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authorSong Liu <songliubraving@fb.com>2019-09-23 15:37:47 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-09-24 15:54:11 -0700
commit31895438e702f48e25b7aa6d88f9c97c795c79c7 (patch)
tree6d3bf756856dcab897ef9f8cf6d284079711435a
parent585e5a7babd91fd85a5cc97b7324c6c2fc29e1ec (diff)
downloadlinux-31895438e702f48e25b7aa6d88f9c97c795c79c7.tar.bz2
filemap: check compound_head(page)->mapping in pagecache_get_page()
Similar to previous patch, pagecache_get_page() avoids race condition with truncate by checking page->mapping == mapping. This does not work for compound pages. This patch let it check compound_head(page)->mapping instead. Link: http://lkml.kernel.org/r/20190801184244.3169074-3-songliubraving@fb.com Signed-off-by: Song Liu <songliubraving@fb.com> Suggested-by: Johannes Weiner <hannes@cmpxchg.org> Acked-by: Johannes Weiner <hannes@cmpxchg.org> Cc: Hillf Danton <hdanton@sina.com> Cc: Hugh Dickins <hughd@google.com> Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com> Cc: Rik van Riel <riel@surriel.com> Cc: William Kucharski <william.kucharski@oracle.com> Cc: Oleg Nesterov <oleg@redhat.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--mm/filemap.c2
1 files changed, 1 insertions, 1 deletions
diff --git a/mm/filemap.c b/mm/filemap.c
index fc7818b4537e..0b301103ea80 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -1647,7 +1647,7 @@ repeat:
}
/* Has the page been truncated? */
- if (unlikely(page->mapping != mapping)) {
+ if (unlikely(compound_head(page)->mapping != mapping)) {
unlock_page(page);
put_page(page);
goto repeat;