[PATCH AUTOSEL 5.2 50/94] drm/amdgpu: fix dma_fence_wait without reference

Sasha Levin
2019-09-04T16:18:05Z

From: Christian König <christian.koenig@amd.com>

[ Upstream commit 42068e1ef961c719f967dbbb4ddcb394a0ba7917 ]

We need to grab a reference to the fence we wait for.

Signed-off-by: Christian König <christian.koenig@amd.com>
Reviewed-by: Chunming Zhou <david1.zhou@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c | 27 ++++++++++++++-----------
1 file changed, 15 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
index a28a3d722ba29..62298ae5c81c0 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ctx.c
@@ -535,21 +535,24 @@ int amdgpu_ctx_wait_prev_fence(struct amdgpu_ctx *ctx,
struct drm_sched_entity *entity)
{
struct amdgpu_ctx_entity *centity = to_amdgpu_ctx_entity(entity);
- unsigned idx = centity->sequence & (amdgpu_sched_jobs - 1);
- struct dma_fence *other = centity->fences[idx];
+ struct dma_fence *other;
+ unsigned idx;
+ long r;

- if (other) {
- signed long r;
- r = dma_fence_wait(other, true);
- if (r < 0) {
- if (r != -ERESTARTSYS)
- DRM_ERROR("Error (%ld) waiting for fence!\n", r);
+ spin_lock(&ctx->ring_lock);
+ idx = centity->sequence & (amdgpu_sched_jobs - 1);
+ other = dma_fence_get(centity->fences[idx]);
+ spin_unlock(&ctx->ring_lock);

- return r;
- }
- }
+ if (!other)
+ return 0;

- return 0;
+ r = dma_fence_wait(other, true);
+ if (r < 0 && r != -ERESTARTSYS)
+ DRM_ERROR("Error (%ld) waiting for fence!\n", r);
+
+ dma_fence_put(other);
+ return r;
}

void amdgpu_ctx_mgr_init(struct amdgpu_ctx_mgr *mgr)
--
2.20.1