From: Rusty Russell <rusty@rustcorp.com.au>
Date: Tue, 18 Mar 2008 03:58:15 +0000 (-0500)
Subject: virtio: handle > 2 billion page balloon targets
X-Git-Tag: v2.6.25-rc7~114^2~2
X-Git-Url: http://pilppa.com/gitweb/?a=commitdiff_plain;h=bdc1681cdf1ab6a65fa935a2b3f8fc63b20c54ea;p=linux-2.6-omap-h63xx.git

virtio: handle > 2 billion page balloon targets

If the host asks for a huge target towards_target() can overflow, and
we up oops as we try to release more pages than we have.  The simple
fix is to use a 64-bit value.

Signed-off-by: Rusty Russell <rusty@rustcorp.com.au>
---

diff --git a/drivers/virtio/virtio_balloon.c b/drivers/virtio/virtio_balloon.c
index c8a4332d113..0b3efc31ee6 100644
--- a/drivers/virtio/virtio_balloon.c
+++ b/drivers/virtio/virtio_balloon.c
@@ -152,7 +152,7 @@ static void virtballoon_changed(struct virtio_device *vdev)
 	wake_up(&vb->config_change);
 }
 
-static inline int towards_target(struct virtio_balloon *vb)
+static inline s64 towards_target(struct virtio_balloon *vb)
 {
 	u32 v;
 	__virtio_config_val(vb->vdev,
@@ -176,7 +176,7 @@ static int balloon(void *_vballoon)
 
 	set_freezable();
 	while (!kthread_should_stop()) {
-		int diff;
+		s64 diff;
 
 		try_to_freeze();
 		wait_event_interruptible(vb->config_change,