NFC: Fixed nfc core and hci unregistration and cleanup

When an adapter is removed, it will unregister itself from hci and/or
nfc core. In order to do that safely, work tasks must first be canceled
and prevented to be scheduled again, before the hci or nfc device can be
destroyed.

Signed-off-by: Eric Lapuyade <eric.lapuyade@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

2 files changed, 31 insertions, 7 deletions

diff --git a/net/nfc/hci/core.c b/net/nfc/hci/core.c
index 7bea574d593..b4b84268653 100644
--- a/net/nfc/hci/core.c
+++ b/net/nfc/hci/core.c
@@ -57,6 +57,8 @@ static void nfc_hci_msg_tx_work(struct work_struct *work)
 	int r = 0;
 
 	mutex_lock(&hdev->msg_tx_mutex);
+	if (hdev->shutting_down)
+		goto exit;
 
 	if (hdev->cmd_pending_msg) {
 		if (timer_pending(&hdev->cmd_timer) == 0) {
@@ -868,6 +870,28 @@ void nfc_hci_unregister_device(struct nfc_hci_dev *hdev)
 {
 	struct hci_msg *msg, *n;
 
+	mutex_lock(&hdev->msg_tx_mutex);
+
+	if (hdev->cmd_pending_msg) {
+		if (hdev->cmd_pending_msg->cb)
+			hdev->cmd_pending_msg->cb(
+					     hdev->cmd_pending_msg->cb_context,
+					     NULL, -ESHUTDOWN);
+		kfree(hdev->cmd_pending_msg);
+		hdev->cmd_pending_msg = NULL;
+	}
+
+	hdev->shutting_down = true;
+
+	mutex_unlock(&hdev->msg_tx_mutex);
+
+	del_timer_sync(&hdev->cmd_timer);
+	cancel_work_sync(&hdev->msg_tx_work);
+
+	cancel_work_sync(&hdev->msg_rx_work);
+
+	nfc_unregister_device(hdev->ndev);
+
 	skb_queue_purge(&hdev->rx_hcp_frags);
 	skb_queue_purge(&hdev->msg_rx_queue);
 
@@ -876,13 +900,6 @@ void nfc_hci_unregister_device(struct nfc_hci_dev *hdev)
 		skb_queue_purge(&msg->msg_frags);
 		kfree(msg);
 	}
-
-	del_timer_sync(&hdev->cmd_timer);
-
-	nfc_unregister_device(hdev->ndev);
-
-	cancel_work_sync(&hdev->msg_tx_work);
-	cancel_work_sync(&hdev->msg_rx_work);
 }
 EXPORT_SYMBOL(nfc_hci_unregister_device);
 
diff --git a/net/nfc/hci/hcp.c b/net/nfc/hci/hcp.c
index bc308a7ca60..b6b4109f234 100644
--- a/net/nfc/hci/hcp.c
+++ b/net/nfc/hci/hcp.c
@@ -105,6 +105,13 @@ int nfc_hci_hcp_message_tx(struct nfc_hci_dev *hdev, u8 pipe,
 	}
 
 	mutex_lock(&hdev->msg_tx_mutex);
+
+	if (hdev->shutting_down) {
+		err = -ESHUTDOWN;
+		mutex_unlock(&hdev->msg_tx_mutex);
+		goto out_skb_err;
+	}
+
 	list_add_tail(&cmd->msg_l, &hdev->msg_tx_queue);
 	mutex_unlock(&hdev->msg_tx_mutex);