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Date: Thu, 8 Apr 2004 23:36:47 +0200
From: Pawel Jakub Dawidek <pjd@FreeBSD.org>
To: freebsd-arch@freebsd.org
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Subject: mtx_lock_recurse/mtx_unlock_recurse functions (proof-of-concept).
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Hi.

As was discussed, it will be helpful to have functions, that are able
to acquire lock recursively, even if lock itself isn't recursable.

Here is a patch, that should implement this functionality:

	http://people.freebsd.org/~pjd/patches/mtx_lock_recurse.patch

I also added a KASSERT() to protect against mixed locking modes, e.g.:

	mtx_lock(&mtx);
	[...]
	mtx_lock_recurse(&mtx);
	[...]
	mtx_unlock(&mtx);
	[...]
	mtx_unlock_recurse(&mtx);

This is not permitted, but this should work just fine:

	mtx_lock(&mtx);
	[...]
	mtx_lock_recurse(&mtx);
	[...]
	mtx_unlock_recurse(&mtx);
	[...]
	mtx_unlock(&mtx);

--=20
Pawel Jakub Dawidek                       http://www.FreeBSD.org
pjd@FreeBSD.org                           http://garage.freebsd.pl
FreeBSD committer                         Am I Evil? Yes, I Am!

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