Update Linux to v5.4.148

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.4.148.tar.gz

Change-Id: Ib3d26c5ba9b022e2e03533005c4fed4d7c30b61b
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/net/bluetooth/hci_sock.c b/net/bluetooth/hci_sock.c
index d32077b..befab85 100644
--- a/net/bluetooth/hci_sock.c
+++ b/net/bluetooth/hci_sock.c
@@ -59,6 +59,17 @@
 	char              comm[TASK_COMM_LEN];
 };
 
+static struct hci_dev *hci_hdev_from_sock(struct sock *sk)
+{
+	struct hci_dev *hdev = hci_pi(sk)->hdev;
+
+	if (!hdev)
+		return ERR_PTR(-EBADFD);
+	if (hci_dev_test_flag(hdev, HCI_UNREGISTER))
+		return ERR_PTR(-EPIPE);
+	return hdev;
+}
+
 void hci_sock_set_flag(struct sock *sk, int nr)
 {
 	set_bit(nr, &hci_pi(sk)->flags);
@@ -752,19 +763,13 @@
 	if (event == HCI_DEV_UNREG) {
 		struct sock *sk;
 
-		/* Detach sockets from device */
+		/* Wake up sockets using this dead device */
 		read_lock(&hci_sk_list.lock);
 		sk_for_each(sk, &hci_sk_list.head) {
-			bh_lock_sock_nested(sk);
 			if (hci_pi(sk)->hdev == hdev) {
-				hci_pi(sk)->hdev = NULL;
 				sk->sk_err = EPIPE;
-				sk->sk_state = BT_OPEN;
 				sk->sk_state_change(sk);
-
-				hci_dev_put(hdev);
 			}
-			bh_unlock_sock(sk);
 		}
 		read_unlock(&hci_sk_list.lock);
 	}
@@ -831,6 +836,8 @@
 	if (!sk)
 		return 0;
 
+	lock_sock(sk);
+
 	switch (hci_pi(sk)->channel) {
 	case HCI_CHANNEL_MONITOR:
 		atomic_dec(&monitor_promisc);
@@ -878,6 +885,7 @@
 	skb_queue_purge(&sk->sk_receive_queue);
 	skb_queue_purge(&sk->sk_write_queue);
 
+	release_sock(sk);
 	sock_put(sk);
 	return 0;
 }
@@ -920,10 +928,10 @@
 static int hci_sock_bound_ioctl(struct sock *sk, unsigned int cmd,
 				unsigned long arg)
 {
-	struct hci_dev *hdev = hci_pi(sk)->hdev;
+	struct hci_dev *hdev = hci_hdev_from_sock(sk);
 
-	if (!hdev)
-		return -EBADFD;
+	if (IS_ERR(hdev))
+		return PTR_ERR(hdev);
 
 	if (hci_dev_test_flag(hdev, HCI_USER_CHANNEL))
 		return -EBUSY;
@@ -1077,6 +1085,18 @@
 
 	lock_sock(sk);
 
+	/* Allow detaching from dead device and attaching to alive device, if
+	 * the caller wants to re-bind (instead of close) this socket in
+	 * response to hci_sock_dev_event(HCI_DEV_UNREG) notification.
+	 */
+	hdev = hci_pi(sk)->hdev;
+	if (hdev && hci_dev_test_flag(hdev, HCI_UNREGISTER)) {
+		hci_pi(sk)->hdev = NULL;
+		sk->sk_state = BT_OPEN;
+		hci_dev_put(hdev);
+	}
+	hdev = NULL;
+
 	if (sk->sk_state == BT_BOUND) {
 		err = -EALREADY;
 		goto done;
@@ -1353,9 +1373,9 @@
 
 	lock_sock(sk);
 
-	hdev = hci_pi(sk)->hdev;
-	if (!hdev) {
-		err = -EBADFD;
+	hdev = hci_hdev_from_sock(sk);
+	if (IS_ERR(hdev)) {
+		err = PTR_ERR(hdev);
 		goto done;
 	}
 
@@ -1715,9 +1735,9 @@
 		goto done;
 	}
 
-	hdev = hci_pi(sk)->hdev;
-	if (!hdev) {
-		err = -EBADFD;
+	hdev = hci_hdev_from_sock(sk);
+	if (IS_ERR(hdev)) {
+		err = PTR_ERR(hdev);
 		goto done;
 	}