From mboxrd@z Thu Jan 1 00:00:00 1970 From: Laurent Pinchart Subject: Re: [PATCH] of: Turn of_match_node into a static inline when CONFIG_OF isn't set Date: Mon, 17 Feb 2014 20:50:34 +0100 Message-ID: <1740750.ctOzzXhXsT@avalon> References: <1392122211-11422-1-git-send-email-laurent.pinchart@ideasonboard.com> <20140217181829.B5F80C40372@trevor.secretlab.ca> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7Bit Return-path: In-Reply-To: <20140217181829.B5F80C40372-WNowdnHR2B42iJbIjFUEsiwD8/FfD2ys@public.gmane.org> Sender: devicetree-owner-u79uwXL29TY76Z2rM5mHXA@public.gmane.org To: Grant Likely Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, devicetree-u79uwXL29TY76Z2rM5mHXA@public.gmane.org, Rob Herring List-Id: devicetree@vger.kernel.org Hi Grant, On Monday 17 February 2014 18:18:29 Grant Likely wrote: > On Tue, 11 Feb 2014 13:36:51 +0100, Laurent Pinchart wrote: > > when CONFIG_OF is disabled of_match_node is defined as a macro that > > evaluates to NULL. This breaks compilation of drivers that dereference > > the function's return value directly. Fix it by turning the macro into a > > static inline function that returns NULL. > > Is it not more problematic that code is dereferencing the return value > directly *without* checking to see if it is NULL first? I suppose it > will cause a runtime oops on all platforms except no-mmu, but still. > Compile time catches are better. There should be no risk of oops if the of_match_ptr() call is guarded by a compiler (as opposed to preprocessor) IS_ENABLED(CONFIG_OF) check. Now, if the check is missing, we'll oops at runtime, but the problem already exists before this patch. Anyway I've decided to drop this patch and use an intermediate variable. > > Signed-off-by: Laurent Pinchart > > --- > > > > include/linux/of.h | 8 +++++++- > > 1 file changed, 7 insertions(+), 1 deletion(-) > > > > diff --git a/include/linux/of.h b/include/linux/of.h > > index 70c64ba..719e69f 100644 > > --- a/include/linux/of.h > > +++ b/include/linux/of.h > > @@ -560,7 +560,13 @@ static inline const char *of_prop_next_string(struct > > property *prop,> > > } > > > > #define of_match_ptr(_ptr) NULL > > > > -#define of_match_node(_matches, _node) NULL > > + > > +static inline const struct of_device_id *of_match_node( > > + const struct of_device_id *matches, const struct device_node *node) > > +{ > > + return NULL; > > +} > > + > > > > #endif /* CONFIG_OF */ > > > > #if defined(CONFIG_OF) && defined(CONFIG_NUMA) -- Regards, Laurent Pinchart -- To unsubscribe from this list: send the line "unsubscribe devicetree" in the body of a message to majordomo-u79uwXL29TY76Z2rM5mHXA@public.gmane.org More majordomo info at http://vger.kernel.org/majordomo-info.html