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

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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: Ping-Ke Shih <pkshih@realtek.com>
Tested-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20230108211324.442823-2-martin.blumenstingl@googlemail.com
This commit is contained in:
Martin Blumenstingl
2023-01-08 22:13:22 +01:00
committed by Kalle Valo
parent 2a86aa9a18
commit 8a1e2fd8e2
1 changed files with 7 additions and 6 deletions
Download Patch File Download Diff File Expand all files Collapse all files

13
drivers/net/wireless/realtek/rtw88/bf.c
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@@ -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,