mm/migrate.c: use helper migrate_vma_collect_skip() in migrate_vma_collect_hole()

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.

Link: https://lkml.kernel.org/r/[email protected]
Signed-off-by: Miaohe Lin <[email protected]>
Reviewed-by: David Hildenbrand <[email protected]>
Cc: Alistair Popple <[email protected]>
Cc: Jerome Glisse <[email protected]>
Cc: Rafael Aquini <[email protected]>
Cc: Yang Shi <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>

1 files changed, 11 insertions, 17 deletions

diff --git a/mm/migrate.c b/mm/migrate.c
index c40075d48ef9..6876696ab302 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2290,44 +2290,38 @@ out:
 #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;