staging: wfx: rewrite wfx_hw_scan()

Scan requests from mac80211 must be splitted in a few hardware requests
(it is necessary to split channels with active scan and channels with
passive scan). Current code schedules a work_struct for each hardware
request and one delayed_work to handle scan timeout.

It is far simpler to run send all the hardware requests synchronously
and replace delayed_work with a simple wait_for_completion_timeout().
Signed-off-by: Jérôme Pouiller <jerome.pouiller@silabs.com>
Link: https://lore.kernel.org/r/20191217161318.31402-51-Jerome.Pouiller@silabs.comSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/staging/wfx/hif_rx.c

@@ -206,7 +206,7 @@ static int hif_scan_complete_indication(struct wfx_dev *wdev,
 	const struct hif_ind_scan_cmpl *body = buf;
 
 	WARN_ON(!wvif);
-	wfx_scan_complete_cb(wvif, body);
+	wfx_scan_complete(wvif, body);
 
 	return 0;
 }

drivers/staging/wfx/scan.c

@@ -22,33 +22,6 @@ static void __ieee80211_scan_completed_compat(struct ieee80211_hw *hw,
 	ieee80211_scan_completed(hw, &info);
 }
 
-static void wfx_scan_restart_delayed(struct wfx_vif *wvif)
-{
-	if (wvif->delayed_unjoin) {
-		wvif->delayed_unjoin = false;
-		if (!schedule_work(&wvif->unjoin_work))
-			wfx_tx_unlock(wvif->wdev);
-	} else if (wvif->delayed_link_loss) {
-		wvif->delayed_link_loss = 0;
-		wfx_cqm_bssloss_sm(wvif, 1, 0, 0);
-	}
-}
-
-static int wfx_scan_start(struct wfx_vif *wvif,
-			  int chan_start_idx, int chan_num)
-{
-	int tmo;
-
-	if (wvif->state == WFX_STATE_PRE_STA)
-		return -EBUSY;
-
-	atomic_set(&wvif->scan.in_progress, 1);
-
-	tmo = hif_scan(wvif, wvif->scan.req, chan_start_idx, chan_num);
-	schedule_delayed_work(&wvif->scan.timeout, tmo);
-	return 0;
-}
-
 static int update_probe_tmpl(struct wfx_vif *wvif,
 			     struct cfg80211_scan_request *req)
 {
@@ -65,153 +38,81 @@ static int update_probe_tmpl(struct wfx_vif *wvif,
 	return 0;
 }
 
-int wfx_hw_scan(struct ieee80211_hw *hw,
-		   struct ieee80211_vif *vif,
+static int send_scan_req(struct wfx_vif *wvif,
+			 struct cfg80211_scan_request *req, int start_idx)
+{
+	int i, ret, timeout;
+	struct ieee80211_channel *ch_start, *ch_cur;
+
+	for (i = start_idx; i < req->n_channels; i++) {
+		ch_start = req->channels[start_idx];
+		ch_cur = req->channels[i];
+		WARN(ch_cur->band != NL80211_BAND_2GHZ, "band not supported");
+		if (ch_cur->max_power != ch_start->max_power)
+			break;
+		if ((ch_cur->flags ^ ch_start->flags) & IEEE80211_CHAN_NO_IR)
+			break;
+	}
+	wfx_tx_lock_flush(wvif->wdev);
+	reinit_completion(&wvif->scan_complete);
+	ret = hif_scan(wvif, req, start_idx, i - start_idx);
+	if (ret < 0)
+		return ret;
+	timeout = ret;
+	ret = wait_for_completion_timeout(&wvif->scan_complete, timeout);
+	if (req->channels[start_idx]->max_power != wvif->wdev->output_power)
+		hif_set_output_power(wvif, wvif->wdev->output_power * 10);
+	wfx_tx_unlock(wvif->wdev);
+	if (!ret) {
+		dev_notice(wvif->wdev->dev, "scan timeout\n");
+		hif_stop_scan(wvif);
+		return -ETIMEDOUT;
+	}
+	return i - start_idx;
+}
+
+int wfx_hw_scan(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 		struct ieee80211_scan_request *hw_req)
 {
 	struct wfx_dev *wdev = hw->priv;
 	struct wfx_vif *wvif = (struct wfx_vif *) vif->drv_priv;
-	struct cfg80211_scan_request *req = &hw_req->req;
-	int i, ret;
+	int chan_cur, ret;
 
-	if (!wvif)
-		return -EINVAL;
+	WARN_ON(hw_req->req.n_channels > HIF_API_MAX_NB_CHANNELS);
 
-	if (wvif->state == WFX_STATE_AP)
+	if (vif->type == NL80211_IFTYPE_AP)
 		return -EOPNOTSUPP;
 
-	if (req->n_ssids == 1 && !req->ssids[0].ssid_len)
-		req->n_ssids = 0;
-
-	if (req->n_ssids > HIF_API_MAX_NB_SSIDS)
-		return -EINVAL;
+	if (wvif->state == WFX_STATE_PRE_STA)
+		return -EBUSY;
 
+	mutex_lock(&wvif->scan_lock);
 	mutex_lock(&wdev->conf_mutex);
-
-	ret = update_probe_tmpl(wvif, req);
-	if (ret)
-		goto failed;
-
-	ret = wfx_fwd_probe_req(wvif, true);
-	if (ret)
-		goto failed;
-
-	wfx_tx_lock_flush(wdev);
-
-	WARN(wvif->scan.req, "unexpected concurrent scan");
-	wvif->scan.req = req;
-	wvif->scan.n_ssids = 0;
-	wvif->scan.status = 0;
-	wvif->scan.begin = &req->channels[0];
-	wvif->scan.curr = wvif->scan.begin;
-	wvif->scan.end = &req->channels[req->n_channels];
-	wvif->scan.output_power = wdev->output_power;
-
-	for (i = 0; i < req->n_ssids; ++i) {
-		struct hif_ssid_def *dst = &wvif->scan.ssids[wvif->scan.n_ssids];
-
-		memcpy(&dst->ssid[0], req->ssids[i].ssid, sizeof(dst->ssid));
-		dst->ssid_length = req->ssids[i].ssid_len;
-		++wvif->scan.n_ssids;
-	}
-	schedule_work(&wvif->scan.work);
-
-failed:
+	update_probe_tmpl(wvif, &hw_req->req);
+	wfx_fwd_probe_req(wvif, true);
+	chan_cur = 0;
+	do {
+		ret = send_scan_req(wvif, &hw_req->req, chan_cur);
+		if (ret > 0)
+			chan_cur += ret;
+	} while (ret > 0 && chan_cur < hw_req->req.n_channels);
+	__ieee80211_scan_completed_compat(hw, ret < 0);
 	mutex_unlock(&wdev->conf_mutex);
-	return ret;
-}
-
-void wfx_scan_work(struct work_struct *work)
-{
-	struct wfx_vif *wvif = container_of(work, struct wfx_vif, scan.work);
-	struct ieee80211_channel **it;
-	struct ieee80211_channel *first;
-	int i;
-
-	down(&wvif->scan.lock);
-	mutex_lock(&wvif->wdev->conf_mutex);
-
-
-	if (!wvif->scan.req || wvif->scan.curr == wvif->scan.end) {
-		if (wvif->scan.output_power != wvif->wdev->output_power)
-			hif_set_output_power(wvif,
-					     wvif->wdev->output_power * 10);
-
-		if (wvif->scan.status < 0)
-			dev_warn(wvif->wdev->dev, "scan failed\n");
-		else if (wvif->scan.req)
-			dev_dbg(wvif->wdev->dev, "scan completed\n");
-		else
-			dev_dbg(wvif->wdev->dev, "scan canceled\n");
-
-		wvif->scan.req = NULL;
-		wfx_scan_restart_delayed(wvif);
-		wfx_tx_unlock(wvif->wdev);
-		mutex_unlock(&wvif->wdev->conf_mutex);
-		__ieee80211_scan_completed_compat(wvif->wdev->hw,
-						  wvif->scan.status ? 1 : 0);
-		up(&wvif->scan.lock);
-		return;
-	}
-	first = *wvif->scan.curr;
-
-	for (it = wvif->scan.curr + 1, i = 1;
-	     it != wvif->scan.end && i < HIF_API_MAX_NB_CHANNELS;
-	     ++it, ++i) {
-		if ((*it)->band != first->band)
-			break;
-		if (((*it)->flags ^ first->flags) &
-				IEEE80211_CHAN_NO_IR)
-			break;
-		if (!(first->flags & IEEE80211_CHAN_NO_IR) &&
-		    (*it)->max_power != first->max_power)
-			break;
-	}
-	if (!(first->flags & IEEE80211_CHAN_NO_IR) &&
-	    wvif->scan.output_power != first->max_power) {
-		wvif->scan.output_power = first->max_power;
-		hif_set_output_power(wvif, wvif->scan.output_power * 10);
+	mutex_unlock(&wvif->scan_lock);
+	if (wvif->delayed_unjoin) {
+		wvif->delayed_unjoin = false;
+		wfx_tx_lock(wdev);
+		if (!schedule_work(&wvif->unjoin_work))
+			wfx_tx_unlock(wdev);
+	} else if (wvif->delayed_link_loss) {
+		wvif->delayed_link_loss = false;
+		wfx_cqm_bssloss_sm(wvif, 1, 0, 0);
 	}
-	wvif->scan.status = wfx_scan_start(wvif,
-					   wvif->scan.curr - wvif->scan.begin,
-					   it - wvif->scan.curr);
-	if (wvif->scan.status)
-		goto fail;
-	wvif->scan.curr = it;
-	mutex_unlock(&wvif->wdev->conf_mutex);
-	return;
-
-fail:
-	wvif->scan.curr = wvif->scan.end;
-	mutex_unlock(&wvif->wdev->conf_mutex);
-	up(&wvif->scan.lock);
-	schedule_work(&wvif->scan.work);
+	return 0;
 }
 
-void wfx_scan_complete_cb(struct wfx_vif *wvif,
+void wfx_scan_complete(struct wfx_vif *wvif,
 		       const struct hif_ind_scan_cmpl *arg)
 {
-	if (cancel_delayed_work_sync(&wvif->scan.timeout) > 0) {
-		wvif->scan.status = 1;
-		schedule_work(&wvif->scan.timeout.work);
-	}
-}
-
-void wfx_scan_timeout(struct work_struct *work)
-{
-	struct wfx_vif *wvif = container_of(work, struct wfx_vif,
-					    scan.timeout.work);
-
-	if (atomic_xchg(&wvif->scan.in_progress, 0)) {
-		if (wvif->scan.status > 0) {
-			wvif->scan.status = 0;
-		} else if (!wvif->scan.status) {
-			dev_warn(wvif->wdev->dev, "timeout waiting for scan complete notification\n");
-			wvif->scan.status = -ETIMEDOUT;
-			wvif->scan.curr = wvif->scan.end;
-			hif_stop_scan(wvif);
-		}
-		up(&wvif->scan.lock);
-		wfx_scan_work(&wvif->scan.work);
-	}
+	complete(&wvif->scan_complete);
 }

drivers/staging/wfx/scan.h

@@ -8,8 +8,6 @@
 #ifndef WFX_SCAN_H
 #define WFX_SCAN_H
 
-#include <linux/semaphore.h>
-#include <linux/workqueue.h>
 #include <net/mac80211.h>
 
 #include "hif_api_cmd.h"
@@ -17,26 +15,9 @@
 struct wfx_dev;
 struct wfx_vif;
 
-struct wfx_scan {
-	struct semaphore lock;
-	struct work_struct work;
-	struct delayed_work timeout;
-	struct cfg80211_scan_request *req;
-	struct ieee80211_channel **begin;
-	struct ieee80211_channel **curr;
-	struct ieee80211_channel **end;
-	struct hif_ssid_def ssids[HIF_API_MAX_NB_SSIDS];
-	int output_power;
-	int n_ssids;
-	int status;
-	atomic_t in_progress;
-};
-
 int wfx_hw_scan(struct ieee80211_hw *hw, struct ieee80211_vif *vif,
 		struct ieee80211_scan_request *req);
-void wfx_scan_work(struct work_struct *work);
-void wfx_scan_timeout(struct work_struct *work);
-void wfx_scan_complete_cb(struct wfx_vif *wvif,
-			  const struct hif_ind_scan_cmpl *arg);
+void wfx_scan_complete(struct wfx_vif *wvif,
+		       const struct hif_ind_scan_cmpl *ind);
 
 #endif /* WFX_SCAN_H */

drivers/staging/wfx/sta.c

@@ -277,13 +277,13 @@ void wfx_configure_filter(struct ieee80211_hw *hw,
 	*total_flags &= FIF_OTHER_BSS | FIF_FCSFAIL | FIF_PROBE_REQ;
 
 	while ((wvif = wvif_iterate(wdev, wvif)) != NULL) {
-		down(&wvif->scan.lock);
+		mutex_lock(&wvif->scan_lock);
 		wvif->filter_bssid = (*total_flags &
 				      (FIF_OTHER_BSS | FIF_PROBE_REQ)) ? 0 : 1;
 		wvif->disable_beacon_filter = !(*total_flags & FIF_PROBE_REQ);
 		wfx_fwd_probe_req(wvif, true);
 		wfx_update_filtering(wvif);
-		up(&wvif->scan.lock);
+		mutex_unlock(&wvif->scan_lock);
 	}
 }
 
@@ -433,9 +433,9 @@ static void wfx_event_handler_work(struct work_struct *work)
 		switch (event->evt.event_id) {
 		case HIF_EVENT_IND_BSSLOST:
 			cancel_work_sync(&wvif->unjoin_work);
-			if (!down_trylock(&wvif->scan.lock)) {
+			if (mutex_trylock(&wvif->scan_lock)) {
 				wfx_cqm_bssloss_sm(wvif, 1, 0, 0);
-				up(&wvif->scan.lock);
+				mutex_unlock(&wvif->scan_lock);
 			} else {
 				/* Scan is in progress. Delay reporting.
 				 * Scan complete will trigger bss_loss_work
@@ -501,7 +501,7 @@ static void wfx_do_unjoin(struct wfx_vif *wvif)
 {
 	mutex_lock(&wvif->wdev->conf_mutex);
 
-	if (atomic_read(&wvif->scan.in_progress)) {
+	if (!mutex_trylock(&wvif->scan_lock)) {
 		if (wvif->delayed_unjoin)
 			dev_dbg(wvif->wdev->dev,
 				"delayed unjoin is already scheduled\n");
@@ -509,6 +509,7 @@ static void wfx_do_unjoin(struct wfx_vif *wvif)
 			wvif->delayed_unjoin = true;
 		goto done;
 	}
+	mutex_unlock(&wvif->scan_lock);
 
 	wvif->delayed_link_loss = false;
 
@@ -613,14 +614,6 @@ static void wfx_do_join(struct wfx_vif *wvif)
 
 	mutex_lock(&wvif->wdev->conf_mutex);
 
-	/* Under the conf lock: check scan status and
-	 * bail out if it is in progress.
-	 */
-	if (atomic_read(&wvif->scan.in_progress)) {
-		wfx_tx_unlock(wvif->wdev);
-		goto done_put;
-	}
-
 	/* Sanity check basic rates */
 	if (!join.basic_rate_set)
 		join.basic_rate_set = 7;
@@ -684,7 +677,6 @@ static void wfx_do_join(struct wfx_vif *wvif)
 	}
 	wfx_update_filtering(wvif);
 
-done_put:
 	mutex_unlock(&wvif->wdev->conf_mutex);
 	if (bss)
 		cfg80211_put_bss(wvif->wdev->hw->wiphy, bss);
@@ -1346,7 +1338,7 @@ int wfx_config(struct ieee80211_hw *hw, u32 changed)
 		return 0;
 	}
 
-	down(&wvif->scan.lock);
+	mutex_lock(&wvif->scan_lock);
 	mutex_lock(&wdev->conf_mutex);
 	if (changed & IEEE80211_CONF_CHANGE_POWER) {
 		wdev->output_power = conf->power_level;
@@ -1361,7 +1353,7 @@ int wfx_config(struct ieee80211_hw *hw, u32 changed)
 	}
 
 	mutex_unlock(&wdev->conf_mutex);
-	up(&wvif->scan.lock);
+	mutex_unlock(&wvif->scan_lock);
 	return ret;
 }
 
@@ -1419,10 +1411,6 @@ int wfx_add_interface(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
 	wvif->wep_default_key_id = -1;
 	INIT_WORK(&wvif->wep_key_work, wfx_wep_key_work);
 
-	sema_init(&wvif->scan.lock, 1);
-	INIT_WORK(&wvif->scan.work, wfx_scan_work);
-	INIT_DELAYED_WORK(&wvif->scan.timeout, wfx_scan_timeout);
-
 	spin_lock_init(&wvif->event_queue_lock);
 	INIT_LIST_HEAD(&wvif->event_queue);
 	INIT_WORK(&wvif->event_handler_work, wfx_event_handler_work);
@@ -1435,8 +1423,11 @@ int wfx_add_interface(struct ieee80211_hw *hw, struct ieee80211_vif *vif)
 	INIT_WORK(&wvif->bss_params_work, wfx_bss_params_work);
 	INIT_WORK(&wvif->set_cts_work, wfx_set_cts_work);
 	INIT_WORK(&wvif->unjoin_work, wfx_unjoin_work);
-
 	INIT_WORK(&wvif->tx_policy_upload_work, wfx_tx_policy_upload_work);
+
+	mutex_init(&wvif->scan_lock);
+	init_completion(&wvif->scan_complete);
+
 	mutex_unlock(&wdev->conf_mutex);
 
 	hif_set_macaddr(wvif, vif->addr);
@@ -1462,10 +1453,6 @@ void wfx_remove_interface(struct ieee80211_hw *hw,
 	struct wfx_vif *wvif = (struct wfx_vif *) vif->drv_priv;
 	int i;
 
-	// If scan is in progress, stop it
-	while (down_trylock(&wvif->scan.lock))
-		schedule();
-	up(&wvif->scan.lock);
 	wait_for_completion_timeout(&wvif->set_pm_mode_complete, msecs_to_jiffies(300));
 
 	mutex_lock(&wdev->conf_mutex);
@@ -1505,8 +1492,6 @@ void wfx_remove_interface(struct ieee80211_hw *hw,
 	/* FIXME: In add to reset MAC address, try to reset interface */
 	hif_set_macaddr(wvif, NULL);
 
-	cancel_delayed_work_sync(&wvif->scan.timeout);
-
 	wfx_cqm_bssloss_sm(wvif, 0, 0, 0);
 	cancel_work_sync(&wvif->unjoin_work);
 	cancel_delayed_work_sync(&wvif->link_id_gc_work);

drivers/staging/wfx/wfx.h

@@ -125,7 +125,9 @@ struct wfx_vif {
 	bool			delayed_unjoin;
 	struct work_struct	unjoin_work;
 
-	struct wfx_scan		scan;
+	/* avoid some operations in parallel with scan */
+	struct mutex		scan_lock;
+	struct completion	scan_complete;
 
 	struct completion	set_pm_mode_complete;