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SubjectRe: [PATCH] 2.6.0 NBD driver: remove send/recieve race for request
Jens Axboe wrote:
>
> On Fri, Aug 08 2003, Lou Langholtz wrote:
> > >@@ -499,12 +508,14 @@ static void do_nbd_request(request_queue
> > > lo->disk->disk_name);
> > > spin_lock(&lo->queue_lock);
> > > list_del_init(&req->queuelist);
> > >+ req->ref_count--;
> > > spin_unlock(&lo->queue_lock);
> > > nbd_end_request(req);
> > > spin_lock_irq(q->queue_lock);
> > > continue;
> > > }
> > >
> > >+ req->ref_count--;
> > > spin_lock_irq(q->queue_lock);
> > >
> > Since ref_count isn't atomic, shouldn't ref_count only be changed while
> > the queue_lock is held???
>
> Indeed, needs to be done after regrabbing the lock.

But req is pulled off of nbd's main request queue at this point, so I
don't think anyone else could be touching it, could they?

--
Paul
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