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authorKirill A. Shutemov <kirill.shutemov@linux.intel.com>2015-09-04 15:47:53 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2015-09-04 16:54:41 -0700
commitd899844e9c98c9c74b4d9926fd3bd66a225f6978 (patch)
treef20414a3a4217e6befb38b5adeefdc2e6a4e8c00
parentce9ce6659a5775047ad529ed77ab119da5fb8b0c (diff)
mm: fix status code which move_pages() returns for zero page
The manpage 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. The use of FOLL_DUMP also means that the upper layer page tables pages are no longer allocated. Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Reviewed-by: Christoph Lameter <cl@linux.com> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/migrate.c18
1 files changed, 6 insertions, 12 deletions
diff --git a/mm/migrate.c b/mm/migrate.c
index eb4267107d1f..5c08cab5419e 100644
--- a/mm/migrate.c
+++ b/mm/migrate.c
@@ -1226,7 +1226,9 @@ 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))
@@ -1236,10 +1238,6 @@ 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);
@@ -1396,18 +1394,14 @@ 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;