From: Haiyang Zhang <redacted>
Date: Thu, 28 Mar 2019 19:16:37 +0000

From: Haiyang Zhang <haiyangz@microsoft.com>

After queue stopped, the wakeup mechanism may wake it up again
when ring buffer usage is lower than a threshold. This may cause
send path panic on NULL pointer when we stopped all tx queues in
netvsc_detach and start removing the netvsc device.

This patch fix it by adding a tx_disable flag to prevent unwanted
queue wakeup.

Fixes: 7b2ee50c0cd5 ("hv_netvsc: common detach logic")
Reported-by: Mohammed Gamal <redacted>
Signed-off-by: Haiyang Zhang <haiyangz@microsoft.com>

Still need to fix the inline issues I mentioned in v1.