[PATCH v4] drm/amdkfd: Use huge page size to check split svm range alignment

[Xiaogang.Chen <xiaogang.chen@amd.com>]

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

Fixes: 7ef6b2d4b7e5 (drm/amdkfd: remap unaligned svm ranges that have split)

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.

Signed-off-by: Xiaogang Chen <xiaogang.chen@amd.com>
---
 drivers/gpu/drm/amd/amdkfd/kfd_svm.c | 46 +++++++++++++++++++---------
 1 file changed, 32 insertions(+), 14 deletions(-)

diff --git a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c b/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
index 521c14c7a789..7fe9d569d416 100644
--- a/drivers/gpu/drm/amd/amdkfd/kfd_svm.c
+++ b/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 > start_align &&
+	    head->last < last_align_down && (!IS_ALIGNED(head->last, 512)))
+		list_add(&head->update_list, remap_list);
+
+	return 0;
 }
 
 static void
-- 
2.34.1