drm/amdkfd: handle errors returned by svm_migrate_copy_to_vram/ram

If migration copy failed because process is killed, or out of VRAM or
system memory, pass error code back to caller to handle error
gracefully.
Signed-off-by: Philip Yang <Philip.Yang@amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>

drivers/gpu/drm/amd/amdkfd/kfd_migrate.c

@@ -460,7 +460,7 @@ svm_migrate_vma_to_vram(struct amdgpu_device *adev, struct svm_range *prange,
 	}
 
 	if (migrate.cpages) {
-		svm_migrate_copy_to_vram(adev, prange, &migrate, &mfence,
+		r = svm_migrate_copy_to_vram(adev, prange, &migrate, &mfence,
 					     scratch);
 		migrate_vma_pages(&migrate);
 		svm_migrate_copy_done(adev, mfence);
@@ -663,7 +663,7 @@ svm_migrate_vma_to_ram(struct amdgpu_device *adev, struct svm_range *prange,
 	pr_debug("cpages %ld\n", migrate.cpages);
 
 	if (migrate.cpages) {
-		svm_migrate_copy_to_ram(adev, prange, &migrate, &mfence,
+		r = svm_migrate_copy_to_ram(adev, prange, &migrate, &mfence,
 					    scratch);
 		migrate_vma_pages(&migrate);
 		svm_migrate_copy_done(adev, mfence);