wil6210: handle multiple connect/disconnect events

In the current solution wil6210 configures the vring in a worker
and holds only one pending CID. This implementation may lead to
race conditions between connect and disconnect events of multiple
stations or fast connect/disconnect events of the same station.

In order to allow the removal of the connect worker and handling of
WMI_VRING_CFG_DONE_EVENTID in the connect event, the WMI replies
that provide the reply in a given buffer needs to be handled
immediately in the WMI event interrupt thread.
To prevent deadlocks, WMI replies that requires additional
handling are still handled via the events list.
Signed-off-by: Maya Erez <qca_merez@qca.qualcomm.com>
Signed-off-by: Kalle Valo <kvalo@qca.qualcomm.com>

drivers/net/wireless/ath/wil6210/main.c

 /*
- * Copyright (c) 2012-2015 Qualcomm Atheros, Inc.
+ * Copyright (c) 2012-2016 Qualcomm Atheros, Inc.
  *
  * Permission to use, copy, modify, and/or distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -155,7 +155,7 @@ __acquires(&sta->tid_rx_lock) __releases(&sta->tid_rx_lock)
 
 	if (sta->status != wil_sta_unused) {
 		if (!from_event)
-			wmi_disconnect_sta(wil, sta->addr, reason_code);
+			wmi_disconnect_sta(wil, sta->addr, reason_code, true);
 
 		switch (wdev->iftype) {
 		case NL80211_IFTYPE_AP:
@@ -195,8 +195,8 @@ static void _wil6210_disconnect(struct wil6210_priv *wil, const u8 *bssid,
 	struct wireless_dev *wdev = wil->wdev;
 
 	might_sleep();
-	wil_dbg_misc(wil, "%s(bssid=%pM, reason=%d, ev%s)\n", __func__, bssid,
-		     reason_code, from_event ? "+" : "-");
+	wil_info(wil, "%s(bssid=%pM, reason=%d, ev%s)\n", __func__, bssid,
+		 reason_code, from_event ? "+" : "-");
 
 	/* Cases are:
 	 * - disconnect single STA, still connected
@@ -258,13 +258,16 @@ static void wil_disconnect_worker(struct work_struct *work)
 static void wil_connect_timer_fn(ulong x)
 {
 	struct wil6210_priv *wil = (void *)x;
+	bool q;
 
-	wil_dbg_misc(wil, "Connect timeout\n");
+	wil_err(wil, "Connect timeout detected, disconnect station\n");
 
 	/* reschedule to thread context - disconnect won't
-	 * run from atomic context
+	 * run from atomic context.
+	 * queue on wmi_wq to prevent race with connect event.
 	 */
-	schedule_work(&wil->disconnect_worker);
+	q = queue_work(wil->wmi_wq, &wil->disconnect_worker);
+	wil_dbg_wmi(wil, "queue_work of disconnect_worker -> %d\n", q);
 }
 
 static void wil_scan_timer_fn(ulong x)
@@ -369,6 +372,32 @@ static int wil_find_free_vring(struct wil6210_priv *wil)
 	return -EINVAL;
 }
 
+int wil_tx_init(struct wil6210_priv *wil, int cid)
+{
+	int rc = -EINVAL, ringid;
+
+	if (cid < 0) {
+		wil_err(wil, "No connection pending\n");
+		goto out;
+	}
+	ringid = wil_find_free_vring(wil);
+	if (ringid < 0) {
+		wil_err(wil, "No free vring found\n");
+		goto out;
+	}
+
+	wil_dbg_wmi(wil, "Configure for connection CID %d vring %d\n",
+		    cid, ringid);
+
+	rc = wil_vring_init_tx(wil, ringid, 1 << tx_ring_order, cid, 0);
+	if (rc)
+		wil_err(wil, "wil_vring_init_tx for CID %d vring %d failed\n",
+			cid, ringid);
+
+out:
+	return rc;
+}
+
 int wil_bcast_init(struct wil6210_priv *wil)
 {
 	int ri = wil->bcast_vring, rc;
@@ -399,41 +428,6 @@ void wil_bcast_fini(struct wil6210_priv *wil)
 	wil_vring_fini_tx(wil, ri);
 }
 
-static void wil_connect_worker(struct work_struct *work)
-{
-	int rc, cid, ringid;
-	struct wil6210_priv *wil = container_of(work, struct wil6210_priv,
-						connect_worker);
-	struct net_device *ndev = wil_to_ndev(wil);
-
-	mutex_lock(&wil->mutex);
-
-	cid = wil->pending_connect_cid;
-	if (cid < 0) {
-		wil_err(wil, "No connection pending\n");
-		goto out;
-	}
-	ringid = wil_find_free_vring(wil);
-	if (ringid < 0) {
-		wil_err(wil, "No free vring found\n");
-		goto out;
-	}
-
-	wil_dbg_wmi(wil, "Configure for connection CID %d vring %d\n",
-		    cid, ringid);
-
-	rc = wil_vring_init_tx(wil, ringid, 1 << tx_ring_order, cid, 0);
-	wil->pending_connect_cid = -1;
-	if (rc == 0) {
-		wil->sta[cid].status = wil_sta_connected;
-		netif_tx_wake_all_queues(ndev);
-	} else {
-		wil_disconnect_cid(wil, cid, WLAN_REASON_UNSPECIFIED, true);
-	}
-out:
-	mutex_unlock(&wil->mutex);
-}
-
 int wil_priv_init(struct wil6210_priv *wil)
 {
 	uint i;
@@ -453,12 +447,10 @@ int wil_priv_init(struct wil6210_priv *wil)
 	init_completion(&wil->wmi_ready);
 	init_completion(&wil->wmi_call);
 
-	wil->pending_connect_cid = -1;
 	wil->bcast_vring = -1;
 	setup_timer(&wil->connect_timer, wil_connect_timer_fn, (ulong)wil);
 	setup_timer(&wil->scan_timer, wil_scan_timer_fn, (ulong)wil);
 
-	INIT_WORK(&wil->connect_worker, wil_connect_worker);
 	INIT_WORK(&wil->disconnect_worker, wil_disconnect_worker);
 	INIT_WORK(&wil->wmi_event_worker, wmi_event_worker);
 	INIT_WORK(&wil->fw_error_worker, wil_fw_error_worker);
@@ -844,7 +836,6 @@ int wil_reset(struct wil6210_priv *wil, bool load_fw)
 	}
 
 	/* init after reset */
-	wil->pending_connect_cid = -1;
 	wil->ap_isolate = 0;
 	reinit_completion(&wil->wmi_ready);
 	reinit_completion(&wil->wmi_call);

drivers/net/wireless/ath/wil6210/txrx.c

@@ -794,6 +794,9 @@ int wil_vring_init_tx(struct wil6210_priv *wil, int id, int size,
 	txdata->dot1x_open = false;
 	txdata->enabled = 0;
 	wil_vring_free(wil, vring, 1);
+	wil->vring2cid_tid[id][0] = WIL6210_MAX_CID;
+	wil->vring2cid_tid[id][1] = 0;
+
  out:
 
 	return rc;

drivers/net/wireless/ath/wil6210/wil6210.h

 /*
- * Copyright (c) 2012-2015 Qualcomm Atheros, Inc.
+ * Copyright (c) 2012-2016 Qualcomm Atheros, Inc.
  *
  * Permission to use, copy, modify, and/or distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -581,12 +581,10 @@ struct wil6210_priv {
 	struct workqueue_struct *wmi_wq; /* for deferred calls */
 	struct work_struct wmi_event_worker;
 	struct workqueue_struct *wq_service;
-	struct work_struct connect_worker;
 	struct work_struct disconnect_worker;
 	struct work_struct fw_error_worker;	/* for FW error recovery */
 	struct timer_list connect_timer;
 	struct timer_list scan_timer; /* detect scan timeout */
-	int pending_connect_cid;
 	struct list_head pending_wmi_ev;
 	/*
 	 * protect pending_wmi_ev
@@ -756,7 +754,8 @@ int wmi_rx_chain_add(struct wil6210_priv *wil, struct vring *vring);
 int wmi_p2p_cfg(struct wil6210_priv *wil, int channel);
 int wmi_rxon(struct wil6210_priv *wil, bool on);
 int wmi_get_temperature(struct wil6210_priv *wil, u32 *t_m, u32 *t_r);
-int wmi_disconnect_sta(struct wil6210_priv *wil, const u8 *mac, u16 reason);
+int wmi_disconnect_sta(struct wil6210_priv *wil, const u8 *mac, u16 reason,
+		       bool full_disconnect);
 int wmi_addba(struct wil6210_priv *wil, u8 ringid, u8 size, u16 timeout);
 int wmi_delba_tx(struct wil6210_priv *wil, u8 ringid, u16 reason);
 int wmi_delba_rx(struct wil6210_priv *wil, u8 cidxtid, u16 reason);
@@ -807,6 +806,7 @@ void wil_rx_fini(struct wil6210_priv *wil);
 int wil_vring_init_tx(struct wil6210_priv *wil, int id, int size,
 		      int cid, int tid);
 void wil_vring_fini_tx(struct wil6210_priv *wil, int id);
+int wil_tx_init(struct wil6210_priv *wil, int cid);
 int wil_vring_init_bcast(struct wil6210_priv *wil, int id, int size);
 int wil_bcast_init(struct wil6210_priv *wil);
 void wil_bcast_fini(struct wil6210_priv *wil);

drivers/net/wireless/ath/wil6210/wmi.c

 /*
- * Copyright (c) 2012-2015 Qualcomm Atheros, Inc.
+ * Copyright (c) 2012-2016 Qualcomm Atheros, Inc.
  *
  * Permission to use, copy, modify, and/or distribute this software for any
  * purpose with or without fee is hereby granted, provided that the above
@@ -426,6 +426,7 @@ static void wmi_evt_connect(struct wil6210_priv *wil, int id, void *d, int len)
 	const size_t assoc_req_ie_offset = sizeof(u16) * 2;
 	/* capinfo(u16) + status_code(u16) + associd(u16) + IEs */
 	const size_t assoc_resp_ie_offset = sizeof(u16) * 3;
+	int rc;
 
 	if (len < sizeof(*evt)) {
 		wil_err(wil, "Connect event too short : %d bytes\n", len);
@@ -445,8 +446,8 @@ static void wmi_evt_connect(struct wil6210_priv *wil, int id, void *d, int len)
 	}
 
 	ch = evt->channel + 1;
-	wil_dbg_wmi(wil, "Connect %pM channel [%d] cid %d\n",
-		    evt->bssid, ch, evt->cid);
+	wil_info(wil, "Connect %pM channel [%d] cid %d\n",
+		 evt->bssid, ch, evt->cid);
 	wil_hex_dump_wmi("connect AI : ", DUMP_PREFIX_OFFSET, 16, 1,
 			 evt->assoc_info, len - sizeof(*evt), true);
 
@@ -468,20 +469,67 @@ static void wmi_evt_connect(struct wil6210_priv *wil, int id, void *d, int len)
 		assoc_resp_ielen = 0;
 	}
 
+	mutex_lock(&wil->mutex);
+	if (test_bit(wil_status_resetting, wil->status) ||
+	    !test_bit(wil_status_fwready, wil->status)) {
+		wil_err(wil, "status_resetting, cancel connect event, CID %d\n",
+			evt->cid);
+		mutex_unlock(&wil->mutex);
+		/* no need for cleanup, wil_reset will do that */
+		return;
+	}
+
 	if ((wdev->iftype == NL80211_IFTYPE_STATION) ||
 	    (wdev->iftype == NL80211_IFTYPE_P2P_CLIENT)) {
 		if (!test_bit(wil_status_fwconnecting, wil->status)) {
 			wil_err(wil, "Not in connecting state\n");
+			mutex_unlock(&wil->mutex);
 			return;
 		}
 		del_timer_sync(&wil->connect_timer);
-		cfg80211_connect_result(ndev, evt->bssid,
-					assoc_req_ie, assoc_req_ielen,
-					assoc_resp_ie, assoc_resp_ielen,
-					WLAN_STATUS_SUCCESS, GFP_KERNEL);
+	}
+
+	/* FIXME FW can transmit only ucast frames to peer */
+	/* FIXME real ring_id instead of hard coded 0 */
+	ether_addr_copy(wil->sta[evt->cid].addr, evt->bssid);
+	wil->sta[evt->cid].status = wil_sta_conn_pending;
 
+	rc = wil_tx_init(wil, evt->cid);
+	if (rc) {
+		wil_err(wil, "%s: config tx vring failed for CID %d, rc (%d)\n",
+			__func__, evt->cid, rc);
+		wmi_disconnect_sta(wil, wil->sta[evt->cid].addr,
+				   WLAN_REASON_UNSPECIFIED, false);
+	} else {
+		wil_info(wil, "%s: successful connection to CID %d\n",
+			 __func__, evt->cid);
+	}
+
+	if ((wdev->iftype == NL80211_IFTYPE_STATION) ||
+	    (wdev->iftype == NL80211_IFTYPE_P2P_CLIENT)) {
+		if (rc) {
+			netif_tx_stop_all_queues(ndev);
+			netif_carrier_off(ndev);
+			wil_err(wil,
+				"%s: cfg80211_connect_result with failure\n",
+				__func__);
+			cfg80211_connect_result(ndev, evt->bssid, NULL, 0,
+						NULL, 0,
+						WLAN_STATUS_UNSPECIFIED_FAILURE,
+						GFP_KERNEL);
+			goto out;
+		} else {
+			cfg80211_connect_result(ndev, evt->bssid,
+						assoc_req_ie, assoc_req_ielen,
+						assoc_resp_ie, assoc_resp_ielen,
+						WLAN_STATUS_SUCCESS,
+						GFP_KERNEL);
+		}
 	} else if ((wdev->iftype == NL80211_IFTYPE_AP) ||
 		   (wdev->iftype == NL80211_IFTYPE_P2P_GO)) {
+		if (rc)
+			goto out;
+
 		memset(&sinfo, 0, sizeof(sinfo));
 
 		sinfo.generation = wil->sinfo_gen++;
@@ -492,17 +540,21 @@ static void wmi_evt_connect(struct wil6210_priv *wil, int id, void *d, int len)
 		}
 
 		cfg80211_new_sta(ndev, evt->bssid, &sinfo, GFP_KERNEL);
+	} else {
+		wil_err(wil, "%s: unhandled iftype %d for CID %d\n",
+			__func__, wdev->iftype, evt->cid);
+		goto out;
 	}
-	clear_bit(wil_status_fwconnecting, wil->status);
-	set_bit(wil_status_fwconnected, wil->status);
 
-	/* FIXME FW can transmit only ucast frames to peer */
-	/* FIXME real ring_id instead of hard coded 0 */
-	ether_addr_copy(wil->sta[evt->cid].addr, evt->bssid);
-	wil->sta[evt->cid].status = wil_sta_conn_pending;
+	wil->sta[evt->cid].status = wil_sta_connected;
+	set_bit(wil_status_fwconnected, wil->status);
+	netif_tx_wake_all_queues(ndev);
 
-	wil->pending_connect_cid = evt->cid;
-	queue_work(wil->wq_service, &wil->connect_worker);
+out:
+	if (rc)
+		wil->sta[evt->cid].status = wil_sta_unused;
+	clear_bit(wil_status_fwconnecting, wil->status);
+	mutex_unlock(&wil->mutex);
 }
 
 static void wmi_evt_disconnect(struct wil6210_priv *wil, int id,
@@ -511,8 +563,8 @@ static void wmi_evt_disconnect(struct wil6210_priv *wil, int id,
 	struct wmi_disconnect_event *evt = d;
 	u16 reason_code = le16_to_cpu(evt->protocol_reason_status);
 
-	wil_dbg_wmi(wil, "Disconnect %pM reason [proto %d wmi %d]\n",
-		    evt->bssid, reason_code, evt->disconnect_reason);
+	wil_info(wil, "Disconnect %pM reason [proto %d wmi %d]\n",
+		 evt->bssid, reason_code, evt->disconnect_reason);
 
 	wil->sinfo_gen++;
 
@@ -727,6 +779,7 @@ void wmi_recv_cmd(struct wil6210_priv *wil)
 	void __iomem *src;
 	ulong flags;
 	unsigned n;
+	unsigned int num_immed_reply = 0;
 
 	if (!test_bit(wil_status_mbox_ready, wil->status)) {
 		wil_err(wil, "Reset in progress. Cannot handle WMI event\n");
@@ -736,6 +789,7 @@ void wmi_recv_cmd(struct wil6210_priv *wil)
 	for (n = 0;; n++) {
 		u16 len;
 		bool q;
+		bool immed_reply = false;
 
 		r->head = wil_r(wil, RGF_MBOX +
 				offsetof(struct wil6210_mbox_ctl, rx.head));
@@ -784,6 +838,13 @@ void wmi_recv_cmd(struct wil6210_priv *wil)
 			struct wil6210_mbox_hdr_wmi *wmi = &evt->event.wmi;
 			u16 id = le16_to_cpu(wmi->id);
 			u32 tstamp = le32_to_cpu(wmi->timestamp);
+			if (wil->reply_id && wil->reply_id == id) {
+				if (wil->reply_buf) {
+					memcpy(wil->reply_buf, wmi,
+					       min(len, wil->reply_size));
+					immed_reply = true;
+				}
+			}
 
 			wil_dbg_wmi(wil, "WMI event 0x%04x MID %d @%d msec\n",
 				    id, wmi->mid, tstamp);
@@ -799,15 +860,24 @@ void wmi_recv_cmd(struct wil6210_priv *wil)
 		wil_w(wil, RGF_MBOX +
 		      offsetof(struct wil6210_mbox_ctl, rx.tail), r->tail);
 
-		/* add to the pending list */
-		spin_lock_irqsave(&wil->wmi_ev_lock, flags);
-		list_add_tail(&evt->list, &wil->pending_wmi_ev);
-		spin_unlock_irqrestore(&wil->wmi_ev_lock, flags);
-		q = queue_work(wil->wmi_wq, &wil->wmi_event_worker);
-		wil_dbg_wmi(wil, "queue_work -> %d\n", q);
+		if (immed_reply) {
+			wil_dbg_wmi(wil, "%s: Complete WMI 0x%04x\n",
+				    __func__, wil->reply_id);
+			kfree(evt);
+			num_immed_reply++;
+			complete(&wil->wmi_call);
+		} else {
+			/* add to the pending list */
+			spin_lock_irqsave(&wil->wmi_ev_lock, flags);
+			list_add_tail(&evt->list, &wil->pending_wmi_ev);
+			spin_unlock_irqrestore(&wil->wmi_ev_lock, flags);
+			q = queue_work(wil->wmi_wq, &wil->wmi_event_worker);
+			wil_dbg_wmi(wil, "queue_work -> %d\n", q);
+		}
 	}
 	/* normally, 1 event per IRQ should be processed */
-	wil_dbg_wmi(wil, "%s -> %d events queued\n", __func__, n);
+	wil_dbg_wmi(wil, "%s -> %d events queued, %d completed\n", __func__,
+		    n - num_immed_reply, num_immed_reply);
 }
 
 int wmi_call(struct wil6210_priv *wil, u16 cmdid, void *buf, u16 len,
@@ -1184,7 +1254,8 @@ int wmi_get_temperature(struct wil6210_priv *wil, u32 *t_bb, u32 *t_rf)
 	return 0;
 }
 
-int wmi_disconnect_sta(struct wil6210_priv *wil, const u8 *mac, u16 reason)
+int wmi_disconnect_sta(struct wil6210_priv *wil, const u8 *mac, u16 reason,
+		       bool full_disconnect)
 {
 	int rc;
 	u16 reason_code;
@@ -1208,19 +1279,20 @@ int wmi_disconnect_sta(struct wil6210_priv *wil, const u8 *mac, u16 reason)
 		return rc;
 	}
 
-	/* call event handler manually after processing wmi_call,
-	 * to avoid deadlock - disconnect event handler acquires wil->mutex
-	 * while it is already held here
-	 */
-	reason_code = le16_to_cpu(reply.evt.protocol_reason_status);
-
-	wil_dbg_wmi(wil, "Disconnect %pM reason [proto %d wmi %d]\n",
-		    reply.evt.bssid, reason_code,
-		    reply.evt.disconnect_reason);
+	if (full_disconnect) {
+		/* call event handler manually after processing wmi_call,
+		 * to avoid deadlock - disconnect event handler acquires
+		 * wil->mutex while it is already held here
+		 */
+		reason_code = le16_to_cpu(reply.evt.protocol_reason_status);
 
-	wil->sinfo_gen++;
-	wil6210_disconnect(wil, reply.evt.bssid, reason_code, true);
+		wil_dbg_wmi(wil, "Disconnect %pM reason [proto %d wmi %d]\n",
+			    reply.evt.bssid, reason_code,
+			    reply.evt.disconnect_reason);
 
+		wil->sinfo_gen++;
+		wil6210_disconnect(wil, reply.evt.bssid, reason_code, true);
+	}
 	return 0;
 }
 
@@ -1348,14 +1420,11 @@ static void wmi_event_handle(struct wil6210_priv *wil,
 			    id, wil->reply_id);
 		/* check if someone waits for this event */
 		if (wil->reply_id && wil->reply_id == id) {
-			if (wil->reply_buf) {
-				memcpy(wil->reply_buf, wmi,
-				       min(len, wil->reply_size));
-			} else {
-				wmi_evt_call_handler(wil, id, evt_data,
-						     len - sizeof(*wmi));
-			}
-			wil_dbg_wmi(wil, "Complete WMI 0x%04x\n", id);
+			WARN_ON(wil->reply_buf);
+			wmi_evt_call_handler(wil, id, evt_data,
+					     len - sizeof(*wmi));
+			wil_dbg_wmi(wil, "%s: Complete WMI 0x%04x\n",
+				    __func__, id);
 			complete(&wil->wmi_call);
 			return;
 		}