Return-Path: Date: Mon, 02 Mar 2015 00:20:00 -0500 (EST) Message-Id: <20150302.002000.2074179681664043670.davem@davemloft.net> To: eyal.birger@gmail.com Cc: willemb@google.com, edumazet@google.com, shmulik.ladkani@gmail.com, linux-bluetooth@vger.kernel.org, marcel@holtmann.org, netdev@vger.kernel.org Subject: Re: [PATCH net-next v3 0/7] net: move skb->dropcount to skb->cb[] From: David Miller In-Reply-To: <1425214711-9562-1-git-send-email-eyal.birger@gmail.com> References: <1425214711-9562-1-git-send-email-eyal.birger@gmail.com> Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Sender: linux-bluetooth-owner@vger.kernel.org List-ID: From: Eyal Birger Date: Sun, 1 Mar 2015 14:58:24 +0200 > Commit 977750076d98 ("af_packet: add interframe drop cmsg (v6)") > unionized skb->mark and skb->dropcount in order to allow recording > of the socket drop count while maintaining struct sk_buff size. > > skb->dropcount was introduced since there was no available room > in skb->cb[] in packet sockets. However, its introduction led to > the inability to export skb->mark to userspace. > > It was considered to alias skb->priority instead of skb->mark. > However, that would lead to the inabilty to export skb->priority > to userspace if desired. Such change may also lead to hard-to-find > issues as skb->priority is assumed to be alias free, and, as noted > by Shmulik Ladkani, is not 'naturally orthogonal' with other skb > fields. > > This patch series follows the suggestions made by Eric Dumazet moving > the dropcount metric to skb->cb[], eliminating this problem > at the expense of 4 bytes less in skb->cb[] for protocol families > using it. > > The patch series include compactization of bluetooth and packet > use of skb->cb[] as well as the infrastructure for placing dropcount > in skb->cb[]. Ok, I think I can live with this. Series applied, thanks.