Bluetooth: Fix Adv Monitor msft_add/remove_monitor_sync()

Do not call skb_pull() in msft_add_monitor_sync() as
msft_le_monitor_advertisement_cb() expects 'status' to be
part of the skb.

Same applies for msft_remove_monitor_sync().

Signed-off-by: Manish Mandlik <mmandlik@google.com>
---

 net/bluetooth/msft.c | 2 --
 1 file changed, 2 deletions(-)

Hi Manish,

On Mon, May 9, 2022 at 2:05 PM Manish Mandlik <mmandlik@google.com> wrote:
>
> Do not call skb_pull() in msft_add_monitor_sync() as
> msft_le_monitor_advertisement_cb() expects 'status' to be
> part of the skb.
>
> Same applies for msft_remove_monitor_sync().
>
> Signed-off-by: Manish Mandlik <mmandlik@google.com>
> ---
>
>  net/bluetooth/msft.c | 2 --
>  1 file changed, 2 deletions(-)
>
> diff --git a/net/bluetooth/msft.c b/net/bluetooth/msft.c
> index f43994523b1f..9990924719aa 100644
> --- a/net/bluetooth/msft.c
> +++ b/net/bluetooth/msft.c
> @@ -387,7 +387,6 @@ static int msft_remove_monitor_sync(struct hci_dev *hdev,
>                 return PTR_ERR(skb);
>
>         status = skb->data[0];
> -       skb_pull(skb, 1);
>
>         msft_le_cancel_monitor_advertisement_cb(hdev, status, hdev->msft_opcode,
>                                                 skb);
> @@ -506,7 +505,6 @@ static int msft_add_monitor_sync(struct hci_dev *hdev,
>                 return PTR_ERR(skb);
>
>         status = skb->data[0];
> -       skb_pull(skb, 1);

Well if it expects it to be part of the skb then there is no reason to
pass it as argument in addition to the skb itself.

>         msft_le_monitor_advertisement_cb(hdev, status, hdev->msft_opcode, skb);
>
> --
> 2.36.0.512.ge40c2bad7a-goog
>

Hi Manish,

On Wed, May 11, 2022 at 5:56 PM Manish Mandlik <mmandlik@google.com> wrote:
>
> Hi Luiz,
>
> On Wed, May 11, 2022 at 2:23 PM Luiz Augusto von Dentz <luiz.dentz@gmail.com> wrote:
>>
>> Hi Manish,
>>
>> On Mon, May 9, 2022 at 2:05 PM Manish Mandlik <mmandlik@google.com> wrote:
>> >
>> > Do not call skb_pull() in msft_add_monitor_sync() as
>> > msft_le_monitor_advertisement_cb() expects 'status' to be
>> > part of the skb.
>> >
>> > Same applies for msft_remove_monitor_sync().
>> >
>> > Signed-off-by: Manish Mandlik <mmandlik@google.com>
>> > ---
>> >
>> >  net/bluetooth/msft.c | 2 --
>> >  1 file changed, 2 deletions(-)
>> >
>> > diff --git a/net/bluetooth/msft.c b/net/bluetooth/msft.c
>> > index f43994523b1f..9990924719aa 100644
>> > --- a/net/bluetooth/msft.c
>> > +++ b/net/bluetooth/msft.c
>> > @@ -387,7 +387,6 @@ static int msft_remove_monitor_sync(struct hci_dev *hdev,
>> >                 return PTR_ERR(skb);
>> >
>> >         status = skb->data[0];
>> > -       skb_pull(skb, 1);
>> >
>> >         msft_le_cancel_monitor_advertisement_cb(hdev, status, hdev->msft_opcode,
>> >                                                 skb);
>> > @@ -506,7 +505,6 @@ static int msft_add_monitor_sync(struct hci_dev *hdev,
>> >                 return PTR_ERR(skb);
>> >
>> >         status = skb->data[0];
>> > -       skb_pull(skb, 1);
>>
>> Well if it expects it to be part of the skb then there is no reason to
>> pass it as argument in addition to the skb itself.
>
> The problem is msft_le_monitor_advertisement_cb() is invoked directly via msft_add_monitor_sync() and also from __msft_add_monitor_pattern() as a callback from hci_req_run_skb(). So, when it is invoked from hci_req_run_skb() it sends status separately as an argument along with the skb and that's why that argument is required.
>
> Looks like some parts of msft.c still use the old way i.e. hci_req_run_skb() instead of __hci_cmd_sync() after hci_sync related refactoring. I am wondering if it was left like this intentionally? If not, then we probably need to refactor msft.c to use __hci_cmd_sync() for all hci requests. In that case, I can work on refactoring and we can discard this patch altogether. Please let me know.

Yes, if you have time please convert it to use hci_sync.c since we
would like to completely deprecate/remove hci_request.c eventually, if
you think that will take some time we can perhaps merge this changes
first though.

>>
>> >         msft_le_monitor_advertisement_cb(hdev, status, hdev->msft_opcode, skb);
>> >
>> > --
>> > 2.36.0.512.ge40c2bad7a-goog
>> >
>>
>>
>> --
>> Luiz Augusto von Dentz
>
> Regards,
> Manish.