From 62c5f5185397f4bd8e5defe6fcb86420deeb2b38 Mon Sep 17 00:00:00 2001 From: Nikolay Aleksandrov Date: Thu, 11 Sep 2014 22:49:23 +0200 Subject: [PATCH] bonding: alb: remove curr_slave_lock First in rlb_teach_disabled_mac_on_primary() it's okay to remove curr_slave_lock as all callers except bond_alb_monitor() already hold RTNL, and in case bond_alb_monitor() is executing we can at most have a period with bad throughput (very unlikely though). In bond_alb_monitor() it's okay to remove the read_lock as the slave list is walked with RCU and the worst that could happen is another transmitter at the same time and thus for a period which currently is 10 seconds (bond_alb.h: BOND_ALB_LP_TICKS). And bond_alb_handle_active_change() is okay because it's always called with RTNL. Removed the ASSERT_RTNL() because it'll be inserted in the parent function in a following patch. Signed-off-by: Nikolay Aleksandrov Signed-off-by: David S. Miller --- drivers/net/bonding/bond_alb.c | 39 +++------------------------------- 1 file changed, 3 insertions(+), 36 deletions(-) diff --git a/drivers/net/bonding/bond_alb.c b/drivers/net/bonding/bond_alb.c index 028496205f39..cf4ede8594ff 100644 --- a/drivers/net/bonding/bond_alb.c +++ b/drivers/net/bonding/bond_alb.c @@ -447,7 +447,7 @@ static struct slave *__rlb_next_rx_slave(struct bonding *bond) /* teach the switch the mac of a disabled slave * on the primary for fault tolerance * - * Caller must hold bond->curr_slave_lock for write or bond lock for write + * Caller must hold RTNL */ static void rlb_teach_disabled_mac_on_primary(struct bonding *bond, u8 addr[]) { @@ -512,12 +512,8 @@ static void rlb_clear_slave(struct bonding *bond, struct slave *slave) _unlock_rx_hashtbl_bh(bond); - write_lock_bh(&bond->curr_slave_lock); - if (slave != bond_deref_active_protected(bond)) rlb_teach_disabled_mac_on_primary(bond, slave->dev->dev_addr); - - write_unlock_bh(&bond->curr_slave_lock); } static void rlb_update_client(struct rlb_client_info *client_info) @@ -1595,13 +1591,6 @@ void bond_alb_monitor(struct work_struct *work) if (bond_info->lp_counter >= BOND_ALB_LP_TICKS(bond)) { bool strict_match; - /* change of curr_active_slave involves swapping of mac addresses. - * in order to avoid this swapping from happening while - * sending the learning packets, the curr_slave_lock must be held for - * read. - */ - read_lock(&bond->curr_slave_lock); - bond_for_each_slave_rcu(bond, slave, iter) { /* If updating current_active, use all currently * user mac addreses (!strict_match). Otherwise, only @@ -1613,17 +1602,11 @@ void bond_alb_monitor(struct work_struct *work) alb_send_learning_packets(slave, slave->dev->dev_addr, strict_match); } - - read_unlock(&bond->curr_slave_lock); - bond_info->lp_counter = 0; } /* rebalance tx traffic */ if (bond_info->tx_rebalance_counter >= BOND_TLB_REBALANCE_TICKS) { - - read_lock(&bond->curr_slave_lock); - bond_for_each_slave_rcu(bond, slave, iter) { tlb_clear_slave(bond, slave, 1); if (slave == rcu_access_pointer(bond->curr_active_slave)) { @@ -1633,9 +1616,6 @@ void bond_alb_monitor(struct work_struct *work) bond_info->unbalanced_load = 0; } } - - read_unlock(&bond->curr_slave_lock); - bond_info->tx_rebalance_counter = 0; } @@ -1775,21 +1755,14 @@ void bond_alb_handle_link_change(struct bonding *bond, struct slave *slave, char * Set the bond->curr_active_slave to @new_slave and handle * mac address swapping and promiscuity changes as needed. * - * If new_slave is NULL, caller must hold curr_slave_lock for write - * - * If new_slave is not NULL, caller must hold RTNL, curr_slave_lock - * for write. Processing here may sleep, so no other locks may be held. + * Caller must hold RTNL */ void bond_alb_handle_active_change(struct bonding *bond, struct slave *new_slave) - __releases(&bond->curr_slave_lock) - __acquires(&bond->curr_slave_lock) { struct slave *swap_slave; struct slave *curr_active; - curr_active = rcu_dereference_protected(bond->curr_active_slave, - !new_slave || - lockdep_is_held(&bond->curr_slave_lock)); + curr_active = rtnl_dereference(bond->curr_active_slave); if (curr_active == new_slave) return; @@ -1820,10 +1793,6 @@ void bond_alb_handle_active_change(struct bonding *bond, struct slave *new_slave tlb_clear_slave(bond, swap_slave, 1); tlb_clear_slave(bond, new_slave, 1); - write_unlock_bh(&bond->curr_slave_lock); - - ASSERT_RTNL(); - /* in TLB mode, the slave might flip down/up with the old dev_addr, * and thus filter bond->dev_addr's packets, so force bond's mac */ @@ -1852,8 +1821,6 @@ void bond_alb_handle_active_change(struct bonding *bond, struct slave *new_slave alb_send_learning_packets(new_slave, bond->dev->dev_addr, false); } - - write_lock_bh(&bond->curr_slave_lock); } /* Called with RTNL */ -- 2.20.1