A small fix for if_em.c, if_igb.c, if_ixgbe.c

[Adrian Chadd]

On 16 December 2013 13:04, Michael Tuexen
<Michael.Tuexen at lurchi.franken.de> wrote:
> On Dec 16, 2013, at 9:15 PM, Adrian Chadd <adrian at freebsd.org> wrote:
>
>> On 16 December 2013 12:06, Michael Tuexen
>> <Michael.Tuexen at lurchi.franken.de> wrote:
>>
>>>> i agree. if_transmit() should return 0 only if:
>>>>
>>>> * the driver queued it internally and intends to try transmitting it later;
>>>> * the driver directly dispatched the frame to the hardware.
>>>>
>>>> If it failed to do either of the above, it should return an error.
>>>>
>>>> How's that sound?
>>> That sounds good. However, The transport layer is interested in the case
>>> where if_transmit() returns a non-zero value.
>>> Does your statement imply:
>>> if_transmit() returns a non-zero value only if the packet will not
>>> make it on the wire (for example, it failed to queue it).
>>
>> If there's a queuing layer in the middle then we can't know that for
>> certain. If the driver can't transmit the frame (eg it fails because
>> of collisions, for example) then again, we can't know that for
>> certain.
>>
>> What we can only know is that it was either queued and may or may not
>> make it on the wire, or it wasn't queued/transmitted and it definitely
>> _won't_ make it on the wire.
> Correct. And I'm only interested in the "it wasn't queued/transmitted
> and it definitely _won't_ make it on the wire." part.
> So I would need something like
>
> if_transmit() returns an error only if it wasn't queued/transmitted
> and it definitely _won't_ make it on the wire.
>
> Acceptable for you?

Sounds like the same thing to me, so yes. :)



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