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");