The patch basically reverts the patch of(blk-mq:
initialize request on allocation) in Jens's tree(already
in -next), and only initialize req->q in allocation
for two reasons:
- presumed cache hotness on completion
- blk_rq_tagged(rq) depends on reset of req->mq_ctx
Signed-off-by: Ming Lei <tom.leim...@gmail.com>
---
block/blk-mq.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 1eff3d9..b7a51ed 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -82,7 +82,6 @@ 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->tags->rqs[tag];
- blk_rq_init(hctx->queue, rq);
rq->tag = tag;
return rq;
@@ -187,6 +186,7 @@ static void blk_mq_rq_ctx_init(struct request_queue *q,
struct blk_mq_ctx *ctx,
if (blk_queue_io_stat(q))
rw_flags |= REQ_IO_STAT;
+ rq->q = q;
rq->mq_ctx = ctx;
rq->cmd_flags = rw_flags;
rq->start_time = jiffies;
@@ -258,6 +258,7 @@ 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);
}
@@ -1194,6 +1195,7 @@ static struct blk_mq_tags *blk_mq_init_rq_map(struct
blk_mq_tag_set *set,
left -= to_do * rq_size;
for (j = 0; j < to_do; j++) {
tags->rqs[i] = p;
+ blk_rq_init(NULL, tags->rqs[i]);
if (set->ops->init_request) {
if (set->ops->init_request(set->driver_data,
tags->rqs[i], hctx_idx, i,
--
1.7.9.5
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