[PATCH 1/3] drm/amdkfd: support concurrent userptr update for HMM

[Yang, Philip]

Userptr restore may have concurrent userptr invalidation after
hmm_vma_fault adds the range to the hmm->ranges list, needs call
hmm_vma_range_done to remove the range from hmm->ranges list first,
then reschedule the restore worker. Otherwise hmm_vma_fault will add
same range to the list, this will cause loop in the list because
range->next point to range itself.

Add function untrack_invalid_user_pages to reduce code duplication.

Change-Id: I31407739dc10554f8e418c7a0e0415d3d95552f1
Signed-off-by: Philip Yang <Philip.Yang at amd.com>
---
 .../gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c  | 28 ++++++++++++++-----
 1 file changed, 21 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
index 314c048fcac6..783d760ccfe3 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_amdkfd_gpuvm.c
@@ -1731,6 +1731,23 @@ static int update_invalid_user_pages(struct amdkfd_process_info *process_info,
 	return 0;
 }
 
+/* Remove invalid userptr BOs from hmm track list
+ *
+ * Stop HMM track the userptr update
+ */
+static void untrack_invalid_user_pages(struct amdkfd_process_info *process_info)
+{
+	struct kgd_mem *mem, *tmp_mem;
+	struct amdgpu_bo *bo;
+
+	list_for_each_entry_safe(mem, tmp_mem,
+				 &process_info->userptr_inval_list,
+				 validate_list.head) {
+		bo = mem->bo;
+		amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm);
+	}
+}
+
 /* Validate invalid userptr BOs
  *
  * Validates BOs on the userptr_inval_list, and moves them back to the
@@ -1848,12 +1865,7 @@ static int validate_invalid_user_pages(struct amdkfd_process_info *process_info)
 out_free:
 	kfree(pd_bo_list_entries);
 out_no_mem:
-	list_for_each_entry_safe(mem, tmp_mem,
-				 &process_info->userptr_inval_list,
-				 validate_list.head) {
-		bo = mem->bo;
-		amdgpu_ttm_tt_get_user_pages_done(bo->tbo.ttm);
-	}
+	untrack_invalid_user_pages(process_info);
 
 	return ret;
 }
@@ -1897,8 +1909,10 @@ static void amdgpu_amdkfd_restore_userptr_worker(struct work_struct *work)
 	 * and we can just restart the queues.
 	 */
 	if (!list_empty(&process_info->userptr_inval_list)) {
-		if (atomic_read(&process_info->evicted_bos) != evicted_bos)
+		if (atomic_read(&process_info->evicted_bos) != evicted_bos) {
+			untrack_invalid_user_pages(process_info);
 			goto unlock_out; /* Concurrent eviction, try again */
+		}
 
 		if (validate_invalid_user_pages(process_info))
 			goto unlock_out;
-- 
2.17.1