Merge tag 'netfs-fixes-20210621' of git://git.kernel.org/pub/scm/linux/kernel/git...

[linux-2.6-microblaze.git] / net / can / raw.c

diff --git a/net/can/raw.c b/net/can/raw.c
index 139d947..ac96fc2 100644 (file)
--- a/net/can/raw.c
+++ b/net/can/raw.c
@@ -83,7 +83,7 @@ struct raw_sock {
        struct sock sk;
        int bound;
        int ifindex;
-       struct notifier_block notifier;
+       struct list_head notifier;
        int loopback;
        int recv_own_msgs;
        int fd_frames;
@@ -95,6 +95,10 @@ struct raw_sock {
        struct uniqframe __percpu *uniq;
 };
 
+static LIST_HEAD(raw_notifier_list);
+static DEFINE_SPINLOCK(raw_notifier_lock);
+static struct raw_sock *raw_busy_notifier;
+
 /* Return pointer to store the extra msg flags for raw_recvmsg().
  * We use the space of one unsigned int beyond the 'struct sockaddr_can'
  * in skb->cb.
@@ -263,21 +267,16 @@ static int raw_enable_allfilters(struct net *net, struct net_device *dev,
        return err;
 }
 
-static int raw_notifier(struct notifier_block *nb,
-                       unsigned long msg, void *ptr)
+static void raw_notify(struct raw_sock *ro, unsigned long msg,
+                      struct net_device *dev)
 {
-       struct net_device *dev = netdev_notifier_info_to_dev(ptr);
-       struct raw_sock *ro = container_of(nb, struct raw_sock, notifier);
        struct sock *sk = &ro->sk;
 
        if (!net_eq(dev_net(dev), sock_net(sk)))
-               return NOTIFY_DONE;
-
-       if (dev->type != ARPHRD_CAN)
-               return NOTIFY_DONE;
+               return;
 
        if (ro->ifindex != dev->ifindex)
-               return NOTIFY_DONE;
+               return;
 
        switch (msg) {
        case NETDEV_UNREGISTER:
@@ -305,7 +304,28 @@ static int raw_notifier(struct notifier_block *nb,
                        sk->sk_error_report(sk);
                break;
        }
+}
+
+static int raw_notifier(struct notifier_block *nb, unsigned long msg,
+                       void *ptr)
+{
+       struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+
+       if (dev->type != ARPHRD_CAN)
+               return NOTIFY_DONE;
+       if (msg != NETDEV_UNREGISTER && msg != NETDEV_DOWN)
+               return NOTIFY_DONE;
+       if (unlikely(raw_busy_notifier)) /* Check for reentrant bug. */
+               return NOTIFY_DONE;
 
+       spin_lock(&raw_notifier_lock);
+       list_for_each_entry(raw_busy_notifier, &raw_notifier_list, notifier) {
+               spin_unlock(&raw_notifier_lock);
+               raw_notify(raw_busy_notifier, msg, dev);
+               spin_lock(&raw_notifier_lock);
+       }
+       raw_busy_notifier = NULL;
+       spin_unlock(&raw_notifier_lock);
        return NOTIFY_DONE;
 }
 
@@ -334,9 +354,9 @@ static int raw_init(struct sock *sk)
                return -ENOMEM;
 
        /* set notifier */
-       ro->notifier.notifier_call = raw_notifier;
-
-       register_netdevice_notifier(&ro->notifier);
+       spin_lock(&raw_notifier_lock);
+       list_add_tail(&ro->notifier, &raw_notifier_list);
+       spin_unlock(&raw_notifier_lock);
 
        return 0;
 }
@@ -351,7 +371,14 @@ static int raw_release(struct socket *sock)
 
        ro = raw_sk(sk);
 
-       unregister_netdevice_notifier(&ro->notifier);
+       spin_lock(&raw_notifier_lock);
+       while (raw_busy_notifier == ro) {
+               spin_unlock(&raw_notifier_lock);
+               schedule_timeout_uninterruptible(1);
+               spin_lock(&raw_notifier_lock);
+       }
+       list_del(&ro->notifier);
+       spin_unlock(&raw_notifier_lock);
 
        lock_sock(sk);
 
@@ -889,6 +916,10 @@ static const struct can_proto raw_can_proto = {
        .prot       = &raw_proto,
 };
 
+static struct notifier_block canraw_notifier = {
+       .notifier_call = raw_notifier
+};
+
 static __init int raw_module_init(void)
 {
        int err;
@@ -898,6 +929,8 @@ static __init int raw_module_init(void)
        err = can_proto_register(&raw_can_proto);
        if (err < 0)
                pr_err("can: registration of raw protocol failed\n");
+       else
+               register_netdevice_notifier(&canraw_notifier);
 
        return err;
 }
@@ -905,6 +938,7 @@ static __init int raw_module_init(void)
 static __exit void raw_module_exit(void)
 {
        can_proto_unregister(&raw_can_proto);
+       unregister_netdevice_notifier(&canraw_notifier);
 }
 
 module_init(raw_module_init);