Re: [PATCH] drivers:net:wireless: Add proper locking for the function, b43_op_beacon_set_tim in main.c

Michael Büsch
2015-01-02T09:28:41Z

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On Fri, 2 Jan 2015 02:34:01 -0500
Nicholas Krause <xerofoify@gmail.com> wrote:

> This adds proper locking for the function, b43_op_beacon_set_tim in main.c by using the mutex lock
> in the structure pointer wl, as embedded into this pointer as a mutex in order to protect against
> multiple access to the pointer wl when updating the templates for this pointer in the function,
> b43_update_templates internally in the function, b43_op_beacon_set_tim.
>
> Signed-off-by: Nicholas Krause <xerofoify@gmail.com>
> ---
> drivers/net/wireless/b43/main.c | 3 ++-
> 1 file changed, 2 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/wireless/b43/main.c b/drivers/net/wireless/b43/main.c
> index 47731cb..d568fc8 100644
> --- a/drivers/net/wireless/b43/main.c
> +++ b/drivers/net/wireless/b43/main.c
> @@ -5094,8 +5094,9 @@ static int b43_op_beacon_set_tim(struct ieee80211_hw *hw,
> {
> struct b43_wl *wl = hw_to_b43_wl(hw);
>
> - /* FIXME: add locking */
> + mutex_lock(&wl->mutex);
> b43_update_templates(wl);
> + mutex_unlock(&wl->mutex);
>
> return 0;
> }

Thanks for the patch.

However, this does not work. We are in atomic context here.
Please see the b43-dev mailing list archives for a recent thread about that.
I'm also pretty sure that this is safe without lock, due to the higher level locks in mac80211.

--
Michael

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