Re: [PATCH V2 RESEND 2/5] blk-mq: add blk-mq flag of BLK_MQ_F_NO_MANAGED_IRQ

[Hannes Reinecke <hare@suse.de>]

On 10/6/19 4:45 AM, Ming Lei wrote:
> We will stop hw queue and wait for completion of in-flight requests
> when one hctx is becoming dead in the following patch. This way may
> cause dead-lock for some stacking blk-mq drivers, such as dm-rq and
> loop.
> 
> Add blk-mq flag of BLK_MQ_F_NO_MANAGED_IRQ and mark it for dm-rq and
> loop, so we needn't to wait for completion of in-flight requests of
> dm-rq & loop, then the potential dead-lock can be avoided.
> 
> Cc: Bart Van Assche <bvanassche@acm.org>
> Cc: Hannes Reinecke <hare@suse.com>
> Cc: Christoph Hellwig <hch@lst.de>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Keith Busch <keith.busch@intel.com>
> Signed-off-by: Ming Lei <ming.lei@redhat.com>
> ---
>  block/blk-mq-debugfs.c | 1 +
>  drivers/block/loop.c   | 2 +-
>  drivers/md/dm-rq.c     | 2 +-
>  include/linux/blk-mq.h | 1 +
>  4 files changed, 4 insertions(+), 2 deletions(-)
> 
I would have preferred to queue this patch after the next one;
introducing a flag which doesn't do anything is a bit odd to me.
But anyway:

Reviewed-by: Hannes Reinecke <hare@suse.com>

Cheers,

Hannes
-- 
Dr. Hannes Reinecke		      Teamlead Storage & Networking
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