drm/amdgpu: Add notifier lock for KFD userptrs

Add a per-process MMU notifier lock for processing notifiers from
userptrs. Use that lock to properly synchronize page table updates with
MMU notifiers.

Signed-off-by: Felix Kuehling <[email protected]>
Reviewed-by: Xiaogang Chen<[email protected]>
Signed-off-by: Alex Deucher <[email protected]>

1 files changed, 12 insertions, 5 deletions

diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
index b4236572eae1..f0e4c7309438 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_ttm.c
@@ -695,8 +695,19 @@ out_unlock:
 	return r;
 }
 
+/* amdgpu_ttm_tt_discard_user_pages - Discard range and pfn array allocations
+ */
+void amdgpu_ttm_tt_discard_user_pages(struct ttm_tt *ttm,
+				      struct hmm_range *range)
+{
+	struct amdgpu_ttm_tt *gtt = (void *)ttm;
+
+	if (gtt && gtt->userptr && range)
+		amdgpu_hmm_range_get_pages_done(range);
+}
+
 /*
- * amdgpu_ttm_tt_userptr_range_done - stop HMM track the CPU page table change
+ * amdgpu_ttm_tt_get_user_pages_done - stop HMM track the CPU page table change
  * Check if the pages backing this ttm range have been invalidated
  *
  * Returns: true if pages are still valid
@@ -714,10 +725,6 @@ bool amdgpu_ttm_tt_get_user_pages_done(struct ttm_tt *ttm,
 
 	WARN_ONCE(!range->hmm_pfns, "No user pages to check\n");
 
-	/*
-	 * FIXME: Must always hold notifier_lock for this, and must
-	 * not ignore the return code.
-	 */
 	return !amdgpu_hmm_range_get_pages_done(range);
 }
 #endif