[PATCH 1/2] mt76: mt7921: add mt7921_mutex_acquire at mt7921_[start, stop]_ap

[Lorenzo Bianconi]

> From: Sean Wang <sean.wang at mediatek.com>
> 
> Add mt7921_mutex_acquire at mt7921_[start, stop]_ap to fix the race
> with the context holding dev->muxtex and the driver might access the
> device in low power state.
> 
> Fixes: 9d958b60ebc2 ("mt76: mt7921: fix command timeout in AP stop period")
> Signed-off-by: Sean Wang <sean.wang at mediatek.com>
> ---
>  .../net/wireless/mediatek/mt76/mt7921/main.c  | 21 ++++++++++++++-----
>  1 file changed, 16 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/main.c b/drivers/net/wireless/mediatek/mt76/mt7921/main.c
> index 1438a9f8d1fd..7a4a3ed1817e 100644
> --- a/drivers/net/wireless/mediatek/mt76/mt7921/main.c
> +++ b/drivers/net/wireless/mediatek/mt76/mt7921/main.c
> @@ -1526,17 +1526,23 @@ mt7921_start_ap(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
>  	struct mt7921_dev *dev = mt7921_hw_dev(hw);
>  	int err;
>  
> +	mt7921_mutex_acquire(dev);
> +
>  	err = mt76_connac_mcu_uni_add_bss(phy->mt76, vif, &mvif->sta.wcid,
>  					  true);
>  	if (err)
> -		return err;
> +		goto failed;
>  
>  	err = mt7921_mcu_set_bss_pm(dev, vif, true);
>  	if (err)
> -		return err;
> +		goto failed;
> +
> +	err = mt7921_mcu_sta_update(dev, NULL, vif, true,
> +				    MT76_STA_INFO_STATE_NONE);

nit: maybe better "out" instead of "failed"

> +failed:
> +	mt7921_mutex_release(dev);
>  
> -	return mt7921_mcu_sta_update(dev, NULL, vif, true,
> -				     MT76_STA_INFO_STATE_NONE);
> +	return err;
>  }
>  
>  static void
> @@ -1548,11 +1554,16 @@ mt7921_stop_ap(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
>  	struct mt7921_dev *dev = mt7921_hw_dev(hw);
>  	int err;
>  
> +	mt7921_mutex_acquire(dev);
> +
>  	err = mt7921_mcu_set_bss_pm(dev, vif, false);
>  	if (err)
> -		return;
> +		goto failed;
>  
>  	mt76_connac_mcu_uni_add_bss(phy->mt76, vif, &mvif->sta.wcid, false);
> +
> +failed:

same here

> +	mt7921_mutex_release(dev);
>  }
>  
>  const struct ieee80211_ops mt7921_ops = {
> -- 
> 2.25.1
> 
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