[PATCH v3 13/28] drm/amdgpu: add missing lock when using ttm entities
From: Pierre-Eric Pelloux-Prayer
Date: Fri Nov 21 2025 - 05:16:53 EST
Taking the entity lock is required to guarantee the ordering of
execution. The next commit will add a check that the lock is
held.
Signed-off-by: Pierre-Eric Pelloux-Prayer <pierre-eric.pelloux-prayer@xxxxxxx>
---
drivers/gpu/drm/amd/amdgpu/amdgpu_benchmark.c | 2 ++
drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c | 2 ++
2 files changed, 4 insertions(+)
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_benchmark.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_benchmark.c
index a050167e76a4..832d9ae101f0 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_benchmark.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_benchmark.c
@@ -35,6 +35,7 @@ static int amdgpu_benchmark_do_move(struct amdgpu_device *adev, unsigned size,
struct dma_fence *fence;
int i, r;
+ mutex_lock(&adev->mman.default_entity.lock);
stime = ktime_get();
for (i = 0; i < n; i++) {
r = amdgpu_copy_buffer(adev, &adev->mman.default_entity,
@@ -47,6 +48,7 @@ static int amdgpu_benchmark_do_move(struct amdgpu_device *adev, unsigned size,
if (r)
goto exit_do_move;
}
+ mutex_unlock(&adev->mman.default_entity.lock);
exit_do_move:
etime = ktime_get();
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index 3a0511d1739f..a803af015d05 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -1501,6 +1501,7 @@ static int amdgpu_ttm_access_memory_sdma(struct ttm_buffer_object *bo,
if (r)
goto out;
+ mutex_lock(&adev->mman.default_entity.lock);
amdgpu_res_first(abo->tbo.resource, offset, len, &src_mm);
src_addr = amdgpu_ttm_domain_start(adev, bo->resource->mem_type) +
src_mm.start;
@@ -1512,6 +1513,7 @@ static int amdgpu_ttm_access_memory_sdma(struct ttm_buffer_object *bo,
PAGE_SIZE, 0);
fence = amdgpu_ttm_job_submit(adev, job, num_dw);
+ mutex_unlock(&adev->mman.default_entity.lock);
if (!dma_fence_wait_timeout(fence, false, adev->sdma_timeout))
r = -ETIMEDOUT;
--
2.43.0