drm/amdkfd: Use huge page size to check split svm range alignment

When split svm ranges that have been mapped using huge page should use huge
page size(2MB) to check split range alignment, not prange->granularity that
means migration granularity.

Fixes: 7ef6b2d ("drm/amdkfd: remap unaligned svm ranges that have split")
Signed-off-by: Xiaogang Chen <xiaogang.chen@amd.com>
Reviewed-by: Philip Yang <Philip.Yang@amd.com>
Signed-off-by: Alex Deucher <alexander.deucher@amd.com>
(cherry picked from commit 448ee45)

Author: xiaogang-chen-amd

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

@@ -1144,30 +1144,48 @@ static int
 svm_range_split_tail(struct svm_range *prange, uint64_t new_last,
 		     struct list_head *insert_list, struct list_head *remap_list)
 {
+	unsigned long last_align_down = ALIGN_DOWN(prange->last, 512);
+	unsigned long start_align = ALIGN(prange->start, 512);
+	bool huge_page_mapping = last_align_down > start_align;
 	struct svm_range *tail = NULL;
-	int r = svm_range_split(prange, prange->start, new_last, &tail);
+	int r;
 
-	if (!r) {
-		list_add(&tail->list, insert_list);
-		if (!IS_ALIGNED(new_last + 1, 1UL << prange->granularity))
-			list_add(&tail->update_list, remap_list);
-	}
-	return r;
+	r = svm_range_split(prange, prange->start, new_last, &tail);
+
+	if (r)
+		return r;
+
+	list_add(&tail->list, insert_list);
+
+	if (huge_page_mapping && tail->start > start_align &&
+	    tail->start < last_align_down && (!IS_ALIGNED(tail->start, 512)))
+		list_add(&tail->update_list, remap_list);
+
+	return 0;
 }
 
 static int
 svm_range_split_head(struct svm_range *prange, uint64_t new_start,
 		     struct list_head *insert_list, struct list_head *remap_list)
 {
+	unsigned long last_align_down = ALIGN_DOWN(prange->last, 512);
+	unsigned long start_align = ALIGN(prange->start, 512);
+	bool huge_page_mapping = last_align_down > start_align;
 	struct svm_range *head = NULL;
-	int r = svm_range_split(prange, new_start, prange->last, &head);
+	int r;
 
-	if (!r) {
-		list_add(&head->list, insert_list);
-		if (!IS_ALIGNED(new_start, 1UL << prange->granularity))
-			list_add(&head->update_list, remap_list);
-	}
-	return r;
+	r = svm_range_split(prange, new_start, prange->last, &head);
+
+	if (r)
+		return r;
+
+	list_add(&head->list, insert_list);
+
+	if (huge_page_mapping && head->last + 1 > start_align &&
+	    head->last + 1 < last_align_down && (!IS_ALIGNED(head->last, 512)))
+		list_add(&head->update_list, remap_list);
+
+	return 0;
 }
 
 static void