[PATCH] swap 1/4 swapon memleak

[Hugh Dickins]

Burton reported Kernel memory leak with swapon/swapoff? LKML 31 May.
swapon uses rw_swap_page_nolock to read swap_header page (peculiar!
should probably rework that sometime), nothing freed the buffers
from the page, and thus the page was also never freed.

--- 2.4.19-pre10/mm/page_io.c	Mon Nov 19 23:19:42 2001
+++ linux/mm/page_io.c	Tue Jun 11 19:02:30 2002
@@ -120,8 +120,10 @@
 		PAGE_BUG(page);
 	/* needs sync_page to wait I/O completation */
 	page->mapping = &swapper_space;
-	if (!rw_swap_page_base(rw, entry, page))
-		UnlockPage(page);
-	wait_on_page(page);
+	if (rw_swap_page_base(rw, entry, page))
+		lock_page(page);
+	if (!block_flushpage(page, 0))
+		PAGE_BUG(page);
 	page->mapping = NULL;
+	UnlockPage(page);
 }