> -----Original Message----- > From: Martin Blumenstingl [mailto:martin.blumenstingl@xxxxxxxxxxxxxx] > Sent: Sunday, July 18, 2021 4:41 AM > To: linux-wireless@xxxxxxxxxxxxxxx > Cc: tony0620emma@xxxxxxxxx; kvalo@xxxxxxxxxxxxxx; johannes@xxxxxxxxxxxxxxxx; netdev@xxxxxxxxxxxxxxx; > linux-kernel@xxxxxxxxxxxxxxx; Neo Jou; Jernej Skrabec; Martin Blumenstingl > Subject: [PATCH RFC v1 5/7] rtw88: Configure the registers from rtw_bf_assoc() outside the RCU lock > > Upcoming SDIO support may sleep in the read/write handlers. Configure > the chip's BFEE configuration set from rtw_bf_assoc() outside the > rcu_read_lock section to prevent a "scheduling while atomic" issue. > > Signed-off-by: Martin Blumenstingl <martin.blumenstingl@xxxxxxxxxxxxxx> > --- > drivers/net/wireless/realtek/rtw88/bf.c | 8 ++++++-- > 1 file changed, 6 insertions(+), 2 deletions(-) > > diff --git a/drivers/net/wireless/realtek/rtw88/bf.c b/drivers/net/wireless/realtek/rtw88/bf.c > index aff70e4ae028..06034d5d6f6c 100644 > --- a/drivers/net/wireless/realtek/rtw88/bf.c > +++ b/drivers/net/wireless/realtek/rtw88/bf.c > @@ -39,6 +39,7 @@ void rtw_bf_assoc(struct rtw_dev *rtwdev, struct ieee80211_vif *vif, > struct ieee80211_sta_vht_cap *vht_cap; > struct ieee80211_sta_vht_cap *ic_vht_cap; > const u8 *bssid = bss_conf->bssid; > + bool config_bfee = false; > u32 sound_dim; > u8 i; > The rcu_read_lock() in this function is used to access ieee80211_find_sta() and protect 'sta'. A simple way is to shrink the critical section, like: rcu_read_lock(); sta = ieee80211_find_sta(vif, bssid); if (!sta) { rtw_warn(rtwdev, "failed to find station entry for bss %pM\n", bssid); rcu_read_unlock(); } vht_cap = &sta->vht_cap; rcu_read_unlock(); -- Ping-Ke
