From: "Martin K. Petersen" <martin.petersen@xxxxxxxxxx>
Discards were globally marked as mergeable and as a result we had
several code paths that explicitly disabled merging when discard was
set. Mark discard requests as unmergable and remove special-casing of
REQ_DISCARD. The relevant nomerge flags are consolidated in blk_types.h,
and rq_mergeable() and bio_mergeable() have been modified to use them.
bio_is_rw() is used in place of bio_has_data() a few places. This is
done to to distinguish true reads and writes from other fs type requests
that carry a payload (e.g. WRITE SAME).
Signed-off-by: Martin K. Petersen <martin.petersen@xxxxxxxxxx>
Acked-by: Mike Snitzer <snitzer@xxxxxxxxxx>
---
block/blk-core.c | 10 +++++-----
block/blk-merge.c | 22 +---------------------
block/elevator.c | 6 ++----
include/linux/bio.h | 23 +++++++++++++++++++++--
include/linux/blk_types.h | 4 ++++
include/linux/blkdev.h | 23 +++++++++++------------
6 files changed, 44 insertions(+), 44 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index 3a78b00..5575230 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -1545,8 +1545,8 @@ generic_make_request_checks(struct bio *bio)
goto end_io;
}
- if (unlikely(!(bio->bi_rw & REQ_DISCARD) &&
- nr_sectors > queue_max_hw_sectors(q))) {
+ if (likely(bio_is_rw(bio) &&
+ nr_sectors > queue_max_hw_sectors(q))) {
printk(KERN_ERR "bio too big device %s (%u > %u)\n",
bdevname(bio->bi_bdev, b),
bio_sectors(bio),
@@ -1698,7 +1698,7 @@ void submit_bio(int rw, struct bio *bio)
* If it's a regular read/write or a barrier with data attached,
* go through the normal accounting stuff before submission.
*/
- if (bio_has_data(bio) && !(rw & REQ_DISCARD)) {
+ if (bio_has_data(bio)) {
if (rw & WRITE) {
count_vm_events(PGPGOUT, count);
} else {
@@ -1744,7 +1744,7 @@ EXPORT_SYMBOL(submit_bio);
*/
int blk_rq_check_limits(struct request_queue *q, struct request *rq)
{
- if (rq->cmd_flags & REQ_DISCARD)
+ if (!rq_mergeable(rq))
return 0;
if (blk_rq_sectors(rq) > queue_max_sectors(q) ||
@@ -2218,7 +2218,7 @@ bool blk_update_request(struct request *req, int error, unsigned int nr_bytes)
req->buffer = bio_data(req->bio);
/* update sector only for requests with clear definition of sector */
- if (req->cmd_type == REQ_TYPE_FS || (req->cmd_flags & REQ_DISCARD))
+ if (req->cmd_type == REQ_TYPE_FS)
req->__sector += total_bytes >> 9;
/* mixed attributes always follow the first bio */
diff --git a/block/blk-merge.c b/block/blk-merge.c
index 160035f..9172606 100644
--- a/block/blk-merge.c
+++ b/block/blk-merge.c
@@ -371,18 +371,6 @@ static int attempt_merge(struct request_queue *q, struct request *req,
return 0;
/*
- * Don't merge file system requests and discard requests
- */
- if ((req->cmd_flags & REQ_DISCARD) != (next->cmd_flags & REQ_DISCARD))
- return 0;
-
- /*
- * Don't merge discard requests and secure discard requests
- */
- if ((req->cmd_flags & REQ_SECURE) != (next->cmd_flags & REQ_SECURE))
- return 0;
-
- /*
* not contiguous
*/
if (blk_rq_pos(req) + blk_rq_sectors(req) != blk_rq_pos(next))
@@ -474,15 +462,7 @@ int blk_attempt_req_merge(struct request_queue *q, struct request *rq,
bool blk_rq_merge_ok(struct request *rq, struct bio *bio)
{
- if (!rq_mergeable(rq))
- return false;
-
- /* don't merge file system requests and discard requests */
- if ((bio->bi_rw & REQ_DISCARD) != (rq->bio->bi_rw & REQ_DISCARD))
- return false;
-
- /* don't merge discard requests and secure discard requests */
- if ((bio->bi_rw & REQ_SECURE) != (rq->bio->bi_rw & REQ_SECURE))
+ if (!rq_mergeable(rq) || !bio_mergeable(bio))
return false;
/* different data direction or already started, don't merge */
diff --git a/block/elevator.c b/block/elevator.c
index f016855..cccfdbf 100644
--- a/block/elevator.c
+++ b/block/elevator.c
@@ -591,8 +591,7 @@ void __elv_add_request(struct request_queue *q, struct request *rq, int where)
if (rq->cmd_flags & REQ_SOFTBARRIER) {
/* barriers are scheduling boundary, update end_sector */
- if (rq->cmd_type == REQ_TYPE_FS ||
- (rq->cmd_flags & REQ_DISCARD)) {
+ if (rq->cmd_type == REQ_TYPE_FS) {
q->end_sector = rq_end_sector(rq);
q->boundary_rq = rq;
}
@@ -634,8 +633,7 @@ void __elv_add_request(struct request_queue *q, struct request *rq, int where)
if (elv_attempt_insert_merge(q, rq))
break;
case ELEVATOR_INSERT_SORT:
- BUG_ON(rq->cmd_type != REQ_TYPE_FS &&
- !(rq->cmd_flags & REQ_DISCARD));
+ BUG_ON(rq->cmd_type != REQ_TYPE_FS);
rq->cmd_flags |= REQ_SORTED;
q->nr_sorted++;
if (rq_mergeable(rq)) {
diff --git a/include/linux/bio.h b/include/linux/bio.h
index 129a9c0..cad2a9c 100644
--- a/include/linux/bio.h
+++ b/include/linux/bio.h
@@ -358,9 +358,28 @@ static inline char *__bio_kmap_irq(struct bio *bio, unsigned short idx,
/*
* Check whether this bio carries any data or not. A NULL bio is allowed.
*/
-static inline int bio_has_data(struct bio *bio)
+static inline bool bio_has_data(struct bio *bio)
{
- return bio && bio->bi_io_vec != NULL;
+ if (bio && bio->bi_io_vec)
+ return true;
+
+ return false;
+}
+
+static inline bool bio_is_rw(struct bio *bio)
+{
+ if (!bio_has_data(bio))
+ return false;
+
+ return true;
+}
+
+static inline bool bio_mergeable(struct bio *bio)
+{
+ if (bio->bi_rw & REQ_NOMERGE_FLAGS)
+ return false;
+
+ return true;
}
/*
diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h
index 4053cbd..1a2727c 100644
--- a/include/linux/blk_types.h
+++ b/include/linux/blk_types.h
@@ -170,6 +170,10 @@ enum rq_flag_bits {
REQ_DISCARD | REQ_NOIDLE | REQ_FLUSH | REQ_FUA | REQ_SECURE)
#define REQ_CLONE_MASK REQ_COMMON_MASK
+#define REQ_NOMERGE_FLAGS \
+ (REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA | \
+ REQ_DISCARD)
+
#define REQ_RAHEAD (1 << __REQ_RAHEAD)
#define REQ_THROTTLED (1 << __REQ_THROTTLED)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 606cf33..3943933 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -512,8 +512,7 @@ static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
#define blk_account_rq(rq) \
(((rq)->cmd_flags & REQ_STARTED) && \
- ((rq)->cmd_type == REQ_TYPE_FS || \
- ((rq)->cmd_flags & REQ_DISCARD)))
+ ((rq)->cmd_type == REQ_TYPE_FS))
#define blk_pm_request(rq) \
((rq)->cmd_type == REQ_TYPE_PM_SUSPEND || \
@@ -569,17 +568,17 @@ static inline void blk_clear_queue_full(struct request_queue *q, int sync)
queue_flag_clear(QUEUE_FLAG_ASYNCFULL, q);
}
+static inline bool rq_mergeable(struct request *rq)
+{
+ if (rq->cmd_type != REQ_TYPE_FS)
+ return false;
+
+ if (rq->cmd_flags & REQ_NOMERGE_FLAGS)
+ return false;
+
+ return true;
+}
-/*
- * mergeable request must not have _NOMERGE or _BARRIER bit set, nor may
- * it already be started by driver.
- */
-#define RQ_NOMERGE_FLAGS \
- (REQ_NOMERGE | REQ_STARTED | REQ_SOFTBARRIER | REQ_FLUSH | REQ_FUA)
-#define rq_mergeable(rq) \
- (!((rq)->cmd_flags & RQ_NOMERGE_FLAGS) && \
- (((rq)->cmd_flags & REQ_DISCARD) || \
- (rq)->cmd_type == REQ_TYPE_FS))
/*
* q->prep_rq_fn return values
--
1.7.8.3.21.gab8a7
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