shadow mm's pin count got increased in workload preparation phase, which
is after workload scanning.
it will get decreased in complete_current_workload() anyway after
workload completion.
Sometimes, if a workload meets a scanning error, its shadow mm pin count
will not get increased but will get decreased in the end.
This patch lets shadow mm's pin count not go below 0.
v2: add fixes tag and cc stable kernel (zhenyu wang)
Fixes: 2707e4446688 ("drm/i915/gvt: vGPU graphics memory virtualization")
Cc: zhenyuw@xxxxxxxxxxxxxxx
Cc: stable@xxxxxxxxxxxxxxx #4.14+
Signed-off-by: Yan Zhao <yan.y.zhao@xxxxxxxxx>
---
upstream commit id: 663a50ceac75c2208d2ad95365bc8382fd42f44d
---
drivers/gpu/drm/i915/gvt/gtt.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/gvt/gtt.c b/drivers/gpu/drm/i915/gvt/gtt.c
index dadacbe558ab..1a1f7eb46d1e 100644
--- a/drivers/gpu/drm/i915/gvt/gtt.c
+++ b/drivers/gpu/drm/i915/gvt/gtt.c
@@ -1629,7 +1629,7 @@ void intel_vgpu_unpin_mm(struct intel_vgpu_mm *mm)
if (WARN_ON(mm->type != INTEL_GVT_MM_PPGTT))
return;
- atomic_dec(&mm->pincount);
+ atomic_dec_if_positive(&mm->pincount);
}
/**
--
2.17.1
