Prev: [PATCH 02/11] block: kill QUEUE_ORDERED_BY_TAG
Next: [PATCH 09/11] block: implement REQ_FLUSH/FUA based interface for FLUSH/FUA requests
From: Tejun Heo on 12 Aug 2010 08:50
Without ordering requirements, barrier and ordering are minomers.
Rename block/blk-barrier.c to block/blk-flush.c. Rename of symbols
will follow.

Signed-off-by: Tejun Heo <tj(a)kernel.org>
Cc: Christoph Hellwig <hch(a)infradead.org>
---
block/Makefile | 2 +-
block/blk-barrier.c | 248 ---------------------------------------------------
block/blk-flush.c | 248 +++++++++++++++++++++++++++++++++++++++++++++++++++
3 files changed, 249 insertions(+), 249 deletions(-)
delete mode 100644 block/blk-barrier.c
create mode 100644 block/blk-flush.c

diff --git a/block/Makefile b/block/Makefile
index 0bb499a..f627e4b 100644
--- a/block/Makefile
+++ b/block/Makefile
@@ -3,7 +3,7 @@
#

obj-$(CONFIG_BLOCK) := elevator.o blk-core.o blk-tag.o blk-sysfs.o \
- blk-barrier.o blk-settings.o blk-ioc.o blk-map.o \
+ blk-flush.o blk-settings.o blk-ioc.o blk-map.o \
blk-exec.o blk-merge.o blk-softirq.o blk-timeout.o \
blk-iopoll.o blk-lib.o ioctl.o genhd.o scsi_ioctl.o

diff --git a/block/blk-barrier.c b/block/blk-barrier.c
deleted file mode 100644
index e8b2e5c..0000000
--- a/block/blk-barrier.c
+++ /dev/null
@@ -1,248 +0,0 @@
-/*
- * Functions related to barrier IO handling
- */
-#include <linux/kernel.h>
-#include <linux/module.h>
-#include <linux/bio.h>
-#include <linux/blkdev.h>
-#include <linux/gfp.h>
-
-#include "blk.h"
-
-static struct request *queue_next_ordseq(struct request_queue *q);
-
-/*
- * Cache flushing for ordered writes handling
- */
-unsigned blk_ordered_cur_seq(struct request_queue *q)
-{
- if (!q->ordseq)
- return 0;
- return 1 << ffz(q->ordseq);
-}
-
-static struct request *blk_ordered_complete_seq(struct request_queue *q,
- unsigned seq, int error)
-{
- struct request *next_rq = NULL;
-
- if (error && !q->orderr)
- q->orderr = error;
-
- BUG_ON(q->ordseq & seq);
- q->ordseq |= seq;
-
- if (blk_ordered_cur_seq(q) != QUEUE_ORDSEQ_DONE) {
- /* not complete yet, queue the next ordered sequence */
- next_rq = queue_next_ordseq(q);
- } else {
- /* complete this barrier request */
- __blk_end_request_all(q->orig_bar_rq, q->orderr);
- q->orig_bar_rq = NULL;
- q->ordseq = 0;
-
- /* dispatch the next barrier if there's one */
- if (!list_empty(&q->pending_barriers)) {
- next_rq = list_entry_rq(q->pending_barriers.next);
- list_move(&next_rq->queuelist, &q->queue_head);
- }
- }
- return next_rq;
-}
-
-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, struct request *rq,
- rq_end_io_fn *end_io)
-{
- blk_rq_init(q, rq);
- rq->cmd_type = REQ_TYPE_FS;
- rq->cmd_flags = REQ_FLUSH;
- rq->rq_disk = q->orig_bar_rq->rq_disk;
- rq->end_io = end_io;
-
- elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
-}
-
-static struct request *queue_next_ordseq(struct request_queue *q)
-{
- struct request *rq = &q->bar_rq;
-
- switch (blk_ordered_cur_seq(q)) {
- case QUEUE_ORDSEQ_PREFLUSH:
- queue_flush(q, rq, pre_flush_end_io);
- break;
-
- case QUEUE_ORDSEQ_BAR:
- /* initialize proxy request and queue it */
- blk_rq_init(q, rq);
- init_request_from_bio(rq, q->orig_bar_rq->bio);
- rq->cmd_flags &= ~REQ_HARDBARRIER;
- if (q->ordered & QUEUE_ORDERED_DO_FUA)
- rq->cmd_flags |= REQ_FUA;
- rq->end_io = bar_end_io;
-
- elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
- break;
-
- case QUEUE_ORDSEQ_POSTFLUSH:
- queue_flush(q, rq, post_flush_end_io);
- break;
-
- default:
- BUG();
- }
- return rq;
-}
-
-struct request *blk_do_ordered(struct request_queue *q, struct request *rq)
-{
- unsigned skip = 0;
-
- if (!(rq->cmd_flags & REQ_HARDBARRIER))
- return rq;
-
- if (q->ordseq) {
- /*
- * Barrier is already in progress and they can't be
- * processed in parallel. Queue for later processing.
- */
- list_move_tail(&rq->queuelist, &q->pending_barriers);
- return NULL;
- }
-
- if (unlikely(q->next_ordered == QUEUE_ORDERED_NONE)) {
- /*
- * Queue ordering not supported. Terminate
- * with prejudice.
- */
- blk_dequeue_request(rq);
- __blk_end_request_all(rq, -EOPNOTSUPP);
- return NULL;
- }
-
- /*
- * Start a new ordered sequence
- */
- q->orderr = 0;
- q->ordered = q->next_ordered;
- q->ordseq |= QUEUE_ORDSEQ_STARTED;
-
- /*
- * For an empty barrier, there's no actual BAR request, which
- * in turn makes POSTFLUSH unnecessary. Mask them off.
- */
- if (!blk_rq_sectors(rq))
- q->ordered &= ~(QUEUE_ORDERED_DO_BAR |
- QUEUE_ORDERED_DO_POSTFLUSH);
-
- /* stash away the original request */
- blk_dequeue_request(rq);
- q->orig_bar_rq = rq;
-
- if (!(q->ordered & QUEUE_ORDERED_DO_PREFLUSH))
- skip |= QUEUE_ORDSEQ_PREFLUSH;
-
- if (!(q->ordered & QUEUE_ORDERED_DO_BAR))
- skip |= QUEUE_ORDSEQ_BAR;
-
- if (!(q->ordered & QUEUE_ORDERED_DO_POSTFLUSH))
- skip |= QUEUE_ORDSEQ_POSTFLUSH;
-
- /* complete skipped sequences and return the first sequence */
- return blk_ordered_complete_seq(q, skip, 0);
-}
-
-static void bio_end_empty_barrier(struct bio *bio, int err)
-{
- if (err) {
- if (err == -EOPNOTSUPP)
- set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
- clear_bit(BIO_UPTODATE, &bio->bi_flags);
- }
- 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. 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, gfp_t gfp_mask,
- sector_t *error_sector, unsigned long flags)
-{
- DECLARE_COMPLETION_ONSTACK(wait);
- struct request_queue *q;
- struct bio *bio;
- int ret = 0;
-
- if (bdev->bd_disk == NULL)
- return -ENXIO;
-
- q = bdev_get_queue(bdev);
- if (!q)
- return -ENXIO;
-
- /*
- * some block devices may not have their queue correctly set up here
- * (e.g. loop device without a backing file) and so issuing a flush
- * here will panic. Ensure there is a request function before issuing
- * the barrier.
- */
- if (!q->make_request_fn)
- return -ENXIO;
-
- bio = bio_alloc(gfp_mask, 0);
- bio->bi_end_io = bio_end_empty_barrier;
- bio->bi_bdev = bdev;
- 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;
- }
-
- if (bio_flagged(bio, BIO_EOPNOTSUPP))
- ret = -EOPNOTSUPP;
- else if (!bio_flagged(bio, BIO_UPTODATE))
- ret = -EIO;
-
- bio_put(bio);
- return ret;
-}
-EXPORT_SYMBOL(blkdev_issue_flush);
diff --git a/block/blk-flush.c b/block/blk-flush.c
new file mode 100644
index 0000000..e8b2e5c
--- /dev/null
+++ b/block/blk-flush.c
@@ -0,0 +1,248 @@
+/*
+ * Functions related to barrier IO handling
+ */
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/bio.h>
+#include <linux/blkdev.h>
+#include <linux/gfp.h>
+
+#include "blk.h"
+
+static struct request *queue_next_ordseq(struct request_queue *q);
+
+/*
+ * Cache flushing for ordered writes handling
+ */
+unsigned blk_ordered_cur_seq(struct request_queue *q)
+{
+ if (!q->ordseq)
+ return 0;
+ return 1 << ffz(q->ordseq);
+}
+
+static struct request *blk_ordered_complete_seq(struct request_queue *q,
+ unsigned seq, int error)
+{
+ struct request *next_rq = NULL;
+
+ if (error && !q->orderr)
+ q->orderr = error;
+
+ BUG_ON(q->ordseq & seq);
+ q->ordseq |= seq;
+
+ if (blk_ordered_cur_seq(q) != QUEUE_ORDSEQ_DONE) {
+ /* not complete yet, queue the next ordered sequence */
+ next_rq = queue_next_ordseq(q);
+ } else {
+ /* complete this barrier request */
+ __blk_end_request_all(q->orig_bar_rq, q->orderr);
+ q->orig_bar_rq = NULL;
+ q->ordseq = 0;
+
+ /* dispatch the next barrier if there's one */
+ if (!list_empty(&q->pending_barriers)) {
+ next_rq = list_entry_rq(q->pending_barriers.next);
+ list_move(&next_rq->queuelist, &q->queue_head);
+ }
+ }
+ return next_rq;
+}
+
+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, struct request *rq,
+ rq_end_io_fn *end_io)
+{
+ blk_rq_init(q, rq);
+ rq->cmd_type = REQ_TYPE_FS;
+ rq->cmd_flags = REQ_FLUSH;
+ rq->rq_disk = q->orig_bar_rq->rq_disk;
+ rq->end_io = end_io;
+
+ elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
+}
+
+static struct request *queue_next_ordseq(struct request_queue *q)
+{
+ struct request *rq = &q->bar_rq;
+
+ switch (blk_ordered_cur_seq(q)) {
+ case QUEUE_ORDSEQ_PREFLUSH:
+ queue_flush(q, rq, pre_flush_end_io);
+ break;
+
+ case QUEUE_ORDSEQ_BAR:
+ /* initialize proxy request and queue it */
+ blk_rq_init(q, rq);
+ init_request_from_bio(rq, q->orig_bar_rq->bio);
+ rq->cmd_flags &= ~REQ_HARDBARRIER;
+ if (q->ordered & QUEUE_ORDERED_DO_FUA)
+ rq->cmd_flags |= REQ_FUA;
+ rq->end_io = bar_end_io;
+
+ elv_insert(q, rq, ELEVATOR_INSERT_FRONT);
+ break;
+
+ case QUEUE_ORDSEQ_POSTFLUSH:
+ queue_flush(q, rq, post_flush_end_io);
+ break;
+
+ default:
+ BUG();
+ }
+ return rq;
+}
+
+struct request *blk_do_ordered(struct request_queue *q, struct request *rq)
+{
+ unsigned skip = 0;
+
+ if (!(rq->cmd_flags & REQ_HARDBARRIER))
+ return rq;
+
+ if (q->ordseq) {
+ /*
+ * Barrier is already in progress and they can't be
+ * processed in parallel. Queue for later processing.
+ */
+ list_move_tail(&rq->queuelist, &q->pending_barriers);
+ return NULL;
+ }
+
+ if (unlikely(q->next_ordered == QUEUE_ORDERED_NONE)) {
+ /*
+ * Queue ordering not supported. Terminate
+ * with prejudice.
+ */
+ blk_dequeue_request(rq);
+ __blk_end_request_all(rq, -EOPNOTSUPP);
+ return NULL;
+ }
+
+ /*
+ * Start a new ordered sequence
+ */
+ q->orderr = 0;
+ q->ordered = q->next_ordered;
+ q->ordseq |= QUEUE_ORDSEQ_STARTED;
+
+ /*
+ * For an empty barrier, there's no actual BAR request, which
+ * in turn makes POSTFLUSH unnecessary. Mask them off.
+ */
+ if (!blk_rq_sectors(rq))
+ q->ordered &= ~(QUEUE_ORDERED_DO_BAR |
+ QUEUE_ORDERED_DO_POSTFLUSH);
+
+ /* stash away the original request */
+ blk_dequeue_request(rq);
+ q->orig_bar_rq = rq;
+
+ if (!(q->ordered & QUEUE_ORDERED_DO_PREFLUSH))
+ skip |= QUEUE_ORDSEQ_PREFLUSH;
+
+ if (!(q->ordered & QUEUE_ORDERED_DO_BAR))
+ skip |= QUEUE_ORDSEQ_BAR;
+
+ if (!(q->ordered & QUEUE_ORDERED_DO_POSTFLUSH))
+ skip |= QUEUE_ORDSEQ_POSTFLUSH;
+
+ /* complete skipped sequences and return the first sequence */
+ return blk_ordered_complete_seq(q, skip, 0);
+}
+
+static void bio_end_empty_barrier(struct bio *bio, int err)
+{
+ if (err) {
+ if (err == -EOPNOTSUPP)
+ set_bit(BIO_EOPNOTSUPP, &bio->bi_flags);
+ clear_bit(BIO_UPTODATE, &bio->bi_flags);
+ }
+ 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. 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, gfp_t gfp_mask,
+ sector_t *error_sector, unsigned long flags)
+{
+ DECLARE_COMPLETION_ONSTACK(wait);
+ struct request_queue *q;
+ struct bio *bio;
+ int ret = 0;
+
+ if (bdev->bd_disk == NULL)
+ return -ENXIO;
+
+ q = bdev_get_queue(bdev);
+ if (!q)
+ return -ENXIO;
+
+ /*
+ * some block devices may not have their queue correctly set up here
+ * (e.g. loop device without a backing file) and so issuing a flush
+ * here will panic. Ensure there is a request function before issuing
+ * the barrier.
+ */
+ if (!q->make_request_fn)
+ return -ENXIO;
+
+ bio = bio_alloc(gfp_mask, 0);
+ bio->bi_end_io = bio_end_empty_barrier;
+ bio->bi_bdev = bdev;
+ 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;
+ }
+
+ if (bio_flagged(bio, BIO_EOPNOTSUPP))
+ ret = -EOPNOTSUPP;
+ else if (!bio_flagged(bio, BIO_UPTODATE))
+ ret = -EIO;
+
+ bio_put(bio);
+ return ret;
+}
+EXPORT_SYMBOL(blkdev_issue_flush);
--
1.7.1

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Prev: [PATCH 02/11] block: kill QUEUE_ORDERED_BY_TAG
Next: [PATCH 09/11] block: implement REQ_FLUSH/FUA based interface for FLUSH/FUA requests