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

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Date:   Thu, 7 Oct 2021 08:53:54 -0700
From:   Luiz Augusto von Dentz <luiz.dentz@...il.com>
To:     Marcel Holtmann <marcel@...tmann.org>
Cc:     Colin King <colin.king@...onical.com>,
        Johan Hedberg <johan.hedberg@...il.com>,
        "David S. Miller" <davem@...emloft.net>,
        Jakub Kicinski <kuba@...nel.org>,
        "linux-bluetooth@...r.kernel.org" <linux-bluetooth@...r.kernel.org>,
        "open list:NETWORKING [GENERAL]" <netdev@...r.kernel.org>,
        kernel-janitors@...r.kernel.org,
        Linux Kernel Mailing List <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH][next] Bluetooth: use bitmap_empty to check if a bitmap
 has any bits set

Hi Marcel,

On Thu, Oct 7, 2021 at 8:47 AM Marcel Holtmann <marcel@...tmann.org> wrote:
>
> Hi Luiz,
>
> >> 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@...onical.com>
> >> ---
> >> 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.
>
> so should I take the patch "Fix wake up suspend_wait_q prematurely” completely out?

Yes, please take it out.

-- 
Luiz Augusto von Dentz