wifi: rtw88: Drop coex mutex

coex->mutex is used in rtw_coex_info_request() only. Most callers of this
function hold rtwdev->mutex already, except for one callsite in the
debugfs code. The debugfs code alone doesn't justify the extra lock, so
acquire rtwdev->mutex there as well and drop the now unnecessary
spinlock.
Signed-off-by: Sascha Hauer <s.hauer@pengutronix.de>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20221202081224.2779981-6-s.hauer@pengutronix.de

drivers/net/wireless/realtek/rtw88/coex.c

@@ -633,7 +633,7 @@ static struct sk_buff *rtw_coex_info_request(struct rtw_dev *rtwdev,
 	struct rtw_coex *coex = &rtwdev->coex;
 	struct sk_buff *skb_resp = NULL;
 
-	mutex_lock(&coex->mutex);
+	lockdep_assert_held(&rtwdev->mutex);
 
 	rtw_fw_query_bt_mp_info(rtwdev, req);
 
@@ -650,7 +650,6 @@ static struct sk_buff *rtw_coex_info_request(struct rtw_dev *rtwdev,
 	}
 
 out:
-	mutex_unlock(&coex->mutex);
 	return skb_resp;
 }
 

drivers/net/wireless/realtek/rtw88/debug.c

@@ -841,7 +841,9 @@ static int rtw_debugfs_get_coex_info(struct seq_file *m, void *v)
 	struct rtw_debugfs_priv *debugfs_priv = m->private;
 	struct rtw_dev *rtwdev = debugfs_priv->rtwdev;
 
+	mutex_lock(&rtwdev->mutex);
 	rtw_coex_display_coex_info(rtwdev, m);
+	mutex_unlock(&rtwdev->mutex);
 
 	return 0;
 }

drivers/net/wireless/realtek/rtw88/main.c

@@ -2071,7 +2071,6 @@ int rtw_core_init(struct rtw_dev *rtwdev)
 	spin_lock_init(&rtwdev->tx_report.q_lock);
 
 	mutex_init(&rtwdev->mutex);
-	mutex_init(&rtwdev->coex.mutex);
 	mutex_init(&rtwdev->hal.tx_power_mutex);
 
 	init_waitqueue_head(&rtwdev->coex.wait);
@@ -2143,7 +2142,6 @@ void rtw_core_deinit(struct rtw_dev *rtwdev)
 	}
 
 	mutex_destroy(&rtwdev->mutex);
-	mutex_destroy(&rtwdev->coex.mutex);
 	mutex_destroy(&rtwdev->hal.tx_power_mutex);
 }
 EXPORT_SYMBOL(rtw_core_deinit);

drivers/net/wireless/realtek/rtw88/main.h

@@ -1501,8 +1501,6 @@ struct rtw_coex_stat {
 };
 
 struct rtw_coex {
-	/* protects coex info request section */
-	struct mutex mutex;
 	struct sk_buff_head queue;
 	wait_queue_head_t wait;