From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [PATCH RFC v2 1/2] can: fix multiple delivery of a single CAN frame for overlapping CAN filters Date: Mon, 30 Mar 2015 15:33:30 +0300 Message-ID: <5519429A.8050000@cogentembedded.com> References: <1427652564-32181-1-git-send-email-socketcan@hartkopp.net> <1427652564-32181-2-git-send-email-socketcan@hartkopp.net> Mime-Version: 1.0 Content-Type: text/plain; charset=windows-1252; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from mail-wg0-f47.google.com ([74.125.82.47]:35043 "EHLO mail-wg0-f47.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752684AbbC3Mdc (ORCPT ); Mon, 30 Mar 2015 08:33:32 -0400 Received: by wgdm6 with SMTP id m6so173012748wgd.2 for ; Mon, 30 Mar 2015 05:33:31 -0700 (PDT) In-Reply-To: <1427652564-32181-2-git-send-email-socketcan@hartkopp.net> Sender: linux-can-owner@vger.kernel.org List-ID: To: Oliver Hartkopp , linux-can@vger.kernel.org Cc: netdev@vger.kernel.org Hello. On 3/29/2015 9:09 PM, Oliver Hartkopp wrote: > The CAN_RAW socket can set multiple CAN identifier specific filters that lead > to multiple filters in the af_can.c filter processing. These filters are > indenpendent from each other which leads to logical OR'ed filters when applied. > This patch makes sure that every CAN frame which is filtered for a specific > socket is only delivered once to the user space. This is independent from the > number of matching CAN filters of this socket. > As the can_raw() function is executed from NET_RX softirq the introduced > variables are implemented as per-CPU variables to avoid extensive locking at > CAN frame reception time. > Signed-off-by: Oliver Hartkopp > --- > net/can/raw.c | 28 ++++++++++++++++++++++++++++ > 1 file changed, 28 insertions(+) > diff --git a/net/can/raw.c b/net/can/raw.c > index 00c13ef..866a9b3 100644 > --- a/net/can/raw.c > +++ b/net/can/raw.c [...] > @@ -123,6 +125,15 @@ static void raw_rcv(struct sk_buff *oskb, void *data) > if (!ro->fd_frames && oskb->len != CAN_MTU) > return; > > + /* eliminate multiple filter matches for the same skb */ > + if (*this_cpu_ptr(ro->uniq_skb) == oskb && > + ktime_equal(*this_cpu_ptr(ro->uniq_tstamp), oskb->tstamp)) { > + return; Over-indented. > + } else { > + *this_cpu_ptr(ro->uniq_skb) = oskb; > + *this_cpu_ptr(ro->uniq_tstamp) = oskb->tstamp; > + } > + > /* clone the given skb to be able to enqueue it into the rcv queue */ > skb = skb_clone(oskb, GFP_ATOMIC); > if (!skb) [...] > @@ -297,6 +309,20 @@ static int raw_init(struct sock *sk) > ro->recv_own_msgs = 0; > ro->fd_frames = 0; > > + ro->uniq_skb = alloc_percpu(struct sk_buff *); > + if (unlikely(ro->uniq_skb == NULL)) > + return -ENOMEM; > + for_each_possible_cpu(cpu) > + *per_cpu_ptr(ro->uniq_skb, cpu) = NULL; > + > + ro->uniq_tstamp = alloc_percpu(ktime_t); > + if (unlikely(ro->uniq_tstamp == NULL)) { !ro->uniq_tstamp is preferred in the networking code. [...] WBR, Sergei