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From: Jakub Kicinski <kuba@kernel.org>
To: Xie He <xie.he.0141@gmail.com>
Cc: Julian Wiedmann <jwi@linux.ibm.com>,
	"David S. Miller" <davem@davemloft.net>,
	Linux X25 <linux-x25@vger.kernel.org>,
	Linux Kernel Network Developers <netdev@vger.kernel.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Martin Schiller <ms@dev.tdt.de>
Subject: Re: [PATCH net] net: lapb: Copy the skb before sending a packet
Date: Mon, 1 Feb 2021 20:42:24 -0800	[thread overview]
Message-ID: <20210201204224.4872ce23@kicinski-fedora-pc1c0hjn.dhcp.thefacebook.com> (raw)
In-Reply-To: <CAJht_EOw4d9h7LqOsXpucADV5=gAGws-fKj5q7BdH2+h0Yv9Vg@mail.gmail.com>

On Mon, 1 Feb 2021 08:14:31 -0800 Xie He wrote:
> On Mon, Feb 1, 2021 at 6:10 AM Julian Wiedmann <jwi@linux.ibm.com> wrote:
> > This sounds a bit like you want skb_cow_head() ... ?  
> 
> Calling "skb_cow_head" before we call "skb_clone" would indeed solve
> the problem of writes to our clones affecting clones in other parts of
> the system. But since we are still writing to the skb after
> "skb_clone", it'd still be better to replace "skb_clone" with
> "skb_copy" to avoid interference between our own clones.

Why call skb_cow_head() before skb_clone()? skb_cow_head should be
called before the data in skb head is modified. I'm assuming you're only
modifying "front" of the frame, right? skb_cow_head() should do nicely
in that case.

  reply	other threads:[~2021-02-02  4:44 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-02-01  5:57 [PATCH net] net: lapb: Copy the skb before sending a packet Xie He
2021-02-01 10:05 ` Martin Schiller
2021-02-01 10:49   ` Xie He
2021-02-01 12:47     ` Martin Schiller
2021-02-01 14:10 ` Julian Wiedmann
2021-02-01 16:14   ` Xie He
2021-02-02  4:42     ` Jakub Kicinski [this message]
2021-02-02  6:25       ` Xie He
2021-02-02 16:41         ` Jakub Kicinski
2021-02-02  9:04     ` David Laight
2021-02-02 16:50 ` patchwork-bot+netdevbpf

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