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| author | Bart Van Assche <bart.vanassche@wdc.com> | 2017-10-16 16:32:26 -0700 |
|---|---|---|
| committer | Jens Axboe <axboe@kernel.dk> | 2017-11-03 12:33:56 -0600 |
| commit | 21e768b442bb587123ea924620e74d6e5655d717 (patch) | |
| tree | 85982dcf7d7e98c8e22f5f0addc32796273f536c /block | |
| parent | c2e82a234873d905260a3bd0aca9577e85619bda (diff) | |
| download | linux-21e768b442bb587123ea924620e74d6e5655d717.tar.gz linux-21e768b442bb587123ea924620e74d6e5655d717.tar.bz2 linux-21e768b442bb587123ea924620e74d6e5655d717.zip | |
blk-mq: Make blk_mq_get_request() error path less confusing
blk_mq_get_tag() can modify data->ctx. This means that in the
error path of blk_mq_get_request() data->ctx should be passed to
blk_mq_put_ctx() instead of local_ctx. Note: since blk_mq_put_ctx()
ignores its argument, this patch does not change any functionality.
References: commit 1ad43c0078b7 ("blk-mq: don't leak preempt counter/q_usage_counter when allocating rq failed")
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Reviewed-by: Hannes Reinecke <hare@suse.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Johannes Thumshirn <jthumshirn@suse.de>
Signed-off-by: Bart Van Assche <bart.vanassche@wdc.com>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Diffstat (limited to 'block')
| -rw-r--r-- | block/blk-mq.c | 12 |
1 files changed, 7 insertions, 5 deletions
diff --git a/block/blk-mq.c b/block/blk-mq.c index 9eea67ce82d9..13cdccef543c 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -337,12 +337,14 @@ 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; + bool put_ctx_on_error = false; blk_queue_enter_live(q); data->q = q; - if (likely(!data->ctx)) - data->ctx = local_ctx = blk_mq_get_ctx(q); + if (likely(!data->ctx)) { + data->ctx = blk_mq_get_ctx(q); + put_ctx_on_error = true; + } if (likely(!data->hctx)) data->hctx = blk_mq_map_queue(q, data->ctx->cpu); if (op & REQ_NOWAIT) @@ -361,8 +363,8 @@ 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); + if (put_ctx_on_error) { + blk_mq_put_ctx(data->ctx); data->ctx = NULL; } blk_queue_exit(q); |