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

From: David Miller
Date: Fri Aug 08 2014 - 01:29:13 EST


From: Zoltan Kiss <zoltan.kiss@xxxxxxxxxx>
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.
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