drm/exynos: fix error handling in exynos_drm_subdrv_open
authorArnd Bergmann <arnd@arndb.de>
Mon, 14 Mar 2016 14:22:25 +0000 (15:22 +0100)
committerInki Dae <daeinki@gmail.com>
Tue, 12 Apr 2016 13:50:48 +0000 (22:50 +0900)
commit55c4b906aa2aec3fa66310ec03c6842e34a04b2a
treed1aae53fb0ac29175ddf511556dd8f3666257873
parent928815245cbdaa611873424759d5e7a7293dd18b
drm/exynos: fix error handling in exynos_drm_subdrv_open

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.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Inki Dae <inki.dae@samsung.com>
drivers/gpu/drm/exynos/exynos_drm_core.c