parport: make lockdep happy with waitlist_lock
Alexander Gordeev [Tue, 25 Jan 2011 23:07:16 +0000 (15:07 -0800)]
parport_unregister_device() should never be used when interrupts are
enabled in hardware and irq handler is registered so there is no need to
disable interrupts when using waitlist_lock.  But there is no way to
explain this subtle semantics to lockdep analyzer.

So disable interrupts here too to simplify things.  The price is
negligible.

Signed-off-by: Alexander Gordeev <lasaine@lvk.cs.msu.su>
Cc: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/parport/share.c

index a2d9d1e..a848e02 100644 (file)
@@ -678,7 +678,7 @@ void parport_unregister_device(struct pardevice *dev)
 
        /* Make sure we haven't left any pointers around in the wait
         * list. */
-       spin_lock (&port->waitlist_lock);
+       spin_lock_irq(&port->waitlist_lock);
        if (dev->waitprev || dev->waitnext || port->waithead == dev) {
                if (dev->waitprev)
                        dev->waitprev->waitnext = dev->waitnext;
@@ -689,7 +689,7 @@ void parport_unregister_device(struct pardevice *dev)
                else
                        port->waittail = dev->waitprev;
        }
-       spin_unlock (&port->waitlist_lock);
+       spin_unlock_irq(&port->waitlist_lock);
 
        kfree(dev->state);
        kfree(dev);