Bluetooth: Remove global mutex hci_task_lock

The hci_task_lock mutex (previously a lock) was supposed to protect the
register/unregister of HCI protocols against RX/TX tasks. This will not
be needed anymore because SCO and L2CAP will always be compiled.

Moreover, with the recent move of RX/TX to workqueues per device the
global hci_task_lock was causing starvation between different HCI
devices.

Signed-off-by: Ulisses Furquim <ulisses@profusion.mobi>
Acked-by: Marcel Holtmann <marcel@holtmann.org>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>

diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
index 884eb85a136a758e99c3f02ad2183be1b8ce42ee..fea8dad72e3ad68d79128bc0a3fd584815b8f23a 100644 (file)
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -61,8 +61,6 @@ static void hci_rx_work(struct work_struct *work);
 static void hci_cmd_work(struct work_struct *work);
 static void hci_tx_work(struct work_struct *work);
 
-static DEFINE_MUTEX(hci_task_lock);
-
 /* HCI device list */
 LIST_HEAD(hci_dev_list);
 DEFINE_RWLOCK(hci_dev_list_lock);
@@ -1832,8 +1830,7 @@ EXPORT_SYMBOL(hci_recv_stream_fragment);
 
 /* ---- Interface to upper protocols ---- */
 
-/* Register/Unregister protocols.
- * hci_task_lock is used to ensure that no tasks are running. */
+/* Register/Unregister protocols. */
 int hci_register_proto(struct hci_proto *hp)
 {
        int err = 0;
@@ -1843,15 +1840,11 @@ int hci_register_proto(struct hci_proto *hp)
        if (hp->id >= HCI_MAX_PROTO)
                return -EINVAL;
 
-       mutex_lock(&hci_task_lock);
-
        if (!hci_proto[hp->id])
                hci_proto[hp->id] = hp;
        else
                err = -EEXIST;
 
-       mutex_unlock(&hci_task_lock);
-
        return err;
 }
 EXPORT_SYMBOL(hci_register_proto);
@@ -1865,15 +1858,11 @@ int hci_unregister_proto(struct hci_proto *hp)
        if (hp->id >= HCI_MAX_PROTO)
                return -EINVAL;
 
-       mutex_lock(&hci_task_lock);
-
        if (hci_proto[hp->id])
                hci_proto[hp->id] = NULL;
        else
                err = -ENOENT;
 
-       mutex_unlock(&hci_task_lock);
-
        return err;
 }
 EXPORT_SYMBOL(hci_unregister_proto);
@@ -2439,8 +2428,6 @@ static void hci_tx_work(struct work_struct *work)
        struct hci_dev *hdev = container_of(work, struct hci_dev, tx_work);
        struct sk_buff *skb;
 
-       mutex_lock(&hci_task_lock);
-
        BT_DBG("%s acl %d sco %d le %d", hdev->name, hdev->acl_cnt,
                hdev->sco_cnt, hdev->le_cnt);
 
@@ -2457,8 +2444,6 @@ static void hci_tx_work(struct work_struct *work)
        /* Send next queued raw (unknown type) packet */
        while ((skb = skb_dequeue(&hdev->raw_q)))
                hci_send_frame(skb);
-
-       mutex_unlock(&hci_task_lock);
 }
 
 /* ----- HCI RX task (incoming data processing) ----- */
@@ -2546,8 +2531,6 @@ static void hci_rx_work(struct work_struct *work)
 
        BT_DBG("%s", hdev->name);
 
-       mutex_lock(&hci_task_lock);
-
        while ((skb = skb_dequeue(&hdev->rx_q))) {
                if (atomic_read(&hdev->promisc)) {
                        /* Send copy to the sockets */
@@ -2591,8 +2574,6 @@ static void hci_rx_work(struct work_struct *work)
                        break;
                }
        }
-
-       mutex_unlock(&hci_task_lock);
 }
 
 static void hci_cmd_work(struct work_struct *work)