On Wed, 16 Aug 2017 14:14:36 -0400
Waiman Long [off-list ref] wrote:

quoted

You also just turned the mutex into a spinlock. What happens if we just
preempted the owner of bdev->bd_mutex and are an RT task with higher
priority? This will turn into a live lock.
 

quoted

+		schedule();
+	}
   

That is OK because I used schedule() instead of cpu_relax() for
inserting delay.

Please explain to me how that is OK? schedule is a nop if the current
task is the highest priority task running, and it preempted the owner
of the lock. Nothing will actually schedule.

-- Steve