drm/amdkfd: set owner ref to svm range prefault

svm_range_prefault is called right before migrations to VRAM,
to make sure pages are resident in system memory before the migration.
With partial migrations, this reference is used by hmm range get pages
to avoid migrating pages that are already in the same VRAM domain.
Signed-off-by: Alex Sierra <alex.sierra@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

@@ -471,7 +471,7 @@ svm_migrate_ram_to_vram(struct svm_range *prange, uint32_t best_loc,
 		 prange->start, prange->last, best_loc);
 
 	/* FIXME: workaround for page locking bug with invalid pages */
-	svm_range_prefault(prange, mm);
+	svm_range_prefault(prange, mm, SVM_ADEV_PGMAP_OWNER(adev));
 
 	start = prange->start << PAGE_SHIFT;
 	end = (prange->last + 1) << PAGE_SHIFT;

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

@@ -2717,7 +2717,8 @@ svm_range_best_prefetch_location(struct svm_range *prange)
 /* FIXME: This is a workaround for page locking bug when some pages are
  * invalid during migration to VRAM
  */
-void svm_range_prefault(struct svm_range *prange, struct mm_struct *mm)
+void svm_range_prefault(struct svm_range *prange, struct mm_struct *mm,
+			void *owner)
 {
 	struct hmm_range *hmm_range;
 	int r;
@@ -2728,7 +2729,7 @@ void svm_range_prefault(struct svm_range *prange, struct mm_struct *mm)
 	r = amdgpu_hmm_range_get_pages(&prange->notifier, mm, NULL,
 				       prange->start << PAGE_SHIFT,
 				       prange->npages, &hmm_range,
-				       false, true, NULL);
+				       false, true, owner);
 	if (!r) {
 		amdgpu_hmm_range_get_pages_done(hmm_range);
 		prange->validated_once = true;

drivers/gpu/drm/amd/amdkfd/kfd_svm.h

@@ -176,7 +176,8 @@ void schedule_deferred_list_work(struct svm_range_list *svms);
 void svm_range_dma_unmap(struct device *dev, dma_addr_t *dma_addr,
 			 unsigned long offset, unsigned long npages);
 void svm_range_free_dma_mappings(struct svm_range *prange);
-void svm_range_prefault(struct svm_range *prange, struct mm_struct *mm);
+void svm_range_prefault(struct svm_range *prange, struct mm_struct *mm,
+			void *owner);
 struct kfd_process_device *
 svm_range_get_pdd_by_adev(struct svm_range *prange, struct amdgpu_device *adev);