If struct fb_ops is defined in a library like cma, fb_open() takes a ref on the library instead of the driver module. Use fb_ops.fb_open/fb_release to ensure that the driver module is pinned.
Add drm_fb_helper_fb_open() and drm_fb_helper_fb_release() to DRM_FB_HELPER_DEFAULT_OPS().
Signed-off-by: Noralf Trønnes noralf@tronnes.org --- drivers/gpu/drm/drm_fb_helper.c | 41 +++++++++++++++++++++++++++++++++++++++++ include/drm/drm_fb_helper.h | 14 ++++++++++++++ 2 files changed, 55 insertions(+)
diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c index 74c1053..b080004 100644 --- a/drivers/gpu/drm/drm_fb_helper.c +++ b/drivers/gpu/drm/drm_fb_helper.c @@ -1037,6 +1037,47 @@ void drm_fb_helper_fb_destroy(struct fb_info *info) EXPORT_SYMBOL(drm_fb_helper_fb_destroy);
/** + * drm_fb_helper_fb_open - implementation for &fb_ops.fb_open + * @info: fbdev registered by the helper + * @user: 1=userspace, 0=fbcon + * + * If &fb_ops is wrapped in a library, pin the driver module. + */ +int drm_fb_helper_fb_open(struct fb_info *info, int user) +{ + struct drm_fb_helper *fb_helper = info->par; + struct drm_device *dev = fb_helper->dev; + + /* Skip fbcon, it detaches itself in unregister_framebuffer() */ + if (user && info->fbops->owner != dev->driver->fops->owner) { + if (!try_module_get(dev->driver->fops->owner)) + return -ENODEV; + } + + return 0; +} +EXPORT_SYMBOL(drm_fb_helper_fb_open); + +/** + * drm_fb_helper_fb_release - implementation for &fb_ops.fb_release + * @info: fbdev registered by the helper + * @user: 1=userspace, 0=fbcon + * + * If &fb_ops is wrapped in a library, unpin the driver module. + */ +int drm_fb_helper_fb_release(struct fb_info *info, int user) +{ + struct drm_fb_helper *fb_helper = info->par; + struct drm_device *dev = fb_helper->dev; + + if (user && info->fbops->owner != dev->driver->fops->owner) + module_put(dev->driver->fops->owner); + + return 0; +} +EXPORT_SYMBOL(drm_fb_helper_fb_release); + +/** * drm_fb_helper_sys_read - wrapper around fb_sys_read * @info: fb_info struct pointer * @buf: userspace buffer to read from framebuffer memory diff --git a/include/drm/drm_fb_helper.h b/include/drm/drm_fb_helper.h index dd78eb3..b44fc62 100644 --- a/include/drm/drm_fb_helper.h +++ b/include/drm/drm_fb_helper.h @@ -233,6 +233,8 @@ struct drm_fb_helper { */ #define DRM_FB_HELPER_DEFAULT_OPS \ .fb_destroy = drm_fb_helper_fb_destroy, \ + .fb_open = drm_fb_helper_fb_open, \ + .fb_release = drm_fb_helper_fb_release, \ .fb_check_var = drm_fb_helper_check_var, \ .fb_set_par = drm_fb_helper_set_par, \ .fb_setcmap = drm_fb_helper_setcmap, \ @@ -270,6 +272,8 @@ void drm_fb_helper_deferred_io(struct fb_info *info, struct list_head *pagelist);
void drm_fb_helper_fb_destroy(struct fb_info *info); +int drm_fb_helper_fb_open(struct fb_info *info, int user); +int drm_fb_helper_fb_release(struct fb_info *info, int user);
ssize_t drm_fb_helper_sys_read(struct fb_info *info, char __user *buf, size_t count, loff_t *ppos); @@ -405,6 +409,16 @@ static inline void drm_fb_helper_fb_destroy(struct fb_info *info) { }
+static inline int drm_fb_helper_fb_open(struct fb_info *info, int user) +{ + return -ENODEV; +} + +static inline int drm_fb_helper_fb_release(struct fb_info *info, int user) +{ + return -ENODEV; +} + static inline ssize_t drm_fb_helper_sys_read(struct fb_info *info, char __user *buf, size_t count, loff_t *ppos)