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

Rob Clark
2015-08-25T19:19:37Z

On Tue, Aug 25, 2015 at 9:45 AM, Daniel Vetter <daniel.vetter@ffwll.ch> wrote:
> 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>

Reviewed-by: Rob Clark <robdclark@gmail.com>

> ---
> 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
>
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