4 files changed, 39 insertions, 9 deletions

diff --git a/net/nfc/nci/core.c b/net/nfc/nci/core.c
index 7cd524884304..b2e922fcc70d 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;
@@ -470,6 +473,11 @@ 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;
@@ -533,9 +541,17 @@ 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);
@@ -570,8 +586,8 @@ 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);
 
@@ -1175,6 +1191,7 @@ 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);
@@ -1252,6 +1269,12 @@ 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);
diff --git a/net/nfc/nci/data.c b/net/nfc/nci/data.c
index ce3382be937f..b002e18f38c8 100644
--- a/net/nfc/nci/data.c
+++ b/net/nfc/nci/data.c
@@ -118,7 +118,7 @@ static int nci_queue_tx_data_frags(struct nci_dev *ndev,
 
 		skb_frag = nci_skb_alloc(ndev,
 					 (NCI_DATA_HDR_SIZE + frag_len),
-					 GFP_KERNEL);
+					 GFP_ATOMIC);
 		if (skb_frag == NULL) {
 			rc = -ENOMEM;
 			goto free_exit;
diff --git a/net/nfc/nci/hci.c b/net/nfc/nci/hci.c
index c18e76d6d8ba..4fe336ff2bfa 100644
--- a/net/nfc/nci/hci.c
+++ b/net/nfc/nci/hci.c
@@ -153,7 +153,7 @@ static int nci_hci_send_data(struct nci_dev *ndev, u8 pipe,
 
 	i = 0;
 	skb = nci_skb_alloc(ndev, conn_info->max_pkt_payload_len +
-			    NCI_DATA_HDR_SIZE, GFP_KERNEL);
+			    NCI_DATA_HDR_SIZE, GFP_ATOMIC);
 	if (!skb)
 		return -ENOMEM;
 
@@ -186,7 +186,7 @@ static int nci_hci_send_data(struct nci_dev *ndev, u8 pipe,
 		if (i < data_len) {
 			skb = nci_skb_alloc(ndev,
 					    conn_info->max_pkt_payload_len +
-					    NCI_DATA_HDR_SIZE, GFP_KERNEL);
+					    NCI_DATA_HDR_SIZE, GFP_ATOMIC);
 			if (!skb)
 				return -ENOMEM;
 
@@ -795,3 +795,8 @@ struct nci_hci_dev *nci_hci_allocate(struct nci_dev *ndev)
 
 	return hdev;
 }
+
+void nci_hci_deallocate(struct nci_dev *ndev)
+{
+	kfree(ndev->hci_dev);
+}
diff --git a/net/nfc/nci/rsp.c b/net/nfc/nci/rsp.c
index a48297b79f34..b0ed2b47ac43 100644
--- a/net/nfc/nci/rsp.c
+++ b/net/nfc/nci/rsp.c
@@ -277,6 +277,8 @@ static void nci_core_conn_close_rsp_packet(struct nci_dev *ndev,
 							 ndev->cur_conn_id);
 		if (conn_info) {
 			list_del(&conn_info->list);
+			if (conn_info == ndev->rf_conn_info)
+				ndev->rf_conn_info = NULL;
 			devm_kfree(&ndev->nfc_dev->dev, conn_info);
 		}
 	}