Patch "drm/exynos: fix error handling in exynos_drm_subdrv_open" has been added to the 4.4-stable tree

This is a note to let you know that I've just added the patch titled

drm/exynos: fix error handling in exynos_drm_subdrv_open

to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary

The filename of the patch is:
drm-exynos-fix-error-handling-in-exynos_drm_subdrv_open.patch
and it can be found in the queue-4.4 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let <[email protected]> know about it.

From: Arnd Bergmann <[email protected]>
Date: Mon, 14 Mar 2016 15:22:25 +0100
Subject: drm/exynos: fix error handling in exynos_drm_subdrv_open

From: Arnd Bergmann <[email protected]>

commit 55c4b906aa2aec3fa66310ec03c6842e34a04b2a upstream.

gcc-6 warns about a pointless loop in exynos_drm_subdrv_open:

drivers/gpu/drm/exynos/exynos_drm_core.c: In function 'exynos_drm_subdrv_open':
drivers/gpu/drm/exynos/exynos_drm_core.c:104:199: error: self-comparison always evaluates to false [-Werror=tautological-compare]
list_for_each_entry_reverse(subdrv, &subdrv->list, list) {

Here, the list_for_each_entry_reverse immediately terminates because the subdrv pointer is compared to itself as the loop end condition.

If we were to take the current subdrv pointer as the start of the list (as we would do if list_for_each_entry_reverse() was not a macro), we would iterate backwards over the &exynos_drm_subdrv_list anchor, which would be even worse.

Instead, we need to use list_for_each_entry_continue_reverse() to go back over each subdrv that was successfully opened until the first entry.

---
 drivers/gpu/drm/exynos/exynos_drm_core.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

@@ -101,7 +101,7 @@ int exynos_drm_subdrv_open(struct drm_de
 	return 0;
 
 err:
-	list_for_each_entry_reverse(subdrv, &subdrv->list, list) {
+	list_for_each_entry_continue_reverse(subdrv, &exynos_drm_subdrv_list, list) {
 		if (subdrv->close)
 			subdrv->close(dev, subdrv->dev, file);
 	}

Patches currently in stable-queue which might be from [email protected] are

queue-4.4/drm-exynos-fix-error-handling-in-exynos_drm_subdrv_open.patch queue-4.4/arm-8584-1-floppy-avoid-gcc-6-warning.patch queue-4.4/powerpc-ptrace-fix-out-of-bounds-array-access-warning.patch queue-4.4/cgroup-avoid-false-positive-gcc-6-warning.patch queue-4.4/smc91x-avoid-self-comparison-warning.patch