tree c1d8ab4df9db25e0efd89dab64dda98f84df1fa6
parent 83097aca8567a0bd593534853b71fe0fa9a75d69
author Anthony Liguori <aliguori@us.ibm.com> 1219097731 -0500
committer Rusty Russell <rusty@rustcorp.com.au> 1219673965 +1000

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)