Re: [PATCH] Revert "scsi-mq: Always unprepare before requeuing a request"

Bart Van Assche
2017-08-17T01:30:02Z

On Wed, 2017-08-16 at 20:52 -0400, Martin K. Petersen wrote:
> Damien,
>
> > Actually, we can keep that commit as it makes the sq case cleaner
> > anyway. But we need something else to prevent deadlock in the mq
> > case...
>
> OK, put it back.
>
> Please send a lockout patch. We can always zap it if we find out what
> went wrong with Bart's patch and queue a "real" fix.

Hello Martin,

I'm 99% sure there is nothing wrong with my patch but that my patch uncovered
a bug in the ipr driver (drivers/scsi/ipr). See also "WARNING: CPU: 15 PID: 0
at block/blk-mq.c:1111 __blk_mq_run_hw_queue+0x1d8/0x1f0F"
(https://marc.info/?l=linux-block&m=150290686719644).

Bart.