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Date: Mon, 18 Feb 2013 13:56:48 -0800
From: Jay Vosburgh <fubar@...ibm.com>
To: Nikolay Aleksandrov <nikolay@...hat.com>
cc: netdev@...r.kernel.org, davem@...emloft.net, andy@...yhouse.net
Subject: Re: [PATCH net-next 3/3] bonding: fix bond_release_all inconsistencies
Nikolay Aleksandrov <nikolay@...hat.com> wrote:
>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.
It might be worthwhile to add an "all" argument to bond_release
that skips some things that don't make sense if all slaves are being
released. I'm thinking in particular of this block:
if (oldcurrent == slave) {
/*
* Note that we hold RTNL over this sequence, so there
* is no concern that another slave add/remove event
* will interfere.
*/
write_unlock_bh(&bond->lock);
read_lock(&bond->lock);
write_lock_bh(&bond->curr_slave_lock);
bond_select_active_slave(bond);
write_unlock_bh(&bond->curr_slave_lock);
read_unlock(&bond->lock);
write_lock_bh(&bond->lock);
}
as it's written now, for the release all case, the code may go
to the trouble of assigning a new active slave each time one slave is
removed (including various log messages, maybe sending IGMPs, etc). If
all slaves are being removed, that's pointless. This could be something
like:
if (release_all) {
bond->curr_active_slave = NULL;
} else if (oldcurrent == slave) {
[ the current block of stuff ]
}
it's safe here to unconditionally set curr_active_slave to NULL
because we hold bond->lock for write. The lock dance stuff for the
bond_select_active_slave() call is to satisfy its locking requirements.
-J
>Signed-off-by: Nikolay Aleksandrov <nikolay@...hat.com>
>---
> drivers/net/bonding/bond_main.c | 106 ++--------------------------------------
> 1 file changed, 5 insertions(+), 101 deletions(-)
>
>diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
>index 94c1534..fcfc880 100644
>--- a/drivers/net/bonding/bond_main.c
>+++ b/drivers/net/bonding/bond_main.c
>@@ -2140,113 +2140,17 @@ 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)
>+static void 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);
>- }
>-
>+ return;
>+ while (bond->first_slave != NULL)
>+ bond_release(bond_dev, bond->first_slave->dev);
> pr_info("%s: released all slaves\n", bond_dev->name);
>
>-out:
>- write_unlock_bh(&bond->lock);
>-
>- bond_compute_features(bond);
>-
>- return 0;
>+ return;
> }
>
> /*
>--
>1.7.11.7
---
-Jay Vosburgh, IBM Linux Technology Center, fubar@...ibm.com
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