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From: Rusty Russell <rusty@rustcorp.com.au>
To: Matthew Wilcox <matthew@wil.cx>
Cc: Michal Schmidt <mschmidt@redhat.com>,
	Daniel Walker <dwalker@mvista.com>,
	linville@tuxdriver.com, mingo@elte.hu,
	linux-kernel@vger.kernel.org, linux-wireless@vger.kernel.org,
	arjan@infradead.org
Subject: Re: [PATCH] net: wireless: airo semaphore to mutex
Date: Tue, 27 May 2008 14:37:22 +1000	[thread overview]
Message-ID: <200805271437.23114.rusty@rustcorp.com.au> (raw)
In-Reply-To: <20080527021503.GH30894@parisc-linux.org>

On Tuesday 27 May 2008 12:15:03 Matthew Wilcox wrote:
> On Tue, May 27, 2008 at 11:17:22AM +1000, Rusty Russell wrote:
> > On Tuesday 27 May 2008 03:29:14 Michal Schmidt wrote:
> > > Mutexes are not allowed in interrupt context, not even mutex_trylock.
> >
> > As an aside, does anyone know why?  I know the documentation says so, but
> > it wasn't immediately obvious to me.  I asked before to no response...
>
> Because mutexes have an owner.  In interrupt context, there is no owner.
> This owner is used to do priority boosts as well as debugging.

Shows how little I know, I didn't see priority boosting in my glance thru 
mutex.c.

But it seems like mutex_trylock_irq would be easy to add if needed, if only 
for clarity.

Thanks!
Rusty.

  parent reply	other threads:[~2008-05-27  4:37 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-05-22 23:21 [PATCH] net: wireless: airo semaphore to mutex Daniel Walker
2008-05-26 17:29 ` Michal Schmidt
2008-05-26 17:59   ` Daniel Walker
2008-05-27  1:17   ` Rusty Russell
2008-05-27  2:15     ` Matthew Wilcox
2008-05-27  4:34       ` Daniel Walker
2008-05-27 11:24         ` Matthew Wilcox
2008-05-27  4:37       ` Rusty Russell [this message]
2008-05-27 13:13 ` Matthew Wilcox
2008-05-27 13:48   ` Dan Williams
2008-05-27 15:08     ` Daniel Walker
2008-05-27 15:34       ` Matthew Wilcox
2008-05-27 16:01         ` Daniel Walker

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