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([2601:282:803:7700:c19e:4650:3a73:fee4]) by smtp.googlemail.com with ESMTPSA id p47sm4268828qta.44.2020.04.22.08.09.39 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Wed, 22 Apr 2020 08:09:40 -0700 (PDT) Subject: Re: [PATCH V4 mlx5-next 01/15] net/core: Introduce netdev_get_xmit_slave To: Maor Gottlieb , davem@davemloft.net, jgg@mellanox.com, dledford@redhat.com, j.vosburgh@gmail.com, vfalico@gmail.com, andy@greyhouse.net, kuba@kernel.org, jiri@mellanox.com, dsahern@kernel.org Cc: leonro@mellanox.com, saeedm@mellanox.com, linux-rdma@vger.kernel.org, netdev@vger.kernel.org, alexr@mellanox.com References: <20200422083951.17424-1-maorg@mellanox.com> <20200422083951.17424-2-maorg@mellanox.com> From: David Ahern Message-ID: <93110507-2ffe-c9f1-f53c-41c6968751ac@gmail.com> Date: Wed, 22 Apr 2020 09:09:38 -0600 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.15; rv:68.0) Gecko/20100101 Thunderbird/68.7.0 MIME-Version: 1.0 In-Reply-To: <20200422083951.17424-2-maorg@mellanox.com> Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-rdma-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-rdma@vger.kernel.org On 4/22/20 2:39 AM, Maor Gottlieb wrote: > diff --git a/net/core/dev.c b/net/core/dev.c > index 9c9e763bfe0e..294553551ba5 100644 > --- a/net/core/dev.c > +++ b/net/core/dev.c > @@ -7785,6 +7785,36 @@ void netdev_bonding_info_change(struct net_device *dev, > } > EXPORT_SYMBOL(netdev_bonding_info_change); > > +/** > + * netdev_get_xmit_slave - Get the xmit slave of master device > + * @skb: The packet > + * @all_slaves: assume all the slaves are active > + * > + * This can be called from any context and does its own locking. > + * The returned handle has the usage count incremented and the caller must > + * use dev_put() to release it when it is no longer needed. > + * %NULL is returned if no slave is found. > + */ > + > +struct net_device *netdev_get_xmit_slave(struct net_device *dev, > + struct sk_buff *skb, > + bool all_slaves) > +{ > + const struct net_device_ops *ops = dev->netdev_ops; > + struct net_device *slave_dev; > + > + if (!ops->ndo_get_xmit_slave) > + return NULL; > + > + rcu_read_lock(); > + slave_dev = ops->ndo_get_xmit_slave(dev, skb, all_slaves); > + if (slave_dev) > + dev_hold(slave_dev); > + rcu_read_unlock(); > + return slave_dev; > +} > +EXPORT_SYMBOL(netdev_get_xmit_slave); > + > static void netdev_adjacent_add_links(struct net_device *dev) > { > struct netdev_adjacent *iter; > The rcu_read_lock and reference seem overkill for a general purpose helper. When this set goes in I want to make modifications for use with XDP and that does not need either. Looking at the mlx5 changes, you could easily handle that in the driver.