Re: Question regarding mutex locking

[Matthias Kaehlcke <matthias.kaehlcke@gmail.com>]

El Wed, Nov 28, 2007 at 08:46:51AM -0600 Larry Finger ha dit:

> Matthias Kaehlcke wrote:
> > El Tue, Nov 27, 2007 at 10:37:00PM -0600 Larry Finger ha dit:
> > 
> >> 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()
> > 
> > this is wont work, a mutex must not be released from another
> > context than the one that acquired it.
> 
> I thought that mutex_trylock() returned 1 if it got the lock and 0 if not. If that is true, wouldn't
> the if statement only unlock if the lock was obtained in this routine?

you're right, sorry i read to fast and interpreted that you want to
release the mutex in any case 

-- 
Matthias Kaehlcke
Linux Application Developer
Barcelona

             You must have a plan. If you don't have a plan,
               you'll become part of somebody else's plan
                                                                 .''`.
    using free software / Debian GNU/Linux | http://debian.org  : :'  :
                                                                `. `'`
gpg --keyserver pgp.mit.edu --recv-keys 47D8E5D4                  `-