linux-kernel - Re: [PATCH net-next 4/7] net: dsa: free orig skb on rcv if reallocated

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Message-ID: <20170530162632.GN22758@lunn.ch>
Date:   Tue, 30 May 2017 18:26:32 +0200
From:   Andrew Lunn <andrew@...n.ch>
To:     Vivien Didelot <vivien.didelot@...oirfairelinux.com>
Cc:     netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        kernel@...oirfairelinux.com,
        "David S. Miller" <davem@...emloft.net>,
        Florian Fainelli <f.fainelli@...il.com>
Subject: Re: [PATCH net-next 4/7] net: dsa: free orig skb on rcv if
 reallocated

On Tue, May 30, 2017 at 11:41:51AM -0400, Vivien Didelot wrote:
> Hi Andrew,
> 
> Andrew Lunn <andrew@...n.ch> writes:
> 
> > On Tue, May 30, 2017 at 10:21:28AM -0400, Vivien Didelot wrote:
> >> If the receive function of a tagger reallocated the SKB, the original
> >> SKB is currently not freed. Fix this and free it on both copy or error.
> >
> > I don't see any of the receive functions reallocate the skb. It might
> > be better to just simplify the code to take away the option to return
> > a different skb.
> 
> I think it was written such way to be symmetrical with the xmit
> implementation, where the trailer tagger does reallocate the skb.

trailer_xmit() releases the original and so does the in-review KSZ
tagger.

So i think in general, Rx and Rx, the tagger should be responsible for
freeing the original, but on error the core should do the free.

	Andrew