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blk-mq: don't leak preempt counter/q_usage_counter when allocating rq failed 

When blk_mq_get_request() failed, preempt counter isn't
released, and blk_mq_make_request() doesn't release the counter
too.

This patch fixes the issue, and makes sure that preempt counter
is only held if rq is allocated successfully. The same policy is
applied on .q_usage_counter too.

Signed-off-by: Ming Lei <minlei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
This commit is contained in:
Ming Lei 2017-08-02 08:01:45 +08:00 committed by Jens Axboe
parent 46d556e6aa
commit 1ad43c0078
1 changed files with 11 additions and 6 deletions
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17
block/blk-mq.c
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@ -301,11 +301,12 @@ static struct request *blk_mq_get_request(struct request_queue *q,
struct elevator_queue *e = q->elevator;
struct request *rq;
unsigned int tag;
struct blk_mq_ctx *local_ctx = NULL;
blk_queue_enter_live(q);
data->q = q;
if (likely(!data->ctx))
data->ctx = blk_mq_get_ctx(q);
data->ctx = local_ctx = blk_mq_get_ctx(q);
if (likely(!data->hctx))
data->hctx = blk_mq_map_queue(q, data->ctx->cpu);
if (op & REQ_NOWAIT)
@ -324,6 +325,10 @@ static struct request *blk_mq_get_request(struct request_queue *q,
tag = blk_mq_get_tag(data);
if (tag == BLK_MQ_TAG_FAIL) {
if (local_ctx) {
blk_mq_put_ctx(local_ctx);
data->ctx = NULL;
}
blk_queue_exit(q);
return NULL;
}
@ -356,12 +361,12 @@ struct request *blk_mq_alloc_request(struct request_queue *q, unsigned int op,
rq = blk_mq_get_request(q, NULL, op, &alloc_data);
blk_mq_put_ctx(alloc_data.ctx);
blk_queue_exit(q);
if (!rq)
return ERR_PTR(-EWOULDBLOCK);
blk_mq_put_ctx(alloc_data.ctx);
blk_queue_exit(q);
rq->__data_len = 0;
rq->__sector = (sector_t) -1;
rq->bio = rq->biotail = NULL;
@ -407,11 +412,11 @@ struct request *blk_mq_alloc_request_hctx(struct request_queue *q,
rq = blk_mq_get_request(q, NULL, op, &alloc_data);
blk_queue_exit(q);
if (!rq)
return ERR_PTR(-EWOULDBLOCK);
blk_queue_exit(q);
return rq;
}
EXPORT_SYMBOL_GPL(blk_mq_alloc_request_hctx);