[PATCH V4] amdgpu: reduce no need mutex_lock area

From: Bernard Zhao
Date: Tue Apr 21 2020 - 03:36:36 EST


Maybe we could reduce the mutex_lock(&mem->lock)`s protected code area,
and no need to protect pr_debug.

Signed-off-by: Bernard Zhao <bernard@xxxxxxxx>

Changes since V1:
*commit message improve

Changes since V2:
*move comment along with the mutex_unlock

Changes since V3:
*lock protect the if check, there is some possibility of multi-threaded
racing modify.

Link for V1:
*https://lore.kernel.org/patchwork/patch/1226588/
---
drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index 327317c54f7c..549bdb429883 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -1289,9 +1289,9 @@ int amdgpu_amdkfd_gpuvm_free_memory_of_gpu(
mutex_lock(&mem->lock);

if (mem->mapped_to_gpu_memory > 0) {
+ mutex_unlock(&mem->lock);
pr_debug("BO VA 0x%llx size 0x%lx is still mapped.\n",
mem->va, bo_size);
- mutex_unlock(&mem->lock);
return -EBUSY;
}

--
2.26.2