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([2601:282:800:fd80:b012:b2bf:173a:b7c3]) by smtp.googlemail.com with ESMTPSA id f23sm3465440ioc.36.2019.09.15.13.05.48 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Sun, 15 Sep 2019 13:05:48 -0700 (PDT) Subject: Re: [patch net-next 02/15] net: fib_notifier: make FIB notifier per-netns To: Jiri Pirko , netdev@vger.kernel.org Cc: davem@davemloft.net, idosch@mellanox.com, jakub.kicinski@netronome.com, tariqt@mellanox.com, saeedm@mellanox.com, kuznet@ms2.inr.ac.ru, yoshfuji@linux-ipv6.org, shuah@kernel.org, mlxsw@mellanox.com References: <20190914064608.26799-1-jiri@resnulli.us> <20190914064608.26799-3-jiri@resnulli.us> From: David Ahern Message-ID: <87139e84-4310-6632-c5d5-64610d4cc56e@gmail.com> Date: Sun, 15 Sep 2019 14:05:47 -0600 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.14; rv:52.0) Gecko/20100101 Thunderbird/52.9.1 MIME-Version: 1.0 In-Reply-To: <20190914064608.26799-3-jiri@resnulli.us> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: netdev-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org Archived-At: List-Archive: List-Post: On 9/14/19 12:45 AM, Jiri Pirko wrote: > #define FIB_DUMP_MAX_RETRIES 5 > -int register_fib_notifier(struct notifier_block *nb, > +int register_fib_notifier(struct net *net, struct notifier_block *nb, > void (*cb)(struct notifier_block *nb)) > { > int retries = 0; > int err; > > do { > - unsigned int fib_seq = fib_seq_sum(); > - struct net *net; > - > - rcu_read_lock(); > - for_each_net_rcu(net) { > - err = fib_net_dump(net, nb); > - if (err) > - goto err_fib_net_dump; > - } > - rcu_read_unlock(); > - > - if (fib_dump_is_consistent(nb, cb, fib_seq)) > + unsigned int fib_seq = fib_seq_sum(net); > + > + err = fib_net_dump(net, nb); > + if (err) > + return err; > + > + if (fib_dump_is_consistent(net, nb, cb, fib_seq)) > return 0; > } while (++retries < FIB_DUMP_MAX_RETRIES); This is still more complicated than it needs to be. Why lump all fib_notifier_ops into 1 dump when they are separate databases with separate seq numbers? Just dump them 1 at a time and retry that 1 database as needed. ie., This: list_for_each_entry_rcu(ops, &net->fib_notifier_ops, list) { should be in register_fib_notifier and not fib_net_dump. as it stands you are potentially replaying way more than is needed when a dump is inconsistent. > > return -EBUSY; > - > -err_fib_net_dump: > - rcu_read_unlock(); > - return err; > } > EXPORT_SYMBOL(register_fib_notifier); > > -int unregister_fib_notifier(struct notifier_block *nb) > +int unregister_fib_notifier(struct net *net, struct notifier_block *nb) > { > - return atomic_notifier_chain_unregister(&fib_chain, nb); > + struct fib_notifier_net *fn_net = net_generic(net, fib_notifier_net_id); > + > + return atomic_notifier_chain_unregister(&fn_net->fib_chain, nb); > } > EXPORT_SYMBOL(unregister_fib_notifier); >