HWPOISON: Add invalidate_inode_page

Add a simple way to invalidate a single page
This is just a refactoring of the truncate.c code.
Originally from Fengguang, modified by Andi Kleen.

Signed-off-by: Andi Kleen <ak@linux.intel.com>

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 8cbc0aa..b05bbde 100644 (file)
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -796,6 +796,8 @@ extern int vmtruncate_range(struct inode * inode, loff_t offset, loff_t end);
 
 int truncate_inode_page(struct address_space *mapping, struct page *page);
 
+int invalidate_inode_page(struct page *page);
+
 #ifdef CONFIG_MMU
 extern int handle_mm_fault(struct mm_struct *mm, struct vm_area_struct *vma,
                        unsigned long address, unsigned int flags);

diff --git a/mm/truncate.c b/mm/truncate.c
index 2519a7c..ea132f7 100644 (file)
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -146,6 +146,24 @@ int truncate_inode_page(struct address_space *mapping, struct page *page)
        return truncate_complete_page(mapping, page);
 }
 
+/*
+ * Safely invalidate one page from its pagecache mapping.
+ * It only drops clean, unused pages. The page must be locked.
+ *
+ * Returns 1 if the page is successfully invalidated, otherwise 0.
+ */
+int invalidate_inode_page(struct page *page)
+{
+       struct address_space *mapping = page_mapping(page);
+       if (!mapping)
+               return 0;
+       if (PageDirty(page) || PageWriteback(page))
+               return 0;
+       if (page_mapped(page))
+               return 0;
+       return invalidate_complete_page(mapping, page);
+}
+
 /**
  * truncate_inode_pages - truncate range of pages specified by start & end byte offsets
  * @mapping: mapping to truncate
@@ -312,12 +330,8 @@ unsigned long invalidate_mapping_pages(struct address_space *mapping,
                        if (lock_failed)
                                continue;
 
-                       if (PageDirty(page) || PageWriteback(page))
-                               goto unlock;
-                       if (page_mapped(page))
-                               goto unlock;
-                       ret += invalidate_complete_page(mapping, page);
-unlock:
+                       ret += invalidate_inode_page(page);
+
                        unlock_page(page);
                        if (next > end)
                                break;