Commit 8a1e2fd8 authored by Martin Blumenstingl's avatar Martin Blumenstingl Committed by Kalle Valo
Browse files

wifi: rtw88: Move register access from rtw_bf_assoc() outside the RCU 



USB and (upcoming) SDIO support may sleep in the read/write handlers.
Shrink the RCU critical section so it only cover the call to
ieee80211_find_sta() and finding the ic_vht_cap/vht_cap based on the
found station. This moves the chip's BFEE configuration outside the
rcu_read_lock section and thus 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).

Reviewed-by: default avatarPing-Ke Shih <pkshih@realtek.com>
Tested-by: default avatarSascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: default avatarMartin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: default avatarKalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230108211324.442823-2-martin.blumenstingl@googlemail.com
parent 2a86aa9a

drivers/net/wireless/realtek/rtw88/bf.c

+7 −6
Original line number Diff line number Diff line
@@ -49,19 +49,23 @@ void rtw_bf_assoc(struct rtw_dev *rtwdev, struct ieee80211_vif *vif, 


	sta = ieee80211_find_sta(vif, bssid);

	if (!sta) {

		rcu_read_unlock();



		rtw_warn(rtwdev, "failed to find station entry for bss %pM\n",

			 bssid);

		goto out_unlock;

		return;

	}



	ic_vht_cap = &hw->wiphy->bands[NL80211_BAND_5GHZ]->vht_cap;

	vht_cap = &sta->deflink.vht_cap;



	rcu_read_unlock();



	if ((ic_vht_cap->cap & IEEE80211_VHT_CAP_MU_BEAMFORMEE_CAPABLE) &&

	    (vht_cap->cap & IEEE80211_VHT_CAP_MU_BEAMFORMER_CAPABLE)) {

		if (bfinfo->bfer_mu_cnt >= chip->bfer_mu_max_num) {

			rtw_dbg(rtwdev, RTW_DBG_BF, "mu bfer number over limit\n");

			goto out_unlock;

			return;

		}



		ether_addr_copy(bfee->mac_addr, bssid);
@@ -75,7 +79,7 @@ void rtw_bf_assoc(struct rtw_dev *rtwdev, struct ieee80211_vif *vif, 
		   (vht_cap->cap & IEEE80211_VHT_CAP_SU_BEAMFORMER_CAPABLE)) {

		if (bfinfo->bfer_su_cnt >= chip->bfer_su_max_num) {

			rtw_dbg(rtwdev, RTW_DBG_BF, "su bfer number over limit\n");

			goto out_unlock;

			return;

		}



		sound_dim = vht_cap->cap &
@@ -98,9 +102,6 @@ void rtw_bf_assoc(struct rtw_dev *rtwdev, struct ieee80211_vif *vif, 


		rtw_chip_config_bfee(rtwdev, rtwvif, bfee, true);

	}



out_unlock:

	rcu_read_unlock();

}



void rtw_bf_init_bfer_entry_mu(struct rtw_dev *rtwdev,