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Message-id: <474CF440.2000001@shaw.ca> Date: Tue, 27 Nov 2007 22:53:20 -0600 From: Robert Hancock <hancockr@...w.ca> To: Larry Finger <Larry.Finger@...inger.net> Cc: LKML <linux-kernel@...r.kernel.org> Subject: Re: Question regarding mutex locking Larry Finger wrote: > If a particular routine needs to lock a mutex, but it may be entered with that mutex already locked, > would the following code be SMP safe? > > hold_lock = mutex_trylock() > > .. > > if (hold_lock) > mutex_unlock() Not if another task could be acquiring that lock at the same time, which is probably the case, otherwise you wouldn't need the mutex. In other words, if you're going to do this, you might as well toss the mutex entirely as it's about the same effect.. -- Robert Hancock Saskatoon, SK, Canada To email, remove "nospam" from hancockr@...pamshaw.ca Home Page: http://www.roberthancock.com/ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.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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