diff mbox

[v4,12/12] blk-mq: Warn when attempting to run a hardware queue that is not mapped

Message ID 20170619220801.12557-13-bart.vanassche@wdc.com (mailing list archive)
State New, archived
Headers show

Commit Message

Bart Van Assche June 19, 2017, 10:08 p.m. UTC 
From: Bart Van Assche <bart.vanassche@sandisk.com>

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>
---
 block/blk-mq.c | 7 ++++---
 1 file changed, 4 insertions(+), 3 deletions(-)

Comments

Jens Axboe June 19, 2017, 11:06 p.m. UTC | #1 
On 06/19/2017 04:08 PM, Bart Van Assche wrote:
> From: Bart Van Assche <bart.vanassche@sandisk.com>
> 
> 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>
> ---
>  block/blk-mq.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index e7b0d69fdf65..c6218f32770d 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -1140,8 +1140,9 @@ 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)))
> +	WARN_ON_ONCE(!blk_mq_hw_queue_mapped(hctx));
> +

	if (WARN_ON_ONCE(!blk_mq_hw_queue_mapped(hctx)))
		return;
Bart Van Assche June 19, 2017, 11:10 p.m. UTC | #2 
On Mon, 2017-06-19 at 17:06 -0600, Jens Axboe wrote:
> On 06/19/2017 04:08 PM, Bart Van Assche wrote:
> > --- a/block/blk-mq.c
> > +++ b/block/blk-mq.c
> > @@ -1140,8 +1140,9 @@ 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)))
> > +	WARN_ON_ONCE(!blk_mq_hw_queue_mapped(hctx));
> > +
> 
> 	if (WARN_ON_ONCE(!blk_mq_hw_queue_mapped(hctx)))
> 		return;

Hello Jens,

Thanks for having reviewed this patch series. I will make the requested
changes, retest and repost this patch series.

Bart.
Hannes Reinecke June 20, 2017, 6:43 a.m. UTC | #3 
On 06/20/2017 12:08 AM, Bart Van Assche wrote:
> From: Bart Van Assche <bart.vanassche@sandisk.com>
> 
> 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>
> ---
>  block/blk-mq.c | 7 ++++---
>  1 file changed, 4 insertions(+), 3 deletions(-)
> 
> diff --git a/block/blk-mq.c b/block/blk-mq.c
> index e7b0d69fdf65..c6218f32770d 100644
> --- a/block/blk-mq.c
> +++ b/block/blk-mq.c
> @@ -1140,8 +1140,9 @@ 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)))
> +	WARN_ON_ONCE(!blk_mq_hw_queue_mapped(hctx));
> +
> +	if (unlikely(blk_mq_hctx_stopped(hctx)))
>  		return;
>  
>  	if (!async && !(hctx->flags & BLK_MQ_F_BLOCKING)) {
> @@ -1306,7 +1307,7 @@ 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;
>  
>  	/*
> 
Reviewed-by: Hannes Reinecke <hare@suse.com>

Cheers,

Hannes
diff mbox

Patch

diff --git a/block/blk-mq.c b/block/blk-mq.c
index e7b0d69fdf65..c6218f32770d 100644
--- a/block/blk-mq.c
+++ b/block/blk-mq.c
@@ -1140,8 +1140,9 @@  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)))
+	WARN_ON_ONCE(!blk_mq_hw_queue_mapped(hctx));
+
+	if (unlikely(blk_mq_hctx_stopped(hctx)))
 		return;
 
 	if (!async && !(hctx->flags & BLK_MQ_F_BLOCKING)) {
@@ -1306,7 +1307,7 @@  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;
 
 	/*