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Commit 62c5f518 authored by Nikolay Aleksandrov's avatar Nikolay Aleksandrov Committed by David S. Miller
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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: default avatarNikolay Aleksandrov <nikolay@redhat.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 86e74986

drivers/net/bonding/bond_alb.c

+3 −36
Original line number Diff line number Diff line
@@ -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 */