From 7b6078146ccbe9bd165d578586b10ea092ac489e Mon Sep 17 00:00:00 2001 From: Bart Van Assche Date: Tue, 20 Jun 2017 11:15:47 -0700 Subject: blk-mq: Document locking assumptions Document the locking assumptions in functions that modify blk_mq_ctx.rq_list to make it easier for humans to verify this code. Signed-off-by: Bart Van Assche Reviewed-by: Christoph Hellwig Cc: Hannes Reinecke Cc: Omar Sandoval Cc: Ming Lei Signed-off-by: Jens Axboe --- block/blk-mq-sched.c | 2 ++ block/blk-mq.c | 4 ++++ 2 files changed, 6 insertions(+) diff --git a/block/blk-mq-sched.c b/block/blk-mq-sched.c index 9f025289da63..191bf82d185e 100644 --- a/block/blk-mq-sched.c +++ b/block/blk-mq-sched.c @@ -150,6 +150,8 @@ static bool blk_mq_attempt_merge(struct request_queue *q, struct request *rq; int checked = 8; + lockdep_assert_held(&ctx->lock); + list_for_each_entry_reverse(rq, &ctx->rq_list, queuelist) { bool merged = false; diff --git a/block/blk-mq.c b/block/blk-mq.c index 6268380c680f..1d8050e49a94 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -1317,6 +1317,8 @@ static inline void __blk_mq_insert_req_list(struct blk_mq_hw_ctx *hctx, { struct blk_mq_ctx *ctx = rq->mq_ctx; + lockdep_assert_held(&ctx->lock); + trace_block_rq_insert(hctx->queue, rq); if (at_head) @@ -1330,6 +1332,8 @@ void __blk_mq_insert_request(struct blk_mq_hw_ctx *hctx, struct request *rq, { struct blk_mq_ctx *ctx = rq->mq_ctx; + lockdep_assert_held(&ctx->lock); + __blk_mq_insert_req_list(hctx, rq, at_head); blk_mq_hctx_mark_pending(hctx, ctx); } -- cgit