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authorHugh Dickins <hughd@google.com>2011-07-25 17:12:25 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2011-07-25 20:57:10 -0700
commitb85e0effd3dcbf9118b896232f59526ab1a39a74 (patch)
tree32200b2e4052d50d4eb1771e555eaf66d7c4cfc8 /mm/filemap.c
parent8a549bea51138be2126a2cc6aabe8f17ef66b79b (diff)
downloadlinaro-lsk-b85e0effd3dcbf9118b896232f59526ab1a39a74.tar.gz
mm: consistent truncate and invalidate loops
Make the pagevec_lookup loops in truncate_inode_pages_range(), invalidate_mapping_pages() and invalidate_inode_pages2_range() more consistent with each other. They were relying upon page->index of an unlocked page, but apologizing for it: accept it, embrace it, add comments and WARN_ONs, and simplify the index handling. invalidate_inode_pages2_range() had special handling for a wrapped page->index + 1 = 0 case; but MAX_LFS_FILESIZE doesn't let us anywhere near there, and a corrupt page->index in the radix_tree could cause more trouble than that would catch. Remove that wrapped handling. invalidate_inode_pages2_range() uses min() to limit the pagevec_lookup when near the end of the range: copy that into the other two, although it's less useful than you might think (it limits the use of the buffer, rather than the indices looked up). Signed-off-by: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'mm/filemap.c')
-rw-r--r--mm/filemap.c2
1 files changed, 2 insertions, 0 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index 2780be4bd49..10a17111327 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -128,6 +128,7 @@ void __delete_from_page_cache(struct page *page)
radix_tree_delete(&mapping->page_tree, page->index);
page->mapping = NULL;
+ /* Leave page->index set: truncation lookup relies upon it */
mapping->nrpages--;
__dec_zone_page_state(page, NR_FILE_PAGES);
if (PageSwapBacked(page))
@@ -483,6 +484,7 @@ int add_to_page_cache_locked(struct page *page, struct address_space *mapping,
spin_unlock_irq(&mapping->tree_lock);
} else {
page->mapping = NULL;
+ /* Leave page->index set: truncation relies upon it */
spin_unlock_irq(&mapping->tree_lock);
mem_cgroup_uncharge_cache_page(page);
page_cache_release(page);