mm: remove file argument from swap_readpage()

The file argument resulted from address_space's readpage long time ago.

We don't use it any more.  Let's remove unnecessary argement.

Signed-off-by: Minchan Kim <minchan.kim@gmail.com>
Acked-by: Hugh Dickins <hugh.dickins@tiscali.co.uk>
Reviewed-by: Rik van Riel <riel@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

mm/page_io.c

@@ -120,7 +120,7 @@ out:
 	return ret;
 }
 
-int swap_readpage(struct file *file, struct page *page)
+int swap_readpage(struct page *page)
 {
 	struct bio *bio;
 	int ret = 0;