[PATCH v7 3/6] wifi: mt76: mt7925: add mutex protection in critical paths

[Zac]

Add proper mutex protection for mt7925 driver operations that access
hardware state without proper synchronization. This fixes race conditions
that can cause system instability during power management and recovery.

Fixes:

1. mac.c: mt7925_mac_reset_work()
   - Wrap ieee80211_iterate_active_interfaces() with mt792x_mutex
   - The vif_connect_iter callback accesses hardware state

2. main.c: mt7925_set_runtime_pm()
   - Add mutex protection around ieee80211_iterate_active_interfaces()
   - Runtime PM can race with other operations

These protections ensure consistent hardware state access during power
management transitions and recovery operations.

Fixes: c948b5da6bbe ("wifi: mt76: mt7925: add Mediatek Wi-Fi7 driver for mt7925 device")
Signed-off-by: Zac Bowling <zac at zacbowling.com>
---
 drivers/net/wireless/mediatek/mt76/mt7925/mac.c  | 2 ++
 drivers/net/wireless/mediatek/mt76/mt7925/main.c | 2 ++
 2 files changed, 4 insertions(+)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/mac.c b/drivers/net/wireless/mediatek/mt76/mt7925/mac.c
index f1f0bc9eab04..88cf214ab452 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/mac.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/mac.c
@@ -1330,9 +1330,11 @@ void mt7925_mac_reset_work(struct work_struct *work)
 	dev->hw_full_reset = false;
 	pm->suspended = false;
 	ieee80211_wake_queues(hw);
+	mt792x_mutex_acquire(dev);
 	ieee80211_iterate_active_interfaces(hw,
 					    IEEE80211_IFACE_ITER_RESUME_ALL,
 					    mt7925_vif_connect_iter, NULL);
+	mt792x_mutex_release(dev);
 	mt76_connac_power_save_sched(&dev->mt76.phy, pm);
 
 	mt7925_regd_change(&dev->phy, "00");
diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/main.c b/drivers/net/wireless/mediatek/mt76/mt7925/main.c
index 88ee90709b75..82de6f30ec27 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/main.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/main.c
@@ -770,9 +770,11 @@ void mt7925_set_runtime_pm(struct mt792x_dev *dev)
 	bool monitor = !!(hw->conf.flags & IEEE80211_CONF_MONITOR);
 
 	pm->enable = pm->enable_user && !monitor;
+	mt792x_mutex_acquire(dev);
 	ieee80211_iterate_active_interfaces(hw,
 					    IEEE80211_IFACE_ITER_RESUME_ALL,
 					    mt7925_pm_interface_iter, dev);
+	mt792x_mutex_release(dev);
 	pm->ds_enable = pm->ds_enable_user && !monitor;
 	mt7925_mcu_set_deep_sleep(dev, pm->ds_enable);
 }
-- 
2.52.0