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>
diff --git a/drivers/net/rionet.c b/drivers/net/rionet.c
index f994fa1..c15d958 100644
--- a/drivers/net/rionet.c
+++ b/drivers/net/rionet.c
@@ -63,6 +63,7 @@
 	spinlock_t lock;
 	spinlock_t tx_lock;
 	u32 msg_enable;
+	bool open;
 };
 
 struct rionet_peer {
@@ -74,6 +75,7 @@
 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 @@
 	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 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 @@
 	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_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 @@
 
 	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 @@
 {
 	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 @@
 	/* 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 @@
 	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 @@
 	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 @@
 	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 @@
 			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_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 @@
 		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;