Re: [PATCH net-next 0/2] xen-netback: Changes around carrier handling

From: Zoltan Kiss <redacted>
Date: Thu, 7 Aug 2014 17:49:37 +0100

David Vrabel pointed out an important question in a reply to the
previous version of this series: this patch deschedule NAPI if the
carrier goes down. The backend doesn't receive packets from the
guest. DavidVr and others said we shouldn't do this, the guest should
be able to transmit even if it's not able/willing to receive. Other
drivers doesn't deschedule NAPI at carrier off as well, however the
"carrier off" information comes from the hardware, not from an
untrusted guest who is not posting buffers on the receive ring.
I don't have any good argument why I did it the current way, other
than a hunch that it feels more natural.
David, do you have an opinion on that?

Unless you have a strong reason for doing so, I don't think disabling
receives when the TX path backs up is necessary.