[PATCH 4.19 67/90] drm/fb-helper: generic: Dont take module ref for fbcon

Greg Kroah-Hartman
2019-07-08T15:29:23Z

[ Upstream commit 6ab20a05f4c7ed45632e24d5397d6284e192567d ]

It's now safe to let fbcon unbind automatically on fbdev unregister.
The crash problem was fixed in commit 2122b40580dd
("fbdev: fbcon: Fix unregister crash when more than one framebuffer")

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Daniel Vetter <daniel.vetter@ffwll.ch>
Link: https://patchwork.freedesktop.org/patch/msgid/20190210131039.52664-13-noralf@tronnes.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/drm_fb_helper.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
index a0663f44e218..8b546fde139d 100644
--- a/drivers/gpu/drm/drm_fb_helper.c
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -2957,7 +2957,8 @@ static int drm_fbdev_fb_open(struct fb_info *info, int user)
{
struct drm_fb_helper *fb_helper = info->par;

- if (!try_module_get(fb_helper->dev->driver->fops->owner))
+ /* No need to take a ref for fbcon because it unbinds on unregister */
+ if (user && !try_module_get(fb_helper->dev->driver->fops->owner))
return -ENODEV;

return 0;
@@ -2967,7 +2968,8 @@ static int drm_fbdev_fb_release(struct fb_info *info, int user)
{
struct drm_fb_helper *fb_helper = info->par;

- module_put(fb_helper->dev->driver->fops->owner);
+ if (user)
+ module_put(fb_helper->dev->driver->fops->owner);

return 0;
}
--
2.20.1