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can: c_can: Provide protection in the xmit path 

The network core does not serialize the access to the hardware. The
xmit related code lets the following happen:

CPU0 	     	       CPU1
interrupt()
 do_poll()
   c_can_do_tx()
    Fiddle with HW and	xmit()
    internal data	  Fiddle with HW and
    	     		  internal data

due the complete lack of serialization.

Add proper locking.

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Marc Kleine-Budde <mkl@pengutronix.de>
This commit is contained in:
Thomas Gleixner 2014-03-18 17:19:12 +00:00 committed by Marc Kleine-Budde
parent 710c56105d
commit bf88a20611
2 changed files with 9 additions and 1 deletions
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9
drivers/net/can/c_can/c_can.c
View File

@ -549,6 +549,7 @@ static netdev_tx_t c_can_start_xmit(struct sk_buff *skb,
if (can_dropped_invalid_skb(dev, skb))
return NETDEV_TX_OK;
spin_lock_bh(&priv->xmit_lock);
msg_obj_no = get_tx_next_msg_obj(priv);
/* prepare message object for transmission */
@ -563,6 +564,7 @@ static netdev_tx_t c_can_start_xmit(struct sk_buff *skb,
if (c_can_is_next_tx_obj_busy(priv, get_tx_next_msg_obj(priv)) ||
(priv->tx_next & C_CAN_NEXT_MSG_OBJ_MASK) == 0)
netif_stop_queue(dev);
spin_unlock_bh(&priv->xmit_lock);
return NETDEV_TX_OK;
}
@ -787,7 +789,9 @@ static void c_can_do_tx(struct net_device *dev)
struct c_can_priv *priv = netdev_priv(dev);
struct net_device_stats *stats = &dev->stats;
for (/* nix */; (priv->tx_next - priv->tx_echo) > 0; priv->tx_echo++) {
spin_lock_bh(&priv->xmit_lock);
for (; (priv->tx_next - priv->tx_echo) > 0; priv->tx_echo++) {
msg_obj_no = get_tx_echo_msg_obj(priv);
val = c_can_read_reg32(priv, C_CAN_TXRQST1_REG);
if (!(val & (1 << (msg_obj_no - 1)))) {
@ -809,6 +813,8 @@ static void c_can_do_tx(struct net_device *dev)
if (((priv->tx_next & C_CAN_NEXT_MSG_OBJ_MASK) != 0) ||
((priv->tx_echo & C_CAN_NEXT_MSG_OBJ_MASK) == 0))
netif_wake_queue(dev);
spin_unlock_bh(&priv->xmit_lock);
}
/*
@ -1262,6 +1268,7 @@ struct net_device *alloc_c_can_dev(void)
return NULL;
priv = netdev_priv(dev);
spin_lock_init(&priv->xmit_lock);
netif_napi_add(dev, &priv->napi, c_can_poll, C_CAN_NAPI_WEIGHT);
priv->dev = dev;

1
drivers/net/can/c_can/c_can.h
View File

@ -156,6 +156,7 @@ struct c_can_priv {
struct napi_struct napi;
struct net_device *dev;
struct device *device;
spinlock_t xmit_lock;
int tx_object;
int current_status;
int last_status;