Messages in this thread | | | Date | Mon, 13 May 2002 15:02:26 +0200 | From | Martin Dalecki <> | Subject | Re: [PATCH] 2.5.15 IDE 62 |
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Uz.ytkownik Jens Axboe napisa?: > On Mon, May 13 2002, Martin Dalecki wrote: > >>Mon May 13 12:38:11 CEST 2002 ide-clean-62 >> >>- Add missing locking around ide_do_request in do_ide_request(). > > > This is broken, do_ide_request() is already called with the request lock > held. tq_disk run -> generic_unplug_device (grab lock) -> > __generic_unplug_device -> do_ide_request(). You just introduced a > deadlock. > > This code would have caused hangs or massive corruption immediately if > ide_lock wasn't ready held there. Not to mention instant spin_unlock > BUG() triggers in queue_command() >
Oops. Indeed I see now that the ide_lock is exported to the upper layers above it in ide-probe.c
blk_init_queue(q, do_ide_request, &ide_lock);
But this is problematic in itself, since it means that we are basically serialiazing between *all* requests on all channels.
So I think we should have per channel locks on this level right? This is anyway our unit for serialization. (I'm just surprised that blk_init_queue() doesn't provide queue specific locking and relies on exported locks from the drivers...)
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