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Subject: Re: A small fix for if_em.c, if_igb.c, if_ixgbe.c
From: Adrian Chadd <adrian@freebsd.org>
To: John Baldwin <jhb@freebsd.org>
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Cc: Yong-Hyeon Pyun <pyunyh@gmail.com>, FreeBSD Net <freebsd-net@freebsd.org>,
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On 13 December 2013 14:17, John Baldwin <jhb@freebsd.org> wrote:

>> Anyone using if_start() failing as "the frame i just queued failed to
>> transmit" is broken and well, we should just replace it with
>> if_transmit().
>
> Hmm,  I was a bit wrong.  Driver if_start routines return void, so they
> only failed if the IFQ filled up completely.  In that case, I think it is
> fine to move forward with what you want (only return an error for failures
> involving the packet passed to if_transmit), but I don't think we should
> hange if_transmit drivers to just always return 0.

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?


-a