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SubjectRe: [patch 5/6] [RFC] Add MMC Password Protection (lock/unlock) support V6
On Fri, Nov 17, 2006 at 09:12:39AM -0400, Anderson Briglia wrote:
> + if (mmc_card_locked(card) && !strncmp(data, "erase", 5)) {
> + /* forced erase only works while card is locked */
> + spin_lock(&mmc_lock);
> + mmc_lock_unlock(card, NULL, MMC_LOCK_MODE_ERASE);
> + spin_unlock(&mmc_lock);

mmc_lock_unlock can sleep; holding a spinlock while sleeping is illegal
and is a serious bug. Inappropriate locking? What's this lock trying
to achieve?

I don't see any requirement for locking here - mmc_lock_unlock() claims
the host, and if that succeeds, it has exclusive access via that host to
the card. No one else will be able to talk on the bus until
mmc_lock_unlock() releases it's claim on the host. So I suspect that
whatever locking you require is already in place.

Ditto for each other instances.

Russell King
Linux kernel 2.6 ARM Linux -
maintainer of: 2.6 Serial core
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