virtio_net: split out ctrl buffer
When sending control commands, virtio net sets up several buffers for
DMA. The buffers are all part of the net device which means it's
actually allocated by kvmalloc so it's in theory (on extreme memory
pressure) possible to get a vmalloc'ed buffer which on some platforms
means we can't DMA there.
Fix up by moving the DMA buffers into a separate structure.
Reported-by: Mikulas Patocka <mpatocka at redhat.com>
Suggested-by: Eric Dumazet <eric.dumazet at gmail.com>
Signed-off-by: Michael S. Tsirkin <mst at redhat.com>
Acked-by: Jason Wang <jasowang at redhat.com>
Signed-off-by: David S. Miller <davem at davemloft.net>
UnifiedSplitRaw
