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Date: Fri, 4 Mar 2011 09:09:11 +0100
From: Nils Carlson <nils.carlson@...csson.com>
To: Jay Vosburgh <fubar@...ibm.com>,
Andy Gospodarek <andy@...yhouse.net>
CC: <netdev@...r.kernel.org>, Nils Carlson <nils.carlson@...csson.com>
Subject: [PATCH 1/2] bonding 802.3ad: Fix the state machine locking v2
Changes since v1:
* Clarify an unclear comment
* Move a (possible) name change to a separate patch
The ad_rx_machine, ad_periodic_machine and ad_port_selection_logic
functions all inspect and alter common fields within the port structure.
Previous to this patch, only the ad_rx_machines were mutexed, and the
periodic and port_selection could run unmutexed against an ad_rx_machine
trigged by an arriving LACPDU.
This patch remedies the situation by protecting all the state machines
from concurrency. This is accomplished by locking around all the state
machines for a given port, which are executed at regular intervals; and
the ad_rx_machine when handling an incoming LACPDU.
Signed-off-by: Nils Carlson <nils.carlson@...csson.com>
---
drivers/net/bonding/bond_3ad.c | 16 +++++++++++-----
1 files changed, 11 insertions(+), 5 deletions(-)
diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c
index 1024ae1..de30c8d 100644
--- a/drivers/net/bonding/bond_3ad.c
+++ b/drivers/net/bonding/bond_3ad.c
@@ -1025,9 +1025,6 @@ static void ad_rx_machine(struct lacpdu *lacpdu, struct port *port)
{
rx_states_t last_state;
- // Lock to prevent 2 instances of this function to run simultaneously(rx interrupt and periodic machine callback)
- __get_rx_machine_lock(port);
-
// keep current State Machine state to compare later if it was changed
last_state = port->sm_rx_state;
@@ -1133,7 +1130,6 @@ static void ad_rx_machine(struct lacpdu *lacpdu, struct port *port)
pr_err("%s: An illegal loopback occurred on adapter (%s).\n"
"Check the configuration to verify that all adapters are connected to 802.3ad compliant switch ports\n",
port->slave->dev->master->name, port->slave->dev->name);
- __release_rx_machine_lock(port);
return;
}
__update_selected(lacpdu, port);
@@ -1153,7 +1149,6 @@ static void ad_rx_machine(struct lacpdu *lacpdu, struct port *port)
break;
}
}
- __release_rx_machine_lock(port);
}
/**
@@ -2155,6 +2150,12 @@ void bond_3ad_state_machine_handler(struct work_struct *work)
goto re_arm;
}
+ /* Lock around state machines to protect data accessed
+ * by all (e.g., port->sm_vars). ad_rx_machine may run
+ * concurrently due to incoming LACPDU.
+ */
+ __get_rx_machine_lock(port);
+
ad_rx_machine(NULL, port);
ad_periodic_machine(port);
ad_port_selection_logic(port);
@@ -2164,6 +2165,8 @@ void bond_3ad_state_machine_handler(struct work_struct *work)
// turn off the BEGIN bit, since we already handled it
if (port->sm_vars & AD_PORT_BEGIN)
port->sm_vars &= ~AD_PORT_BEGIN;
+
+ __release_rx_machine_lock(port);
}
re_arm:
@@ -2200,7 +2203,10 @@ static void bond_3ad_rx_indication(struct lacpdu *lacpdu, struct slave *slave, u
case AD_TYPE_LACPDU:
pr_debug("Received LACPDU on port %d\n",
port->actor_port_number);
+ /* Protect against concurrent state machines */
+ __get_rx_machine_lock(port);
ad_rx_machine(lacpdu, port);
+ __release_rx_machine_lock(port);
break;
case AD_TYPE_MARKER:
--
1.7.1
--
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