rapidio/rionet: add locking into add/remove device

Add spinlock protection when handling list of connected peers and
ability to handle new peer device addition after the RIONET device was
open.  Before his update RIONET was sending JOIN requests only when it
have been opened, peer devices added later have been missing from this
process.
Signed-off-by: Alexandre Bounine <alexandre.bounine@idt.com>
Cc: Matt Porter <mporter@kernel.crashing.org>
Cc: Aurelien Jacquiot <a-jacquiot@ti.com>
Cc: Andre van Herk <andre.van.herk@prodrive-technologies.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/net/rionet.c

@@ -63,6 +63,7 @@ struct rionet_private {
 	spinlock_t lock;
 	spinlock_t tx_lock;
 	u32 msg_enable;
+	bool open;
 };
 
 struct rionet_peer {
@@ -74,6 +75,7 @@ struct rionet_peer {
 struct rionet_net {
 	struct net_device *ndev;
 	struct list_head peers;
+	spinlock_t lock;	/* net info access lock */
 	struct rio_dev **active;
 	int nact;	/* number of active peers */
 };
@@ -235,26 +237,32 @@ static void rionet_dbell_event(struct rio_mport *mport, void *dev_id, u16 sid, u
 	struct net_device *ndev = dev_id;
 	struct rionet_private *rnet = netdev_priv(ndev);
 	struct rionet_peer *peer;
+	unsigned char netid = rnet->mport->id;
 
 	if (netif_msg_intr(rnet))
 		printk(KERN_INFO "%s: doorbell sid %4.4x tid %4.4x info %4.4x",
 		       DRV_NAME, sid, tid, info);
 	if (info == RIONET_DOORBELL_JOIN) {
-		if (!nets[rnet->mport->id].active[sid]) {
-			list_for_each_entry(peer,
-					   &nets[rnet->mport->id].peers, node) {
+		if (!nets[netid].active[sid]) {
+			spin_lock(&nets[netid].lock);
+			list_for_each_entry(peer, &nets[netid].peers, node) {
 				if (peer->rdev->destid == sid) {
-					nets[rnet->mport->id].active[sid] =
-								peer->rdev;
-					nets[rnet->mport->id].nact++;
+					nets[netid].active[sid] = peer->rdev;
+					nets[netid].nact++;
 				}
 			}
+			spin_unlock(&nets[netid].lock);
+
 			rio_mport_send_doorbell(mport, sid,
 						RIONET_DOORBELL_JOIN);
 		}
 	} else if (info == RIONET_DOORBELL_LEAVE) {
-		nets[rnet->mport->id].active[sid] = NULL;
-		nets[rnet->mport->id].nact--;
+		spin_lock(&nets[netid].lock);
+		if (nets[netid].active[sid]) {
+			nets[netid].active[sid] = NULL;
+			nets[netid].nact--;
+		}
+		spin_unlock(&nets[netid].lock);
 	} else {
 		if (netif_msg_intr(rnet))
 			printk(KERN_WARNING "%s: unhandled doorbell\n",
@@ -308,8 +316,10 @@ static void rionet_outb_msg_event(struct rio_mport *mport, void *dev_id, int mbo
 static int rionet_open(struct net_device *ndev)
 {
 	int i, rc = 0;
-	struct rionet_peer *peer, *tmp;
+	struct rionet_peer *peer;
 	struct rionet_private *rnet = netdev_priv(ndev);
+	unsigned char netid = rnet->mport->id;
+	unsigned long flags;
 
 	if (netif_msg_ifup(rnet))
 		printk(KERN_INFO "%s: open\n", DRV_NAME);
@@ -348,20 +358,13 @@ static int rionet_open(struct net_device *ndev)
 	netif_carrier_on(ndev);
 	netif_start_queue(ndev);
 
-	list_for_each_entry_safe(peer, tmp,
-				 &nets[rnet->mport->id].peers, node) {
-		if (!(peer->res = rio_request_outb_dbell(peer->rdev,
-							 RIONET_DOORBELL_JOIN,
-							 RIONET_DOORBELL_LEAVE)))
-		{
-			printk(KERN_ERR "%s: error requesting doorbells\n",
-			       DRV_NAME);
-			continue;
-		}
-
+	spin_lock_irqsave(&nets[netid].lock, flags);
+	list_for_each_entry(peer, &nets[netid].peers, node) {
 		/* Send a join message */
 		rio_send_doorbell(peer->rdev, RIONET_DOORBELL_JOIN);
 	}
+	spin_unlock_irqrestore(&nets[netid].lock, flags);
+	rnet->open = true;
 
       out:
 	return rc;
@@ -370,7 +373,9 @@ static int rionet_open(struct net_device *ndev)
 static int rionet_close(struct net_device *ndev)
 {
 	struct rionet_private *rnet = netdev_priv(ndev);
-	struct rionet_peer *peer, *tmp;
+	struct rionet_peer *peer;
+	unsigned char netid = rnet->mport->id;
+	unsigned long flags;
 	int i;
 
 	if (netif_msg_ifup(rnet))
@@ -378,18 +383,21 @@ static int rionet_close(struct net_device *ndev)
 
 	netif_stop_queue(ndev);
 	netif_carrier_off(ndev);
+	rnet->open = false;
 
 	for (i = 0; i < RIONET_RX_RING_SIZE; i++)
 		kfree_skb(rnet->rx_skb[i]);
 
-	list_for_each_entry_safe(peer, tmp,
-				 &nets[rnet->mport->id].peers, node) {
-		if (nets[rnet->mport->id].active[peer->rdev->destid]) {
+	spin_lock_irqsave(&nets[netid].lock, flags);
+	list_for_each_entry(peer, &nets[netid].peers, node) {
+		if (nets[netid].active[peer->rdev->destid]) {
 			rio_send_doorbell(peer->rdev, RIONET_DOORBELL_LEAVE);
-			nets[rnet->mport->id].active[peer->rdev->destid] = NULL;
+			nets[netid].active[peer->rdev->destid] = NULL;
 		}
-		rio_release_outb_dbell(peer->rdev, peer->res);
+		if (peer->res)
+			rio_release_outb_dbell(peer->rdev, peer->res);
 	}
+	spin_unlock_irqrestore(&nets[netid].lock, flags);
 
 	rio_release_inb_dbell(rnet->mport, RIONET_DOORBELL_JOIN,
 			      RIONET_DOORBELL_LEAVE);
@@ -403,22 +411,38 @@ static void rionet_remove_dev(struct device *dev, struct subsys_interface *sif)
 {
 	struct rio_dev *rdev = to_rio_dev(dev);
 	unsigned char netid = rdev->net->hport->id;
-	struct rionet_peer *peer, *tmp;
+	struct rionet_peer *peer;
+	int state, found = 0;
+	unsigned long flags;
 
-	if (dev_rionet_capable(rdev)) {
-		list_for_each_entry_safe(peer, tmp, &nets[netid].peers, node) {
-			if (peer->rdev == rdev) {
-				if (nets[netid].active[rdev->destid]) {
-					nets[netid].active[rdev->destid] = NULL;
-					nets[netid].nact--;
+	if (!dev_rionet_capable(rdev))
+		return;
+
+	spin_lock_irqsave(&nets[netid].lock, flags);
+	list_for_each_entry(peer, &nets[netid].peers, node) {
+		if (peer->rdev == rdev) {
+			list_del(&peer->node);
+			if (nets[netid].active[rdev->destid]) {
+				state = atomic_read(&rdev->state);
+				if (state != RIO_DEVICE_GONE &&
+				    state != RIO_DEVICE_INITIALIZING) {
+					rio_send_doorbell(rdev,
+							RIONET_DOORBELL_LEAVE);
 				}
-
-				list_del(&peer->node);
-				kfree(peer);
-				break;
+				nets[netid].active[rdev->destid] = NULL;
+				nets[netid].nact--;
 			}
+			found = 1;
+			break;
 		}
 	}
+	spin_unlock_irqrestore(&nets[netid].lock, flags);
+
+	if (found) {
+		if (peer->res)
+			rio_release_outb_dbell(rdev, peer->res);
+		kfree(peer);
+	}
 }
 
 static void rionet_get_drvinfo(struct net_device *ndev,
@@ -492,6 +516,7 @@ static int rionet_setup_netdev(struct rio_mport *mport, struct net_device *ndev)
 	/* Set up private area */
 	rnet = netdev_priv(ndev);
 	rnet->mport = mport;
+	rnet->open = false;
 
 	/* Set the default MAC address */
 	device_id = rio_local_get_device_id(mport);
@@ -514,8 +539,11 @@ static int rionet_setup_netdev(struct rio_mport *mport, struct net_device *ndev)
 	rnet->msg_enable = RIONET_DEFAULT_MSGLEVEL;
 
 	rc = register_netdev(ndev);
-	if (rc != 0)
+	if (rc != 0) {
+		free_pages((unsigned long)nets[mport->id].active,
+			   get_order(rionet_active_bytes));
 		goto out;
+	}
 
 	printk(KERN_INFO "%s: %s %s Version %s, MAC %pM, %s\n",
 	       ndev->name,
@@ -529,8 +557,6 @@ static int rionet_setup_netdev(struct rio_mport *mport, struct net_device *ndev)
 	return rc;
 }
 
-static unsigned long net_table[RIONET_MAX_NETS/sizeof(unsigned long) + 1];
-
 static int rionet_add_dev(struct device *dev, struct subsys_interface *sif)
 {
 	int rc = -ENODEV;
@@ -539,19 +565,16 @@ static int rionet_add_dev(struct device *dev, struct subsys_interface *sif)
 	struct net_device *ndev = NULL;
 	struct rio_dev *rdev = to_rio_dev(dev);
 	unsigned char netid = rdev->net->hport->id;
-	int oldnet;
 
 	if (netid >= RIONET_MAX_NETS)
 		return rc;
 
-	oldnet = test_and_set_bit(netid, net_table);
-
 	/*
 	 * If first time through this net, make sure local device is rionet
 	 * capable and setup netdev (this step will be skipped in later probes
 	 * on the same net).
 	 */
-	if (!oldnet) {
+	if (!nets[netid].ndev) {
 		rio_local_read_config_32(rdev->net->hport, RIO_SRC_OPS_CAR,
 					 &lsrc_ops);
 		rio_local_read_config_32(rdev->net->hport, RIO_DST_OPS_CAR,
@@ -569,30 +592,56 @@ static int rionet_add_dev(struct device *dev, struct subsys_interface *sif)
 			rc = -ENOMEM;
 			goto out;
 		}
-		nets[netid].ndev = ndev;
+
 		rc = rionet_setup_netdev(rdev->net->hport, ndev);
 		if (rc) {
 			printk(KERN_ERR "%s: failed to setup netdev (rc=%d)\n",
 			       DRV_NAME, rc);
+			free_netdev(ndev);
 			goto out;
 		}
 
 		INIT_LIST_HEAD(&nets[netid].peers);
+		spin_lock_init(&nets[netid].lock);
 		nets[netid].nact = 0;
-	} else if (nets[netid].ndev == NULL)
-		goto out;
+		nets[netid].ndev = ndev;
+	}
 
 	/*
 	 * If the remote device has mailbox/doorbell capabilities,
 	 * add it to the peer list.
 	 */
 	if (dev_rionet_capable(rdev)) {
-		if (!(peer = kmalloc(sizeof(struct rionet_peer), GFP_KERNEL))) {
+		struct rionet_private *rnet;
+		unsigned long flags;
+
+		rnet = netdev_priv(nets[netid].ndev);
+
+		peer = kzalloc(sizeof(*peer), GFP_KERNEL);
+		if (!peer) {
 			rc = -ENOMEM;
 			goto out;
 		}
 		peer->rdev = rdev;
+		peer->res = rio_request_outb_dbell(peer->rdev,
+						RIONET_DOORBELL_JOIN,
+						RIONET_DOORBELL_LEAVE);
+		if (!peer->res) {
+			pr_err("%s: error requesting doorbells\n", DRV_NAME);
+			kfree(peer);
+			rc = -ENOMEM;
+			goto out;
+		}
+
+		spin_lock_irqsave(&nets[netid].lock, flags);
 		list_add_tail(&peer->node, &nets[netid].peers);
+		spin_unlock_irqrestore(&nets[netid].lock, flags);
+		pr_debug("%s: %s add peer %s\n",
+			 DRV_NAME, __func__, rio_name(rdev));
+
+		/* If netdev is already opened, send join request to new peer */
+		if (rnet->open)
+			rio_send_doorbell(peer->rdev, RIONET_DOORBELL_JOIN);
 	}
 
 	return 0;
@@ -603,7 +652,8 @@ static int rionet_add_dev(struct device *dev, struct subsys_interface *sif)
 static int rionet_shutdown(struct notifier_block *nb, unsigned long code,
 			   void *unused)
 {
-	struct rionet_peer *peer, *tmp;
+	struct rionet_peer *peer;
+	unsigned long flags;
 	int i;
 
 	pr_debug("%s: %s\n", DRV_NAME, __func__);
@@ -612,13 +662,15 @@ static int rionet_shutdown(struct notifier_block *nb, unsigned long code,
 		if (!nets[i].ndev)
 			continue;
 
-		list_for_each_entry_safe(peer, tmp, &nets[i].peers, node) {
+		spin_lock_irqsave(&nets[i].lock, flags);
+		list_for_each_entry(peer, &nets[i].peers, node) {
 			if (nets[i].active[peer->rdev->destid]) {
 				rio_send_doorbell(peer->rdev,
 						  RIONET_DOORBELL_LEAVE);
 				nets[i].active[peer->rdev->destid] = NULL;
 			}
 		}
+		spin_unlock_irqrestore(&nets[i].lock, flags);
 	}
 
 	return NOTIFY_DONE;