2 files changed, 169 insertions, 118 deletions

diff --git a/include/net/caif/cfcnfg.h b/include/net/caif/cfcnfg.h
index f33d36341132..e0a1eb5d7eaf 100644
--- a/include/net/caif/cfcnfg.h
+++ b/include/net/caif/cfcnfg.h
@@ -145,4 +145,14 @@ struct dev_info *cfcnfg_get_phyid(struct cfcnfg *cnfg,
  * @ifi:	ifindex obtained from socket.c bindtodevice.
  */
 int cfcnfg_get_id_from_ifi(struct cfcnfg *cnfg, int ifi);
+
+/**
+ * cfcnfg_set_phy_state() - Set the state of the physical interface device.
+ * @cnfg:	Configuration object
+ * @phy_layer:	Physical Layer representation
+ * @up:	State of device
+ */
+int cfcnfg_set_phy_state(struct cfcnfg *cnfg, struct cflayer *phy_layer,
+				bool up);
+
 #endif				/* CFCNFG_H_ */
diff --git a/net/caif/caif_dev.c b/net/caif/caif_dev.c
index 75e00d59eb49..6d1d86be187b 100644
--- a/net/caif/caif_dev.c
+++ b/net/caif/caif_dev.c
@@ -12,14 +12,11 @@
 #define pr_fmt(fmt) KBUILD_MODNAME ":%s(): " fmt, __func__
 
 #include <linux/version.h>
-#include <linux/module.h>
 #include <linux/kernel.h>
 #include <linux/if_arp.h>
 #include <linux/net.h>
 #include <linux/netdevice.h>
-#include <linux/skbuff.h>
-#include <linux/sched.h>
-#include <linux/wait.h>
+#include <linux/mutex.h>
 #include <net/netns/generic.h>
 #include <net/net_namespace.h>
 #include <net/pkt_sched.h>
@@ -30,23 +27,19 @@
 #include <net/caif/cfcnfg.h>
 
 MODULE_LICENSE("GPL");
-#define TIMEOUT (HZ*5)
 
 /* Used for local tracking of the CAIF net devices */
 struct caif_device_entry {
 	struct cflayer layer;
 	struct list_head list;
-	atomic_t in_use;
-	atomic_t state;
-	u16 phyid;
 	struct net_device *netdev;
-	wait_queue_head_t event;
+	int __percpu *pcpu_refcnt;
 };
 
 struct caif_device_entry_list {
 	struct list_head list;
 	/* Protects simulanous deletes in list */
-	spinlock_t lock;
+	struct mutex lock;
 };
 
 struct caif_net {
@@ -65,19 +58,39 @@ static struct caif_device_entry_list *caif_device_list(struct net *net)
 	return &caifn->caifdevs;
 }
 
+static void caifd_put(struct caif_device_entry *e)
+{
+	irqsafe_cpu_dec(*e->pcpu_refcnt);
+}
+
+static void caifd_hold(struct caif_device_entry *e)
+{
+	irqsafe_cpu_inc(*e->pcpu_refcnt);
+}
+
+static int caifd_refcnt_read(struct caif_device_entry *e)
+{
+	int i, refcnt = 0;
+	for_each_possible_cpu(i)
+		refcnt += *per_cpu_ptr(e->pcpu_refcnt, i);
+	return refcnt;
+}
+
 /* Allocate new CAIF device. */
 static struct caif_device_entry *caif_device_alloc(struct net_device *dev)
 {
 	struct caif_device_entry_list *caifdevs;
 	struct caif_device_entry *caifd;
+
 	caifdevs = caif_device_list(dev_net(dev));
 	BUG_ON(!caifdevs);
+
 	caifd = kzalloc(sizeof(*caifd), GFP_ATOMIC);
 	if (!caifd)
 		return NULL;
+	caifd->pcpu_refcnt = alloc_percpu(int);
 	caifd->netdev = dev;
-	list_add(&caifd->list, &caifdevs->list);
-	init_waitqueue_head(&caifd->event);
+	dev_hold(dev);
 	return caifd;
 }
 
@@ -87,35 +100,13 @@ static struct caif_device_entry *caif_get(struct net_device *dev)
 	    caif_device_list(dev_net(dev));
 	struct caif_device_entry *caifd;
 	BUG_ON(!caifdevs);
-	list_for_each_entry(caifd, &caifdevs->list, list) {
+	list_for_each_entry_rcu(caifd, &caifdevs->list, list) {
 		if (caifd->netdev == dev)
 			return caifd;
 	}
 	return NULL;
 }
 
-static void caif_device_destroy(struct net_device *dev)
-{
-	struct caif_device_entry_list *caifdevs =
-	    caif_device_list(dev_net(dev));
-	struct caif_device_entry *caifd;
-	ASSERT_RTNL();
-	if (dev->type != ARPHRD_CAIF)
-		return;
-
-	spin_lock_bh(&caifdevs->lock);
-	caifd = caif_get(dev);
-	if (caifd == NULL) {
-		spin_unlock_bh(&caifdevs->lock);
-		return;
-	}
-
-	list_del(&caifd->list);
-	spin_unlock_bh(&caifdevs->lock);
-
-	kfree(caifd);
-}
-
 static int transmit(struct cflayer *layer, struct cfpkt *pkt)
 {
 	struct caif_device_entry *caifd =
@@ -130,23 +121,8 @@ static int transmit(struct cflayer *layer, struct cfpkt *pkt)
 	return 0;
 }
 
-static int modemcmd(struct cflayer *layr, enum caif_modemcmd ctrl)
-{
-	struct caif_device_entry *caifd;
-	caifd = container_of(layr, struct caif_device_entry, layer);
-	if (ctrl == _CAIF_MODEMCMD_PHYIF_USEFULL) {
-		atomic_set(&caifd->in_use, 1);
-		wake_up_interruptible(&caifd->event);
-
-	} else if (ctrl == _CAIF_MODEMCMD_PHYIF_USELESS) {
-		atomic_set(&caifd->in_use, 0);
-		wake_up_interruptible(&caifd->event);
-	}
-	return 0;
-}
-
 /*
- * Stuff received packets to associated sockets.
+ * Stuff received packets into the CAIF stack.
  * On error, returns non-zero and releases the skb.
  */
 static int receive(struct sk_buff *skb, struct net_device *dev,
@@ -154,14 +130,27 @@ static int receive(struct sk_buff *skb, struct net_device *dev,
 {
 	struct cfpkt *pkt;
 	struct caif_device_entry *caifd;
+
 	pkt = cfpkt_fromnative(CAIF_DIR_IN, skb);
+
+	rcu_read_lock();
 	caifd = caif_get(dev);
-	if (!caifd || !caifd->layer.up || !caifd->layer.up->receive)
-		return NET_RX_DROP;
 
-	if (caifd->layer.up->receive(caifd->layer.up, pkt))
+	if (!caifd || !caifd->layer.up || !caifd->layer.up->receive ||
+			!netif_oper_up(caifd->netdev)) {
+		rcu_read_unlock();
+		kfree_skb(skb);
 		return NET_RX_DROP;
+	}
+
+	/* Hold reference to netdevice while using CAIF stack */
+	caifd_hold(caifd);
+	rcu_read_unlock();
 
+	caifd->layer.up->receive(caifd->layer.up, pkt);
+
+	/* Release reference to stack upwards */
+	caifd_put(caifd);
 	return 0;
 }
 
@@ -172,15 +161,25 @@ static struct packet_type caif_packet_type __read_mostly = {
 
 static void dev_flowctrl(struct net_device *dev, int on)
 {
-	struct caif_device_entry *caifd = caif_get(dev);
-	if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd)
+	struct caif_device_entry *caifd;
+
+	rcu_read_lock();
+
+	caifd = caif_get(dev);
+	if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) {
+		rcu_read_unlock();
 		return;
+	}
+
+	caifd_hold(caifd);
+	rcu_read_unlock();
 
 	caifd->layer.up->ctrlcmd(caifd->layer.up,
 				 on ?
 				 _CAIF_CTRLCMD_PHYIF_FLOW_ON_IND :
 				 _CAIF_CTRLCMD_PHYIF_FLOW_OFF_IND,
 				 caifd->layer.id);
+	caifd_put(caifd);
 }
 
 /* notify Caif of device events */
@@ -192,34 +191,22 @@ static int caif_device_notify(struct notifier_block *me, unsigned long what,
 	struct caif_dev_common *caifdev;
 	enum cfcnfg_phy_preference pref;
 	enum cfcnfg_phy_type phy_type;
+	struct caif_device_entry_list *caifdevs =
+	    caif_device_list(dev_net(dev));
 
 	if (dev->type != ARPHRD_CAIF)
 		return 0;
 
 	switch (what) {
 	case NETDEV_REGISTER:
-		netdev_info(dev, "register\n");
 		caifd = caif_device_alloc(dev);
-		if (caifd == NULL)
-			break;
+		if (!caifd)
+			return 0;
+
 		caifdev = netdev_priv(dev);
 		caifdev->flowctrl = dev_flowctrl;
-		atomic_set(&caifd->state, what);
-		break;
 
-	case NETDEV_UP:
-		netdev_info(dev, "up\n");
-		caifd = caif_get(dev);
-		if (caifd == NULL)
-			break;
-		caifdev = netdev_priv(dev);
-		if (atomic_read(&caifd->state) == NETDEV_UP) {
-			netdev_info(dev, "already up\n");
-			break;
-		}
-		atomic_set(&caifd->state, what);
 		caifd->layer.transmit = transmit;
-		caifd->layer.modemcmd = modemcmd;
 
 		if (caifdev->use_frag)
 			phy_type = CFPHYTYPE_FRAG;
@@ -237,62 +224,95 @@ static int caif_device_notify(struct notifier_block *me, unsigned long what,
 			pref = CFPHYPREF_HIGH_BW;
 			break;
 		}
-		dev_hold(dev);
+		strncpy(caifd->layer.name, dev->name,
+			sizeof(caifd->layer.name) - 1);
+		caifd->layer.name[sizeof(caifd->layer.name) - 1] = 0;
+
+		mutex_lock(&caifdevs->lock);
+		list_add_rcu(&caifd->list, &caifdevs->list);
+
 		cfcnfg_add_phy_layer(cfg,
 				     phy_type,
 				     dev,
 				     &caifd->layer,
-				     &caifd->phyid,
+				     0,
 				     pref,
 				     caifdev->use_fcs,
 				     caifdev->use_stx);
-		strncpy(caifd->layer.name, dev->name,
-			sizeof(caifd->layer.name) - 1);
-		caifd->layer.name[sizeof(caifd->layer.name) - 1] = 0;
+		mutex_unlock(&caifdevs->lock);
 		break;
 
-	case NETDEV_GOING_DOWN:
+	case NETDEV_UP:
+		rcu_read_lock();
+
 		caifd = caif_get(dev);
-		if (caifd == NULL)
+		if (caifd == NULL) {
+			rcu_read_unlock();
 			break;
-		netdev_info(dev, "going down\n");
+		}
 
-		if (atomic_read(&caifd->state) == NETDEV_GOING_DOWN ||
-			atomic_read(&caifd->state) == NETDEV_DOWN)
-			break;
+		cfcnfg_set_phy_state(cfg, &caifd->layer, true);
+		rcu_read_unlock();
 
-		atomic_set(&caifd->state, what);
-		if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd)
-			return -EINVAL;
-		caifd->layer.up->ctrlcmd(caifd->layer.up,
-					 _CAIF_CTRLCMD_PHYIF_DOWN_IND,
-					 caifd->layer.id);
-		might_sleep();
-		wait_event_interruptible_timeout(caifd->event,
-					atomic_read(&caifd->in_use) == 0,
-					TIMEOUT);
 		break;
 
 	case NETDEV_DOWN:
+		rcu_read_lock();
+
 		caifd = caif_get(dev);
-		if (caifd == NULL)
-			break;
-		netdev_info(dev, "down\n");
-		if (atomic_read(&caifd->in_use))
-			netdev_warn(dev,
-				    "Unregistering an active CAIF device\n");
-		cfcnfg_del_phy_layer(cfg, &caifd->layer);
-		dev_put(dev);
-		atomic_set(&caifd->state, what);
+		if (!caifd || !caifd->layer.up || !caifd->layer.up->ctrlcmd) {
+			rcu_read_unlock();
+			return -EINVAL;
+		}
+
+		cfcnfg_set_phy_state(cfg, &caifd->layer, false);
+		caifd_hold(caifd);
+		rcu_read_unlock();
+
+		caifd->layer.up->ctrlcmd(caifd->layer.up,
+					 _CAIF_CTRLCMD_PHYIF_DOWN_IND,
+					 caifd->layer.id);
+		caifd_put(caifd);
 		break;
 
 	case NETDEV_UNREGISTER:
+		mutex_lock(&caifdevs->lock);
+
 		caifd = caif_get(dev);
-		if (caifd == NULL)
+		if (caifd == NULL) {
+			mutex_unlock(&caifdevs->lock);
 			break;
-		netdev_info(dev, "unregister\n");
-		atomic_set(&caifd->state, what);
-		caif_device_destroy(dev);
+		}
+		list_del_rcu(&caifd->list);
+
+		/*
+		 * NETDEV_UNREGISTER is called repeatedly until all reference
+		 * counts for the net-device are released. If references to
+		 * caifd is taken, simply ignore NETDEV_UNREGISTER and wait for
+		 * the next call to NETDEV_UNREGISTER.
+		 *
+		 * If any packets are in flight down the CAIF Stack,
+		 * cfcnfg_del_phy_layer will return nonzero.
+		 * If no packets are in flight, the CAIF Stack associated
+		 * with the net-device un-registering is freed.
+		 */
+
+		if (caifd_refcnt_read(caifd) != 0 ||
+			cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0) {
+
+			pr_info("Wait for device inuse\n");
+			/* Enrole device if CAIF Stack is still in use */
+			list_add_rcu(&caifd->list, &caifdevs->list);
+			mutex_unlock(&caifdevs->lock);
+			break;
+		}
+
+		synchronize_rcu();
+		dev_put(caifd->netdev);
+		free_percpu(caifd->pcpu_refcnt);
+		kfree(caifd);
+
+		mutex_unlock(&caifdevs->lock);
 		break;
 	}
 	return 0;
@@ -304,8 +324,8 @@ static struct notifier_block caif_device_notifier = {
 };
 
 int caif_connect_client(struct caif_connect_request *conn_req,
-			struct cflayer *client_layer, int *ifindex,
-			int *headroom, int *tailroom)
+		       struct cflayer *client_layer, int *ifindex,
+		       int *headroom, int *tailroom)
 {
 	struct cfctrl_link_param param;
 	int ret;
@@ -315,8 +335,8 @@ int caif_connect_client(struct caif_connect_request *conn_req,
 		return ret;
 	/* Hook up the adaptation layer. */
 	return cfcnfg_add_adaptation_layer(cfg, &param,
-					client_layer, ifindex,
-					headroom, tailroom);
+				       client_layer, ifindex,
+				       headroom, tailroom);
 }
 EXPORT_SYMBOL(caif_connect_client);
 
@@ -331,20 +351,40 @@ static int caif_init_net(struct net *net)
 {
 	struct caif_net *caifn = net_generic(net, caif_net_id);
 	INIT_LIST_HEAD(&caifn->caifdevs.list);
-	spin_lock_init(&caifn->caifdevs.lock);
+	mutex_init(&caifn->caifdevs.lock);
 	return 0;
 }
 
 static void caif_exit_net(struct net *net)
 {
-	struct net_device *dev;
+	struct caif_device_entry *caifd, *tmp;
+	struct caif_device_entry_list *caifdevs =
+	    caif_device_list(net);
+
 	rtnl_lock();
-	for_each_netdev(net, dev) {
-		if (dev->type != ARPHRD_CAIF)
-			continue;
-		dev_close(dev);
-		caif_device_destroy(dev);
+	mutex_lock(&caifdevs->lock);
+
+	list_for_each_entry_safe(caifd, tmp, &caifdevs->list, list) {
+		int i = 0;
+		list_del_rcu(&caifd->list);
+		cfcnfg_set_phy_state(cfg, &caifd->layer, false);
+
+		while (i < 10 &&
+			(caifd_refcnt_read(caifd) != 0 ||
+			cfcnfg_del_phy_layer(cfg, &caifd->layer) != 0)) {
+
+			pr_info("Wait for device inuse\n");
+			msleep(250);
+			i++;
+		}
+		synchronize_rcu();
+		dev_put(caifd->netdev);
+		free_percpu(caifd->pcpu_refcnt);
+		kfree(caifd);
 	}
+
+
+	mutex_unlock(&caifdevs->lock);
 	rtnl_unlock();
 }
 
@@ -359,6 +399,7 @@ static struct pernet_operations caif_net_ops = {
 static int __init caif_device_init(void)
 {
 	int result;
+
 	cfg = cfcnfg_create();
 	if (!cfg) {
 		pr_warn("can't create cfcnfg\n");