[PATCH 1/4] drm: Make drm_fb_unregister/remove accept NULL fb

Daniel Vetter
2015-08-25T13:45:23Z

These functions are used by drivers to release fbdev emulation
buffers. We need to make them resilient to NULL pointers to
make the fbdev compile/runtime knobs not cause Oopses on module
unload.

Cc: Archit Taneja <architt@codeaurora.org>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
drivers/gpu/drm/drm_crtc.c | 14 ++++++++++++--
1 file changed, 12 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_crtc.c b/drivers/gpu/drm/drm_crtc.c
index 33d877c65ced..884690c81094 100644
--- a/drivers/gpu/drm/drm_crtc.c
+++ b/drivers/gpu/drm/drm_crtc.c
@@ -538,7 +538,12 @@ EXPORT_SYMBOL(drm_framebuffer_reference);
*/
void drm_framebuffer_unregister_private(struct drm_framebuffer *fb)
{
- struct drm_device *dev = fb->dev;
+ struct drm_device *dev;
+
+ if (!fb)
+ return;
+
+ dev = fb->dev;

mutex_lock(&dev->mode_config.fb_lock);
/* Mark fb as reaped and drop idr ref. */
@@ -589,12 +594,17 @@ EXPORT_SYMBOL(drm_framebuffer_cleanup);
*/
void drm_framebuffer_remove(struct drm_framebuffer *fb)
{
- struct drm_device *dev = fb->dev;
+ struct drm_device *dev;
struct drm_crtc *crtc;
struct drm_plane *plane;
struct drm_mode_set set;
int ret;

+ if (!fb)
+ return;
+
+ dev = fb->dev;
+
WARN_ON(!list_empty(&fb->filp_head));

/*
--
1.8.3.1