wifi: wfx: scan_lock is global to the device

Currently, one scan_lock is associated to each vif. However, concurrent
scan on vifs is explicitly prohibited by the device. Currently,
scan_lock is associated with a vif but it is always locked with
conf_mutex (there is a case where conf_mutex is not associated to
scan_lock but scan_lock is tested on all interfaces). So concurrent scan
on vifs cannot happen.

So, this patch relocate scan_lock to the device and simplify the code.
Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Signed-off-by: Kalle Valo <kvalo@kernel.org>
Link: https://lore.kernel.org/r/20231004172843.195332-7-jerome.pouiller@silabs.com

drivers/net/wireless/silabs/wfx/main.c

@@ -246,6 +246,7 @@ static void wfx_free_common(void *data)
 
 	mutex_destroy(&wdev->tx_power_loop_info_lock);
 	mutex_destroy(&wdev->rx_stats_lock);
+	mutex_destroy(&wdev->scan_lock);
 	mutex_destroy(&wdev->conf_mutex);
 	ieee80211_free_hw(wdev->hw);
 }
@@ -314,6 +315,7 @@ struct wfx_dev *wfx_init_common(struct device *dev, const struct wfx_platform_da
 		gpiod_set_consumer_name(wdev->pdata.gpio_wakeup, "wfx wakeup");
 
 	mutex_init(&wdev->conf_mutex);
+	mutex_init(&wdev->scan_lock);
 	mutex_init(&wdev->rx_stats_lock);
 	mutex_init(&wdev->tx_power_loop_info_lock);
 	init_completion(&wdev->firmware_ready);

drivers/net/wireless/silabs/wfx/scan.c

@@ -95,7 +95,7 @@ void wfx_hw_scan_work(struct work_struct *work)
 	int chan_cur, ret, err;
 
 	mutex_lock(&wvif->wdev->conf_mutex);
-	mutex_lock(&wvif->scan_lock);
+	mutex_lock(&wvif->wdev->scan_lock);
 	if (wvif->join_in_progress) {
 		dev_info(wvif->wdev->dev, "abort in-progress REQ_JOIN");
 		wfx_reset(wvif);
@@ -116,7 +116,7 @@ void wfx_hw_scan_work(struct work_struct *work)
 			ret = -ETIMEDOUT;
 		}
 	} while (ret >= 0 && chan_cur < hw_req->req.n_channels);
-	mutex_unlock(&wvif->scan_lock);
+	mutex_unlock(&wvif->wdev->scan_lock);
 	mutex_unlock(&wvif->wdev->conf_mutex);
 	wfx_ieee80211_scan_completed_compat(wvif->wdev->hw, ret < 0);
 }

drivers/net/wireless/silabs/wfx/sta.c

@@ -97,7 +97,7 @@ void wfx_configure_filter(struct ieee80211_hw *hw, unsigned int changed_flags,
 			FIF_PROBE_REQ | FIF_PSPOLL;
 
 	/* Filters are ignored during the scan. No frames are filtered. */
-	if (mutex_is_locked(&wvif->scan_lock))
+	if (mutex_is_locked(&wdev->scan_lock))
 		return;
 
 	mutex_lock(&wdev->conf_mutex);
@@ -621,18 +621,14 @@ int wfx_set_tim(struct ieee80211_hw *hw, struct ieee80211_sta *sta, bool set)
 
 void wfx_suspend_resume_mc(struct wfx_vif *wvif, enum sta_notify_cmd notify_cmd)
 {
-	struct wfx_vif *wvif_it;
-
 	if (notify_cmd != STA_NOTIFY_AWAKE)
 		return;
 
 	/* Device won't be able to honor CAB if a scan is in progress on any interface. Prefer to
 	 * skip this DTIM and wait for the next one.
 	 */
-	wvif_it = NULL;
-	while ((wvif_it = wvif_iterate(wvif->wdev, wvif_it)) != NULL)
-		if (mutex_is_locked(&wvif_it->scan_lock))
-			return;
+	if (mutex_is_locked(&wvif->wdev->scan_lock))
+		return;
 
 	if (!wfx_tx_queues_has_cab(wvif) || wvif->after_dtim_tx_allowed)
 		dev_warn(wvif->wdev->dev, "incorrect sequence (%d CAB in queue)",
@@ -730,7 +726,6 @@ int wfx_add_interface(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
 	complete(&wvif->set_pm_mode_complete);
 	INIT_WORK(&wvif->tx_policy_upload_work, wfx_tx_policy_upload_work);
 
-	mutex_init(&wvif->scan_lock);
 	init_completion(&wvif->scan_complete);
 	INIT_WORK(&wvif->scan_work, wfx_hw_scan_work);
 

drivers/net/wireless/silabs/wfx/wfx.h

@@ -43,6 +43,7 @@ struct wfx_dev {
 	struct delayed_work        cooling_timeout_work;
 	bool                       poll_irq;
 	bool                       chip_frozen;
+	struct mutex               scan_lock;
 	struct mutex               conf_mutex;
 
 	struct wfx_hif_cmd         hif_cmd;
@@ -80,8 +81,6 @@ struct wfx_vif {
 
 	unsigned long              uapsd_mask;
 
-	/* avoid some operations in parallel with scan */
-	struct mutex               scan_lock;
 	struct work_struct         scan_work;
 	struct completion          scan_complete;
 	int                        scan_nb_chan_done;