv_merge(q, &req, bio);
switch (el_ret) {
- case ELEVATOR_BACK_MERGE:
- BUG_ON(!rq_mergeable(req));
+ case ELEVATOR_BACK_MERGE:
+ BUG_ON(!rq_mergeable(req));
- if (!ll_back_merge_fn(q, req, bio))
- break;
+ if (!ll_back_merge_fn(q, req, bio))
+ break;
- blk_add_trace_bio(q, bio, BLK_TA_BACKMERGE);
+ 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;
+ 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));
+ case ELEVATOR_FRONT_MERGE:
+ BUG_ON(!rq_mergeable(req));
- if (!ll_front_merge_fn(q, req, bio))
- break;
+ if (!ll_front_merge_fn(q, req, bio))
+ break;
- blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
+ blk_add_trace_bio(q, bio, BLK_TA_FRONTMERGE);
- bio->bi_next = req->bio;
- req->bio = bio;
+ 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:
- ;
+ /*
+ * 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:
}
if (unlikely(nr_sectors > q->max_hw_sectors)) {
- printk("bio too big device %s (%u > %u)\n",
+ printk(KERN_ERR "bio too big device %s (%u > %u)\n",
bdevname(bio->bi_bdev, b),
bio_sectors(bio),
q->max_hw_sectors);
} while (bio);
current->bio_tail = NULL; /* deactivate */
}
-
EXPORT_SYMBOL(generic_make_request);
/**
current->comm, task_pid_nr(current),
(rw & WRITE) ? "WRITE" : "READ",
(unsigned long long)bio->bi_sector,
- bdevname(bio->bi_bdev,b));
+ bdevname(bio->bi_bdev, b));
}
}
generic_make_request(bio);
}
-
EXPORT_SYMBOL(submit_bio);
-static void blk_recalc_rq_sectors(struct request *rq, int nsect)
-{
- if (blk_fs_request(rq)) {
- rq->hard_sector += nsect;
- rq->hard_nr_sectors -= nsect;
-
- /*
- * Move the I/O submission pointers ahead if required.
- */
- if ((rq->nr_sectors >= rq->hard_nr_sectors) &&
- (rq->sector <= rq->hard_sector)) {
- rq->sector = rq->hard_sector;
- rq->nr_sectors = rq->hard_nr_sectors;
- rq->hard_cur_sectors = bio_cur_sectors(rq->bio);
- rq->current_nr_sectors = rq->hard_cur_sectors;
- rq->buffer = bio_data(rq->bio);
- }
-
- /*
- * if total number of sectors is less than the first segment
- * size, something has gone terribly wrong
- */
- if (rq->nr_sectors < rq->current_nr_sectors) {
- printk("blk: request botched\n");
- rq->nr_sectors = rq->current_nr_sectors;
- }
- }
-}
-
/**
* __end_that_request_first - end I/O on a request
* @req: the request being processed
if (!blk_pc_request(req))
req->errors = 0;
- if (error) {
- if (blk_fs_request(req) && !(req->cmd_flags & REQ_QUIET))
- printk("end_request: I/O error, dev %s, sector %llu\n",
+ 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 (unlikely(bio->bi_idx >= bio->bi_vcnt)) {
blk_dump_rq_flags(req, "__end_that");
- printk("%s: bio idx %d >= vcnt %d\n",
- __FUNCTION__,
- bio->bi_idx, bio->bi_vcnt);
+ printk(KERN_ERR "%s: bio idx %d >= vcnt %d\n",
+ __FUNCTION__, bio->bi_idx,
+ bio->bi_vcnt);
break;
}
total_bytes += nbytes;
nr_bytes -= nbytes;
- if ((bio = req->bio)) {
+ bio = req->bio;
+ if (bio) {
/*
* end more in this run, or just return 'not-done'
*/
local_irq_enable();
while (!list_empty(&local_list)) {
- struct request *rq = list_entry(local_list.next, struct request, donelist);
+ 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)
+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
unsigned long flags;
BUG_ON(!req->q->softirq_done_fn);
-
+
local_irq_save(flags);
cpu_list = &__get_cpu_var(blk_cpu_done);
local_irq_restore(flags);
}
-
EXPORT_SYMBOL(blk_complete_request);
-
+
/*
* queue lock must be held
*/
* 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, int nr_bytes,
- int bidi_bytes, int (drv_callback)(struct request *))
+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;
* 0 - we are done with this request
* 1 - still buffers pending for this request
**/
-int blk_end_request(struct request *rq, int error, int nr_bytes)
+int blk_end_request(struct request *rq, int error, unsigned int nr_bytes)
{
return blk_end_io(rq, error, nr_bytes, 0, NULL);
}
* 0 - we are done with this request
* 1 - still buffers pending for this request
**/
-int __blk_end_request(struct request *rq, int error, int nr_bytes)
+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))
* 0 - we are done with this request
* 1 - still buffers pending for this request
**/
-int blk_end_bidi_request(struct request *rq, int error, int nr_bytes,
- int bidi_bytes)
+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);
}
* 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, int nr_bytes,
+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);
-static void blk_rq_bio_prep(struct request_queue *q, struct request *rq,
- struct bio *bio)
+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);
{
return queue_work(kblockd_workqueue, work);
}
-
EXPORT_SYMBOL(kblockd_schedule_work);
void kblockd_flush_work(struct work_struct *work)
blk_requestq_cachep = kmem_cache_create("blkdev_queue",
sizeof(struct request_queue), 0, SLAB_PANIC, NULL);
- iocontext_cachep = kmem_cache_create("blkdev_ioc",
- sizeof(struct io_context), 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);
- blk_max_low_pfn = max_low_pfn - 1;
- blk_max_pfn = max_pfn - 1;
-
- return 0;
-}
-
-static void cfq_dtor(struct io_context *ioc)
-{
- struct cfq_io_context *cic[1];
- int r;
-
- /*
- * We don't have a specific key to lookup with, so use the gang
- * lookup to just retrieve the first item stored. The cfq exit
- * function will iterate the full tree, so any member will do.
- */
- r = radix_tree_gang_lookup(&ioc->radix_root, (void **) cic, 0, 1);
- if (r > 0)
- cic[0]->dtor(ioc);
-}
-
-/*
- * IO Context helper functions. put_io_context() returns 1 if there are no
- * more users of this io context, 0 otherwise.
- */
-int put_io_context(struct io_context *ioc)
-{
- if (ioc == NULL)
- return 1;
-
- BUG_ON(atomic_read(&ioc->refcount) == 0);
-
- if (atomic_dec_and_test(&ioc->refcount)) {
- rcu_read_lock();
- if (ioc->aic && ioc->aic->dtor)
- ioc->aic->dtor(ioc->aic);
- rcu_read_unlock();
- cfq_dtor(ioc);
-
- kmem_cache_free(iocontext_cachep, ioc);
- return 1;
- }
return 0;
}
-EXPORT_SYMBOL(put_io_context);
-
-static void cfq_exit(struct io_context *ioc)
-{
- struct cfq_io_context *cic[1];
- int r;
-
- rcu_read_lock();
- /*
- * See comment for cfq_dtor()
- */
- r = radix_tree_gang_lookup(&ioc->radix_root, (void **) cic, 0, 1);
- rcu_read_unlock();
-
- if (r > 0)
- cic[0]->exit(ioc);
-}
-
-/* Called by the exitting task */
-void exit_io_context(void)
-{
- struct io_context *ioc;
-
- task_lock(current);
- ioc = current->io_context;
- current->io_context = NULL;
- task_unlock(current);
-
- if (atomic_dec_and_test(&ioc->nr_tasks)) {
- if (ioc->aic && ioc->aic->exit)
- ioc->aic->exit(ioc->aic);
- cfq_exit(ioc);
-
- put_io_context(ioc);
- }
-}
-
-struct io_context *alloc_io_context(gfp_t gfp_flags, int node)
-{
- struct io_context *ret;
-
- ret = kmem_cache_alloc_node(iocontext_cachep, gfp_flags, node);
- if (ret) {
- atomic_set(&ret->refcount, 1);
- atomic_set(&ret->nr_tasks, 1);
- spin_lock_init(&ret->lock);
- ret->ioprio_changed = 0;
- ret->ioprio = 0;
- ret->last_waited = jiffies; /* doesn't matter... */
- ret->nr_batch_requests = 0; /* because this is 0 */
- ret->aic = NULL;
- INIT_RADIX_TREE(&ret->radix_root, GFP_ATOMIC | __GFP_HIGH);
- ret->ioc_data = NULL;
- }
-
- return ret;
-}
-
-/*
- * If the current task has no IO context then create one and initialise it.
- * Otherwise, return its existing IO context.
- *
- * This returned IO context doesn't have a specifically elevated refcount,
- * but since the current task itself holds a reference, the context can be
- * used in general code, so long as it stays within `current` context.
- */
-static struct io_context *current_io_context(gfp_t gfp_flags, int node)
-{
- struct task_struct *tsk = current;
- struct io_context *ret;
-
- ret = tsk->io_context;
- if (likely(ret))
- return ret;
-
- ret = alloc_io_context(gfp_flags, node);
- if (ret) {
- /* make sure set_task_ioprio() sees the settings above */
- smp_wmb();
- tsk->io_context = ret;
- }
-
- return ret;
-}
-
-/*
- * If the current task has no IO context then create one and initialise it.
- * If it does have a context, take a ref on it.
- *
- * This is always called in the context of the task which submitted the I/O.
- */
-struct io_context *get_io_context(gfp_t gfp_flags, int node)
-{
- struct io_context *ret = NULL;
-
- /*
- * Check for unlikely race with exiting task. ioc ref count is
- * zero when ioc is being detached.
- */
- do {
- ret = current_io_context(gfp_flags, node);
- if (unlikely(!ret))
- break;
- } while (!atomic_inc_not_zero(&ret->refcount));
-
- return ret;
-}
-EXPORT_SYMBOL(get_io_context);
-
-void copy_io_context(struct io_context **pdst, struct io_context **psrc)
-{
- struct io_context *src = *psrc;
- struct io_context *dst = *pdst;
-
- if (src) {
- BUG_ON(atomic_read(&src->refcount) == 0);
- atomic_inc(&src->refcount);
- put_io_context(dst);
- *pdst = src;
- }
-}
-EXPORT_SYMBOL(copy_io_context);
-
-void swap_io_context(struct io_context **ioc1, struct io_context **ioc2)
-{
- struct io_context *temp;
- temp = *ioc1;
- *ioc1 = *ioc2;
- *ioc2 = temp;
-}
-EXPORT_SYMBOL(swap_io_context);