From: Arnd Bergmann Date: Mon, 14 Mar 2016 14:22:25 +0000 (+0100) Subject: drm/exynos: fix error handling in exynos_drm_subdrv_open X-Git-Tag: v4.9.8~2035^2~34^2~38 X-Git-Url: http://review.tizen.org/git/?a=commitdiff_plain;h=0a938697d7fb8d729afb1ec028566e08854d17f6;p=platform%2Fkernel%2Flinux-rpi3.git 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 Signed-off-by: Inki Dae --- diff --git a/drivers/gpu/drm/exynos/exynos_drm_core.c b/drivers/gpu/drm/exynos/exynos_drm_core.c index 7f55ba6..011211e 100644 --- a/drivers/gpu/drm/exynos/exynos_drm_core.c +++ b/drivers/gpu/drm/exynos/exynos_drm_core.c @@ -101,7 +101,7 @@ int exynos_drm_subdrv_open(struct drm_device *dev, struct drm_file *file) 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); }