The MMU-notifier code is needed only in case we copied a page. In the
original code, as the tail call was explicit, we had to handle it as a
special case there. However, now that the unlock flow is a separate
function, this is not the case. We explicitly call
mmu_notifier_invalidate_range_end in wp_page_copy, after finishing all
of the unlock logic. This also makes it much easier to see the pairing
of mmu_notifier_invalidate_range_start and
mmu_notifier_invalidate_range_end in the same function.
Signed-off-by: Shachar Raindel <raindel@xxxxxxxxxxxx>
---
mm/memory.c | 11 ++++-------
1 file changed, 4 insertions(+), 7 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c
index 8023cf3..68fab34 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2100,13 +2100,10 @@ static int wp_page_reuse(struct mm_struct *mm, struct vm_area_struct *vma,
*/
static int wp_page_unlock(struct mm_struct *mm, struct vm_area_struct *vma,
pte_t *page_table, spinlock_t *ptl,
- unsigned long mmun_start, unsigned long mmun_end,
struct page *old_page, int page_copied)
__releases(ptl)
{
pte_unmap_unlock(page_table, ptl);
- if (mmun_end > mmun_start)
- mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
if (old_page) {
/*
* Don't let another task, with possibly unlocked vma,
@@ -2143,6 +2140,7 @@ static int wp_page_copy(struct mm_struct *mm, struct vm_area_struct *vma,
struct page *new_page = NULL;
pte_t entry;
int page_copied = 0;
+ int ret = 0;
const unsigned long mmun_start = address & PAGE_MASK; /* For mmu_notifiers */
const unsigned long mmun_end = mmun_start + PAGE_SIZE; /* For mmu_notifiers */
struct mem_cgroup *memcg;
@@ -2238,8 +2236,9 @@ static int wp_page_copy(struct mm_struct *mm, struct vm_area_struct *vma,
if (new_page)
page_cache_release(new_page);
- return wp_page_unlock(mm, vma, page_table, ptl, mmun_start,
- mmun_end, old_page, page_copied);
+ ret = wp_page_unlock(mm, vma, page_table, ptl, old_page, page_copied);
+ mmu_notifier_invalidate_range_end(mm, mmun_start, mmun_end);
+ return ret;
oom_free_new:
page_cache_release(new_page);
oom:
@@ -2283,7 +2282,6 @@ static int wp_page_shared_vma(struct mm_struct *mm, struct vm_area_struct *vma,
if (!pte_same(*page_table, orig_pte)) {
unlock_page(old_page);
return wp_page_unlock(mm, vma, page_table, ptl,
- 0, 0,
old_page, 0);
}
@@ -2352,7 +2350,6 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
if (!pte_same(*page_table, orig_pte)) {
unlock_page(old_page);
return wp_page_unlock(mm, vma, page_table, ptl,
- 0, 0,
old_page, 0);
}
page_cache_release(old_page);
--
1.7.11.2
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