Commit d899844e authored by Kirill A. Shutemov's avatar Kirill A. Shutemov Committed by Linus Torvalds
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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: default avatarKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: default avatarChristoph Lameter <cl@linux.com>
Cc: Hugh Dickins <hughd@google.com>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent ce9ce665

mm/migrate.c

+6 −12
Original line number Diff line number Diff line
@@ -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;