mm/migrate.c: initialize pud_entry in migrate_vma()

When CONFIG_MIGRATE_VMA_HELPER is enabled, migrate_vma() calls
migrate_vma_collect() which initializes a struct mm_walk but didn't
initialize mm_walk.pud_entry.  (Found by code inspection) Use a C
structure initialization to make sure it is set to NULL.

Link: http://lkml.kernel.org/r/20190719233225.12243-1-rcampbell@nvidia.com
Fixes: 8763cb45ab967 ("mm/migrate: new memory migration helper for use with device memory")
Signed-off-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: John Hubbard <jhubbard@nvidia.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: <stable@vger.kernel.org>
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 515718392b249922c7f5148183ef834761cc4139..a42858d8e00b7bae8d43e9746fb786a16a64e809 100644 (file)
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -2340,16 +2340,13 @@ next:
 static void migrate_vma_collect(struct migrate_vma *migrate)
 {
        struct mmu_notifier_range range;
-       struct mm_walk mm_walk;
-
-       mm_walk.pmd_entry = migrate_vma_collect_pmd;
-       mm_walk.pte_entry = NULL;
-       mm_walk.pte_hole = migrate_vma_collect_hole;
-       mm_walk.hugetlb_entry = NULL;
-       mm_walk.test_walk = NULL;
-       mm_walk.vma = migrate->vma;
-       mm_walk.mm = migrate->vma->vm_mm;
-       mm_walk.private = migrate;
+       struct mm_walk mm_walk = {
+               .pmd_entry = migrate_vma_collect_pmd,
+               .pte_hole = migrate_vma_collect_hole,
+               .vma = migrate->vma,
+               .mm = migrate->vma->vm_mm,
+               .private = migrate,
+       };
 
        mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, NULL, mm_walk.mm,
                                migrate->start,