Hello, 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() / blk_queue_exit() > calls in the hot path: > > https://git.kernel.org/pub/scm/linux/kernel/git/axboe/linux-block.git/commit/?h=for-linus&id=37f9579f4c31a6d698dbf3016d7bf132f9288d30 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. Thanks. -- tejun
