On Thu, Apr 12, 2018 at 04:29:09PM +0000, Bart Van Assche wrote:
> Any code that submits a bio or request needs blk_queue_enter() /
> blk_queue_exit() anyway. Please have a look at the following commit - you will
> see that that commit reduces the number of blk_queue_enter() /
> calls in the hot path:
So, this can work, but it's still pretty fragile.
* Lock switching is fragile and we really should get rid of it. This
is very likely to come back and bite us.
* Right now, blk_queue_enter/exit() doesn't have any annotations.
IOW, there's no way for paths which need enter locked to actually
assert that. If we're gonna protect more things with queue
enter/exit, it gotta be annotated.