[PATCH v2 4/5] mm/migrate.c: use helper migrate_vma_collect_skip() in migrate_vma_collect_hole()

[Miaohe Lin <linmiaohe@huawei.com>]

It's more recommended to use helper function migrate_vma_collect_skip() to
skip the unexpected case and it also helps remove some duplicated codes.
Move migrate_vma_collect_skip() above migrate_vma_collect_hole() to avoid
compiler warning.

Reviewed-by: David Hildenbrand <david@redhat.com>
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
---
 mm/migrate.c | 28 +++++++++++-----------------
 1 file changed, 11 insertions(+), 17 deletions(-)

diff --git a/mm/migrate.c b/mm/migrate.c
index d372be3da9b2..5357a8527ca2 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2315,44 +2315,38 @@ int migrate_misplaced_transhuge_page(struct mm_struct *mm,
 #endif /* CONFIG_NUMA */
 
 #ifdef CONFIG_DEVICE_PRIVATE
-static int migrate_vma_collect_hole(unsigned long start,
+static int migrate_vma_collect_skip(unsigned long start,
 				    unsigned long end,
-				    __always_unused int depth,
 				    struct mm_walk *walk)
 {
 	struct migrate_vma *migrate = walk->private;
 	unsigned long addr;
 
-	/* Only allow populating anonymous memory. */
-	if (!vma_is_anonymous(walk->vma)) {
-		for (addr = start; addr < end; addr += PAGE_SIZE) {
-			migrate->src[migrate->npages] = 0;
-			migrate->dst[migrate->npages] = 0;
-			migrate->npages++;
-		}
-		return 0;
-	}
-
 	for (addr = start; addr < end; addr += PAGE_SIZE) {
-		migrate->src[migrate->npages] = MIGRATE_PFN_MIGRATE;
 		migrate->dst[migrate->npages] = 0;
-		migrate->npages++;
-		migrate->cpages++;
+		migrate->src[migrate->npages++] = 0;
 	}
 
 	return 0;
 }
 
-static int migrate_vma_collect_skip(unsigned long start,
+static int migrate_vma_collect_hole(unsigned long start,
 				    unsigned long end,
+				    __always_unused int depth,
 				    struct mm_walk *walk)
 {
 	struct migrate_vma *migrate = walk->private;
 	unsigned long addr;
 
+	/* Only allow populating anonymous memory. */
+	if (!vma_is_anonymous(walk->vma))
+		return migrate_vma_collect_skip(start, end, walk);
+
 	for (addr = start; addr < end; addr += PAGE_SIZE) {
+		migrate->src[migrate->npages] = MIGRATE_PFN_MIGRATE;
 		migrate->dst[migrate->npages] = 0;
-		migrate->src[migrate->npages++] = 0;
+		migrate->npages++;
+		migrate->cpages++;
 	}
 
 	return 0;
-- 
2.19.1