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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: Naoya 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: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
hifive-unleashed-5.1
Naoya Horiguchi 2016-07-26 15:24:03 -07:00 committed by Linus Torvalds
parent e3a2713c3c
commit 337d9abf1c
4 changed files with 6 additions and 3 deletions
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2
mm/gup.c
View File

@ -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);

2
mm/mempolicy.c
View File

@ -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) {

2
mm/mprotect.c
View File

@ -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,

3
mm/mremap.c
View File

@ -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;