Re: [patch net-next V3] bond: have random dev address by default instead of zeroes

[Jay Vosburgh <fubar@us.ibm.com>]

Jiri Pirko <jiri@resnulli.us> wrote:

>Makes more sense to have randomly generated address by default than to
>have all zeroes. It also allows user to for example put the bond into
>bridge without need to have any slaves in it.
>
>Also note that this changes only behaviour of bonds with no slaves. Once
>the first slave device is enslaved, its address will be used (no change
>here).
>
>Also, fix dev_assign_type values on the way.
>
>Reported-by: Pavel Šimerda <psimerda@redhat.com>
>Signed-off-by: Jiri Pirko <jiri@resnulli.us>
>---
>
>v2->v3:
>- call_netdevice_notifiers is called after dev_addr change.
>- use bond->get_dev_addr_from_first_slave to know when to get addr from the
>  first slave

	Was there a problem with using the dev_addr_type to determine
this?  If it's really necessary, I think the name of this field is
really verbose; even "addr_from_first" should be sufficient in my mind.

	-J

---
	-Jay Vosburgh, IBM Linux Technology Center, fubar@us.ibm.com


>v1->v2:
>- fixed assign value of bond_dev->addr_assign_type in bond_set_dev_addr()
>- added note to patch description
>
> drivers/net/bonding/bond_main.c | 38 +++++++++++++++++++-------------------
> drivers/net/bonding/bonding.h   |  1 +
> 2 files changed, 20 insertions(+), 19 deletions(-)
>
>diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
>index 564cf42..8692df8 100644
>--- a/drivers/net/bonding/bond_main.c
>+++ b/drivers/net/bonding/bond_main.c
>@@ -1320,14 +1320,15 @@ static void bond_netpoll_cleanup(struct net_device *bond_dev)
>
> /*---------------------------------- IOCTL ----------------------------------*/
>
>-static int bond_sethwaddr(struct net_device *bond_dev,
>-			  struct net_device *slave_dev)
>+static void bond_set_dev_addr(struct net_device *bond_dev,
>+			      struct net_device *slave_dev)
> {
> 	pr_debug("bond_dev=%p\n", bond_dev);
> 	pr_debug("slave_dev=%p\n", slave_dev);
> 	pr_debug("slave_dev->addr_len=%d\n", slave_dev->addr_len);
> 	memcpy(bond_dev->dev_addr, slave_dev->dev_addr, slave_dev->addr_len);
>-	return 0;
>+	bond_dev->addr_assign_type = NET_ADDR_SET;
>+	call_netdevice_notifiers(NETDEV_CHANGEADDR, bond_dev);
> }
>
> static netdev_features_t bond_fix_features(struct net_device *dev,
>@@ -1628,10 +1629,8 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
>
> 	/* If this is the first slave, then we need to set the master's hardware
> 	 * address to be the same as the slave's. */
>-	if (is_zero_ether_addr(bond->dev->dev_addr))
>-		memcpy(bond->dev->dev_addr, slave_dev->dev_addr,
>-		       slave_dev->addr_len);
>-
>+	if (bond->get_dev_addr_from_first_slave)
>+		bond_set_dev_addr(bond->dev, slave_dev);
>
> 	new_slave = kzalloc(sizeof(struct slave), GFP_KERNEL);
> 	if (!new_slave) {
>@@ -2048,12 +2047,8 @@ int bond_release(struct net_device *bond_dev, struct net_device *slave_dev)
>
> 	if (bond->slave_cnt == 0) {
> 		bond_set_carrier(bond);
>-
>-		/* if the last slave was removed, zero the mac address
>-		 * of the master so it will be set by the application
>-		 * to the mac address of the first slave
>-		 */
>-		memset(bond_dev->dev_addr, 0, bond_dev->addr_len);
>+		eth_hw_addr_random(bond_dev);
>+		bond->get_dev_addr_from_first_slave = true;
>
> 		if (bond_vlan_used(bond)) {
> 			pr_warning("%s: Warning: clearing HW address of %s while it still has VLANs.\n",
>@@ -2234,11 +2229,8 @@ static int bond_release_all(struct net_device *bond_dev)
> 		write_lock_bh(&bond->lock);
> 	}
>
>-	/* zero the mac address of the master so it will be
>-	 * set by the application to the mac address of the
>-	 * first slave
>-	 */
>-	memset(bond_dev->dev_addr, 0, bond_dev->addr_len);
>+	eth_hw_addr_random(bond_dev);
>+	bond->get_dev_addr_from_first_slave = true;
>
> 	if (bond_vlan_used(bond)) {
> 		pr_warning("%s: Warning: clearing HW address of %s while it still has VLANs.\n",
>@@ -3708,7 +3700,8 @@ static int bond_do_ioctl(struct net_device *bond_dev, struct ifreq *ifr, int cmd
> 			break;
> 		case BOND_SETHWADDR_OLD:
> 		case SIOCBONDSETHWADDR:
>-			res = bond_sethwaddr(bond_dev, slave_dev);
>+			bond_set_dev_addr(bond_dev, slave_dev);
>+			res = 0;
> 			break;
> 		case BOND_CHANGE_ACTIVE_OLD:
> 		case SIOCBONDCHANGEACTIVE:
>@@ -4858,6 +4851,13 @@ static int bond_init(struct net_device *bond_dev)
>
> 	bond_debug_register(bond);
>
>+	/* Ensure valid dev_addr */
>+	if (is_zero_ether_addr(bond_dev->dev_addr) &&
>+	    bond_dev->addr_assign_type == NET_ADDR_PERM) {
>+		eth_hw_addr_random(bond_dev);
>+		bond->get_dev_addr_from_first_slave = true;
>+	}
>+
> 	__hw_addr_init(&bond->mc_list);
> 	return 0;
> }
>diff --git a/drivers/net/bonding/bonding.h b/drivers/net/bonding/bonding.h
>index 0d282d2..3200638 100644
>--- a/drivers/net/bonding/bonding.h
>+++ b/drivers/net/bonding/bonding.h
>@@ -248,6 +248,7 @@ struct bonding {
> 	/* debugging support via debugfs */
> 	struct	 dentry *debug_dir;
> #endif /* CONFIG_DEBUG_FS */
>+	bool	get_dev_addr_from_first_slave;
> };
>
> static inline bool bond_vlan_used(struct bonding *bond)
>-- 
>1.8.1
>