Re: [PATCH][next] Bluetooth: use bitmap_empty to check if a bitmap has any bits set

[Colin Ian King]

On 07/10/2021 16:34, Luiz Augusto von Dentz wrote:
> Hi Colin,
>
> On Thu, Oct 7, 2021 at 4:17 AM Colin King <colin.king@xxxxxxxxxxxxx> wrote:
> > From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> >
> > The check to see if any tasks are left checks if bitmap array is zero
> > rather than using the appropriate bitmap helper functions to check the
> > bits in the array. Fix this by using bitmap_empty on the bitmap.
> >
> > Addresses-Coverity: (" Array compared against 0")
> > Fixes: 912730b52552 ("Bluetooth: Fix wake up suspend_wait_q prematurely")
> > Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> > ---
> >   net/bluetooth/hci_request.c | 2 +-
> >   1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/net/bluetooth/hci_request.c b/net/bluetooth/hci_request.c
> > index 209f4fe17237..bad3b9c895ba 100644
> > --- a/net/bluetooth/hci_request.c
> > +++ b/net/bluetooth/hci_request.c
> > @@ -1108,7 +1108,7 @@ static void suspend_req_complete(struct hci_dev *hdev, u8 status, u16 opcode)
> >          clear_bit(SUSPEND_SET_ADV_FILTER, hdev->suspend_tasks);
> >
> >          /* Wake up only if there are no tasks left */
> > -       if (!hdev->suspend_tasks)
> > +       if (!bitmap_empty(hdev->suspend_tasks, __SUSPEND_NUM_TASKS))
> >                  wake_up(&hdev->suspend_wait_q);
> >   }
> >
> > --
> > 2.32.0
>
> I was going to revert this change since it appears wake_up does
> actually check the wake condition there is no premature wake up after
> all.
OK, makes sense.

Colin