[PATCH 4/6] drm/i915/gvt: Refine error handling for intel_vgpu_pin_mm

[fred gao]

When it is failed in shadow_mm, the pin_count should rollback
to the original states before return.

v2:
- split the mixed several error paths for better review. (Zhenyu)

Signed-off-by: fred gao <fred.gao at intel.com>
---
 drivers/gpu/drm/i915/gvt/gtt.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c
index 66374db..8f46019 100644
--- a/drivers/gpu/drm/i915/gvt/gtt.c
+++ b/drivers/gpu/drm/i915/gvt/gtt.c
@@ -1630,8 +1630,10 @@ int intel_vgpu_pin_mm(struct intel_vgpu_mm *mm)
 
 	if (!mm->shadowed) {
 		ret = shadow_mm(mm);
-		if (ret)
+		if (ret) {
+			atomic_dec(&mm->pincount);
 			return ret;
+		}
 	}
 
 	list_del_init(&mm->lru_list);
-- 
2.7.4