Messages in this thread | | | Date | Tue, 14 Nov 2006 11:24:09 +0000 | From | Russell King <> | Subject | Re: device_del() and references |
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On Tue, Nov 14, 2006 at 08:40:00AM +0100, Pierre Ossman wrote: > When a card driver has obtained a reference to a card, what makes sure > we do not destroy that card from under its feet?
Essentially, the driver model. (see the answer to your paragraph below.)
> I suspect that device_del() doesn't return until remove() has been > called and that our requirement is that the card driver must have > released all references to the card before its remove routine exits.
Your sentence is confusing - which "remove()" are you talking about here? If you're talking about mmc_blk_remove() then that's correct.
> If so, then there is the risk of a race in mmc_block. What guarantees > that the request handler isn't running in parallel with the remove > function? Again, I suspect that del_gendisk() might grab the queue lock, > but as there might be stuff left in the queue, this seems insufficient.
Hmm, not sure here. I think you might be right, but the block layer is *extremely* finaky when it comes to removing stuff.
In short, I don't know - I've forgotten quite a bit about the low level block interface with MMC since it's something I did once and only once.
Maybe Jens has some ideas?
-- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: 2.6 Serial core - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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