It is nontrivial to derive from the blk-mq source code when blk_mq_tags.active_queues is decremented. Hence add a comment that explains this.
Signed-off-by: Bart Van Assche <[email protected]> Cc: Christoph Hellwig <[email protected]> Cc: Hannes Reinecke <[email protected]> Cc: Johannes Thumshirn <[email protected]> --- v2: Rewrote the comment based on feedback from Jens. block/blk-mq.c | 6 ++++++ 1 file changed, 6 insertions(+) diff --git a/block/blk-mq.c b/block/blk-mq.c index f84d145490bf..09ee74056f93 100644 --- a/block/blk-mq.c +++ b/block/blk-mq.c @@ -834,6 +834,12 @@ static void blk_mq_timeout_work(struct work_struct *work) } else { struct blk_mq_hw_ctx *hctx; + /* + * Request timeouts are handled as a forward rolling timer. If + * we end up here it means that no requests are pending and + * also that no request has been pending for a while. Mark + * each hctx as idle. + */ queue_for_each_hw_ctx(q, hctx, i) { /* the hctx may be unmapped, so check it here */ if (blk_mq_hw_queue_mapped(hctx)) -- 2.14.0
