linux/drivers/gpu
Jani Nikula 95150bdf78 drm/i915: fix potential dangling else problems in for_each_ macros
We have serious dangling else bugs waiting to happen in our for_each_
style macros with ifs. Consider, for example,

 #define for_each_power_domain(domain, mask)                         \
         for ((domain) = 0; (domain) < POWER_DOMAIN_NUM; (domain)++) \
                 if ((1 << (domain)) & (mask))

If this is used in context:

	if (condition)
		for_each_power_domain(domain, mask);
	else
		foo();

foo() will be called for each domain *not* in mask, if condition holds,
and not at all if condition doesn't hold.

Fix this by reversing the conditions in the macros, and adding an else
branch for the "for each" block, so that other if/else blocks can't
interfere. Provide a "for_each_if" helper macro to make it easier to get
this right.

v2: move for_each_if to drmP.h in a separate patch.

Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Signed-off-by: Jani Nikula <jani.nikula@intel.com>
Link: http://patchwork.freedesktop.org/patch/msgid/1448392916-2281-2-git-send-email-jani.nikula@intel.com
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
2015-11-25 09:29:32 +01:00
..
drm drm/i915: fix potential dangling else problems in for_each_ macros 2015-11-25 09:29:32 +01:00
host1x gpu: host1x: Fix MLOCK's debug info 2015-10-02 14:40:12 +02:00
ipu-v3 imx-drm fixes and color format updates 2015-11-05 11:06:56 +10:00
vga vga_switcheroo: Drop client power state VGA_SWITCHEROO_INIT 2015-11-05 11:07:36 +10:00
Makefile