On Wed, Jul 02 2008, James Bottomley wrote: > On Wed, 2008-07-02 at 13:50 +0200, Jens Axboe wrote: > > On Wed, Jul 02 2008, Elias Oltmanns wrote: > > > > The blk_plug_queue change looks reasonable ... however, blk_plug_queue > > > > itself looks like it might not entirely need the queue lock ... I need > > > > to investigate more closely. > > > > > > Well, I rather think it does. We have to serialise access to the > > > unplug_timer and there is a call to __set_bit() which, as I understand, > > > requires the calling function to ensure atomicity. > > > > Yep, blk_plug_device() needs to be called with the queue lock held. > > That's what the comment says ... but if you replaced the test_bit with > an atomic operation then the rest of it does look to be in no need of > serialisation ... unless there's something I missed? Indeed, but then you would have to use atomic bitops everywhere and that is the bit we moved away from. -- Jens Axboe -- To unsubscribe from this list: send the line "unsubscribe linux-scsi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
