Hi Marcel,
On Tue, Dec 20, 2011 at 6:58 PM, Marcel Holtmann <marcel@xxxxxxxxxxxx> wrote:
> Hi Ulisses,
>
>> 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@xxxxxxxxxxxxxx>
>> ---
>> net/bluetooth/hci_core.c | 21 +--------------------
>> 1 files changed, 1 insertions(+), 20 deletions(-)
>
> Acked-by: Marcel Holtmann <marcel@xxxxxxxxxxxx>
>
>> diff --git a/net/bluetooth/hci_core.c b/net/bluetooth/hci_core.c
>> index d6382db..b45b745 100644
>> --- 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);
>> @@ -1800,8 +1798,7 @@ 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;
>> @@ -1811,15 +1808,11 @@ 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;
>> }
>
> This only works fine because we are registering the protocols from the
> module init. So what I like to see is that we get rid of this altogether
> and just call directly into the specific event functions for L2CAP and
> SCO since there are the only users anyway. Making them replaceable was a
> nice idea, but it is not practical anymore.
Exactly, I'm on it right now.
> Regards
>
> Marcel
Regards,
--
Ulisses Furquim
ProFUSION embedded systems
http://profusion.mobi
Mobile: +55 19 9250 0942
Skype: ulissesffs
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