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Subject[PATCH 08/12] mm, ksm: convert write_protect_page() to page_check_walk()
Date
For consistency, it worth converting all page_check_address() to
page_check_walk(), so we could drop the former.

Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
---
mm/ksm.c | 34 ++++++++++++++++++----------------
1 file changed, 18 insertions(+), 16 deletions(-)

diff --git a/mm/ksm.c b/mm/ksm.c
index 9ae6011a41f8..6653ca186cfe 100644
--- a/mm/ksm.c
+++ b/mm/ksm.c
@@ -850,33 +850,35 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page,
pte_t *orig_pte)
{
struct mm_struct *mm = vma->vm_mm;
- unsigned long addr;
- pte_t *ptep;
- spinlock_t *ptl;
+ struct page_check_walk pcw = {
+ .page = page,
+ .vma = vma,
+ };
int swapped;
int err = -EFAULT;
unsigned long mmun_start; /* For mmu_notifiers */
unsigned long mmun_end; /* For mmu_notifiers */

- addr = page_address_in_vma(page, vma);
- if (addr == -EFAULT)
+ pcw.address = page_address_in_vma(page, vma);
+ if (pcw.address == -EFAULT)
goto out;

BUG_ON(PageTransCompound(page));

- mmun_start = addr;
- mmun_end = addr + PAGE_SIZE;
+ mmun_start = pcw.address;
+ mmun_end = pcw.address + PAGE_SIZE;
mmu_notifier_invalidate_range_start(mm, mmun_start, mmun_end);

- ptep = page_check_address(page, mm, addr, &ptl, 0);
- if (!ptep)
+ if (!page_check_walk(&pcw))
goto out_mn;
+ if (WARN_ONCE(!pcw.pte, "Unexpected PMD mapping?"))
+ goto out_unlock;

- if (pte_write(*ptep) || pte_dirty(*ptep)) {
+ if (pte_write(*pcw.pte) || pte_dirty(*pcw.pte)) {
pte_t entry;

swapped = PageSwapCache(page);
- flush_cache_page(vma, addr, page_to_pfn(page));
+ flush_cache_page(vma, pcw.address, page_to_pfn(page));
/*
* Ok this is tricky, when get_user_pages_fast() run it doesn't
* take any lock, therefore the check that we are going to make
@@ -886,25 +888,25 @@ static int write_protect_page(struct vm_area_struct *vma, struct page *page,
* this assure us that no O_DIRECT can happen after the check
* or in the middle of the check.
*/
- entry = ptep_clear_flush_notify(vma, addr, ptep);
+ entry = ptep_clear_flush_notify(vma, pcw.address, pcw.pte);
/*
* Check that no O_DIRECT or similar I/O is in progress on the
* page
*/
if (page_mapcount(page) + 1 + swapped != page_count(page)) {
- set_pte_at(mm, addr, ptep, entry);
+ set_pte_at(mm, pcw.address, pcw.pte, entry);
goto out_unlock;
}
if (pte_dirty(entry))
set_page_dirty(page);
entry = pte_mkclean(pte_wrprotect(entry));
- set_pte_at_notify(mm, addr, ptep, entry);
+ set_pte_at_notify(mm, pcw.address, pcw.pte, entry);
}
- *orig_pte = *ptep;
+ *orig_pte = *pcw.pte;
err = 0;

out_unlock:
- pte_unmap_unlock(ptep, ptl);
+ page_check_walk_done(&pcw);
out_mn:
mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
out:
--
2.11.0
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