Commit 337d9abf authored by Naoya Horiguchi's avatar Naoya Horiguchi Committed by Linus Torvalds
Browse files

mm: thp: check pmd_trans_unstable() after split_huge_pmd() 

split_huge_pmd() doesn't guarantee that the pmd is normal pmd pointing
to pte entries, which can be checked with pmd_trans_unstable().  Some
callers make this assertion and some do it differently and some not, so
let's do it in a unified manner.

Link: http://lkml.kernel.org/r/1464741400-12143-1-git-send-email-n-horiguchi@ah.jp.nec.com


Signed-off-by: default avatarNaoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Hugh Dickins <hughd@google.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent e3a2713c

mm/gup.c

+2 −0
Original line number Diff line number Diff line
@@ -279,6 +279,8 @@ struct page *follow_page_mask(struct vm_area_struct *vma, 
			spin_unlock(ptl);

			ret = 0;

			split_huge_pmd(vma, pmd, address);

			if (pmd_trans_unstable(pmd))

				ret = -EBUSY;

		} else {

			get_page(page);

			spin_unlock(ptl);

mm/mempolicy.c

+2 −0
Original line number Diff line number Diff line
@@ -512,6 +512,8 @@ static int queue_pages_pte_range(pmd_t *pmd, unsigned long addr, 
		}

	}



	if (pmd_trans_unstable(pmd))

		return 0;

retry:

	pte = pte_offset_map_lock(walk->mm, pmd, addr, &ptl);

	for (; addr != end; pte++, addr += PAGE_SIZE) {

mm/mprotect.c

+1 −1
Original line number Diff line number Diff line
@@ -163,7 +163,7 @@ static inline unsigned long change_pmd_range(struct vm_area_struct *vma, 
		if (pmd_trans_huge(*pmd) || pmd_devmap(*pmd)) {

			if (next - addr != HPAGE_PMD_SIZE) {

				split_huge_pmd(vma, pmd, addr);

				if (pmd_none(*pmd))

				if (pmd_trans_unstable(pmd))

					continue;

			} else {

				int nr_ptes = change_huge_pmd(vma, pmd, addr,

mm/mremap.c

+1 −2
Original line number Diff line number Diff line
@@ -210,9 +210,8 @@ unsigned long move_page_tables(struct vm_area_struct *vma, 
				}

			}

			split_huge_pmd(vma, old_pmd, old_addr);

			if (pmd_none(*old_pmd))

			if (pmd_trans_unstable(old_pmd))

				continue;

			VM_BUG_ON(pmd_trans_huge(*old_pmd));

		}

		if (pte_alloc(new_vma->vm_mm, new_pmd, new_addr))

			break;

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