Currently we duplicate handling of shared write faults in
wp_page_reuse() and do_shared_fault(). Factor them out into a common
function.
Signed-off-by: Jan Kara <jack@xxxxxxx>
---
mm/memory.c | 78 +++++++++++++++++++++++++++++--------------------------------
1 file changed, 37 insertions(+), 41 deletions(-)
diff --git a/mm/memory.c b/mm/memory.c
index 61902a5b75c2..56b5fe8421a9 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -2059,6 +2059,41 @@ static int do_page_mkwrite(struct vm_area_struct *vma, struct page *page,
}
/*
+ * Handle dirtying of a page in shared file mapping on a write fault.
+ *
+ * The function expects the page to be locked and unlocks it.
+ */
+static void fault_dirty_shared_page(struct vm_area_struct *vma,
+ struct page *page)
+{
+ struct address_space *mapping;
+ bool dirtied;
+ bool page_mkwrite = vma->vm_ops->page_mkwrite;
+
+ dirtied = set_page_dirty(page);
+ VM_BUG_ON_PAGE(PageAnon(page), page);
+ /*
+ * Take a local copy of the address_space - page.mapping may be zeroed
+ * by truncate after unlock_page(). The address_space itself remains
+ * pinned by vma->vm_file's reference. We rely on unlock_page()'s
+ * release semantics to prevent the compiler from undoing this copying.
+ */
+ mapping = page_rmapping(page);
+ unlock_page(page);
+
+ 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);
+}
+
+/*
* Handle write page faults for pages that can be reused in the current vma
*
* This can happen either due to the mapping being with the VM_SHARED flag,
@@ -2090,28 +2125,11 @@ static inline int wp_page_reuse(struct mm_struct *mm,
pte_unmap_unlock(page_table, ptl);
if (dirty_shared) {
- struct address_space *mapping;
- int dirtied;
-
if (!page_mkwrite)
lock_page(page);
- dirtied = set_page_dirty(page);
- VM_BUG_ON_PAGE(PageAnon(page), page);
- mapping = page->mapping;
- unlock_page(page);
+ fault_dirty_shared_page(vma, page);
put_page(page);
-
- 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 VM_FAULT_WRITE;
@@ -3125,9 +3143,7 @@ uncharge_out:
static int do_shared_fault(struct mm_struct *mm, struct vm_area_struct *vma,
struct vm_fault *vmf)
{
- struct address_space *mapping;
unsigned long address = (unsigned long)vmf->virtual_address;
- int dirtied = 0;
int ret, tmp;
ret = __do_fault(vma, vmf);
@@ -3155,27 +3171,7 @@ static int do_shared_fault(struct mm_struct *mm, struct vm_area_struct *vma,
return ret;
}
- if (set_page_dirty(vmf->page))
- dirtied = 1;
- /*
- * Take a local copy of the address_space - page.mapping may be zeroed
- * by truncate after unlock_page(). The address_space itself remains
- * pinned by vma->vm_file's reference. We rely on unlock_page()'s
- * release semantics to prevent the compiler from undoing this copying.
- */
- mapping = page_rmapping(vmf->page);
- unlock_page(vmf->page);
- if ((dirtied || vma->vm_ops->page_mkwrite) && mapping) {
- /*
- * Some device drivers do not set page.mapping but still
- * dirty their pages
- */
- balance_dirty_pages_ratelimited(mapping);
- }
-
- if (!vma->vm_ops->page_mkwrite)
- file_update_time(vma->vm_file);
-
+ fault_dirty_shared_page(vma, vmf->page);
return ret;
}
--
2.6.6
--
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