[PATCH net] hv_netvsc: split sub-channel setup into async and sync

[David Miller]

From: Haiyang Zhang <haiyangz at linuxonhyperv.com>
Date: Fri, 29 Jun 2018 14:07:16 -0700

> From: Stephen Hemminger <sthemmin at microsoft.com>
> 
> When doing device hotplug the sub channel must be async to avoid
> deadlock issues because device is discovered in softirq context.
> 
> When doing changes to MTU and number of channels, the setup
> must be synchronous to avoid races such as when MTU and device
> settings are done in a single ip command.
> 
> Reported-by: Thomas Walker <Thomas.Walker at twosigma.com>
> Fixes: 8195b1396ec8 ("hv_netvsc: fix deadlock on hotplug")
> Fixes: 732e49850c5e ("netvsc: fix race on sub channel creation")
> Signed-off-by: Stephen Hemminger <sthemmin at microsoft.com>
> Signed-off-by: Haiyang Zhang <haiyangz at microsoft.com>

Applied and queued up for -stable.