From mboxrd@z Thu Jan 1 00:00:00 1970 From: David Miller Subject: Re: [PATCH net V3 2/2] net: core: explicitly select a txq before doing l2 forwarding Date: Fri, 10 Jan 2014 13:24:28 -0500 (EST) Message-ID: <20140110.132428.2182820842932734377.davem@davemloft.net> References: <1389341906-2367-1-git-send-email-jasowang@redhat.com> <1389341906-2367-2-git-send-email-jasowang@redhat.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Cc: nhorman@tuxdriver.com, mst@redhat.com, e1000-devel@lists.sourceforge.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, john.r.fastabend@intel.com To: jasowang@redhat.com Return-path: In-Reply-To: <1389341906-2367-2-git-send-email-jasowang@redhat.com> List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: e1000-devel-bounces@lists.sourceforge.net List-Id: netdev.vger.kernel.org From: Jason Wang Date: Fri, 10 Jan 2014 16:18:26 +0800 > Currently, the tx queue were selected implicitly in ndo_dfwd_start_xmit(). The > will cause several issues: > > - NETIF_F_LLTX were removed for macvlan, so txq lock were done for macvlan > instead of lower device which misses the necessary txq synchronization for > lower device such as txq stopping or frozen required by dev watchdog or > control path. > - dev_hard_start_xmit() was called with NULL txq which bypasses the net device > watchdog. > - dev_hard_start_xmit() does not check txq everywhere which will lead a crash > when tso is disabled for lower device. > > Fix this by explicitly introducing a new param for .ndo_select_queue() for just > selecting queues in the case of l2 forwarding offload. netdev_pick_tx() was also > extended to accept this parameter and dev_queue_xmit_accel() was used to do l2 > forwarding transmission. > > With this fixes, NETIF_F_LLTX could be preserved for macvlan and there's no need > to check txq against NULL in dev_hard_start_xmit(). Also there's no need to keep > a dedicated ndo_dfwd_start_xmit() and we can just reuse the code of > dev_queue_xmit() to do the transmission. > > In the future, it was also required for macvtap l2 forwarding support since it > provides a necessary synchronization method. > > Cc: John Fastabend > Cc: Neil Horman > Cc: e1000-devel@lists.sourceforge.net > Signed-off-by: Jason Wang Applied. ------------------------------------------------------------------------------ CenturyLink Cloud: The Leader in Enterprise Cloud Services. Learn Why More Businesses Are Choosing CenturyLink Cloud For Critical Workloads, Development Environments & Everything In Between. Get a Quote or Start a Free Trial Today. http://pubads.g.doubleclick.net/gampad/clk?id=119420431&iu=/4140/ostg.clktrk _______________________________________________ E1000-devel mailing list E1000-devel@lists.sourceforge.net https://lists.sourceforge.net/lists/listinfo/e1000-devel To learn more about Intel® Ethernet, visit http://communities.intel.com/community/wired