bonding: Convert balance-rr transmit to new locking
Change locking in balance-rr transmit processing to use a free
running counter to determine which slave to transmit on. Instead, a
free-running counter is maintained, and modulo arithmetic used to select
a slave for transmit.
This removes lock operations from the TX path, and eliminates
a deadlock introduced by the conversion to work queues.
Signed-off-by: Andy Gospodarek <andy@greyhouse.net>
Signed-off-by: Jay Vosburgh <fubar@us.ibm.com>
Signed-off-by: Jeff Garzik <jeff@garzik.org>
diff --git a/drivers/net/bonding/bond_main.c b/drivers/net/bonding/bond_main.c
index ed361d6..862ed8e 100644
--- a/drivers/net/bonding/bond_main.c
+++ b/drivers/net/bonding/bond_main.c
@@ -4057,8 +4057,7 @@
{
struct bonding *bond = bond_dev->priv;
struct slave *slave, *start_at;
- int i;
- int res = 1;
+ int i, slave_no, res = 1;
read_lock(&bond->lock);
@@ -4066,29 +4065,29 @@
goto out;
}
- read_lock(&bond->curr_slave_lock);
- slave = start_at = bond->curr_active_slave;
- read_unlock(&bond->curr_slave_lock);
+ /*
+ * Concurrent TX may collide on rr_tx_counter; we accept that
+ * as being rare enough not to justify using an atomic op here
+ */
+ slave_no = bond->rr_tx_counter++ % bond->slave_cnt;
- if (!slave) {
- goto out;
+ bond_for_each_slave(bond, slave, i) {
+ slave_no--;
+ if (slave_no < 0) {
+ break;
+ }
}
+ start_at = slave;
bond_for_each_slave_from(bond, slave, i, start_at) {
if (IS_UP(slave->dev) &&
(slave->link == BOND_LINK_UP) &&
(slave->state == BOND_STATE_ACTIVE)) {
res = bond_dev_queue_xmit(bond, skb, slave->dev);
-
- write_lock(&bond->curr_slave_lock);
- bond->curr_active_slave = slave->next;
- write_unlock(&bond->curr_slave_lock);
-
break;
}
}
-
out:
if (res) {
/* no suitable interface, frame not sent */