[PATCH] mm: fix status code move_pages() returns for zero page
From: Kirill A. Shutemov <hidden>
Date: 2015-06-24 10:24:06
Also in:
linux-mm, lkml
Subsystem:
memory management, memory management - memory policy and migration, the rest · Maintainers:
Andrew Morton, David Hildenbrand, Linus Torvalds
Man page for move_pages(2) specifies that status code for zero page is supposed to be -EFAULT. Currently kernel return -ENOENT in this case. follow_page() can do it for us, if we would ask for FOLL_DUMP. Signed-off-by: Kirill A. Shutemov <kirill.shutemov-VuQAYsv1563Yd54FQh9/CA@public.gmane.org> Cc: Christoph Lameter <redacted> Cc: Hugh Dickins <redacted> --- mm/migrate.c | 18 ++++++------------ 1 file changed, 6 insertions(+), 12 deletions(-)
diff --git a/mm/migrate.c b/mm/migrate.c
index 236ee25e79d9..d3529d620a5b 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c@@ -1222,7 +1222,9 @@ static int do_move_page_to_node_array(struct mm_struct *mm, if (!vma || pp->addr < vma->vm_start || !vma_migratable(vma)) goto set_status; - page = follow_page(vma, pp->addr, FOLL_GET|FOLL_SPLIT); + /* FOLL_DUMP to ignore special (like zero) pages */ + page = follow_page(vma, pp->addr, + FOLL_GET | FOLL_SPLIT | FOLL_DUMP); err = PTR_ERR(page); if (IS_ERR(page))
@@ -1232,10 +1234,6 @@ static int do_move_page_to_node_array(struct mm_struct *mm, if (!page) goto set_status; - /* Use PageReserved to check for zero page */ - if (PageReserved(page)) - goto put_and_set; - pp->page = page; err = page_to_nid(page);
@@ -1392,18 +1390,14 @@ static void do_pages_stat_array(struct mm_struct *mm, unsigned long nr_pages, if (!vma || addr < vma->vm_start) goto set_status; - page = follow_page(vma, addr, 0); + /* FOLL_DUMP to ignore special (like zero) pages */ + page = follow_page(vma, addr, FOLL_DUMP); err = PTR_ERR(page); if (IS_ERR(page)) goto set_status; - err = -ENOENT; - /* Use PageReserved to check for zero page */ - if (!page || PageReserved(page)) - goto set_status; - - err = page_to_nid(page); + err = page ? page_to_nid(page) : -ENOENT; set_status: *status = err;
--
2.1.4