nl80211: allow multiple active scheduled scan requests

This patch implements the idea to have multiple scheduled scan requests
running concurrently. It mainly illustrates how to deal with the incoming
request from user-space in terms of backward compatibility. In order to
use multiple scheduled scans user-space needs to provide a flag attribute
NL80211_ATTR_SCHED_SCAN_MULTI to indicate support. If not the request is
treated as a legacy scan.

Drivers currently supporting scheduled scan are now indicating they support
a single scheduled scan request. This obsoletes WIPHY_FLAG_SUPPORTS_SCHED_SCAN.

Reviewed-by: Hante Meuleman <hante.meuleman@broadcom.com>
Reviewed-by: Pieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>
Reviewed-by: Franky Lin <franky.lin@broadcom.com>
Signed-off-by: Arend van Spriel <arend.vanspriel@broadcom.com>
[clean up netlink destroy path to avoid allocations, code cleanups]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

drivers/net/wireless/ath/ath6kl/cfg80211.c

@@ -3973,7 +3973,7 @@ int ath6kl_cfg80211_init(struct ath6kl *ar)
 			    WIPHY_FLAG_AP_PROBE_RESP_OFFLOAD;
 
 	if (test_bit(ATH6KL_FW_CAPABILITY_SCHED_SCAN_V2, ar->fw_capabilities))
-		ar->wiphy->flags |= WIPHY_FLAG_SUPPORTS_SCHED_SCAN;
+		ar->wiphy->max_sched_scan_reqs = 1;
 
 	if (test_bit(ATH6KL_FW_CAPABILITY_INACTIVITY_TIMEOUT,
 		     ar->fw_capabilities))

drivers/net/wireless/broadcom/brcm80211/brcmfmac/cfg80211.c

@@ -6374,11 +6374,11 @@ err:
 static void brcmf_wiphy_pno_params(struct wiphy *wiphy)
 {
 	/* scheduled scan settings */
+	wiphy->max_sched_scan_reqs = 1;
 	wiphy->max_sched_scan_ssids = BRCMF_PNO_MAX_PFN_COUNT;
 	wiphy->max_match_sets = BRCMF_PNO_MAX_PFN_COUNT;
 	wiphy->max_sched_scan_ie_len = BRCMF_SCAN_IE_LEN_MAX;
 	wiphy->max_sched_scan_plan_interval = BRCMF_PNO_SCHED_SCAN_MAX_PERIOD;
-	wiphy->flags |= WIPHY_FLAG_SUPPORTS_SCHED_SCAN;
 }
 
 #ifdef CONFIG_PM

drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c

@@ -620,7 +620,7 @@ int iwl_mvm_mac_setup_register(struct iwl_mvm *mvm)
 	else
 		hw->wiphy->flags &= ~WIPHY_FLAG_PS_ON_BY_DEFAULT;
 
-	hw->wiphy->flags |= WIPHY_FLAG_SUPPORTS_SCHED_SCAN;
+	hw->wiphy->max_sched_scan_reqs = 1;
 	hw->wiphy->max_sched_scan_ssids = PROBE_OPTION_MAX;
 	hw->wiphy->max_match_sets = IWL_SCAN_MAX_PROFILES;
 	/* we create the 802.11 header and zero length SSID IE. */

drivers/net/wireless/marvell/mwifiex/cfg80211.c

@@ -4297,7 +4297,6 @@ int mwifiex_register_cfg80211(struct mwifiex_adapter *adapter)
 	wiphy->flags |= WIPHY_FLAG_HAVE_AP_SME |
 			WIPHY_FLAG_AP_PROBE_RESP_OFFLOAD |
 			WIPHY_FLAG_AP_UAPSD |
-			WIPHY_FLAG_SUPPORTS_SCHED_SCAN |
 			WIPHY_FLAG_HAS_REMAIN_ON_CHANNEL |
 			WIPHY_FLAG_HAS_CHANNEL_SWITCH |
 			WIPHY_FLAG_PS_ON_BY_DEFAULT;
@@ -4316,6 +4315,7 @@ int mwifiex_register_cfg80211(struct mwifiex_adapter *adapter)
 				    NL80211_PROBE_RESP_OFFLOAD_SUPPORT_WPS2 |
 				    NL80211_PROBE_RESP_OFFLOAD_SUPPORT_P2P;
 
+	wiphy->max_sched_scan_reqs = 1;
 	wiphy->max_sched_scan_ssids = MWIFIEX_MAX_SSID_LIST_LENGTH;
 	wiphy->max_sched_scan_ie_len = MWIFIEX_MAX_VSIE_LEN;
 	wiphy->max_match_sets = MWIFIEX_MAX_SSID_LIST_LENGTH;

drivers/net/wireless/ti/wlcore/main.c

@@ -6128,6 +6128,7 @@ static int wl1271_init_ieee80211(struct wl1271 *wl)
 	wl->hw->wiphy->max_scan_ie_len = WL1271_CMD_TEMPL_MAX_SIZE -
 			sizeof(struct ieee80211_header);
 
+	wl->hw->wiphy->max_sched_scan_reqs = 1;
 	wl->hw->wiphy->max_sched_scan_ie_len = WL1271_CMD_TEMPL_MAX_SIZE -
 		sizeof(struct ieee80211_header);
 
@@ -6135,7 +6136,6 @@ static int wl1271_init_ieee80211(struct wl1271 *wl)
 
 	wl->hw->wiphy->flags |= WIPHY_FLAG_AP_UAPSD |
 				WIPHY_FLAG_HAS_REMAIN_ON_CHANNEL |
-				WIPHY_FLAG_SUPPORTS_SCHED_SCAN |
 				WIPHY_FLAG_HAS_CHANNEL_SWITCH;
 
 	wl->hw->wiphy->features |= NL80211_FEATURE_AP_SCAN;

include/net/cfg80211.h

@@ -1678,6 +1678,8 @@ struct cfg80211_bss_select_adjust {
  * @rcu_head: RCU callback used to free the struct
  * @owner_nlportid: netlink portid of owner (if this should is a request
  *	owned by a particular socket)
+ * @nl_owner_dead: netlink owner socket was closed - this request be freed
+ * @list: for keeping list of requests.
  * @delay: delay in seconds to use before starting the first scan
  *	cycle.  The driver may ignore this parameter and start
  *	immediately (or at any other time), if this feature is not
@@ -1722,6 +1724,8 @@ struct cfg80211_sched_scan_request {
 	unsigned long scan_start;
 	struct rcu_head rcu_head;
 	u32 owner_nlportid;
+	bool nl_owner_dead;
+	struct list_head list;
 
 	/* keep last */
 	struct ieee80211_channel *channels[0];
@@ -3213,7 +3217,7 @@ enum wiphy_flags {
 	WIPHY_FLAG_CONTROL_PORT_PROTOCOL	= BIT(7),
 	WIPHY_FLAG_IBSS_RSN			= BIT(8),
 	WIPHY_FLAG_MESH_AUTH			= BIT(10),
-	WIPHY_FLAG_SUPPORTS_SCHED_SCAN		= BIT(11),
+	/* use hole at 11 */
 	/* use hole at 12 */
 	WIPHY_FLAG_SUPPORTS_FW_ROAM		= BIT(13),
 	WIPHY_FLAG_AP_UAPSD			= BIT(14),
@@ -3551,6 +3555,8 @@ struct wiphy_iftype_ext_capab {
  *	this variable determines its size
  * @max_scan_ssids: maximum number of SSIDs the device can scan for in
  *	any given scan
+ * @max_sched_scan_reqs: maximum number of scheduled scan requests that
+ *	the device can run concurrently.
  * @max_sched_scan_ssids: maximum number of SSIDs the device can scan
  *	for in any given scheduled scan
  * @max_match_sets: maximum number of match sets the device can handle
@@ -3687,6 +3693,7 @@ struct wiphy {
 
 	int bss_priv_size;
 	u8 max_scan_ssids;
+	u8 max_sched_scan_reqs;
 	u8 max_sched_scan_ssids;
 	u8 max_match_sets;
 	u16 max_scan_ie_len;

include/uapi/linux/nl80211.h

@@ -387,7 +387,9 @@
  *	are used.  Extra IEs can also be passed from the userspace by
  *	using the %NL80211_ATTR_IE attribute.  The first cycle of the
  *	scheduled scan can be delayed by %NL80211_ATTR_SCHED_SCAN_DELAY
- *	is supplied.
+ *	is supplied. If the device supports multiple concurrent scheduled
+ *	scans, it will allow such when the caller provides the flag attribute
+ *	%NL80211_ATTR_SCHED_SCAN_MULTI to indicate user-space support for it.
  * @NL80211_CMD_STOP_SCHED_SCAN: stop a scheduled scan. Returns -ENOENT if
  *	scheduled scan is not running. The caller may assume that as soon
  *	as the call returns, it is safe to start a new scheduled scan again.
@@ -2081,6 +2083,11 @@ enum nl80211_commands {
  * @NL80211_ATTR_PMK: PMK for the PMKSA identified by %NL80211_ATTR_PMKID.
  *	This is used with @NL80211_CMD_SET_PMKSA.
  *
+ * @NL80211_ATTR_SCHED_SCAN_MULTI: flag attribute which user-space shall use to
+ *	indicate that it supports multiple active scheduled scan requests.
+ * @NL80211_ATTR_SCHED_SCAN_MAX_REQS: indicates maximum number of scheduled
+ *	scan request that may be active for the device (u32).
+ *
  * @NUM_NL80211_ATTR: total number of nl80211_attrs available
  * @NL80211_ATTR_MAX: highest attribute number currently defined
  * @__NL80211_ATTR_AFTER_LAST: internal use
@@ -2500,6 +2507,9 @@ enum nl80211_attrs {
 
 	NL80211_ATTR_PMK,
 
+	NL80211_ATTR_SCHED_SCAN_MULTI,
+	NL80211_ATTR_SCHED_SCAN_MAX_REQS,
+
 	/* add attributes here, update the policy in nl80211.c */
 
 	__NL80211_ATTR_AFTER_LAST,

net/wireless/core.c

@@ -330,14 +330,16 @@ static void cfg80211_destroy_iface_wk(struct work_struct *work)
 static void cfg80211_sched_scan_stop_wk(struct work_struct *work)
 {
 	struct cfg80211_registered_device *rdev;
+	struct cfg80211_sched_scan_request *req, *tmp;
 
 	rdev = container_of(work, struct cfg80211_registered_device,
 			   sched_scan_stop_wk);
 
 	rtnl_lock();
-
-	__cfg80211_stop_sched_scan(rdev, false);
-
+	list_for_each_entry_safe(req, tmp, &rdev->sched_scan_req_list, list) {
+		if (req->nl_owner_dead)
+			cfg80211_stop_sched_scan_req(rdev, req, false);
+	}
 	rtnl_unlock();
 }
 
@@ -452,6 +454,7 @@ use_default_name:
 	spin_lock_init(&rdev->beacon_registrations_lock);
 	spin_lock_init(&rdev->bss_lock);
 	INIT_LIST_HEAD(&rdev->bss_list);
+	INIT_LIST_HEAD(&rdev->sched_scan_req_list);
 	INIT_WORK(&rdev->scan_done_wk, __cfg80211_scan_done);
 	INIT_WORK(&rdev->sched_scan_results_wk, __cfg80211_sched_scan_results);
 	INIT_LIST_HEAD(&rdev->mlme_unreg);
@@ -1028,7 +1031,7 @@ void __cfg80211_leave(struct cfg80211_registered_device *rdev,
 		      struct wireless_dev *wdev)
 {
 	struct net_device *dev = wdev->netdev;
-	struct cfg80211_sched_scan_request *sched_scan_req;
+	struct cfg80211_sched_scan_request *pos, *tmp;
 
 	ASSERT_RTNL();
 	ASSERT_WDEV_LOCK(wdev);
@@ -1039,9 +1042,11 @@ void __cfg80211_leave(struct cfg80211_registered_device *rdev,
 		break;
 	case NL80211_IFTYPE_P2P_CLIENT:
 	case NL80211_IFTYPE_STATION:
-		sched_scan_req = rtnl_dereference(rdev->sched_scan_req);
-		if (sched_scan_req && dev == sched_scan_req->dev)
-			__cfg80211_stop_sched_scan(rdev, false);
+		list_for_each_entry_safe(pos, tmp, &rdev->sched_scan_req_list,
+					 list) {
+			if (dev == pos->dev)
+				cfg80211_stop_sched_scan_req(rdev, pos, false);
+		}
 
 #ifdef CONFIG_CFG80211_WEXT
 		kfree(wdev->wext.ie);
@@ -1116,7 +1121,7 @@ static int cfg80211_netdev_notifier_call(struct notifier_block *nb,
 	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
 	struct wireless_dev *wdev = dev->ieee80211_ptr;
 	struct cfg80211_registered_device *rdev;
-	struct cfg80211_sched_scan_request *sched_scan_req;
+	struct cfg80211_sched_scan_request *pos, *tmp;
 
 	if (!wdev)
 		return NOTIFY_DONE;
@@ -1193,10 +1198,10 @@ static int cfg80211_netdev_notifier_call(struct notifier_block *nb,
 			___cfg80211_scan_done(rdev, false);
 		}
 
-		sched_scan_req = rtnl_dereference(rdev->sched_scan_req);
-		if (WARN_ON(sched_scan_req &&
-			    sched_scan_req->dev == wdev->netdev)) {
-			__cfg80211_stop_sched_scan(rdev, false);
+		list_for_each_entry_safe(pos, tmp,
+					 &rdev->sched_scan_req_list, list) {
+			if (WARN_ON(pos && pos->dev == wdev->netdev))
+				cfg80211_stop_sched_scan_req(rdev, pos, false);
 		}
 
 		rdev->opencount--;

net/wireless/core.h

@@ -74,7 +74,7 @@ struct cfg80211_registered_device {
 	u32 bss_entries;
 	struct cfg80211_scan_request *scan_req; /* protected by RTNL */
 	struct sk_buff *scan_msg;
-	struct cfg80211_sched_scan_request __rcu *sched_scan_req;
+	struct list_head sched_scan_req_list;
 	unsigned long suspend_at;
 	struct work_struct scan_done_wk;
 	struct work_struct sched_scan_results_wk;
@@ -416,9 +416,16 @@ int cfg80211_validate_key_settings(struct cfg80211_registered_device *rdev,
 void __cfg80211_scan_done(struct work_struct *wk);
 void ___cfg80211_scan_done(struct cfg80211_registered_device *rdev,
 			   bool send_message);
+void cfg80211_add_sched_scan_req(struct cfg80211_registered_device *rdev,
+				 struct cfg80211_sched_scan_request *req);
+int cfg80211_sched_scan_req_possible(struct cfg80211_registered_device *rdev,
+				     bool want_multi);
 void __cfg80211_sched_scan_results(struct work_struct *wk);
+int cfg80211_stop_sched_scan_req(struct cfg80211_registered_device *rdev,
+				 struct cfg80211_sched_scan_request *req,
+				 bool driver_initiated);
 int __cfg80211_stop_sched_scan(struct cfg80211_registered_device *rdev,
-			       bool driver_initiated);
+			       u64 reqid, bool driver_initiated);
 void cfg80211_upload_connect_keys(struct wireless_dev *wdev);
 int cfg80211_change_iface(struct cfg80211_registered_device *rdev,
 			  struct net_device *dev, enum nl80211_iftype ntype,

net/wireless/nl80211.c

@@ -419,6 +419,7 @@ static const struct nla_policy nl80211_policy[NUM_NL80211_ATTR] = {
 					.len = FILS_ERP_MAX_RRK_LEN },
 	[NL80211_ATTR_FILS_CACHE_ID] = { .len = 2 },
 	[NL80211_ATTR_PMK] = { .type = NLA_BINARY, .len = PMK_MAX_LEN },
+	[NL80211_ATTR_SCHED_SCAN_MULTI] = { .type = NLA_FLAG },
 };
 
 /* policy for the key attributes */
@@ -1376,7 +1377,7 @@ static int nl80211_add_commands_unsplit(struct cfg80211_registered_device *rdev,
 		CMD(tdls_mgmt, TDLS_MGMT);
 		CMD(tdls_oper, TDLS_OPER);
 	}
-	if (rdev->wiphy.flags & WIPHY_FLAG_SUPPORTS_SCHED_SCAN)
+	if (rdev->wiphy.max_sched_scan_reqs)
 		CMD(sched_scan_start, START_SCHED_SCAN);
 	CMD(probe_client, PROBE_CLIENT);
 	CMD(set_noack_map, SET_NOACK_MAP);
@@ -1815,6 +1816,11 @@ static int nl80211_send_wiphy(struct cfg80211_registered_device *rdev,
 		    nla_put_flag(msg, NL80211_ATTR_WIPHY_SELF_MANAGED_REG))
 			goto nla_put_failure;
 
+		if (rdev->wiphy.max_sched_scan_reqs &&
+		    nla_put_u32(msg, NL80211_ATTR_SCHED_SCAN_MAX_REQS,
+				rdev->wiphy.max_sched_scan_reqs))
+			goto nla_put_failure;
+
 		if (nla_put(msg, NL80211_ATTR_EXT_FEATURES,
 			    sizeof(rdev->wiphy.ext_features),
 			    rdev->wiphy.ext_features))
@@ -7336,14 +7342,16 @@ static int nl80211_start_sched_scan(struct sk_buff *skb,
 	struct net_device *dev = info->user_ptr[1];
 	struct wireless_dev *wdev = dev->ieee80211_ptr;
 	struct cfg80211_sched_scan_request *sched_scan_req;
+	bool want_multi;
 	int err;
 
-	if (!(rdev->wiphy.flags & WIPHY_FLAG_SUPPORTS_SCHED_SCAN) ||
-	    !rdev->ops->sched_scan_start)
+	if (!rdev->wiphy.max_sched_scan_reqs || !rdev->ops->sched_scan_start)
 		return -EOPNOTSUPP;
 
-	if (rdev->sched_scan_req)
-		return -EINPROGRESS;
+	want_multi = info->attrs[NL80211_ATTR_SCHED_SCAN_MULTI];
+	err = cfg80211_sched_scan_req_possible(rdev, want_multi);
+	if (err)
+		return err;
 
 	sched_scan_req = nl80211_parse_sched_scan(&rdev->wiphy, wdev,
 						  info->attrs,
@@ -7353,6 +7361,14 @@ static int nl80211_start_sched_scan(struct sk_buff *skb,
 	if (err)
 		goto out_err;
 
+	/* leave request id zero for legacy request
+	 * or if driver does not support multi-scheduled scan
+	 */
+	if (want_multi && rdev->wiphy.max_sched_scan_reqs > 1) {
+		while (!sched_scan_req->reqid)
+			sched_scan_req->reqid = rdev->wiphy.cookie_counter++;
+	}
+
 	err = rdev_sched_scan_start(rdev, dev, sched_scan_req);
 	if (err)
 		goto out_free;
@@ -7363,7 +7379,7 @@ static int nl80211_start_sched_scan(struct sk_buff *skb,
 	if (info->attrs[NL80211_ATTR_SOCKET_OWNER])
 		sched_scan_req->owner_nlportid = info->snd_portid;
 
-	rcu_assign_pointer(rdev->sched_scan_req, sched_scan_req);
+	cfg80211_add_sched_scan_req(rdev, sched_scan_req);
 
 	nl80211_send_sched_scan(sched_scan_req, NL80211_CMD_START_SCHED_SCAN);
 	return 0;
@@ -7377,13 +7393,27 @@ out_err:
 static int nl80211_stop_sched_scan(struct sk_buff *skb,
 				   struct genl_info *info)
 {
+	struct cfg80211_sched_scan_request *req;
 	struct cfg80211_registered_device *rdev = info->user_ptr[0];
+	u64 cookie;
 
-	if (!(rdev->wiphy.flags & WIPHY_FLAG_SUPPORTS_SCHED_SCAN) ||
-	    !rdev->ops->sched_scan_stop)
+	if (!rdev->wiphy.max_sched_scan_reqs || !rdev->ops->sched_scan_stop)
 		return -EOPNOTSUPP;
 
-	return __cfg80211_stop_sched_scan(rdev, false);
+	if (info->attrs[NL80211_ATTR_COOKIE]) {
+		cookie = nla_get_u64(info->attrs[NL80211_ATTR_COOKIE]);
+		return __cfg80211_stop_sched_scan(rdev, cookie, false);
+	}
+
+	req = list_first_or_null_rcu(&rdev->sched_scan_req_list,
+				     struct cfg80211_sched_scan_request,
+				     list);
+	if (!req || req->reqid ||
+	    (req->owner_nlportid &&
+	     req->owner_nlportid != info->snd_portid))
+		return -ENOENT;
+
+	return cfg80211_stop_sched_scan_req(rdev, req, false);
 }
 
 static int nl80211_start_radar_detection(struct sk_buff *skb,
@@ -14883,16 +14913,15 @@ static int nl80211_netlink_notify(struct notifier_block * nb,
 	rcu_read_lock();
 
 	list_for_each_entry_rcu(rdev, &cfg80211_rdev_list, list) {
-		struct cfg80211_sched_scan_request *sched_scan_req =
-			rcu_dereference(rdev->sched_scan_req);
-
-		if (sched_scan_req && notify->portid &&
-		    sched_scan_req->owner_nlportid == notify->portid) {
-			sched_scan_req->owner_nlportid = 0;
+		struct cfg80211_sched_scan_request *sched_scan_req;
 
-			if (rdev->ops->sched_scan_stop &&
-			    rdev->wiphy.flags & WIPHY_FLAG_SUPPORTS_SCHED_SCAN)
+		list_for_each_entry_rcu(sched_scan_req,
+					&rdev->sched_scan_req_list,
+					list) {
+			if (sched_scan_req->owner_nlportid == notify->portid) {
+				sched_scan_req->nl_owner_dead = true;
 				schedule_work(&rdev->sched_scan_stop_wk);
+			}
 		}
 
 		list_for_each_entry_rcu(wdev, &rdev->wiphy.wdev_list, list) {

net/wireless/rdev-ops.h

@@ -813,7 +813,7 @@ rdev_sched_scan_start(struct cfg80211_registered_device *rdev,
 		      struct cfg80211_sched_scan_request *request)
 {
 	int ret;
-	trace_rdev_sched_scan_start(&rdev->wiphy, dev, request);
+	trace_rdev_sched_scan_start(&rdev->wiphy, dev, request->reqid);
 	ret = rdev->ops->sched_scan_start(&rdev->wiphy, dev, request);
 	trace_rdev_return_int(&rdev->wiphy, ret);
 	return ret;

net/wireless/scan.c

@@ -300,6 +300,70 @@ void cfg80211_scan_done(struct cfg80211_scan_request *request,
 }
 EXPORT_SYMBOL(cfg80211_scan_done);
 
+void cfg80211_add_sched_scan_req(struct cfg80211_registered_device *rdev,
+				 struct cfg80211_sched_scan_request *req)
+{
+	ASSERT_RTNL();
+
+	list_add_rcu(&req->list, &rdev->sched_scan_req_list);
+}
+
+static void cfg80211_del_sched_scan_req(struct cfg80211_registered_device *rdev,
+					struct cfg80211_sched_scan_request *req)
+{
+	ASSERT_RTNL();
+
+	list_del_rcu(&req->list);
+	kfree_rcu(req, rcu_head);
+}
+
+static struct cfg80211_sched_scan_request *
+cfg80211_find_sched_scan_req(struct cfg80211_registered_device *rdev, u64 reqid)
+{
+	struct cfg80211_sched_scan_request *pos;
+
+	ASSERT_RTNL();
+
+	list_for_each_entry(pos, &rdev->sched_scan_req_list, list) {
+		if (pos->reqid == reqid)
+			return pos;
+	}
+	return ERR_PTR(-ENOENT);
+}
+
+/*
+ * Determines if a scheduled scan request can be handled. When a legacy
+ * scheduled scan is running no other scheduled scan is allowed regardless
+ * whether the request is for legacy or multi-support scan. When a multi-support
+ * scheduled scan is running a request for legacy scan is not allowed. In this
+ * case a request for multi-support scan can be handled if resources are
+ * available, ie. struct wiphy::max_sched_scan_reqs limit is not yet reached.
+ */
+int cfg80211_sched_scan_req_possible(struct cfg80211_registered_device *rdev,
+				     bool want_multi)
+{
+	struct cfg80211_sched_scan_request *pos;
+	int i = 0;
+
+	list_for_each_entry(pos, &rdev->sched_scan_req_list, list) {
+		/* request id zero means legacy in progress */
+		if (!i && !pos->reqid)
+			return -EINPROGRESS;
+		i++;
+	}
+
+	if (i) {
+		/* no legacy allowed when multi request(s) are active */
+		if (!want_multi)
+			return -EINPROGRESS;
+
+		/* resource limit reached */
+		if (i == rdev->wiphy.max_sched_scan_reqs)
+			return -ENOSPC;
+	}
+	return 0;
+}
+
 void __cfg80211_sched_scan_results(struct work_struct *wk)
 {
 	struct cfg80211_registered_device *rdev;
@@ -310,10 +374,10 @@ void __cfg80211_sched_scan_results(struct work_struct *wk)
 
 	rtnl_lock();
 
-	request = rtnl_dereference(rdev->sched_scan_req);
+	request = cfg80211_find_sched_scan_req(rdev, 0);
 
 	/* we don't have sched_scan_req anymore if the scan is stopping */
-	if (request) {
+	if (!IS_ERR(request)) {
 		if (request->flags & NL80211_SCAN_FLAG_FLUSH) {
 			/* flush entries from previous scans */
 			spin_lock_bh(&rdev->bss_lock);
@@ -329,10 +393,17 @@ void __cfg80211_sched_scan_results(struct work_struct *wk)
 
 void cfg80211_sched_scan_results(struct wiphy *wiphy)
 {
+	struct cfg80211_registered_device *rdev = wiphy_to_rdev(wiphy);
+	struct cfg80211_sched_scan_request *request;
+
 	trace_cfg80211_sched_scan_results(wiphy);
 	/* ignore if we're not scanning */
 
-	if (rcu_access_pointer(wiphy_to_rdev(wiphy)->sched_scan_req))
+	rtnl_lock();
+	request = cfg80211_find_sched_scan_req(rdev, 0);
+	rtnl_unlock();
+
+	if (!IS_ERR(request))
 		queue_work(cfg80211_wq,
 			   &wiphy_to_rdev(wiphy)->sched_scan_results_wk);
 }
@@ -346,7 +417,7 @@ void cfg80211_sched_scan_stopped_rtnl(struct wiphy *wiphy)
 
 	trace_cfg80211_sched_scan_stopped(wiphy);
 
-	__cfg80211_stop_sched_scan(rdev, true);
+	__cfg80211_stop_sched_scan(rdev, 0, true);
 }
 EXPORT_SYMBOL(cfg80211_sched_scan_stopped_rtnl);
 
@@ -358,34 +429,40 @@ void cfg80211_sched_scan_stopped(struct wiphy *wiphy)
 }
 EXPORT_SYMBOL(cfg80211_sched_scan_stopped);
 
-int __cfg80211_stop_sched_scan(struct cfg80211_registered_device *rdev,
-			       bool driver_initiated)
+int cfg80211_stop_sched_scan_req(struct cfg80211_registered_device *rdev,
+				 struct cfg80211_sched_scan_request *req,
+				 bool driver_initiated)
 {
-	struct cfg80211_sched_scan_request *sched_scan_req;
-	struct net_device *dev;
-
 	ASSERT_RTNL();
 
-	if (!rdev->sched_scan_req)
-		return -ENOENT;
-
-	sched_scan_req = rtnl_dereference(rdev->sched_scan_req);
-	dev = sched_scan_req->dev;
-
 	if (!driver_initiated) {
-		int err = rdev_sched_scan_stop(rdev, dev);
+		int err = rdev_sched_scan_stop(rdev, req->dev);
 		if (err)
 			return err;
 	}
 
-	nl80211_send_sched_scan(sched_scan_req, NL80211_CMD_SCHED_SCAN_STOPPED);
+	nl80211_send_sched_scan(req, NL80211_CMD_SCHED_SCAN_STOPPED);
 
-	RCU_INIT_POINTER(rdev->sched_scan_req, NULL);
-	kfree_rcu(sched_scan_req, rcu_head);
+	cfg80211_del_sched_scan_req(rdev, req);
 
 	return 0;
 }
 
+int __cfg80211_stop_sched_scan(struct cfg80211_registered_device *rdev,
+			       u64 reqid, bool driver_initiated)
+{
+	struct cfg80211_sched_scan_request *sched_scan_req;
+
+	ASSERT_RTNL();
+
+	sched_scan_req = cfg80211_find_sched_scan_req(rdev, reqid);
+	if (IS_ERR(sched_scan_req))
+		return PTR_ERR(sched_scan_req);
+
+	return cfg80211_stop_sched_scan_req(rdev, sched_scan_req,
+					    driver_initiated);
+}
+
 void cfg80211_bss_age(struct cfg80211_registered_device *rdev,
                       unsigned long age_secs)
 {

net/wireless/trace.h

@@ -1610,20 +1610,26 @@ DEFINE_EVENT(tx_rx_evt, rdev_set_antenna,
 	TP_ARGS(wiphy, rx, tx)
 );
 
-TRACE_EVENT(rdev_sched_scan_start,
-	TP_PROTO(struct wiphy *wiphy, struct net_device *netdev,
-		 struct cfg80211_sched_scan_request *request),
-	TP_ARGS(wiphy, netdev, request),
+DECLARE_EVENT_CLASS(wiphy_netdev_id_evt,
+	TP_PROTO(struct wiphy *wiphy, struct net_device *netdev, u64 id),
+	TP_ARGS(wiphy, netdev, id),
 	TP_STRUCT__entry(
 		WIPHY_ENTRY
 		NETDEV_ENTRY
+		__field(u64, id)
 	),
 	TP_fast_assign(
 		WIPHY_ASSIGN;
 		NETDEV_ASSIGN;
+		__entry->id = id;
 	),
-	TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT,
-		  WIPHY_PR_ARG, NETDEV_PR_ARG)
+	TP_printk(WIPHY_PR_FMT ", " NETDEV_PR_FMT ", id: %llu",
+		  WIPHY_PR_ARG, NETDEV_PR_ARG, __entry->id)
+);
+
+DEFINE_EVENT(wiphy_netdev_id_evt, rdev_sched_scan_start,
+	TP_PROTO(struct wiphy *wiphy, struct net_device *netdev, u64 id),
+	TP_ARGS(wiphy, netdev, id)
 );
 
 TRACE_EVENT(rdev_tdls_mgmt,