1 files changed, 35 insertions, 7 deletions

diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c
index 074960154993..33723d843e47 100644
--- a/net/nfc/nci/core.c
+++ b/net/nfc/nci/core.c
@@ -156,12 +156,15 @@ 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;
@@ -482,6 +485,11 @@ 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;
@@ -534,7 +542,7 @@ static int nci_open_device(struct nci_dev *ndev)
 		skb_queue_purge(&ndev->tx_q);
 
 		ndev->ops->close(ndev);
-		ndev->flags = 0;
+		ndev->flags &= BIT(NCI_UNREG);
 	}
 
 done:
@@ -545,9 +553,17 @@ 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)) {
+		/* Need to flush the cmd wq in case
+		 * there is a queued/running cmd_work
+		 */
+		flush_workqueue(ndev->cmd_wq);
 		del_timer_sync(&ndev->cmd_timer);
 		del_timer_sync(&ndev->data_timer);
 		mutex_unlock(&ndev->req_lock);
@@ -582,8 +598,8 @@ static int nci_close_device(struct nci_dev *ndev)
 	/* Flush cmd wq */
 	flush_workqueue(ndev->cmd_wq);
 
-	/* Clear flags */
-	ndev->flags = 0;
+	/* Clear flags except NCI_UNREG */
+	ndev->flags &= BIT(NCI_UNREG);
 
 	mutex_unlock(&ndev->req_lock);
 
@@ -890,6 +906,11 @@ static int nci_activate_target(struct nfc_dev *nfc_dev,
 		return -EINVAL;
 	}
 
+	if (protocol >= NFC_PROTO_MAX) {
+		pr_err("the requested nfc protocol is invalid\n");
+		return -EINVAL;
+	}
+
 	if (!(nci_target->supported_protocols & (1 << protocol))) {
 		pr_err("target does not support the requested protocol 0x%x\n",
 		       protocol);
@@ -1187,6 +1208,7 @@ EXPORT_SYMBOL(nci_allocate_device);
 void nci_free_device(struct nci_dev *ndev)
 {
 	nfc_free_device(ndev->nfc_dev);
+	nci_hci_deallocate(ndev);
 	kfree(ndev);
 }
 EXPORT_SYMBOL(nci_free_device);
@@ -1264,6 +1286,12 @@ 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);