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@xxxxxxxxxxx>
Tested-by: Sascha Hauer <s.hauer@xxxxxxxxxxxxxx>
Signed-off-by: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx>
---
v1 -> v2:
- Added Ping-Ke's Reviewed-by (thank you!)
v2 -> v3:
- Added Sascha's Tested-by (thank you!)
- added "wifi" prefix to the subject and reworded the title accordingly
drivers/net/wireless/realtek/rtw88/bf.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/drivers/net/wireless/realtek/rtw88/bf.c b/drivers/net/wireless/realtek/rtw88/bf.c
index 038a30b170ef..c827c4a2814b 100644
--- a/drivers/net/wireless/realtek/rtw88/bf.c
+++ b/drivers/net/wireless/realtek/rtw88/bf.c
@@ -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,
--
2.39.0
