staging: most: aim-network: fix interrupt unsafe spinlocks

The networking AIM does not use the *_irqsave and *_irqrestore flavored
spinlock functions. The rx_completion callback, however, can be called
from an interrupt context.

This patch is needed to fix this problem.
Signed-off-by: Andrey Shvetsov <andrey.shvetsov@k2l.de>
Signed-off-by: Christian Gromm <christian.gromm@microchip.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/most/aim-network/networking.c

@@ -298,15 +298,16 @@ static struct net_dev_context *get_net_dev_context(
 	struct most_interface *iface)
 {
 	struct net_dev_context *nd, *tmp;
+	unsigned long flags;
 
-	spin_lock(&list_lock);
+	spin_lock_irqsave(&list_lock, flags);
 	list_for_each_entry_safe(nd, tmp, &net_devices, list) {
 		if (nd->iface == iface) {
-			spin_unlock(&list_lock);
+			spin_unlock_irqrestore(&list_lock, flags);
 			return nd;
 		}
 	}
-	spin_unlock(&list_lock);
+	spin_unlock_irqrestore(&list_lock, flags);
 	return NULL;
 }
 
@@ -316,6 +317,7 @@ static int aim_probe_channel(struct most_interface *iface, int channel_idx,
 {
 	struct net_dev_context *nd;
 	struct net_dev_channel *ch;
+	unsigned long flags;
 
 	if (!iface)
 		return -EINVAL;
@@ -332,9 +334,9 @@ static int aim_probe_channel(struct most_interface *iface, int channel_idx,
 
 		nd->iface = iface;
 
-		spin_lock(&list_lock);
+		spin_lock_irqsave(&list_lock, flags);
 		list_add(&nd->list, &net_devices);
-		spin_unlock(&list_lock);
+		spin_unlock_irqrestore(&list_lock, flags);
 	}
 
 	ch = ccfg->direction == MOST_CH_TX ? &nd->tx : &nd->rx;
@@ -377,6 +379,7 @@ static int aim_disconnect_channel(struct most_interface *iface,
 {
 	struct net_dev_context *nd;
 	struct net_dev_channel *ch;
+	unsigned long flags;
 
 	nd = get_net_dev_context(iface);
 	if (!nd)
@@ -398,9 +401,9 @@ static int aim_disconnect_channel(struct most_interface *iface,
 	most_net_rm_netdev_safe(nd);
 
 	if (!nd->rx.linked && !nd->tx.linked) {
-		spin_lock(&list_lock);
+		spin_lock_irqsave(&list_lock, flags);
 		list_del(&nd->list);
-		spin_unlock(&list_lock);
+		spin_unlock_irqrestore(&list_lock, flags);
 		kfree(nd);
 	}
 
@@ -514,20 +517,21 @@ static int __init most_net_init(void)
 static void __exit most_net_exit(void)
 {
 	struct net_dev_context *nd, *tmp;
+	unsigned long flags;
 
-	spin_lock(&list_lock);
+	spin_lock_irqsave(&list_lock, flags);
 	list_for_each_entry_safe(nd, tmp, &net_devices, list) {
 		list_del(&nd->list);
-		spin_unlock(&list_lock);
+		spin_unlock_irqrestore(&list_lock, flags);
 		/*
 		 * do not call most_stop_channel() here, because channels are
 		 * going to be closed in ndo_stop() after unregister_netdev()
 		 */
 		most_net_rm_netdev_safe(nd);
 		kfree(nd);
-		spin_lock(&list_lock);
+		spin_lock_irqsave(&list_lock, flags);
 	}
-	spin_unlock(&list_lock);
+	spin_unlock_irqrestore(&list_lock, flags);
 
 	most_deregister_aim(&aim);
 	pr_info("most_net_exit()\n");