[PATCH v3] drm/pagemap_util: Ensure proper cache lock management on free

[Jonathan Cavitt <jonathan.cavitt@intel.com>]

Static analysis issue:

Though probably unnecessary given the cache is being freed at this step,
for the sake of consistency, ensure that the cache lock is always
unlocked after drm_pagemap_cache_fini.

v2:
- Use requested code flow (Maarten)

v3:
- Clear cache->dpagemap (Matt Brost, Maarten)

Fixes: 77f14f2f2d73f ("drm/pagemap: Add a drm_pagemap cache and shrinker")
Signed-off-by: Jonathan Cavitt <jonathan.cavitt@intel.com>
Cc: Thomas Hellstrom <thomas.hellstrom@linux.intel.com>
Cc: Matthew Brost <matthew.brost@intel.com>
Cc: Maarten Lankhorst <maarten.lankhorst@linux.intel.com>
---
 drivers/gpu/drm/drm_pagemap_util.c | 14 +++++---------
 1 file changed, 5 insertions(+), 9 deletions(-)

diff --git a/drivers/gpu/drm/drm_pagemap_util.c b/drivers/gpu/drm/drm_pagemap_util.c
index 14ddb948a32e..6111d90a38e2 100644
--- a/drivers/gpu/drm/drm_pagemap_util.c
+++ b/drivers/gpu/drm/drm_pagemap_util.c
@@ -65,18 +65,14 @@ static void drm_pagemap_cache_fini(void *arg)
 	drm_dbg(cache->shrinker->drm, "Destroying dpagemap cache.\n");
 	spin_lock(&cache->lock);
 	dpagemap = cache->dpagemap;
-	if (!dpagemap) {
-		spin_unlock(&cache->lock);
-		goto out;
-	}
+	cache->dpagemap = NULL;
+	if (dpagemap && !drm_pagemap_shrinker_cancel(dpagemap))
+		dpagemap = NULL;
+	spin_unlock(&cache->lock);
 
-	if (drm_pagemap_shrinker_cancel(dpagemap)) {
-		cache->dpagemap = NULL;
-		spin_unlock(&cache->lock);
+	if (dpagemap)
 		drm_pagemap_destroy(dpagemap, false);
-	}
 
-out:
 	mutex_destroy(&cache->lookup_mutex);
 	kfree(cache);
 }
-- 
2.43.0