[PATCH 3/3] vhost: fix get_user_pages_fast error handling

Michael S. Tsirkin
2010-02-23T16:57:58Z

get_user_pages_fast returns number of pages on success, negative value
on failure, but never 0. Fix vhost code to match this logic.

Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
---
drivers/vhost/vhost.c | 3 ++-
1 files changed, 2 insertions(+), 1 deletions(-)

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);
--
1.7.0.18.g0d53a5