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>
This commit is contained in:
Kirill A. Shutemov 2015-09-04 15:47:53 -07:00 committed by Linus Torvalds
parent ce9ce6659a
commit d899844e9c

View File

@ -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;