[PATCH 5.15 045/230] mt76: mt7921: fix a possible race enabling/disabling runtime-pm

Greg Kroah-Hartman
2022-07-11T09:43:46Z

From: Lorenzo Bianconi <lorenzo@kernel.org>

[ Upstream commit d430dffbe9dd30759f3c64b65bf85b0245c8d8ab ]

Fix a possible race enabling/disabling runtime-pm between
mt7921_pm_set() and mt7921_poll_rx() since mt7921_pm_wake_work()
always schedules rx-napi callback and it will trigger
mt7921_pm_power_save_work routine putting chip to in low-power state
during mt7921_pm_set processing.

Suggested-by: Deren Wu <deren.wu@mediatek.com>
Tested-by: Deren Wu <deren.wu@mediatek.com>
Fixes: 1d8efc741df8 ("mt76: mt7921: introduce Runtime PM support")
Signed-off-by: Lorenzo Bianconi <lorenzo@kernel.org>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/0f3e075a2033dc05f09dab4059e5be8cbdccc239.1640094847.git.lorenzo@kernel.org
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/net/wireless/mediatek/mt76/mt76_connac_mac.c | 3 ---
drivers/net/wireless/mediatek/mt76/mt7921/debugfs.c | 12 +++++++++---
2 files changed, 9 insertions(+), 6 deletions(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt76_connac_mac.c b/drivers/net/wireless/mediatek/mt76/mt76_connac_mac.c
index af43bcb54578..306e9eaea917 100644
--- a/drivers/net/wireless/mediatek/mt76/mt76_connac_mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt76_connac_mac.c
@@ -7,9 +7,6 @@ int mt76_connac_pm_wake(struct mt76_phy *phy, struct mt76_connac_pm *pm)
{
struct mt76_dev *dev = phy->dev;

- if (!pm->enable)
- return 0;
-
if (mt76_is_usb(dev))
return 0;

diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/debugfs.c b/drivers/net/wireless/mediatek/mt76/mt7921/debugfs.c
index 82fb2585f413..b9f25599227d 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7921/debugfs.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/debugfs.c
@@ -276,7 +276,7 @@ mt7921_pm_set(void *data, u64 val)
struct mt7921_dev *dev = data;
struct mt76_connac_pm *pm = &dev->pm;

- mt7921_mutex_acquire(dev);
+ mutex_lock(&dev->mt76.mutex);

if (val == pm->enable)
goto out;
@@ -285,7 +285,11 @@ mt7921_pm_set(void *data, u64 val)
pm->stats.last_wake_event = jiffies;
pm->stats.last_doze_event = jiffies;
}
- pm->enable = val;
+ /* make sure the chip is awake here and ps_work is scheduled
+ * just at end of the this routine.
+ */
+ pm->enable = false;
+ mt76_connac_pm_wake(&dev->mphy, pm);

ieee80211_iterate_active_interfaces(mt76_hw(dev),
IEEE80211_IFACE_ITER_RESUME_ALL,
@@ -293,8 +297,10 @@ mt7921_pm_set(void *data, u64 val)

mt76_connac_mcu_set_deep_sleep(&dev->mt76, pm->ds_enable);

+ pm->enable = val;
+ mt76_connac_power_save_sched(&dev->mphy, pm);
out:
- mt7921_mutex_release(dev);
+ mutex_unlock(&dev->mt76.mutex);

return 0;
}
--
2.35.1