mt76: mt76_connac: create mcu library

Hello Lorenzo Bianconi,

The patch d0e274af2f2e: "mt76: mt76_connac: create mcu library" from Jan 26, 2021, leads to the following static checker warning:

	drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.c:837 mt76_connac_mcu_add_sta_cmd()
	error: 'wtbl_hdr' dereferencing possible ERR_PTR()

drivers/net/wireless/mediatek/mt76/mt76_connac_mcu.c
810 int mt76_connac_mcu_add_sta_cmd(struct mt76_phy *phy,

   811                                  struct ieee80211_vif *vif,
   812                                  struct ieee80211_sta *sta,
   813                                  struct mt76_wcid *wcid,
   814                                  bool enable, int cmd)
   815  {
   816          struct mt76_vif *mvif = (struct mt76_vif *)vif->drv_priv;
   817          struct mt76_dev *dev = phy->dev;
   818          struct wtbl_req_hdr *wtbl_hdr;
   819          struct tlv *sta_wtbl;
   820          struct sk_buff *skb;

821
822 skb = mt76_connac_mcu_alloc_sta_req(dev, mvif, wcid);
823 if (IS_ERR(skb))
824 return PTR_ERR(skb);
825
826 mt76_connac_mcu_sta_basic_tlv(skb, vif, sta, enable);
827 if (enable && sta)
828 mt76_connac_mcu_sta_tlv(phy, skb, sta, vif);
829
830 sta_wtbl = mt76_connac_mcu_add_tlv(skb, STA_REC_WTBL,
831 sizeof(struct tlv));
832
833 wtbl_hdr = mt76_connac_mcu_alloc_wtbl_req(dev, wcid,
834 WTBL_RESET_AND_SET,
835 sta_wtbl, &skb);

if (IS_ERR(wtbl_hdr)) {
	do some cleanup?
	return PTR_ERR(wtbl_hdr);
}

836 if (enable) {
837 mt76_connac_mcu_wtbl_generic_tlv(dev, skb, vif, sta, sta_wtbl,
838 wtbl_hdr);
839 if (sta)
840 mt76_connac_mcu_wtbl_ht_tlv(dev, skb, sta, sta_wtbl,
841 wtbl_hdr);
842 }
843
844 return mt76_mcu_skb_send_msg(dev, skb, cmd, true);
845 }

regards,
dan carpenter

Hi Dan,

I think this is a false positive since reviewing mt76_connac_mcu_alloc_wtbl_req(), it can return ERR_PTR(-ENOMEM) only if nskb is NULL and it is not the case.

Regards,
Lorenzo