[PATCH] Swap Migration V5: PF_SWAPWRITE to allow writing to swap

Add PF_SWAPWRITE to control a processes permission to write to swap.

- Use PF_SWAPWRITE in may_write_to_queue() instead of checking for kswapd
  and pdflush

- Set PF_SWAPWRITE flag for kswapd and pdflush

Signed-off-by: Christoph Lameter <clameter@sgi.com>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/mm/pdflush.c b/mm/pdflush.c
index 52822c9..c4b6d0a 100644
--- a/mm/pdflush.c
+++ b/mm/pdflush.c
@@ -90,7 +90,7 @@
 
 static int __pdflush(struct pdflush_work *my_work)
 {
-	current->flags |= PF_FLUSHER;
+	current->flags |= PF_FLUSHER | PF_SWAPWRITE;
 	my_work->fn = NULL;
 	my_work->who = current;
 	INIT_LIST_HEAD(&my_work->list);