netdev - Re: [net PATCH] mlx4: fix XDP_TX is acting like XDP

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Message-ID: <20160916204350.GA20076@gmail.com>
Date:   Fri, 16 Sep 2016 13:43:50 -0700
From:   Brenden Blanco <bblanco@...mgrid.com>
To:     Jesper Dangaard Brouer <brouer@...hat.com>
Cc:     netdev@...r.kernel.org, tariqt@...lanox.com,
        Eric Dumazet <eric.dumazet@...il.com>, tom@...bertland.com,
        rana.shahot@...il.com, "David S. Miller" <davem@...emloft.net>
Subject: Re: [net PATCH] mlx4: fix XDP_TX is acting like XDP_PASS on TX ring
 full

On Fri, Sep 16, 2016 at 10:36:12PM +0200, Jesper Dangaard Brouer wrote:
> The XDP_TX action can fail transmitting the frame in case the TX ring
> is full or port is down.  In case of TX failure it should drop the
> frame, and not as now call 'break' which is the same as XDP_PASS.
> 
> Fixes: 9ecc2d86171a ("net/mlx4_en: add xdp forwarding and data write support")
> Signed-off-by: Jesper Dangaard Brouer <brouer@...hat.com>

You could in theory have also tried to recycle the page instead of
dropping it, but that's probably not worth optimizing when tx is backed
up, as you'll only save a handful of page_put's. The code to do so
wouldn't have been pretty.

Reviewed-by: Brenden Blanco <bblanco@...mgrid.com>