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From: "Michael S. Tsirkin" <mst@redhat.com>
Subject: Re: [PATCH] net: orphan queued skbs if device tx can stall
Date: Tue, 8 May 2012 22:35:08 +0300
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Cc: netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
	"David S. Miller" <davem@davemloft.net>,
	Jamal Hadi Salim <hadi@cyberus.ca>,
	Stephen Hemminger <shemminger@vyatta.com>,
	Jason Wang <jasowang@redhat.com>,
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To: Eric Dumazet <eric.dumazet@gmail.com>
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On Tue, Apr 10, 2012 at 03:52:09PM +0200, Eric Dumazet wrote:
> By the way, skb orphaning should already be done in skb_orphan_try(),
> not sure why its done again in tun_net_xmit().

Because we need to force it for skbs which have tx_flags set.

> Note we perform orphaning
> right before giving skb to device on premise it'll be sent (and freed)
> in a reasonable amount of time.

It is usually the case. I think this assumption holds for
tun normally.