[PATCH] splice: switch to using page_cache_readahead()

Avoids doing useless work, when the file is fully cached.

Signed-off-by: Jens Axboe <axboe@suse.de>
diff --git a/fs/splice.c b/fs/splice.c
index 447ebc0..dc205f6 100644
--- a/fs/splice.c
+++ b/fs/splice.c
@@ -299,8 +299,8 @@
 	 * read-ahead if this is a non-zero offset (we are likely doing small
 	 * chunk splice and the page is already there) for a single page.
 	 */
-	if (!loff || spd.nr_pages > 1)
-		do_page_cache_readahead(mapping, in, index, spd.nr_pages);
+	if (!loff || nr_pages > 1)
+		page_cache_readahead(mapping, &in->f_ra, in, index, nr_pages);
 
 	/*
 	 * Now fill in the holes: