readahead: apply max_sane_readahead() limit in ondemand_readahead()

Just in case someone aggressively sets a huge readahead size.

Cc: Nick Piggin <npiggin@suse.de>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
Cc: Ying Han <yinghan@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/mm/readahead.c b/mm/readahead.c
index a224182..bd0f0e8 100644 (file)
--- a/mm/readahead.c
+++ b/mm/readahead.c
@@ -357,7 +357,7 @@ ondemand_readahead(struct address_space *mapping,
                   bool hit_readahead_marker, pgoff_t offset,
                   unsigned long req_size)
 {
-       int     max = ra->ra_pages;     /* max readahead pages */
+       unsigned long max = max_sane_readahead(ra->ra_pages);
        pgoff_t prev_offset;
        int     sequential;