Re: [PULL REQUEST] md bug fixes and minor improvements

[Jens Axboe <jens.axboe@oracle.com>]

On Fri, Aug 01 2008, Dan Williams wrote:
> 
> On Fri, 2008-08-01 at 19:22 +0200, Jens Axboe wrote:
> > It is a bit asymmetrical, largely due to the fact that the ->unplug_fn()
> > itself grabs the lock. The below patch should fix it, since Neil has
> > added a proper queue lock to the md queues. If someone can confirm that
> > this fixes it, I'll queue up a patch with proper descriptions.
> > 
> > > I guess Jens is gone too..
> > 
> > I'm back, just been busy this week :-)
> > 
> > diff --git a/drivers/md/bitmap.c b/drivers/md/bitmap.c
> > index 621a272..f19b52f 100644
> > --- a/drivers/md/bitmap.c
> > +++ b/drivers/md/bitmap.c
> > @@ -1234,7 +1234,9 @@ int bitmap_startwrite(struct bitmap *bitmap, sector_t offset, unsigned long sect
> >  		case 0:
> >  			bitmap_file_set_bit(bitmap, offset);
> >  			bitmap_count_page(bitmap,offset, 1);
> > +			spin_lock_irq(&bitmap->mddev->queue->queue_lock);
> >  			blk_plug_device(bitmap->mddev->queue);
> > +			spin_unlock_irq(&bitmap->mddev->queue->queue_lock);
> >  			/* fall through */
> >  		case 1:
> >  			*bmc = 2;
> > 
> 
> We also need to protect the blk_plug_device call a few lines down (and
> an obvious compile fix).

Old source I guess, just one blk_plug_device() in the copy I have here.
Just checked latest git, still just one blk_plug_device(), are you
diffing against -mm or something like that? Or linux-next?

And queue_lock is of course a pointer, I didn't even compile the
thing... Thanks for the updated variant!

-- 
Jens Axboe