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authorBenjamin LaHaise <bcrl@kvack.org>2013-12-22 02:56:08 +0400
committerBenjamin LaHaise <bcrl@kvack.org>2013-12-22 02:56:08 +0400
commit8e321fefb0e60bae4e2a28d20fc4fa30758d27c6 (patch)
treec00de123ad058cc2d69a2e3d59dd7a2bb7500542 /include/linux/migrate.h
parent1881686f842065d2f92ec9c6424830ffc17d23b0 (diff)
downloadlinux-8e321fefb0e60bae4e2a28d20fc4fa30758d27c6.tar.xz
aio/migratepages: make aio migrate pages sane
The arbitrary restriction on page counts offered by the core migrate_page_move_mapping() code results in rather suspicious looking fiddling with page reference counts in the aio_migratepage() operation. To fix this, make migrate_page_move_mapping() take an extra_count parameter that allows aio to tell the code about its own reference count on the page being migrated. While cleaning up aio_migratepage(), make it validate that the old page being passed in is actually what aio_migratepage() expects to prevent misbehaviour in the case of races. Signed-off-by: Benjamin LaHaise <bcrl@kvack.org>
Diffstat (limited to 'include/linux/migrate.h')
-rw-r--r--include/linux/migrate.h3
1 files changed, 2 insertions, 1 deletions
diff --git a/include/linux/migrate.h b/include/linux/migrate.h
index b7717d74da7f..f015c059e159 100644
--- a/include/linux/migrate.h
+++ b/include/linux/migrate.h
@@ -55,7 +55,8 @@ extern int migrate_huge_page_move_mapping(struct address_space *mapping,
struct page *newpage, struct page *page);
extern int migrate_page_move_mapping(struct address_space *mapping,
struct page *newpage, struct page *page,
- struct buffer_head *head, enum migrate_mode mode);
+ struct buffer_head *head, enum migrate_mode mode,
+ int extra_count);
#else
static inline void putback_lru_pages(struct list_head *l) {}