virtio_balloon: fix towards_target when deflating balloon
authorAnthony Liguori <aliguori@us.ibm.com>
Mon, 18 Aug 2008 22:15:31 +0000 (17:15 -0500)
committerRusty Russell <rusty@rustcorp.com.au>
Mon, 25 Aug 2008 14:19:25 +0000 (00:19 +1000)
commit532a6086e35fa3b5761e68af36d4e42a550eba15
treec1d8ab4df9db25e0efd89dab64dda98f84df1fa6
parent83097aca8567a0bd593534853b71fe0fa9a75d69
virtio_balloon: fix towards_target when deflating balloon

Both v and vb->num_pages are u32 and unsigned int respectively.  If v is less
than vb->num_pages (and it is, when deflating the balloon), the result is a
very large 32-bit number.  Since we're returning a s64, instead of getting the
same negative number we desire, we get a very large positive number.

This handles the case where v < vb->num_pages and ensures we get a small,
negative, s64 as the result.

Rusty: please push this for 2.6.27-rc4.  It's probably appropriate for the
stable tree too as it will cause an unexpected OOM when ballooning.

Signed-off-by: Anthony Liguori <aliguori@us.ibm.com>
Signed-off-by: Rusty Russell <rusty@rustcorp.com.au> (simplified)
drivers/virtio/virtio_balloon.c