Merge branch 'writeback-for-linus' of git://github.com/fengguang/linux

[pandora-kernel.git] / mm / truncate.c

diff --git a/mm/truncate.c b/mm/truncate.c
index 232eb27..b40ac6d 100644 (file)
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -336,6 +336,14 @@ unsigned long invalidate_mapping_pages(struct address_space *mapping,
        unsigned long count = 0;
        int i;
 
+       /*
+        * Note: this function may get called on a shmem/tmpfs mapping:
+        * pagevec_lookup() might then return 0 prematurely (because it
+        * got a gangful of swap entries); but it's hardly worth worrying
+        * about - it can rarely have anything to free from such a mapping
+        * (most pages are dirty), and already skips over any difficulties.
+        */
+
        pagevec_init(&pvec, 0);
        while (index <= end && pagevec_lookup(&pvec, mapping, index,
                        min(end - index, (pgoff_t)PAGEVEC_SIZE - 1) + 1)) {