[PATCH 3.14 68/92] xtensa: ISS: fix locking in TAP network adapter

Greg Kroah-Hartman
2015-05-02T19:47:36Z

From: Max Filippov <jcmvbkbc@gmail.com>

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: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
arch/xtensa/platforms/iss/network.c | 29 +++++++++++++++--------------
1 file changed, 15 insertions(+), 14 deletions(-)

--- a/arch/xtensa/platforms/iss/network.c
+++ b/arch/xtensa/platforms/iss/network.c
@@ -349,8 +349,8 @@ static void iss_net_timer(unsigned long
{
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);
}
@@ -361,7 +361,7 @@ static int iss_net_open(struct net_devic
struct iss_net_private *lp = netdev_priv(dev);
int err;

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

err = lp->tp.open(lp);
if (err < 0)
@@ -376,9 +376,11 @@ static int iss_net_open(struct net_devic
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;
@@ -387,7 +389,7 @@ static int iss_net_open(struct net_devic
mod_timer(&lp->timer, jiffies + lp->timer_val);

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

@@ -395,7 +397,7 @@ static int iss_net_close(struct net_devi
{
struct iss_net_private *lp = netdev_priv(dev);
netif_stop_queue(dev);
- spin_lock(&lp->lock);
+ spin_lock_bh(&lp->lock);

spin_lock(&opened_lock);
list_del(&opened);
@@ -405,18 +407,17 @@ static int iss_net_close(struct net_devi

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);

@@ -438,7 +439,7 @@ static int iss_net_start_xmit(struct sk_
pr_err("%s: %s failed(%d)\n", dev->name, __func__, len);
}

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

dev_kfree_skb(skb);
return NETDEV_TX_OK;
@@ -466,9 +467,9 @@ static int iss_net_set_mac(struct net_de

if (!is_valid_ether_addr(hwaddr->sa_data))
return -EADDRNOTAVAIL;
- 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);
return 0;
}

@@ -520,11 +521,11 @@ static int iss_net_configure(int index,
*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,
- };
+ };

+ spin_lock_init(&lp->lock);
/*
* If this name ends up conflicting with an existing registered
* netdevice, that is OK, register_netdev{,ice}() will notice this