Merge branch 'vsock-virtio-make-the-credit-mechanism-more-robust'

Stefano Garzarella says:

====================
vsock/virtio: make the credit mechanism more robust

This series makes the credit mechanism implemented in the
virtio-vsock devices more robust.
Patch 1 sends an update to the remote peer when the buf_alloc
change.
Patch 2 prevents a malicious peer (especially the guest) can
consume all the memory of the other peer, discarding packets
when the credit available is not respected.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>