[PATCH v5 2/6] block: wire-up support for passthrough plugging

[Christoph Hellwig]

On Thu, May 12, 2022 at 01:25:24PM +0800, Ming Lei wrote:
> This way may cause nested plugging, and breaks xfstests generic/131.
> Also may cause io hang since request can't be polled before flushing
> plug in blk_execute_rq().

Looking at this again, yes blk_mq_request_bypass_insert is probably the
wrong place.

> I'd suggest to apply the plug in blk_execute_rq_nowait(), such as:

Do we really need the use_plug parameter and the extra helper?  If
someone holds a plug over passthrough command submission I think
we can assume they actually do want to use it.  Otherwise this does
indeed look like the better plan.