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Subject[PATCH] WAN: protect Cisco HDLC state changes with a spinlock.
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WAN: protect Cisco HDLC state changes with a spinlock.

Signed-off-by: Krzysztof Hałasa <khc@pm.waw.pl>

--- a/drivers/net/wan/hdlc_cisco.c
+++ b/drivers/net/wan/hdlc_cisco.c
@@ -55,6 +55,7 @@ struct cisco_state {
cisco_proto settings;

struct timer_list timer;
+ spinlock_t lock;
unsigned long last_poll;
int up;
int request_sent;
@@ -157,6 +158,7 @@ static int cisco_rx(struct sk_buff *skb)
{
struct net_device *dev = skb->dev;
hdlc_device *hdlc = dev_to_hdlc(dev);
+ struct cisco_state *st = state(hdlc);
struct hdlc_header *data = (struct hdlc_header*)skb->data;
struct cisco_packet *cisco_data;
struct in_device *in_dev;
@@ -219,11 +221,12 @@ static int cisco_rx(struct sk_buff *skb)
goto rx_error;

case CISCO_KEEPALIVE_REQ:
- state(hdlc)->rxseq = ntohl(cisco_data->par1);
- if (state(hdlc)->request_sent &&
- ntohl(cisco_data->par2) == state(hdlc)->txseq) {
- state(hdlc)->last_poll = jiffies;
- if (!state(hdlc)->up) {
+ spin_lock(&st->lock);
+ st->rxseq = ntohl(cisco_data->par1);
+ if (st->request_sent &&
+ ntohl(cisco_data->par2) == st->txseq) {
+ st->last_poll = jiffies;
+ if (!st->up) {
u32 sec, min, hrs, days;
sec = ntohl(cisco_data->time) / 1000;
min = sec / 60; sec -= min * 60;
@@ -231,12 +234,12 @@ static int cisco_rx(struct sk_buff *skb)
days = hrs / 24; hrs -= days * 24;
printk(KERN_INFO "%s: Link up (peer "
"uptime %ud%uh%um%us)\n",
- dev->name, days, hrs,
- min, sec);
+ dev->name, days, hrs, min, sec);
netif_dormant_off(dev);
- state(hdlc)->up = 1;
+ st->up = 1;
}
}
+ spin_unlock(&st->lock);

dev_kfree_skb_any(skb);
return NET_RX_SUCCESS;
@@ -260,24 +263,25 @@ static void cisco_timer(unsigned long arg)
{
struct net_device *dev = (struct net_device *)arg;
hdlc_device *hdlc = dev_to_hdlc(dev);
+ struct cisco_state *st = state(hdlc);

- if (state(hdlc)->up &&
- time_after(jiffies, state(hdlc)->last_poll +
- state(hdlc)->settings.timeout * HZ)) {
- state(hdlc)->up = 0;
+ spin_lock(&st->lock);
+ if (st->up &&
+ time_after(jiffies, st->last_poll + st->settings.timeout * HZ)) {
+ st->up = 0;
printk(KERN_INFO "%s: Link down\n", dev->name);
netif_dormant_on(dev);
}

- cisco_keepalive_send(dev, CISCO_KEEPALIVE_REQ,
- htonl(++state(hdlc)->txseq),
- htonl(state(hdlc)->rxseq));
- state(hdlc)->request_sent = 1;
- state(hdlc)->timer.expires = jiffies +
- state(hdlc)->settings.interval * HZ;
- state(hdlc)->timer.function = cisco_timer;
- state(hdlc)->timer.data = arg;
- add_timer(&state(hdlc)->timer);
+ cisco_keepalive_send(dev, CISCO_KEEPALIVE_REQ, htonl(++st->txseq),
+ htonl(st->rxseq));
+ st->request_sent = 1;
+ spin_unlock(&st->lock);
+
+ st->timer.expires = jiffies + st->settings.interval * HZ;
+ st->timer.function = cisco_timer;
+ st->timer.data = arg;
+ add_timer(&st->timer);
}


@@ -285,15 +289,20 @@ static void cisco_timer(unsigned long arg)
static void cisco_start(struct net_device *dev)
{
hdlc_device *hdlc = dev_to_hdlc(dev);
- state(hdlc)->up = 0;
- state(hdlc)->request_sent = 0;
- state(hdlc)->txseq = state(hdlc)->rxseq = 0;
-
- init_timer(&state(hdlc)->timer);
- state(hdlc)->timer.expires = jiffies + HZ; /*First poll after 1s*/
- state(hdlc)->timer.function = cisco_timer;
- state(hdlc)->timer.data = (unsigned long)dev;
- add_timer(&state(hdlc)->timer);
+ struct cisco_state *st = state(hdlc);
+ unsigned long flags;
+
+ spin_lock_irqsave(&st->lock, flags);
+ st->up = 0;
+ st->request_sent = 0;
+ st->txseq = st->rxseq = 0;
+ spin_unlock_irqrestore(&st->lock, flags);
+
+ init_timer(&st->timer);
+ st->timer.expires = jiffies + HZ; /* First poll after 1 s */
+ st->timer.function = cisco_timer;
+ st->timer.data = (unsigned long)dev;
+ add_timer(&st->timer);
}


@@ -301,10 +310,16 @@ static void cisco_start(struct net_device *dev)
static void cisco_stop(struct net_device *dev)
{
hdlc_device *hdlc = dev_to_hdlc(dev);
- del_timer_sync(&state(hdlc)->timer);
+ struct cisco_state *st = state(hdlc);
+ unsigned long flags;
+
+ del_timer_sync(&st->timer);
+
+ spin_lock_irqsave(&st->lock, flags);
netif_dormant_on(dev);
- state(hdlc)->up = 0;
- state(hdlc)->request_sent = 0;
+ st->up = 0;
+ st->request_sent = 0;
+ spin_unlock_irqrestore(&st->lock, flags);
}


@@ -366,6 +381,7 @@ static int cisco_ioctl(struct net_device *dev, struct ifreq *ifr)
return result;

memcpy(&state(hdlc)->settings, &new_settings, size);
+ spin_lock_init(&state(hdlc)->lock);
dev->hard_start_xmit = hdlc->xmit;
dev->header_ops = &cisco_header_ops;
dev->type = ARPHRD_CISCO;
--
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