xtensa: ISS: fix locking in TAP network adapter

- 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.

Cc: <stable@vger.kernel.org>
Signed-off-by: Max Filippov <jcmvbkbc@gmail.com>

1 files changed, 15 insertions, 14 deletions

diff --git a/arch/xtensa/platforms/iss/network.c b/arch/xtensa/platforms/iss/network.c
index d05f8feeb8d7..17b1ef3232e4 100644
--- 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 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);
 }
@@ -361,7 +361,7 @@ static int iss_net_open(struct net_device *dev)
         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_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;
@@ -387,7 +389,7 @@ 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;
 }
 
@@ -395,7 +397,7 @@ static int iss_net_close(struct net_device *dev)
 {
         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_device *dev)
 
         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_buff *skb, struct net_device *dev)
                 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_device *dev, void *addr)
 
         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, 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,
-                };
+        };
 
+        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