wifi: mt76: mt7921: refactor regd update to fix recursive mutex deadlock

Split mt7921_mcu_regd_update() into two functions to prevent recursive
mutex acquisition. Introduce __mt7921_mcu_regd_update() as the internal
implementation that assumes the mutex is already held by the caller,
while mt7921_mcu_regd_update() remains as the external interface that
handles mutex acquisition and release.

This fixes a deadlock issue when mt7921_regd_set_6ghz_power_type() is
called with the device mutex already held. Without this change, calling
mt7921_mcu_regd_update() would attempt to acquire the same mutex again,
causing a recursive lock deadlock.

The __mt7921_mcu_regd_update() function can be safely called when the
caller has already acquired the device mutex, avoiding the deadlock
while maintaining proper synchronization for regulatory domain updates.

Fixes: dc2608cf5224 ("wifi: mt76: mt7921: refactor regulatory notifier flow")
Signed-off-by: Charlie-cy Wu <Charlie-cy.Wu@mediatek.com>
Tested-by: Mikhail Gavrilov <mikhail.v.gavrilov@gmail.com>
Tested-by: Devin Wittmayer <lucid_duck@justthetip.ca>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/main.c b/drivers/net/wireless/mediatek/mt76/mt7921/main.c
index 3480205d5fb91be510e6c6bacd36b6cabee68da1..68a059504e838274ffa8308bdb21f8d989585400 100644 (file)
--- a/drivers/net/wireless/mediatek/mt76/mt7921/main.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/main.c
@@ -802,7 +802,7 @@ mt7921_regd_set_6ghz_power_type(struct ieee80211_vif *vif, bool is_add)
 
 out:
        if (vif->bss_conf.chanreq.oper.chan->band == NL80211_BAND_6GHZ)
-               mt7921_mcu_regd_update(dev, dev->mt76.alpha2, dev->country_ie_env);
+               __mt7921_mcu_regd_update(dev, dev->mt76.alpha2, dev->country_ie_env);
 }
 
 int mt7921_mac_sta_add(struct mt76_dev *mdev, struct ieee80211_vif *vif,

diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/regd.c b/drivers/net/wireless/mediatek/mt76/mt7921/regd.c
index c0e2b48a50bf09b5800cf7181e142ba0f275b2e6..4722007abafd5c69c0e3a9e76e08448cb87a75bf 100644 (file)
--- a/drivers/net/wireless/mediatek/mt76/mt7921/regd.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/regd.c
@@ -71,36 +71,44 @@ mt7921_regd_channel_update(struct wiphy *wiphy, struct mt792x_dev *dev)
        }
 }
 
-int mt7921_mcu_regd_update(struct mt792x_dev *dev, u8 *alpha2,
-                          enum environment_cap country_ie_env)
+/* Internal version that assumes mutex is already held by caller */
+int __mt7921_mcu_regd_update(struct mt792x_dev *dev, u8 *alpha2,
+                            enum environment_cap country_ie_env)
 {
        struct mt76_dev *mdev = &dev->mt76;
        struct ieee80211_hw *hw = mdev->hw;
        struct wiphy *wiphy = hw->wiphy;
        int ret = 0;
 
-       dev->regd_in_progress = true;
-
-       mt792x_mutex_acquire(dev);
        if (!dev->regd_change)
-               goto err;
+               return 0;
 
        ret = mt7921_mcu_set_clc(dev, alpha2, country_ie_env);
        if (ret < 0)
-               goto err;
+               return ret;
 
        mt7921_regd_channel_update(wiphy, dev);
 
        ret = mt76_connac_mcu_set_channel_domain(hw->priv);
        if (ret < 0)
-               goto err;
+               return ret;
 
        ret = mt7921_set_tx_sar_pwr(hw, NULL);
-       if (ret < 0)
-               goto err;
 
-err:
+       return ret;
+}
+
+int mt7921_mcu_regd_update(struct mt792x_dev *dev, u8 *alpha2,
+                          enum environment_cap country_ie_env)
+{
+       int ret = 0;
+
+       dev->regd_in_progress = true;
+
+       mt792x_mutex_acquire(dev);
+       ret = __mt7921_mcu_regd_update(dev, alpha2, country_ie_env);
        mt792x_mutex_release(dev);
+
        dev->regd_change = false;
        dev->regd_in_progress = false;
        wake_up(&dev->wait);

diff --git a/drivers/net/wireless/mediatek/mt76/mt7921/regd.h b/drivers/net/wireless/mediatek/mt76/mt7921/regd.h
index 571f31629e9e015756bef9df39a30c38cced7d32..5b24d0902c369ca2141db0486519bad0f6657284 100644 (file)
--- a/drivers/net/wireless/mediatek/mt76/mt7921/regd.h
+++ b/drivers/net/wireless/mediatek/mt76/mt7921/regd.h
@@ -10,6 +10,8 @@ struct regulatory_request;
 
 int mt7921_mcu_regd_update(struct mt792x_dev *dev, u8 *alpha2,
                           enum environment_cap country_ie_env);
+int __mt7921_mcu_regd_update(struct mt792x_dev *dev, u8 *alpha2,
+                            enum environment_cap country_ie_env);
 void mt7921_regd_notifier(struct wiphy *wiphy,
                          struct regulatory_request *request);
 bool mt7921_regd_clc_supported(struct mt792x_dev *dev);