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From: David Miller <davem@davemloft.net>
To: johannes@sipsolutions.net
Cc: tomasw@gmail.com, linville@tuxdriver.com, netdev@vger.kernel.org,
	linux-wireless@vger.kernel.org
Subject: Re: [RFC v2] mac80211: assign needed_headroom/tailroom for netdevs
Date: Mon, 05 May 2008 16:14:58 -0700 (PDT)	[thread overview]
Message-ID: <20080505.161458.46071527.davem@davemloft.net> (raw)
In-Reply-To: <1210027447.8012.15.camel@johannes.berg>

From: Johannes Berg <johannes@sipsolutions.net>
Date: Tue, 06 May 2008 00:44:07 +0200

> Right, that makes sense. But will it ever return false? skb_cloned()
> returns true often enough, and we only accept linear skbs, but I think I
> don't understand yet what skb_header_cloned() vs. skb_cloned() refers
> to. Which exactly is the header space I'm allowed to modify when
> skb_header_cloned() returns false?

skb_header_cloned() will return false always if the buffer is not
cloned.

If it is cloned, it makes sure the data reference count allows
for modification of the buffer.

For normal traffic, you should see skb_header_cloned() always return
false unless a network tap like tcpdump is registered.

  reply	other threads:[~2008-05-05 23:14 UTC|newest]

Thread overview: 38+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2008-05-04 21:24 [RFC] mac80211: assign needed_headroom/tailroom for netdevs Johannes Berg
2008-05-04 21:31 ` Johannes Berg
2008-05-04 21:32 ` [RFC v2] " Johannes Berg
2008-05-05  0:30   ` David Miller
2008-05-05  7:22     ` Johannes Berg
2008-05-05 14:27       ` Tomas Winkler
2008-05-05 15:22         ` Johannes Berg
2008-05-05 17:15           ` Tomas Winkler
2008-05-05 17:57             ` Johannes Berg
2008-05-05 18:58               ` David Miller
2008-05-05 19:05                 ` Johannes Berg
2008-05-05 19:50                   ` David Miller
2008-05-05 19:57                     ` Johannes Berg
2008-05-05 20:02                       ` David Miller
2008-05-05 20:10                         ` Johannes Berg
2008-05-05 20:44                           ` David Miller
2008-05-05 20:57                             ` Johannes Berg
2008-05-05 21:01                               ` David Miller
2008-05-05 22:37                               ` David Miller
2008-05-05 22:44                                 ` Johannes Berg
2008-05-05 23:14                                   ` David Miller [this message]
2008-05-05 23:23                                     ` Johannes Berg
2008-05-05 23:39                                       ` David Miller
2008-05-06  0:01                                         ` Johannes Berg
2008-05-06  0:08                                           ` David Miller
2008-05-06 11:13                                             ` Johannes Berg
2008-05-06  1:32                                         ` Herbert Xu
2008-05-13  5:01                                 ` David Miller
2008-05-05 23:03           ` David Miller
2008-05-05 23:17             ` Johannes Berg
2008-05-05 23:24               ` David Miller
2008-05-05 23:30                 ` Johannes Berg
2008-05-05 23:36             ` Johannes Berg
2008-05-05 23:40               ` David Miller
2008-05-13  3:52   ` David Miller
2008-05-13  9:01     ` Johannes Berg
2008-05-13  9:45       ` David Miller
2008-05-13 10:07         ` Johannes Berg

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