From 56be6503aab2bc3a30beae408071b9be5e1bae51 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Noralf=20Tr=C3=B8nnes?= <noralf@tronnes.org>
Date: Mon, 25 Feb 2019 15:42:26 +0100
Subject: [PATCH] drm/drv: Hold ref on parent device during drm_device lifetime
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Git-commit: 56be6503aab2bc3a30beae408071b9be5e1bae51
Patch-mainline: v5.2-rc1
References: bsc#1051510

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

Signed-off-by: Noralf Trønnes <noralf@tronnes.org>
Reviewed-by: Gerd Hoffmann <kraxel@redhat.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20190225144232.20761-2-noralf@tronnes.org
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 drivers/gpu/drm/drm_drv.c |    5 ++++-
 1 file changed, 4 insertions(+), 1 deletion(-)

--- a/drivers/gpu/drm/drm_drv.c
+++ b/drivers/gpu/drm/drm_drv.c
@@ -503,7 +503,7 @@ int drm_dev_init(struct drm_device *dev,
 	}
 
 	kref_init(&dev->ref);
-	dev->dev = parent;
+	dev->dev = get_device(parent);
 	dev->driver = driver;
 
 	INIT_LIST_HEAD(&dev->filelist);
@@ -572,6 +572,7 @@ err_minors:
 	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);
@@ -607,6 +608,8 @@ 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);