From: Nils Carlson Date: Thu, 3 Mar 2011 22:09:11 +0000 (+0000) Subject: bonding 802.3ad: Fix the state machine locking v2 X-Git-Url: https://git.stricted.de/?a=commitdiff_plain;h=16d79d7dc98e56d4700054b9b785a92102d8998c;p=GitHub%2Fmoto-9609%2Fandroid_kernel_motorola_exynos9610.git 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 Signed-off-by: David S. Miller --- diff --git a/drivers/net/bonding/bond_3ad.c b/drivers/net/bonding/bond_3ad.c index 1024ae158227..de30c8d6301e 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: