| Message ID | 20221228133547.633797-3-martin.blumenstingl@googlemail.com |
|---|---|
| State | Superseded |
| Headers | show |
| Series | rtw88: Four fixes found while working on SDIO support | expand |
> -----Original Message----- > From: Martin Blumenstingl <martin.blumenstingl@googlemail.com> > Sent: Wednesday, December 28, 2022 9:36 PM > To: linux-wireless@vger.kernel.org > Cc: tony0620emma@gmail.com; kvalo@kernel.org; Ping-Ke Shih <pkshih@realtek.com>; tehuang@realtek.com; > s.hauer@pengutronix.de; netdev@vger.kernel.org; linux-kernel@vger.kernel.org; Martin Blumenstingl > <martin.blumenstingl@googlemail.com> > Subject: [PATCH 2/4] rtw88: Configure the registers from rtw_bf_assoc() outside the RCU lock > > 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). > > Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com> Reviewed-by: Ping-Ke Shih <pkshih@realtek.com> > --- > 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
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,
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). Signed-off-by: Martin Blumenstingl <martin.blumenstingl@googlemail.com> --- drivers/net/wireless/realtek/rtw88/bf.c | 13 +++++++------ 1 file changed, 7 insertions(+), 6 deletions(-)