--- /dev/null
+/*
+ * Functions related to barrier IO handling
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+
+#include "blk.h"
+
+/**
+ * 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 bio_end_empty_barrier(struct bio *bio, int err)
+{
+ if (err)
+ clear_bit(BIO_UPTODATE, &bio->bi_flags);
+
+ complete(bio->bi_private);
+}
+
+/**
+ * blkdev_issue_flush - queue a flush
+ * @bdev: blockdev to issue flush for
+ * @error_sector: error sector
+ *
+ * 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.
+ */
+int blkdev_issue_flush(struct block_device *bdev, sector_t *error_sector)
+{
+ 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);
+
+ /*
+ * 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.
+ */
+ if (error_sector)
+ *error_sector = bio->bi_sector;
+
+ ret = 0;
+ if (!bio_flagged(bio, BIO_UPTODATE))
+ ret = -EIO;
+
+ bio_put(bio);
+ return ret;
+}
+
+EXPORT_SYMBOL(blkdev_issue_flush);
#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 "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
*/
struct kmem_cache *blk_requestq_cachep = NULL;
-/*
- * For io context allocations
- */
-static struct kmem_cache *iocontext_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)
-
-/* Number of requests a "batching" process may submit */
-#define BLK_BATCH_REQ 32
-
void blk_queue_congestion_threshold(struct request_queue *q)
{
int nr;
}
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.
- */
-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->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)
{
}
}
-/**
- * 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;
return 1;
}
-static int ll_back_merge_fn(struct request_queue *q, struct request *req,
- struct bio *bio)
+int ll_back_merge_fn(struct request_queue *q, struct request *req,
+ struct bio *bio)
{
unsigned short max_sectors;
int len;
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;
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
- *
- * Description:
- * Insert a fully prepared request at the back of the io scheduler queue
- * for execution. Don't wait for completion.
- */
-void blk_execute_rq_nowait(struct request_queue *q, struct gendisk *bd_disk,
- struct request *rq, int at_head,
- rq_end_io_fn *done)
-{
- 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);
-}
-EXPORT_SYMBOL_GPL(blk_execute_rq_nowait);
-
-/**
- * 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
- *
- * Description:
- * Insert a fully prepared request at the back of the io scheduler queue
- * for execution and wait for completion.
- */
-int blk_execute_rq(struct request_queue *q, struct gendisk *bd_disk,
- struct request *rq, int at_head)
-{
- 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);
-
-static void bio_end_empty_barrier(struct bio *bio, int err)
-{
- if (err)
- clear_bit(BIO_UPTODATE, &bio->bi_flags);
-
- complete(bio->bi_private);
-}
-
-/**
- * blkdev_issue_flush - queue a flush
- * @bdev: blockdev to issue flush for
- * @error_sector: error sector
- *
- * 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.
- */
-int blkdev_issue_flush(struct block_device *bdev, sector_t *error_sector)
-{
- 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);
-
- /*
- * 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.
- */
- if (error_sector)
- *error_sector = bio->bi_sector;
-
- ret = 0;
- if (!bio_flagged(bio, BIO_UPTODATE))
- ret = -EIO;
-
- bio_put(bio);
- return ret;
-}
-
-EXPORT_SYMBOL(blkdev_issue_flush);
-
static void drive_stat_acct(struct request *rq, int new_io)
{
int rw = rq_data_dir(rq);
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
*/
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;
}
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);
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);
--- /dev/null
+/*
+ * Functions related to setting various queue properties from drivers
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/init.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/bootmem.h> /* for max_pfn/max_low_pfn */
+
+#include "blk.h"
+
+unsigned long blk_max_low_pfn, blk_max_pfn;
+EXPORT_SYMBOL(blk_max_low_pfn);
+EXPORT_SYMBOL(blk_max_pfn);
+
+/**
+ * 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.
+ */
+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);
+
+/**
+ * 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);
+
+int __init blk_settings_init(void)
+{
+ blk_max_low_pfn = max_low_pfn - 1;
+ blk_max_pfn = max_pfn - 1;
+ return 0;
+}
+subsys_initcall(blk_settings_init);
projects / linux-2.6 / commitdiff