2023-01-08 21:15:56

by Martin Blumenstingl

[permalink] [raw]
Subject: [PATCH v3 3/3] wifi: rtw88: Use non-atomic sta iterator in rtw_ra_mask_info_update()

USB and (upcoming) SDIO support may sleep in the read/write handlers.
Use non-atomic rtw_iterate_stas() in rtw_ra_mask_info_update() because
the iterator function rtw_ra_mask_info_update_iter() needs to read and
write registers from within rtw_update_sta_info(). Using the non-atomic
iterator ensures that we can sleep during USB and SDIO register reads
and writes. This fixes "scheduling while atomic" or "Voluntary context
switch within RCU read-side critical section!" warnings as seen by SDIO
card users (but it also affects USB cards).

Fixes: 78d5bf925f30 ("wifi: rtw88: iterate over vif/sta list non-atomically")
Suggested-by: Ping-Ke Shih <[email protected]>
Reviewed-by: Ping-Ke Shih <[email protected]>
Tested-by: Sascha Hauer <[email protected]>
Signed-off-by: Martin Blumenstingl <[email protected]>
---
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/mac80211.c | 4 +++-
1 file changed, 3 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/realtek/rtw88/mac80211.c b/drivers/net/wireless/realtek/rtw88/mac80211.c
index 776a9a9884b5..3b92ac611d3f 100644
--- a/drivers/net/wireless/realtek/rtw88/mac80211.c
+++ b/drivers/net/wireless/realtek/rtw88/mac80211.c
@@ -737,7 +737,7 @@ static void rtw_ra_mask_info_update(struct rtw_dev *rtwdev,
br_data.rtwdev = rtwdev;
br_data.vif = vif;
br_data.mask = mask;
- rtw_iterate_stas_atomic(rtwdev, rtw_ra_mask_info_update_iter, &br_data);
+ rtw_iterate_stas(rtwdev, rtw_ra_mask_info_update_iter, &br_data);
}

static int rtw_ops_set_bitrate_mask(struct ieee80211_hw *hw,
@@ -746,7 +746,9 @@ static int rtw_ops_set_bitrate_mask(struct ieee80211_hw *hw,
{
struct rtw_dev *rtwdev = hw->priv;

+ mutex_lock(&rtwdev->mutex);
rtw_ra_mask_info_update(rtwdev, vif, mask);
+ mutex_unlock(&rtwdev->mutex);

return 0;
}
--
2.39.0