2 files changed, 42 insertions, 20 deletions

diff --git a/net/nfc/core.c b/net/nfc/core.c
index 3c645c1d99c9..dc7a2404efdf 100644
--- a/net/nfc/core.c
+++ b/net/nfc/core.c
@@ -94,13 +94,13 @@ int nfc_dev_up(struct nfc_dev *dev)
 
 	device_lock(&dev->dev);
 
-	if (dev->rfkill && rfkill_blocked(dev->rfkill)) {
-		rc = -ERFKILL;
+	if (!device_is_registered(&dev->dev)) {
+		rc = -ENODEV;
 		goto error;
 	}
 
-	if (!device_is_registered(&dev->dev)) {
-		rc = -ENODEV;
+	if (dev->rfkill && rfkill_blocked(dev->rfkill)) {
+		rc = -ERFKILL;
 		goto error;
 	}
 
@@ -1125,11 +1125,7 @@ int nfc_register_device(struct nfc_dev *dev)
 	if (rc)
 		pr_err("Could not register llcp device\n");
 
-	rc = nfc_genl_device_added(dev);
-	if (rc)
-		pr_debug("The userspace won't be notified that the device %s was added\n",
-			 dev_name(&dev->dev));
-
+	device_lock(&dev->dev);
 	dev->rfkill = rfkill_alloc(dev_name(&dev->dev), &dev->dev,
 				   RFKILL_TYPE_NFC, &nfc_rfkill_ops, dev);
 	if (dev->rfkill) {
@@ -1138,6 +1134,12 @@ int nfc_register_device(struct nfc_dev *dev)
 			dev->rfkill = NULL;
 		}
 	}
+	device_unlock(&dev->dev);
+
+	rc = nfc_genl_device_added(dev);
+	if (rc)
+		pr_debug("The userspace won't be notified that the device %s was added\n",
+			 dev_name(&dev->dev));
 
 	return 0;
 }
@@ -1154,10 +1156,17 @@ void nfc_unregister_device(struct nfc_dev *dev)
 
 	pr_debug("dev_name=%s\n", dev_name(&dev->dev));
 
+	rc = nfc_genl_device_removed(dev);
+	if (rc)
+		pr_debug("The userspace won't be notified that the device %s "
+			 "was removed\n", dev_name(&dev->dev));
+
+	device_lock(&dev->dev);
 	if (dev->rfkill) {
 		rfkill_unregister(dev->rfkill);
 		rfkill_destroy(dev->rfkill);
 	}
+	device_unlock(&dev->dev);
 
 	if (dev->ops->check_presence) {
 		device_lock(&dev->dev);
@@ -1167,11 +1176,6 @@ void nfc_unregister_device(struct nfc_dev *dev)
 		cancel_work_sync(&dev->check_pres_work);
 	}
 
-	rc = nfc_genl_device_removed(dev);
-	if (rc)
-		pr_debug("The userspace won't be notified that the device %s "
-			 "was removed\n", dev_name(&dev->dev));
-
 	nfc_llcp_unregister_device(dev);
 
 	mutex_lock(&nfc_devlist_mutex);
diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c
index 6fd873aa86be..d2537383a3e8 100644
--- a/net/nfc/nci/core.c
+++ b/net/nfc/nci/core.c
@@ -144,12 +144,15 @@ inline int nci_request(struct nci_dev *ndev,
 {
 	int rc;
 
-	if (!test_bit(NCI_UP, &ndev->flags))
-		return -ENETDOWN;
-
 	/* Serialize all requests */
 	mutex_lock(&ndev->req_lock);
-	rc = __nci_request(ndev, req, opt, timeout);
+	/* check the state after obtaing the lock against any races
+	 * from nci_close_device when the device gets removed.
+	 */
+	if (test_bit(NCI_UP, &ndev->flags))
+		rc = __nci_request(ndev, req, opt, timeout);
+	else
+		rc = -ENETDOWN;
 	mutex_unlock(&ndev->req_lock);
 
 	return rc;
@@ -473,6 +476,11 @@ static int nci_open_device(struct nci_dev *ndev)
 
 	mutex_lock(&ndev->req_lock);
 
+	if (test_bit(NCI_UNREG, &ndev->flags)) {
+		rc = -ENODEV;
+		goto done;
+	}
+
 	if (test_bit(NCI_UP, &ndev->flags)) {
 		rc = -EALREADY;
 		goto done;
@@ -545,6 +553,10 @@ done:
 static int nci_close_device(struct nci_dev *ndev)
 {
 	nci_req_cancel(ndev, ENODEV);
+
+	/* This mutex needs to be held as a barrier for
+	 * caller nci_unregister_device
+	 */
 	mutex_lock(&ndev->req_lock);
 
 	if (!test_and_clear_bit(NCI_UP, &ndev->flags)) {
@@ -582,8 +594,8 @@ static int nci_close_device(struct nci_dev *ndev)
 
 	del_timer_sync(&ndev->cmd_timer);
 
-	/* Clear flags */
-	ndev->flags = 0;
+	/* Clear flags except NCI_UNREG */
+	ndev->flags &= BIT(NCI_UNREG);
 
 	mutex_unlock(&ndev->req_lock);
 
@@ -1266,6 +1278,12 @@ void nci_unregister_device(struct nci_dev *ndev)
 {
 	struct nci_conn_info *conn_info, *n;
 
+	/* This set_bit is not protected with specialized barrier,
+	 * However, it is fine because the mutex_lock(&ndev->req_lock);
+	 * in nci_close_device() will help to emit one.
+	 */
+	set_bit(NCI_UNREG, &ndev->flags);
+
 	nci_close_device(ndev);
 
 	destroy_workqueue(ndev->cmd_wq);