From c6d600c65ebfa10a2a10d3e9183a24527ebe2aa4 Mon Sep 17 00:00:00 2001
From: Jens Axboe <axboe@fb.com>
Date: Wed, 30 Apr 2014 13:43:56 -0600
Subject: [PATCH] blk-mq: refactor request insertion/merging
Refactor the logic around adding a new bio to a software queue,
so we nest the ctx->lock where we really need it (merge and
insertion) and don't hold it when we don't (init and IO start
accounting).
Signed-off-by: Jens Axboe <axboe@fb.com>
---
block/blk-mq.c | 22 +++++++++++++++-------
1 file changed, 15 insertions(+), 7 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 77308a84dfb2..ca51ee4aa485 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1037,17 +1037,25 @@ static void blk_mq_make_request(struct request_queue *q, struct bio *bio)
}
}
- spin_lock(&ctx->lock);
+ if (!(hctx->flags & BLK_MQ_F_SHOULD_MERGE)) {
+ init_request_from_bio(rq, bio);
- if ((hctx->flags & BLK_MQ_F_SHOULD_MERGE) &&
- blk_mq_attempt_merge(q, ctx, bio))
- __blk_mq_free_request(hctx, ctx, rq);
- else {
- blk_mq_bio_to_request(rq, bio);
+ spin_lock(&ctx->lock);
+insert_rq:
__blk_mq_insert_request(hctx, rq, false);
+ spin_unlock(&ctx->lock);
+ blk_account_io_start(rq, 1);
+ } else {
+ spin_lock(&ctx->lock);
+ if (!blk_mq_attempt_merge(q, ctx, bio)) {
+ init_request_from_bio(rq, bio);
+ goto insert_rq;
+ }
+
+ spin_unlock(&ctx->lock);
+ __blk_mq_free_request(hctx, ctx, rq);
}
- spin_unlock(&ctx->lock);
/*
* For a SYNC request, send it to the hardware immediately. For an
--
2.34.1