Minki/linux
1
0
Fork 1
mirror of https://github.com/torvalds/linux.git synced 2024-11-22 20:22:09 +00:00
Code Issues Packages Projects Releases Wiki Activity

blk-mq: don't dispatch request in blk_mq_request_direct_issue if queue is busy

Browse Source 
If we run into blk_mq_request_direct_issue(), when queue is busy, we
don't want to dispatch this request into hctx->dispatch_list, and
what we need to do is to return the queue busy info to caller, so
that caller can deal with it well.

Fixes: 396eaf21ee ("blk-mq: improve DM's blk-mq IO merging via blk_insert_cloned_request feedback")
Reported-by: Laurence Oberman <loberman@redhat.com>
Reviewed-by: Mike Snitzer <snitzer@redhat.com>
Signed-off-by: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Ming Lei 2018-01-18 12:06:59 +08:00 committed by Jens Axboe
parent de99a34688
commit 23d4ee19e7
1 changed files with 10 additions and 12 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

22
block/blk-mq.c
View File

@ -1773,15 +1773,6 @@ static blk_status_t __blk_mq_issue_directly(struct blk_mq_hw_ctx *hctx,
return ret; return ret;
} }
static void __blk_mq_fallback_to_insert(struct request *rq,
bool run_queue, bool bypass_insert)
{
if (!bypass_insert)
blk_mq_sched_insert_request(rq, false, run_queue, false);
else
blk_mq_request_bypass_insert(rq, run_queue);
}
static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx, static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
struct request *rq, struct request *rq,
blk_qc_t *cookie, blk_qc_t *cookie,
@ -1790,9 +1781,16 @@ static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
struct request_queue *q = rq->q; struct request_queue *q = rq->q;
bool run_queue = true; bool run_queue = true;
/* RCU or SRCU read lock is needed before checking quiesced flag */ /*
* RCU or SRCU read lock is needed before checking quiesced flag.
*
* When queue is stopped or quiesced, ignore 'bypass_insert' from
* blk_mq_request_direct_issue(), and return BLK_STS_OK to caller,
* and avoid driver to try to dispatch again.
*/
if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q)) { if (blk_mq_hctx_stopped(hctx) || blk_queue_quiesced(q)) {
run_queue = false; run_queue = false;
bypass_insert = false;
goto insert; goto insert;
} }
@ -1809,10 +1807,10 @@ static blk_status_t __blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
return __blk_mq_issue_directly(hctx, rq, cookie); return __blk_mq_issue_directly(hctx, rq, cookie);
insert: insert:
__blk_mq_fallback_to_insert(rq, run_queue, bypass_insert);
if (bypass_insert) if (bypass_insert)
return BLK_STS_RESOURCE; return BLK_STS_RESOURCE;
blk_mq_sched_insert_request(rq, false, run_queue, false);
return BLK_STS_OK; return BLK_STS_OK;
} }
@ -1828,7 +1826,7 @@ static void blk_mq_try_issue_directly(struct blk_mq_hw_ctx *hctx,
ret = __blk_mq_try_issue_directly(hctx, rq, cookie, false); ret = __blk_mq_try_issue_directly(hctx, rq, cookie, false);
if (ret == BLK_STS_RESOURCE) if (ret == BLK_STS_RESOURCE)
__blk_mq_fallback_to_insert(rq, true, false); blk_mq_sched_insert_request(rq, false, true, false);
else if (ret != BLK_STS_OK) else if (ret != BLK_STS_OK)
blk_mq_end_request(rq, ret); blk_mq_end_request(rq, ret);