#include <linux/module.h>
#include <linux/bio.h>
#include <linux/blkdev.h>
+#include <linux/gfp.h>
#include "blk.h"
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 "%s: prepare_flush_fn required\n",
- __FUNCTION__);
+ if (!prepare_flush_fn && (ordered & (QUEUE_ORDERED_DO_PREFLUSH |
+ QUEUE_ORDERED_DO_POSTFLUSH))) {
+ printk(KERN_ERR "%s: prepare_flush_fn required\n", __func__);
return -EINVAL;
}
/*
* Cache flushing for ordered writes handling
*/
-inline unsigned blk_ordered_cur_seq(struct request_queue *q)
+unsigned blk_ordered_cur_seq(struct request_queue *q)
{
if (!q->ordseq)
return 0;
return QUEUE_ORDSEQ_DONE;
}
-void blk_ordered_complete_seq(struct request_queue *q, unsigned seq, int error)
+bool blk_ordered_complete_seq(struct request_queue *q, unsigned seq, int error)
{
struct request *rq;
q->ordseq |= seq;
if (blk_ordered_cur_seq(q) != QUEUE_ORDSEQ_DONE)
- return;
+ return false;
/*
* Okay, sequence complete.
*/
q->ordseq = 0;
rq = q->orig_bar_rq;
-
- if (__blk_end_request(rq, q->orderr, blk_rq_bytes(rq)))
- BUG();
+ __blk_end_request_all(rq, q->orderr);
+ return true;
}
static void pre_flush_end_io(struct request *rq, int error)
struct request *rq;
rq_end_io_fn *end_io;
- if (which == QUEUE_ORDERED_PREFLUSH) {
+ if (which == QUEUE_ORDERED_DO_PREFLUSH) {
rq = &q->pre_flush_rq;
end_io = pre_flush_end_io;
} else {
end_io = post_flush_end_io;
}
+ blk_rq_init(q, rq);
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)
+static inline bool start_ordered(struct request_queue *q, struct request **rqp)
{
+ struct request *rq = *rqp;
+ unsigned skip = 0;
+
q->orderr = 0;
q->ordered = q->next_ordered;
q->ordseq |= QUEUE_ORDSEQ_STARTED;
/*
- * Prep proxy barrier request.
+ * For an empty barrier, there's no actual BAR request, which
+ * in turn makes POSTFLUSH unnecessary. Mask them off.
*/
- blkdev_dequeue_request(rq);
+ if (!blk_rq_sectors(rq)) {
+ q->ordered &= ~(QUEUE_ORDERED_DO_BAR |
+ QUEUE_ORDERED_DO_POSTFLUSH);
+ /*
+ * Empty barrier on a write-through device w/ ordered
+ * tag has no command to issue and without any command
+ * to issue, ordering by tag can't be used. Drain
+ * instead.
+ */
+ if ((q->ordered & QUEUE_ORDERED_BY_TAG) &&
+ !(q->ordered & QUEUE_ORDERED_DO_PREFLUSH)) {
+ q->ordered &= ~QUEUE_ORDERED_BY_TAG;
+ q->ordered |= QUEUE_ORDERED_BY_DRAIN;
+ }
+ }
+
+ /* stash away the original request */
+ blk_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;
+ rq = NULL;
/*
* 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.
+ * request gets inbetween ordered sequence.
*/
- if ((q->ordered & QUEUE_ORDERED_POSTFLUSH) && !blk_empty_barrier(rq))
- queue_flush(q, QUEUE_ORDERED_POSTFLUSH);
- else
- q->ordseq |= QUEUE_ORDSEQ_POSTFLUSH;
+ if (q->ordered & QUEUE_ORDERED_DO_POSTFLUSH) {
+ queue_flush(q, QUEUE_ORDERED_DO_POSTFLUSH);
+ rq = &q->post_flush_rq;
+ } else
+ skip |= QUEUE_ORDSEQ_POSTFLUSH;
- elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
+ if (q->ordered & QUEUE_ORDERED_DO_BAR) {
+ rq = &q->bar_rq;
+
+ /* initialize proxy request and queue it */
+ blk_rq_init(q, rq);
+ if (bio_data_dir(q->orig_bar_rq->bio) == WRITE)
+ rq->cmd_flags |= REQ_RW;
+ if (q->ordered & QUEUE_ORDERED_DO_FUA)
+ rq->cmd_flags |= REQ_FUA;
+ init_request_from_bio(rq, q->orig_bar_rq->bio);
+ rq->end_io = bar_end_io;
+
+ elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
+ } else
+ skip |= QUEUE_ORDSEQ_BAR;
- if (q->ordered & QUEUE_ORDERED_PREFLUSH) {
- queue_flush(q, QUEUE_ORDERED_PREFLUSH);
+ if (q->ordered & QUEUE_ORDERED_DO_PREFLUSH) {
+ queue_flush(q, QUEUE_ORDERED_DO_PREFLUSH);
rq = &q->pre_flush_rq;
} else
- q->ordseq |= QUEUE_ORDSEQ_PREFLUSH;
+ skip |= QUEUE_ORDSEQ_PREFLUSH;
- if ((q->ordered & QUEUE_ORDERED_TAG) || q->in_flight == 0)
- q->ordseq |= QUEUE_ORDSEQ_DRAIN;
- else
+ if ((q->ordered & QUEUE_ORDERED_BY_DRAIN) && queue_in_flight(q))
rq = NULL;
+ else
+ skip |= QUEUE_ORDSEQ_DRAIN;
- return rq;
+ *rqp = rq;
+
+ /*
+ * Complete skipped sequences. If whole sequence is complete,
+ * return false to tell elevator that this request is gone.
+ */
+ return !blk_ordered_complete_seq(q, skip, 0);
}
-int blk_do_ordered(struct request_queue *q, struct request **rqp)
+bool 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;
+ return true;
- if (q->next_ordered != QUEUE_ORDERED_NONE) {
- *rqp = start_ordered(q, rq);
- return 1;
- } else {
+ if (q->next_ordered != QUEUE_ORDERED_NONE)
+ return start_ordered(q, rqp);
+ else {
/*
- * This can happen when the queue switches to
- * ORDERED_NONE while this request is on it.
+ * Queue ordering not supported. Terminate
+ * with prejudice.
*/
- blkdev_dequeue_request(rq);
- if (__blk_end_request(rq, -EOPNOTSUPP,
- blk_rq_bytes(rq)))
- BUG();
+ blk_dequeue_request(rq);
+ __blk_end_request_all(rq, -EOPNOTSUPP);
*rqp = NULL;
- return 0;
+ return false;
}
}
/* 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;
+ return true;
- if (q->ordered & QUEUE_ORDERED_TAG) {
+ if (q->ordered & QUEUE_ORDERED_BY_TAG) {
/* Ordered by tag. Blocking the next barrier is enough. */
if (is_barrier && rq != &q->bar_rq)
*rqp = NULL;
*rqp = NULL;
}
- return 1;
+ return true;
}
static void bio_end_empty_barrier(struct bio *bio, int err)
set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
clear_bit(BIO_UPTODATE, &bio->bi_flags);
}
-
- complete(bio->bi_private);
+ if (bio->bi_private)
+ complete(bio->bi_private);
+ bio_put(bio);
}
/**
* blkdev_issue_flush - queue a flush
* @bdev: blockdev to issue flush for
+ * @gfp_mask: memory allocation flags (for bio_alloc)
* @error_sector: error sector
+ * @flags: BLKDEV_IFL_* flags to control behaviour
*
* 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.
+ * wish to. If WAIT flag is not passed then caller may check only what
+ * request was pushed in some internal queue for later handling.
*/
-int blkdev_issue_flush(struct block_device *bdev, sector_t *error_sector)
+int blkdev_issue_flush(struct block_device *bdev, gfp_t gfp_mask,
+ sector_t *error_sector, unsigned long flags)
{
DECLARE_COMPLETION_ONSTACK(wait);
struct request_queue *q;
struct bio *bio;
- int ret;
+ int ret = 0;
if (bdev->bd_disk == NULL)
return -ENXIO;
if (!q)
return -ENXIO;
- bio = bio_alloc(GFP_KERNEL, 0);
- if (!bio)
- return -ENOMEM;
-
+ bio = bio_alloc(gfp_mask, 0);
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;
+ if (test_bit(BLKDEV_WAIT, &flags))
+ bio->bi_private = &wait;
+
+ bio_get(bio);
+ submit_bio(WRITE_BARRIER, bio);
+ if (test_bit(BLKDEV_WAIT, &flags)) {
+ 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 blk_rq_pos(rq).
+ */
+ if (error_sector)
+ *error_sector = bio->bi_sector;
+ }
- ret = 0;
if (bio_flagged(bio, BIO_EOPNOTSUPP))
ret = -EOPNOTSUPP;
else if (!bio_flagged(bio, BIO_UPTODATE))
git://ftp.safe.ca / safe / jmp / linux-2.6 / blobdiff