[3/3] vhost: fix get_user_pages_fast error handling

Commit Message

Michael S. Tsirkin Feb. 23, 2010, 4:57 p.m. UTC

None

Patch

diff --git a/drivers/vhost/vhost.c b/drivers/vhost/vhost.c
index d4f8fdf..d003504 100644
--- a/drivers/vhost/vhost.c
+++ b/drivers/vhost/vhost.c
@@ -646,8 +646,9 @@  static int set_bit_to_user(int nr, void __user *addr)
 	int bit = nr + (log % PAGE_SIZE) * 8;
 	int r;
 	r = get_user_pages_fast(log, 1, 1, &page);
-	if (r)
+	if (r < 0)
 		return r;
+	BUG_ON(r != 1);
 	base = kmap_atomic(page, KM_USER0);
 	set_bit(bit, base);
 	kunmap_atomic(base, KM_USER0);