Messages in this thread | | | Date | Wed, 24 Jul 2002 13:53:22 +0200 | From | Jens Axboe <> | Subject | Re: please DON'T run 2.5.27 with IDE! |
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On Wed, Jul 24 2002, Marcin Dalecki wrote: > >>So look at drivers which call blk_start_queue() from within > >>q->request_fn context, which is, well, causing deliberate *recursion*. > >> > > > > > >Are you sure? If so they should first check whether queue is > >started/stopped, if they don't it is a bug. > > void blk_start_queue(request_queue_t *q) > { > if (test_bit(QUEUE_FLAG_STOPPED, &q->queue_flags)) { > unsigned long flags; > > ================== possigle race here for qeue_flags BTW. > > spin_lock_irqsave(q->queue_lock, flags); > clear_bit(QUEUE_FLAG_STOPPED, &q->queue_flags); > > if (!elv_queue_empty(q)) > q->request_fn(q); > ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ > If we call it from within request_fn then if this isn't recursion on the > kernel stack then I don't know... > > spin_unlock_irqrestore(q->queue_lock, flags); > } > }
Care to enlighten us on exactly which block drivers call blk_start_queue() from request_fn?
-- Jens Axboe
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