On Wed, 2017-01-18 at 10:48 +0100, Hannes Reinecke wrote:
> @@ -1488,26 +1487,13 @@ static unsigned long disk_events_poll_jiffies(struct gendisk *disk)
> void disk_block_events(struct gendisk *disk)
> {
> struct disk_events *ev = disk->ev;
> - unsigned long flags;
> - bool cancel;
>
> if (!ev)
> return;
>
> - /*
> - * Outer mutex ensures that the first blocker completes canceling
> - * the event work before further blockers are allowed to finish.
> - */
> - mutex_lock(&ev->block_mutex);
> -
> - spin_lock_irqsave(&ev->lock, flags);
> - cancel = !ev->block++;
> - spin_unlock_irqrestore(&ev->lock, flags);
> -
> - if (cancel)
> + if (atomic_inc_return(&ev->block) == 1)
> cancel_delayed_work_sync(&disk->ev->dwork);
>
> - mutex_unlock(&ev->block_mutex);
> }
Hello Hannes,
I have already encountered a few times a deadlock that was caused by the
event checking code so I agree with you that it would be a big step forward
if such deadlocks wouldn't occur anymore. However, this patch realizes a
change that has not been described in the patch description, namely that
disk_block_events() calls are no longer serialized. Are you sure it is safe
to drop the serialization of disk_block_events() calls?
Thanks,
Bart.--
To unsubscribe from this list: send the line "unsubscribe linux-block" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
