From: Eric Dumazet <eric.dumazet@gmail.com>
To: Will Deacon <will.deacon@arm.com>
Cc: "netdev@vger.kernel.org" <netdev@vger.kernel.org>,
Steve Glendinning <steve.glendinning@smsc.com>
Subject: Re: [PATCH] net: smsc911x: fix RX FIFO fastforwarding when dropping packets
Date: Thu, 12 Apr 2012 16:01:39 +0200 [thread overview]
Message-ID: <1334239299.5300.6478.camel@edumazet-glaptop> (raw)
In-Reply-To: <20120412134757.GH16025@mudshark.cambridge.arm.com>
On Thu, 2012-04-12 at 14:47 +0100, Will Deacon wrote:
>
> I don't think we want an skb_reserve at all, since the hardware shifts the
> data in the RX FIFO, meaning that we will read two bytes of 0 anyway before
> valid data.
>
> > skb_put(skb, pktlength - 4);
>
> I can move the put here if you like, but we need to use pktwords << 2 to
> make sure that we read the leading and trailing zeroes inserted by the
> hardware.
before calling linux stack, you'll have to skip those 2 bytes.
This is skb_reserve() purpose.
next prev parent reply other threads:[~2012-04-12 14:01 UTC|newest]
Thread overview: 11+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-04-12 9:07 [PATCH] net: smsc911x: fix RX FIFO fastforwarding when dropping packets Will Deacon
2012-04-12 9:20 ` Eric Dumazet
2012-04-12 12:53 ` Will Deacon
2012-04-12 13:06 ` Eric Dumazet
2012-04-12 13:47 ` Will Deacon
2012-04-12 14:01 ` Eric Dumazet [this message]
2012-04-12 15:54 ` Will Deacon
2012-04-12 16:08 ` Eric Dumazet
2012-04-12 17:03 ` Will Deacon
2012-04-12 17:41 ` Eric Dumazet
2012-04-13 18:08 ` David Miller
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