From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-4.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_PASS,URIBL_BLOCKED autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id C3FE3C10F0E for ; Mon, 8 Apr 2019 02:34:49 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 87F6220863 for ; Mon, 8 Apr 2019 02:34:49 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726638AbfDHCes (ORCPT ); Sun, 7 Apr 2019 22:34:48 -0400 Received: from shards.monkeyblade.net ([23.128.96.9]:56030 "EHLO shards.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726632AbfDHCes (ORCPT ); Sun, 7 Apr 2019 22:34:48 -0400 Received: from localhost (unknown [IPv6:2601:601:9f80:35cd::d71]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (Client did not present a certificate) (Authenticated sender: davem-davemloft) by shards.monkeyblade.net (Postfix) with ESMTPSA id A0B5F133E9762; Sun, 7 Apr 2019 19:34:47 -0700 (PDT) Date: Sun, 07 Apr 2019 19:34:46 -0700 (PDT) Message-Id: <20190407.193446.222511969891972229.davem@davemloft.net> To: vladbu@mellanox.com Cc: netdev@vger.kernel.org, jhs@mojatatu.com, xiyou.wangcong@gmail.com, jiri@resnulli.us, john.hurley@netronome.com Subject: Re: [PATCH net-next] net: sched: flower: insert filter to ht before offloading it to hw From: David Miller In-Reply-To: <20190405175626.4123-1-vladbu@mellanox.com> References: <20190405175626.4123-1-vladbu@mellanox.com> X-Mailer: Mew version 6.8 on Emacs 26.1 Mime-Version: 1.0 Content-Type: Text/Plain; charset=us-ascii Content-Transfer-Encoding: 7bit X-Greylist: Sender succeeded SMTP AUTH, not delayed by milter-greylist-4.5.12 (shards.monkeyblade.net [149.20.54.216]); Sun, 07 Apr 2019 19:34:47 -0700 (PDT) Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org From: Vlad Buslov Date: Fri, 5 Apr 2019 20:56:26 +0300 > John reports: > > Recent refactoring of fl_change aims to use the classifier spinlock to > avoid the need for rtnl lock. In doing so, the fl_hw_replace_filer() > function was moved to before the lock is taken. This can create problems > for drivers if duplicate filters are created (commmon in ovs tc offload > due to filters being triggered by user-space matches). > > Drivers registered for such filters will now receive multiple copies of > the same rule, each with a different cookie value. This means that the > drivers would need to do a full match field lookup to determine > duplicates, repeating work that will happen in flower __fl_lookup(). > Currently, drivers do not expect to receive duplicate filters. > > To fix this, verify that filter with same key is not present in flower > classifier hash table and insert the new filter to the flower hash table > before offloading it to hardware. Implement helper function > fl_ht_insert_unique() to atomically verify/insert a filter. > > This change makes filter visible to fast path at the beginning of > fl_change() function, which means it can no longer be freed directly in > case of error. Refactor fl_change() error handling code to deallocate the > filter with rcu timeout. > > Fixes: 620da4860827 ("net: sched: flower: refactor fl_change") > Reported-by: John Hurley > Signed-off-by: Vlad Buslov Applied, thanks Vlad.