[PATCH 5.1 397/405] drm/drv: Hold ref on parent device during drm_device lifetime

From: Greg Kroah-Hartman
Date: Thu May 30 2019 - 00:41:30 EST


[ Upstream commit 56be6503aab2bc3a30beae408071b9be5e1bae51 ]

This makes it safe to access drm_device->dev after the parent device has
been removed/unplugged.

Signed-off-by: Noralf TrÃnnes <noralf@xxxxxxxxxxx>
Reviewed-by: Gerd Hoffmann <kraxel@xxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20190225144232.20761-2-noralf@xxxxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/gpu/drm/drm_drv.c | 5 ++++-
1 file changed, 4 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/drm_drv.c b/drivers/gpu/drm/drm_drv.c
index 05bbc2b622fc1..04aa6ccdfb242 100644
--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -497,7 +497,7 @@ int drm_dev_init(struct drm_device *dev,
BUG_ON(!parent);

kref_init(&dev->ref);
- dev->dev = parent;
+ dev->dev = get_device(parent);
dev->driver = driver;

/* no per-device feature limits by default */
@@ -567,6 +567,7 @@ int drm_dev_init(struct drm_device *dev,
drm_minor_free(dev, DRM_MINOR_RENDER);
drm_fs_inode_free(dev->anon_inode);
err_free:
+ put_device(dev->dev);
mutex_destroy(&dev->master_mutex);
mutex_destroy(&dev->ctxlist_mutex);
mutex_destroy(&dev->clientlist_mutex);
@@ -602,6 +603,8 @@ void drm_dev_fini(struct drm_device *dev)
drm_minor_free(dev, DRM_MINOR_PRIMARY);
drm_minor_free(dev, DRM_MINOR_RENDER);

+ put_device(dev->dev);
+
mutex_destroy(&dev->master_mutex);
mutex_destroy(&dev->ctxlist_mutex);
mutex_destroy(&dev->clientlist_mutex);
--
2.20.1