K 10
svn:author
V 2
kp
K 8
svn:date
V 27
2020-12-11T15:39:22.901743Z
K 7
svn:log
V 923
MFC r368020, r368025:

if: Protect V_ifnet in vnet_if_return()

When we terminate a vnet (i.e. jail) we move interfaces back to their home
vnet. We need to protect our access to the V_ifnet CK_LIST.

We could enter NET_EPOCH, but if_detach_internal() (called from if_vmove())
waits for net epoch callback completion. That's not possible from NET_EPOCH.
Instead, we take the IFNET_WLOCK, build a list of the interfaces that need to
move and, once we've released the lock, move them back to their home vnet.

We cannot hold the IFNET_WLOCK() during if_vmove(), because that results in a
LOR between ifnet_sx, in_multi_sx and iflib ctx lock.

Separate out moving the ifp into or out of V_ifnet, so we can hold the lock as
we do the list manipulation, but do not hold it as we if_vmove().

if: Fix non-VIMAGE build

if_link_ifnet() and if_unlink_ifnet() are needed even when VIMAGE is not
enabled.

Sponsored by:	Modirum MDPay

END