Re: BLKSECDISCARD ioctl and hung tasks

[Jesse Barnes]

On Fri, Feb 14, 2020 at 7:47 PM Ming Lei <ming.lei@xxxxxxxxxx> wrote:
> What are the 'other operations'? Are they block IOs?
>
> If yes, that is why I suggest to fix submit_bio_wait(), which should cover
> most of sync bio submission.
>
> Anyway, the fix is simple & generic enough, I'd plan to post a formal
> patch if no one figures out better doable approaches.

Yeah I think any block I/O operation that occurs after the
BLKSECDISCARD is submitted will also potentially be affected by the
hung task timeouts, and I think your patch will address that.  My only
concern with it is that it might hide some other I/O "hangs" that are
due to device misbehavior instead.  Yes driver and device timeouts
should generally catch those, but with this in place we might miss a
few bugs.

Given the nature of these types of storage devices though, I think
that's a minor issue and not worth blocking the patch on, given that
it should prevent a lot of false positive hang reports as Salman
demonstrated.

Thanks,
Jesse