> -----Original Message-----
> From: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>
> Sent: Wednesday, December 28, 2022 9:36 PM
> To: linux-wireless@xxxxxxxxxxxxxxx
> Cc: tony0620emma@xxxxxxxxx; kvalo@xxxxxxxxxx; Ping-Ke Shih <pkshih@xxxxxxxxxxx>; tehuang@xxxxxxxxxxx;
> s.hauer@xxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; linux-kernel@xxxxxxxxxxxxxxx; Martin Blumenstingl
> <martin.blumenstingl@xxxxxxxxxxxxxx>
> Subject: [PATCH 3/4] rtw88: Use rtw_iterate_vifs() for rtw_vif_watch_dog_iter()
>
> USB and (upcoming) SDIO support may sleep in the read/write handlers.
> Make rtw_watch_dog_work() use rtw_iterate_vifs() to prevent "scheduling
> while atomic" or "Voluntary context switch within RCU read-side
> critical section!" warnings when accessing the registers using an SDIO
> card (which is where this issue has been spotted in the real world but
> it also affects USB cards).
>
> Fixes: 78d5bf925f30 ("wifi: rtw88: iterate over vif/sta list non-atomically")
> Suggested-by: Ping-Ke Shih <pkshih@xxxxxxxxxxx>
> Signed-off-by: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>
Reviewed-by: Ping-Ke Shih <pkshih@xxxxxxxxxxx>
> ---
> drivers/net/wireless/realtek/rtw88/main.c | 6 ++++--
> 1 file changed, 4 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/wireless/realtek/rtw88/main.c b/drivers/net/wireless/realtek/rtw88/main.c
> index 888427cf3bdf..b2e78737bd5d 100644
> --- a/drivers/net/wireless/realtek/rtw88/main.c
> +++ b/drivers/net/wireless/realtek/rtw88/main.c
> @@ -241,8 +241,10 @@ static void rtw_watch_dog_work(struct work_struct *work)
> rtw_phy_dynamic_mechanism(rtwdev);
>
> data.rtwdev = rtwdev;
> - /* use atomic version to avoid taking local->iflist_mtx mutex */
> - rtw_iterate_vifs_atomic(rtwdev, rtw_vif_watch_dog_iter, &data);
> + /* rtw_iterate_vifs internally uses an atomic iterator which is needed
> + * to avoid taking local->iflist_mtx mutex
> + */
> + rtw_iterate_vifs(rtwdev, rtw_vif_watch_dog_iter, &data);
>
> /* fw supports only one station associated to enter lps, if there are
> * more than two stations associated to the AP, then we can not enter
> --
> 2.39.0
