[dm-devel] Re: [PATCH 2.6.19 5/5] fs: freeze_bdev with semaphore not mutex
Ingo Molnar
mingo at elte.hu
Tue Nov 7 23:39:38 UTC 2006
* Andrew Morton <akpm at osdl.org> wrote:
> If so, it's a bit sad to switch to semaphore just because of some
> errant debugging code. Perhaps it would be better to create a new
> mutex_unlock_stfu() which suppresses the warning?
the code was not using semaphores as a pure mutex thing. For example
unlocking by non-owner is not legal. AFAICS the code returns to
userspace with a held in-kernel mutex. That makes it hard for the kernel
to determine for example whether the lock has been 'forgotten', or kept
like that intentionally. Alasdair, what is the motivation for doing it
like that?
Ingo
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