Re: [PATCH] use spinlock instead of binary mutex in idt77252 driver
From: Matthias Kaehlcke
Date: Mon Apr 23 2007 - 03:54:36 EST
hi,
El Mon, Apr 23, 2007 at 09:40:19AM +0200 Eddie C. Dost ha dit:
> as long as mutexes are not converted to nop when CONFIG_SMP is not
> defined (I don't know what current kernels do), this is of course
> correct. You need to verify the headerfiles for the above.
i just checked this, neither the mutex header nor implementation files
handle things different for CONFIG_SMP.
thanks for your comments
> On Mon, Apr 23, 2007 at 09:40:26AM +0200, Matthias Kaehlcke wrote:
> > El Mon, Apr 23, 2007 at 09:16:08AM +0200 Eddie C. Dost ha dit:
> >
> > > Please note that the semaphore is used to lock the idt77252 config
> > > tables among multiple users including atmsigd even on single processor
> > > machines. Does this work with mutexes?
> >
> > afaik mutexes have the same behaviour as binary semaphores that are
> > used as mutexes (always locked and unlocked by the same
> > process/thread):
> >
> > ".. the semaphore type can officially be considered to be on its way
> > out. New code should not use semaphores, and old code which uses
> > semaphores as mutexes should be converted over when an opportunity
> > presents itself."
> >
> > http://lwn.net/Articles/167034/
> >
> > please correct me if i'm wrong, i'm just doing my first steps with
> > linux kernel development
--
Matthias Kaehlcke
Linux Application Developer
Barcelona
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