linux-kernel - Re: [PATCH] use mutex instead of semaphore in RocketPort driver

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Message-ID: <20070424181949.GD6798@traven>
Date:	Tue, 24 Apr 2007 20:19:49 +0200
From:	Matthias Kaehlcke <matthias.kaehlcke@...il.com>
To:	Oliver Neukum <oneukum@...e.de>
Cc:	linux-kernel@...r.kernel.org
Subject: Re: [PATCH] use mutex instead of semaphore in RocketPort driver

El Tue, Apr 24, 2007 at 07:53:04PM +0200 Oliver Neukum ha dit:

> Am Dienstag, 24. April 2007 19:49 schrieb Matthias Kaehlcke:
> > @@ -1706,7 +1706,7 @@ static int rp_write(struct tty_struct *tty,
> >         if (count <= 0 || rocket_paranoia_check(info, "rp_write"))
> >                 return 0;
> >  
> > -       down_interruptible(&info->write_sem);
> > +       mutex_lock_interruptible(&info->write_mtx);
> 
> This is a bug. It is also present in the current code, but nevertheless
> it is a bug. If you use an interruptible lock, you must be ready to deal
> with interrupts, which are ignored by this code.

i fear i don't have the experience/knowledge to fix this bug, thanks
for your remark. 

i'm a bit confused now about the interruptible locks, i thought using
them means that the process will be waked up when receiving a
signal. what role are playing interrupts when using interruptible locks?

-- 
Matthias Kaehlcke
Linux Application Developer
Barcelona

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                        (Subcomandante Marcos)
                                                                 .''`.
    using free software / Debian GNU/Linux | http://debian.org  : :'  :
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