From mboxrd@z Thu Jan 1 00:00:00 1970 From: Geert Uytterhoeven Date: Tue, 10 May 2011 09:42:01 +0000 Subject: Re: [PATCH] omap2/omapfb: make DBG() more resistant in if-else constructions Message-Id: List-Id: References: <1305019249-9898-1-git-send-email-ndevos@redhat.com> In-Reply-To: <1305019249-9898-1-git-send-email-ndevos@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 8bit To: Niels de Vos Cc: linux-omap@vger.kernel.org, linux-fbdev@vger.kernel.org, linux-kernel@vger.kernel.org On Tue, May 10, 2011 at 11:20, Niels de Vos wrote: > When DBG() is used in a simple if-else, the resulting code path > currently depends on the definition of DBG(). Inserting the statement in > a "do { ... } while (0)" prevents this possible misuse. > > Signed-off-by: Niels de Vos > --- a/drivers/video/omap2/omapfb/omapfb.h > +++ b/drivers/video/omap2/omapfb/omapfb.h > @@ -34,8 +34,10 @@ >  #ifdef DEBUG >  extern unsigned int omapfb_debug; >  #define DBG(format, ...) \ > -       if (omapfb_debug) \ > -               printk(KERN_DEBUG "OMAPFB: " format, ## __VA_ARGS__) > +       do { \ > +               if (omapfb_debug) \ > +                       printk(KERN_DEBUG "OMAPFB: " format, ## __VA_ARGS__); \ > +       while (0) Where's the closing '}'? >  #else >  #define DBG(format, ...) BTW, no printf()-style format checking here. >  #endif What about using the standard pr_debug()/dev_dbg() instead? With dynamic debug, it can be enabled at run time. As a bonus, you get printf()-style format checking if debugging is disabled. Gr{oetje,eeting}s,                         Geert -- Geert Uytterhoeven -- There's lots of Linux beyond ia32 -- geert@linux-m68k.org In personal conversations with technical people, I call myself a hacker. But when I'm talking to journalists I just say "programmer" or something like that.                                 -- Linus Torvalds