From 5435c023b92ee1cfb896d924d28c6d31d8386aa0 Mon Sep 17 00:00:00 2001
From: Bart Van Assche <bart.vanassche@sandisk.com>
Date: Tue, 20 Jun 2017 11:15:49 -0700
Subject: [PATCH] blk-mq: Warn when attempting to run a hardware queue that is
not mapped
Git-commit: 5435c023b92ee1cfb896d924d28c6d31d8386aa0
Patch-mainline: v4.13-rc1
References: fate#322738,fate#322919,fate#322950,fate#323773
A queue must be frozen while the mapped state of a hardware queue
is changed. Additionally, any change of the mapped state is
followed by a call to blk_mq_map_swqueue() (see also
blk_mq_init_allocated_queue() and blk_mq_update_nr_hw_queues()).
Since blk_mq_map_swqueue() does not map any unmapped hardware
queue onto any software queue, no attempt will be made to run
an unmapped hardware queue. Hence issue a warning upon attempts
to run an unmapped hardware queue.
Signed-off-by: Bart Van Assche <bart.vanassche@sandisk.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Hannes Reinecke <hare@suse.com>
Cc: Omar Sandoval <osandov@fb.com>
Cc: Ming Lei <ming.lei@redhat.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Coly Li <colyli@suse.de>
---
block/blk-mq.c | 8 +++++---
1 file changed, 5 insertions(+), 3 deletions(-)
diff --git a/block/blk-mq.c b/block/blk-mq.c
index 1d8050e49a94..1c4f1f4978c6 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1129,8 +1129,10 @@ static int blk_mq_hctx_next_cpu(struct blk_mq_hw_ctx *hctx)
static void __blk_mq_delay_run_hw_queue(struct blk_mq_hw_ctx *hctx, bool async,
unsigned long msecs)
{
- if (unlikely(blk_mq_hctx_stopped(hctx) ||
- !blk_mq_hw_queue_mapped(hctx)))
+ if (WARN_ON_ONCE(!blk_mq_hw_queue_mapped(hctx)))
+ return;
+
+ if (unlikely(blk_mq_hctx_stopped(hctx)))
return;
if (!async && !(hctx->flags & BLK_MQ_F_BLOCKING)) {
@@ -1295,7 +1297,7 @@ static void blk_mq_run_work_fn(struct work_struct *work)
void blk_mq_delay_queue(struct blk_mq_hw_ctx *hctx, unsigned long msecs)
{
- if (unlikely(!blk_mq_hw_queue_mapped(hctx)))
+ if (WARN_ON_ONCE(!blk_mq_hw_queue_mapped(hctx)))
return;
/*
--
2.13.1