From: Thierry Reding <treding@nvidia.com>
Date: Fri, 8 Nov 2013 11:30:37 +0000 (+0100)
Subject: drm/tegra: Make CRTC upcasting safer
X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=37826519c4dca037bda5d008b4d687c2e6f8d405;p=linux-beck.git

drm/tegra: Make CRTC upcasting safer

When upcasting a NULL CRTC object, propagate the NULL pointer instead of
some invalid pointer. This allows subsequent code to check that the cast
object is valid.

Signed-off-by: Thierry Reding <treding@nvidia.com>
---

diff --git a/drivers/gpu/drm/tegra/drm.h b/drivers/gpu/drm/tegra/drm.h
index fdfe259ed7f8..7da0b923131f 100644
--- a/drivers/gpu/drm/tegra/drm.h
+++ b/drivers/gpu/drm/tegra/drm.h
@@ -116,7 +116,7 @@ host1x_client_to_dc(struct host1x_client *client)
 
 static inline struct tegra_dc *to_tegra_dc(struct drm_crtc *crtc)
 {
-	return container_of(crtc, struct tegra_dc, base);
+	return crtc ? container_of(crtc, struct tegra_dc, base) : NULL;
 }
 
 static inline void tegra_dc_writel(struct tegra_dc *dc, unsigned long value,