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Date: Fri, 24 Dec 2004 04:52:25 -0800 (PST)
From: "Kamal R. Prasad" <kamalpr@yahoo.com>
To: Jan Engelhardt <jengelh@linux01.gwdg.de>
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cc: freebsd-hackers@freebsd.org
Subject: Re: Kernel crash w/o reason
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--- Jan Engelhardt <jengelh@linux01.gwdg.de> wrote:

> >> What should I use instead? A semaphore?
> 
> >You shouldn't have unrelated kernel threads waiting
> for a user
> >process at all, so this sounds like a design
> problem, regardless
> >of which mutual exclusion primitive you use.  (Bear
> in mind that I
> >haven't actually looked into what you're trying to
> do.)  In any
> >case, you can always use mutexes to implement
> whatever other
> >synchronization mechanism you need.
> 
> I wanted that the device can only be opened once,
> and holding a mutex while it
> is open seemed like a simple idea. (Since
> mtx_trylock() will then fail -- easy
> to implement.)

An even more simpler idea would be to set a flag in
the softc data structure on initialization, so as to
avoid initializing again.

regards
-kamal

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