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authorJens Axboe <axboe@fb.com>2014-08-15 12:44:08 -0600
committerJens Axboe <axboe@fb.com>2014-08-21 20:37:45 -0500
commit274a5843ff2f08a89464589d90c64eb65f2c0847 (patch)
tree6354be68a6e49f6b3579289e33cf15b75f6baa14 /block
parent8a58d1f1f373238cb0d6d7f8d3dd723aa164b8ac (diff)
blk-mq: don't allow merges if turned off for the queue
blk-mq uses BLK_MQ_F_SHOULD_MERGE, as set by the driver at init time, to determine whether it should merge IO or not. However, this could also be disabled by the admin, if merging is switched off through sysfs. So check the general queue state as well before attempting to merge IO. Reported-by: Rob Elliott <Elliott@hp.com> Tested-by: Rob Elliott <Elliott@hp.com> Signed-off-by: Jens Axboe <axboe@fb.com>
Diffstat (limited to 'block')
-rw-r--r--block/blk-mq.c12
1 files changed, 9 insertions, 3 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c
index ac8a0413664e..c9e89a8792e3 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1068,13 +1068,17 @@ static void blk_mq_bio_to_request(struct request *rq, struct bio *bio)
blk_account_io_start(rq, 1);
}
+static inline bool hctx_allow_merges(struct blk_mq_hw_ctx *hctx)
+{
+ return (hctx->flags & BLK_MQ_F_SHOULD_MERGE) &&
+ !blk_queue_nomerges(hctx->queue);
+}
+
static inline bool blk_mq_merge_queue_io(struct blk_mq_hw_ctx *hctx,
struct blk_mq_ctx *ctx,
struct request *rq, struct bio *bio)
{
- struct request_queue *q = hctx->queue;
-
- if (!(hctx->flags & BLK_MQ_F_SHOULD_MERGE)) {
+ if (!hctx_allow_merges(hctx)) {
blk_mq_bio_to_request(rq, bio);
spin_lock(&ctx->lock);
insert_rq:
@@ -1082,6 +1086,8 @@ insert_rq:
spin_unlock(&ctx->lock);
return false;
} else {
+ struct request_queue *q = hctx->queue;
+
spin_lock(&ctx->lock);
if (!blk_mq_attempt_merge(q, ctx, bio)) {
blk_mq_bio_to_request(rq, bio);