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>

1 files changed, 18 insertions, 117 deletions

diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index 94c1534dd578..e242dd12e5a3 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -1937,7 +1937,8 @@ err_undo_flags:
 /*
  * 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:
@@ -1945,7 +1946,9 @@ err_undo_flags:
  *   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.
@@ -2138,118 +2149,6 @@ static int  bond_release_and_destroy(struct net_device *bond_dev,
 }
 
 /*
- * 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.
  *  - <slave_dev> is not found in the list.
@@ -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);