[PATCH 3.12 061/142] xtensa: ISS: fix locking in TAP network adapter

Jiri Slaby
2015-05-16T08:03:34Z

From: Max Filippov <jcmvbkbc@gmail.com>

3.12-stable review patch. If anyone has any objections, please let me know.

===============

commit 24e94454c8cb6a13634f5a2f5a01da53a546a58d upstream.

- don't lock lp->lock in the iss_net_timer for the call of iss_net_poll,
it will lock it itself;
- invert order of lp->lock and opened_lock acquisition in the
iss_net_open to make it consistent with iss_net_poll;
- replace spin_lock with spin_lock_bh when acquiring locks used in
iss_net_timer from non-atomic context;
- replace spin_lock_irqsave with spin_lock_bh in the iss_net_start_xmit
as the driver doesn't use lp->lock in the hard IRQ context;
- replace __SPIN_LOCK_UNLOCKED(lp.lock) with spin_lock_init, otherwise
lockdep is unhappy about using non-static key.

Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
arch/xtensa/platforms/iss/network.c | 31 ++++++++++++++++---------------
1 file changed, 16 insertions(+), 15 deletions(-)

diff --git a/arch/xtensa/platforms/iss/network.c b/arch/xtensa/platforms/iss/network.c
index e9e1aad8c271..37141c8cd1a4 100644
--- a/arch/xtensa/platforms/iss/network.c
+++ b/arch/xtensa/platforms/iss/network.c
@@ -395,10 +395,10 @@ static void iss_net_timer(unsigned long priv)
{
struct iss_net_private* lp = (struct iss_net_private*) priv;

- spin_lock(&lp->lock);
-
iss_net_poll();

+ spin_lock(&lp->lock);
+
mod_timer(&lp->timer, jiffies + lp->timer_val);

spin_unlock(&lp->lock);
@@ -411,7 +411,7 @@ static int iss_net_open(struct net_device *dev)
char addr[sizeof "255.255.255.255\0"];
int err;

- spin_lock(&lp->lock);
+ spin_lock_bh(&lp->lock);

if ((err = lp->tp.open(lp)) < 0)
goto out;
@@ -430,9 +430,11 @@ static int iss_net_open(struct net_device *dev)
while ((err = iss_net_rx(dev)) > 0)
;

- spin_lock(&opened_lock);
+ spin_unlock_bh(&lp->lock);
+ spin_lock_bh(&opened_lock);
list_add(&lp->opened_list, &opened);
- spin_unlock(&opened_lock);
+ spin_unlock_bh(&opened_lock);
+ spin_lock_bh(&lp->lock);

init_timer(&lp->timer);
lp->timer_val = ISS_NET_TIMER_VALUE;
@@ -441,7 +443,7 @@ static int iss_net_open(struct net_device *dev)
mod_timer(&lp->timer, jiffies + lp->timer_val);

out:
- spin_unlock(&lp->lock);
+ spin_unlock_bh(&lp->lock);
return err;
}

@@ -450,7 +452,7 @@ static int iss_net_close(struct net_device *dev)
struct iss_net_private *lp = netdev_priv(dev);
printk("iss_net_close!\n");
netif_stop_queue(dev);
- spin_lock(&lp->lock);
+ spin_lock_bh(&lp->lock);

spin_lock(&opened_lock);
list_del(&opened);
@@ -460,18 +462,17 @@ printk("iss_net_close!\n");

lp->tp.close(lp);

- spin_unlock(&lp->lock);
+ spin_unlock_bh(&lp->lock);
return 0;
}

static int iss_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
{
struct iss_net_private *lp = netdev_priv(dev);
- unsigned long flags;
int len;

netif_stop_queue(dev);
- spin_lock_irqsave(&lp->lock, flags);
+ spin_lock_bh(&lp->lock);

len = lp->tp.write(lp, &skb);

@@ -493,7 +494,7 @@ static int iss_net_start_xmit(struct sk_buff *skb, struct net_device *dev)
printk(KERN_ERR "iss_net_start_xmit: failed(%d)\n", len);
}

- spin_unlock_irqrestore(&lp->lock, flags);
+ spin_unlock_bh(&lp->lock);

dev_kfree_skb(skb);
return NETDEV_TX_OK;
@@ -532,9 +533,9 @@ static int iss_net_set_mac(struct net_device *dev, void *addr)
struct iss_net_private *lp = netdev_priv(dev);
struct sockaddr *hwaddr = addr;

- spin_lock(&lp->lock);
+ spin_lock_bh(&lp->lock);
memcpy(dev->dev_addr, hwaddr->sa_data, ETH_ALEN);
- spin_unlock(&lp->lock);
+ spin_unlock_bh(&lp->lock);
#endif

return 0;
@@ -604,14 +605,14 @@ static int iss_net_configure(int index, char *init)
*lp = ((struct iss_net_private) {
.device_list = LIST_HEAD_INIT(lp->device_list),
.opened_list = LIST_HEAD_INIT(lp->opened_list),
- .lock = __SPIN_LOCK_UNLOCKED(lp.lock),
.dev = dev,
.index = index,
//.fd = -1,
.mac = { 0xfe, 0xfd, 0x0, 0x0, 0x0, 0x0 },
.have_mac = 0,
- });
+ });

+ spin_lock_init(&lp->lock);
/*
* Try all transport protocols.
* Note: more protocols can be added by adding '&& !X_init(lp, eth)'.
--
2.3.7