bonding: fix bond_release_all inconsistencies

This patch fixes the following inconsistencies in bond_release_all:
- IFF_BONDING flag is not stripped from slaves
- MTU is not restored
- no netdev notifiers are sent
Instead of trying to keep bond_release and bond_release_all in sync
I think we can re-use bond_release as the environment for calling it
is correct (RTNL is held). I have been running tests for the past
week and they came out successful. The only way for bond_release to fail
is for the slave to be attached in a different bond or to not be a slave
but that cannot happen as RTNL is held and no slave manipulations can be
achieved.

V2: As suggested bond_release is renamed to __bond_release_one with a
new parameter "all" introduced so to avoid calling unnecessary code while
destroying a bond, and a wrapper for it called bond_release is created
because of ndo_del_link. bond_release_all() is removed.

Signed-off-by: Nikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

drivers/net/bonding/bond_main.c

@@ -1937,15 +1937,18 @@ int bond_enslave(struct net_device *bond_dev, struct net_device *slave_dev)
 /*
  * Try to release the slave device <slave> from the bond device <master>
  * It is legal to access curr_active_slave without a lock because all the function
- * is write-locked.
+ * is write-locked. If "all" is true it means that the function is being called
+ * while destroying a bond interface and all slaves are being released.
  *
  * The rules for slave state should be:
  *   for Active/Backup:
  *     Active stays on all backups go down
  *   for Bonded connections:
  *     The first up interface should be left on and all others downed.
  */
-int bond_release(struct net_device *bond_dev, struct net_device *slave_dev)
+static int __bond_release_one(struct net_device *bond_dev,
+			      struct net_device *slave_dev,
+			      bool all)
 {
 	struct bonding *bond = netdev_priv(bond_dev);
 	struct slave *slave, *oldcurrent;
@@ -1982,7 +1985,7 @@ int bond_release(struct net_device *bond_dev, struct net_device *slave_dev)
 	synchronize_net();
 	write_lock_bh(&bond->lock);
 
-	if (!bond->params.fail_over_mac) {
+	if (!all && !bond->params.fail_over_mac) {
 		if (ether_addr_equal(bond_dev->dev_addr, slave->perm_hwaddr) &&
 		    bond->slave_cnt > 1)
 			pr_warning("%s: Warning: the permanent HWaddr of %s - %pM - is still in use by %s. Set the HWaddr of %s to a different address to avoid conflicts.\n",
@@ -2028,7 +2031,9 @@ int bond_release(struct net_device *bond_dev, struct net_device *slave_dev)
 		write_lock_bh(&bond->lock);
 	}
 
-	if (oldcurrent == slave) {
+	if (all) {
+		bond->curr_active_slave = NULL;
+	} else if (oldcurrent == slave) {
 		/*
 		 * Note that we hold RTNL over this sequence, so there
 		 * is no concern that another slave add/remove event
@@ -2117,6 +2122,12 @@ int bond_release(struct net_device *bond_dev, struct net_device *slave_dev)
 	return 0;  /* deletion OK */
 }
 
+/* A wrapper used because of ndo_del_link */
+int bond_release(struct net_device *bond_dev, struct net_device *slave_dev)
+{
+	return __bond_release_one(bond_dev, slave_dev, false);
+}
+
 /*
 * First release a slave and then destroy the bond if no more slaves are left.
 * Must be under rtnl_lock when this function is called.
@@ -2137,118 +2148,6 @@ static int  bond_release_and_destroy(struct net_device *bond_dev,
 	return ret;
 }
 
-/*
- * This function releases all slaves.
- */
-static int bond_release_all(struct net_device *bond_dev)
-{
-	struct bonding *bond = netdev_priv(bond_dev);
-	struct slave *slave;
-	struct net_device *slave_dev;
-	struct sockaddr addr;
-
-	write_lock_bh(&bond->lock);
-
-	netif_carrier_off(bond_dev);
-
-	if (bond->slave_cnt == 0)
-		goto out;
-
-	bond->current_arp_slave = NULL;
-	bond->primary_slave = NULL;
-	bond_change_active_slave(bond, NULL);
-
-	while ((slave = bond->first_slave) != NULL) {
-		/* Inform AD package of unbinding of slave
-		 * before slave is detached from the list.
-		 */
-		if (bond->params.mode == BOND_MODE_8023AD)
-			bond_3ad_unbind_slave(slave);
-
-		slave_dev = slave->dev;
-		bond_detach_slave(bond, slave);
-
-		/* now that the slave is detached, unlock and perform
-		 * all the undo steps that should not be called from
-		 * within a lock.
-		 */
-		write_unlock_bh(&bond->lock);
-
-		/* unregister rx_handler early so bond_handle_frame wouldn't
-		 * be called for this slave anymore.
-		 */
-		netdev_rx_handler_unregister(slave_dev);
-		synchronize_net();
-
-		if (bond_is_lb(bond)) {
-			/* must be called only after the slave
-			 * has been detached from the list
-			 */
-			bond_alb_deinit_slave(bond, slave);
-		}
-
-		bond_destroy_slave_symlinks(bond_dev, slave_dev);
-		bond_del_vlans_from_slave(bond, slave_dev);
-
-		/* If the mode USES_PRIMARY, then we should only remove its
-		 * promisc and mc settings if it was the curr_active_slave, but that was
-		 * already taken care of above when we detached the slave
-		 */
-		if (!USES_PRIMARY(bond->params.mode)) {
-			/* unset promiscuity level from slave */
-			if (bond_dev->flags & IFF_PROMISC)
-				dev_set_promiscuity(slave_dev, -1);
-
-			/* unset allmulti level from slave */
-			if (bond_dev->flags & IFF_ALLMULTI)
-				dev_set_allmulti(slave_dev, -1);
-
-			/* flush master's mc_list from slave */
-			netif_addr_lock_bh(bond_dev);
-			bond_mc_list_flush(bond_dev, slave_dev);
-			netif_addr_unlock_bh(bond_dev);
-		}
-
-		bond_upper_dev_unlink(bond_dev, slave_dev);
-
-		slave_disable_netpoll(slave);
-
-		/* close slave before restoring its mac address */
-		dev_close(slave_dev);
-
-		if (!bond->params.fail_over_mac) {
-			/* restore original ("permanent") mac address*/
-			memcpy(addr.sa_data, slave->perm_hwaddr, ETH_ALEN);
-			addr.sa_family = slave_dev->type;
-			dev_set_mac_address(slave_dev, &addr);
-		}
-
-		kfree(slave);
-
-		/* re-acquire the lock before getting the next slave */
-		write_lock_bh(&bond->lock);
-	}
-
-	eth_hw_addr_random(bond_dev);
-	bond->dev_addr_from_first = true;
-
-	if (bond_vlan_used(bond)) {
-		pr_warning("%s: Warning: clearing HW address of %s while it still has VLANs.\n",
-			   bond_dev->name, bond_dev->name);
-		pr_warning("%s: When re-adding slaves, make sure the bond's HW address matches its VLANs'.\n",
-			   bond_dev->name);
-	}
-
-	pr_info("%s: released all slaves\n", bond_dev->name);
-
-out:
-	write_unlock_bh(&bond->lock);
-
-	bond_compute_features(bond);
-
-	return 0;
-}
-
 /*
  * This function changes the active slave to slave <slave_dev>.
  * It returns -EINVAL in the following cases.
@@ -4440,7 +4339,9 @@ static void bond_uninit(struct net_device *bond_dev)
 	bond_netpoll_cleanup(bond_dev);
 
 	/* Release the bonded slaves */
-	bond_release_all(bond_dev);
+	while (bond->first_slave != NULL)
+		__bond_release_one(bond_dev, bond->first_slave->dev, true);
+	pr_info("%s: released all slaves\n", bond_dev->name);
 
 	list_del(&bond->bond_list);