[PATCH] splice: always call into page_cache_readahead()

Don't try to guess what the read-ahead logic will do, allow it
to make its own decisions.
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

fs/splice.c

@@ -289,12 +289,10 @@ __generic_file_splice_read(struct file *in, loff_t *ppos,
 		nr_pages = PIPE_BUFFERS;
 
 	/*
-	 * Initiate read-ahead on this page range. however, don't call into
-	 * 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.
+	 * Don't try to 2nd guess the read-ahead logic, call into
+	 * page_cache_readahead() like the page cache reads would do.
 	 */
-	if (!loff || nr_pages > 1)
-		page_cache_readahead(mapping, &in->f_ra, in, index, nr_pages);
+	page_cache_readahead(mapping, &in->f_ra, in, index, nr_pages);
 
 	/*
 	 * Now fill in the holes: