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Diffstat (limited to 'mm')
-rw-r--r--mm/memory.c48
1 files changed, 17 insertions, 31 deletions
diff --git a/mm/memory.c b/mm/memory.c
index 0e9b32610655..988d3099a25d 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2005,7 +2005,7 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
pte_t entry;
int ret = 0;
int page_mkwrite = 0;
- struct page *dirty_page = NULL;
+ bool dirty_shared = false;
unsigned long mmun_start = 0; /* For mmu_notifiers */
unsigned long mmun_end = 0; /* For mmu_notifiers */
struct mem_cgroup *memcg;
@@ -2056,6 +2056,7 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
unlock_page(old_page);
} else if (unlikely((vma->vm_flags & (VM_WRITE|VM_SHARED)) ==
(VM_WRITE|VM_SHARED))) {
+ page_cache_get(old_page);
/*
* Only catch write-faults on shared writable pages,
* read-only shared pages can get COWed by
@@ -2063,7 +2064,7 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
*/
if (vma->vm_ops && vma->vm_ops->page_mkwrite) {
int tmp;
- page_cache_get(old_page);
+
pte_unmap_unlock(page_table, ptl);
tmp = do_page_mkwrite(vma, old_page, address);
if (unlikely(!tmp || (tmp &
@@ -2083,11 +2084,10 @@ static int do_wp_page(struct mm_struct *mm, struct vm_area_struct *vma,
unlock_page(old_page);
goto unlock;
}
-
page_mkwrite = 1;
}
- dirty_page = old_page;
- get_page(dirty_page);
+
+ dirty_shared = true;
reuse:
/*
@@ -2106,43 +2106,29 @@ reuse:
pte_unmap_unlock(page_table, ptl);
ret |= VM_FAULT_WRITE;
- if (!dirty_page)
- return ret;
-
- if (!page_mkwrite) {
+ if (dirty_shared) {
struct address_space *mapping;
int dirtied;
- lock_page(dirty_page);
- dirtied = set_page_dirty(dirty_page);
- VM_BUG_ON_PAGE(PageAnon(dirty_page), dirty_page);
- mapping = dirty_page->mapping;
- unlock_page(dirty_page);
+ if (!page_mkwrite)
+ lock_page(old_page);
- if (dirtied && mapping) {
- /*
- * Some device drivers do not set page.mapping
- * but still dirty their pages
- */
- balance_dirty_pages_ratelimited(mapping);
- }
+ dirtied = set_page_dirty(old_page);
+ VM_BUG_ON_PAGE(PageAnon(old_page), old_page);
+ mapping = old_page->mapping;
+ unlock_page(old_page);
+ page_cache_release(old_page);
- file_update_time(vma->vm_file);
- }
- put_page(dirty_page);
- if (page_mkwrite) {
- struct address_space *mapping = dirty_page->mapping;
-
- set_page_dirty(dirty_page);
- unlock_page(dirty_page);
- page_cache_release(dirty_page);
- if (mapping) {
+ if ((dirtied || page_mkwrite) && mapping) {
/*
* Some device drivers do not set page.mapping
* but still dirty their pages
*/
balance_dirty_pages_ratelimited(mapping);
}
+
+ if (!page_mkwrite)
+ file_update_time(vma->vm_file);
}
return ret;