[PATCH 2/4] blk-mq: initialize request on allocation

From: Christoph Hellwig
Date: Mon Mar 31 2014 - 10:44:22 EST


If we want to share tag and request allocation between queues we cannot
initialize the request at init/free time, but need to initialize it
at allocation time as it might get used for different queues over its
lifetime.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
block/blk-mq.c | 4 +---
1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/block/blk-mq.c b/block/blk-mq.c
index 871acd6..ec0c276 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -82,6 +82,7 @@ static struct request *__blk_mq_alloc_request(struct blk_mq_hw_ctx *hctx,
tag = blk_mq_get_tag(hctx->tags, gfp, reserved);
if (tag != BLK_MQ_TAG_FAIL) {
rq = hctx->rqs[tag];
+ blk_rq_init(hctx->queue, rq);
rq->tag = tag;

return rq;
@@ -254,9 +255,7 @@ static void __blk_mq_free_request(struct blk_mq_hw_ctx *hctx,
const int tag = rq->tag;
struct request_queue *q = rq->q;

- blk_rq_init(hctx->queue, rq);
blk_mq_put_tag(hctx->tags, tag);
-
blk_mq_queue_exit(q);
}

@@ -1128,7 +1127,6 @@ static int blk_mq_init_rq_map(struct blk_mq_hw_ctx *hctx,
left -= to_do * rq_size;
for (j = 0; j < to_do; j++) {
hctx->rqs[i] = p;
- blk_rq_init(hctx->queue, hctx->rqs[i]);
p += rq_size;
i++;
}
--
1.7.10.4

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