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/20210325131524.48181-5-linmiaohe@huawei.com
Signed-off-by: Miaohe Lin <linmiaohe@huawei.com>
Reviewed-by: David Hildenbrand <david@redhat.com>
Cc: Alistair Popple <apopple@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Rafael Aquini <aquini@redhat.com>
Cc: Yang Shi <shy828301@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/migrate.c b/mm/migrate.c
index c40075d..6876696 100644 (file)
--- 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;