[PATCH] drm/amdkfd: Remove skiping userptr buffer mapping when mmu notifier marks it as invalid

[Alex Deucher]

From: Xiaogang Chen <xiaogang.chen at amd.com>

mmu notifier does not always hold mm->sem during call back. That causes
a race condition between kfd userprt buffer mapping and mmu notifier
which leds to gpu shadder or SDMA access userptr buffer before it has been
mapped to gpu VM. Always map userptr buffer to avoid that though it may make
some userprt buffers mapped two times.

Suggested-by: Felix Kuehling <Felix.Kuehling at amd.com>
Signed-off-by: Xiaogang Chen <xiaogang.chen at amd.com>
Reviewed-by: Felix Kuehling <Felix.Kuehling at amd.com>
Signed-off-by: Alex Deucher <alexander.deucher at amd.com>
---
 drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c | 10 ----------
 1 file changed, 10 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index 58a774647573..40078c0a5585 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -1942,16 +1942,6 @@ int amdgpu_amdkfd_gpuvm_map_memory_to_gpu(
 	 */
 	mutex_lock(&mem->process_info->lock);
 
-	/* Lock notifier lock. If we find an invalid userptr BO, we can be
-	 * sure that the MMU notifier is no longer running
-	 * concurrently and the queues are actually stopped
-	 */
-	if (amdgpu_ttm_tt_get_usermm(bo->tbo.ttm)) {
-		mutex_lock(&mem->process_info->notifier_lock);
-		is_invalid_userptr = !!mem->invalid;
-		mutex_unlock(&mem->process_info->notifier_lock);
-	}
-
 	mutex_lock(&mem->lock);
 
 	domain = mem->domain;
-- 
2.40.1