[Intel-xe] [PATCH] drm/xe: Fix engine lookup refcount race

["Thomas Hellström" <thomas.hellstrom@linux.intel.com>]

Fix a race where the engine could disappear between lookup unlock and
xe_engine_get().

Signed-off-by: Thomas Hellström <thomas.hellstrom@linux.intel.com>
---
 drivers/gpu/drm/xe/xe_engine.c | 3 +--
 1 file changed, 1 insertion(+), 2 deletions(-)

diff --git a/drivers/gpu/drm/xe/xe_engine.c b/drivers/gpu/drm/xe/xe_engine.c
index 094ec17d3004..3a400a546dfe 100644
--- a/drivers/gpu/drm/xe/xe_engine.c
+++ b/drivers/gpu/drm/xe/xe_engine.c
@@ -161,10 +161,9 @@ struct xe_engine *xe_engine_lookup(struct xe_file *xef, u32 id)
 
 	mutex_lock(&xef->engine.lock);
 	e = xa_load(&xef->engine.xa, id);
-	mutex_unlock(&xef->engine.lock);
-
 	if (e)
 		xe_engine_get(e);
+	mutex_unlock(&xef->engine.lock);
 
 	return e;
 }
-- 
2.39.2