Messages in this thread | | | From | Grant Likely <> | Subject | Re: [PATCH] of: Turn of_match_node into a static inline when CONFIG_OF isn't set | Date | Mon, 17 Feb 2014 18:19:53 +0000 |
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On Tue, 11 Feb 2014 10:48:26 -0600, Josh Cartwright <joshc@codeaurora.org> wrote: > On Tue, Feb 11, 2014 at 03:55:35PM +0100, Laurent Pinchart wrote: > > Hi Josh, > > > > On Tuesday 11 February 2014 08:41:08 Josh Cartwright wrote: > > > On Tue, Feb 11, 2014 at 01:36:51PM +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. > > > > > > Just this past week I did the same thing, but noticed that it breaks the > > > following usecase: > > > > > > #ifdef CONFIG_OF > > > static const struct of_device_id foobar_matches[] = { > > > { .compatible = "foobar,whatsit", }, > > > { }, > > > }; > > > #endif > > > > > > static int probeme(struct platform_device *pdev) > > > { > > > struct of_device_id *id; > > > > > > id = of_match_node(foobar_matches, pdev->dev.of_node); > > > if (id) { > > > /* ... */ > > > } > > > return 0; > > > } > > > > > > When !CONFIG_OF and with your change, this will fail to build due to > > > foobar_matches being undefined. > > > > Good point. What would you think about > > > > #define of_match_node(_matches, _node) ((const struct of_device_id *)NULL) > > I've just sent out a patchset that cleans up at least a couple of users > that directly do of_match_node(matches, np)->data using > of_find_matching_node_and_match. Not sure if that will fix the usage > you have in mind, though. > > I am a bit weary about having an of_match_node() user that both directly > dereferences the result (i.e. of_match_node(matches, np)->data) _and_ > builds when !CONFIG_OF; most likely due to a traumatic childhood event > where demons flew out my nose.
As is supposed to happen when code dereferrences pointers blindly.
g.
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