On Thu, Jan 11 2018 at 12:47pm -0500, Bart Van Assche <Bart.VanAssche@xxxxxxx> wrote: > On Thu, 2018-01-11 at 12:29 -0500, Mike Snitzer wrote: > > On Thu, Jan 11 2018 at 12:18pm -0500, > > Bart Van Assche <Bart.VanAssche@xxxxxxx> wrote: > > > > > On Thu, 2018-01-11 at 12:04 -0500, Mike Snitzer wrote: > > > > So my v4, that I'll send out shortly, won't be using test_and_clear_bit() > > > > > > Please use queue_flag_set(), queue_flag_clear(), queue_flag_test_and_clear() and/or > > > queue_flag_test_and_set() to manipulate queue flags. > > > > Can you please expand on this? My patch is only using test_bit(). > > Hello Mike, > > I was referring to the following code, which apparenly is existing code: > > mutex_lock(&q->sysfs_lock); > queue_flag_clear_unlocked(QUEUE_FLAG_REGISTERED, q); > mutex_unlock(&q->sysfs_lock); > > The above code is wrong. Other code that changes the queue flags protects > these changes with the the queue lock. The above code should be changed into > the following: > > spin_lock_irq(q->queue_lock); > queue_flag_clear(QUEUE_FLAG_REGISTERED, q); > spin_unlock_irq(q->queue_lock); > > The only functions from which it is safe to call queue_flag_(set|clear)_unlocked() > without holding the queue lock are blk_alloc_queue_node() and > __blk_release_queue() because for these functions it is guaranteed that no queue > flag changes can happen from another context, e.g. through a blk_set_queue_dying() > call. Yes, I noticed the use of sysfs_lock also. I've fixed it up earlier in my v4 patchset and build on it. I'll add your Reported-by too. Mike
