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Commit e2fd5dbc authored by Johannes Berg's avatar Johannes Berg
Browse files

mac80211: make scan_sdata pointer usable with RCU 



Making the scan_sdata pointer usable with RCU makes
it possible to dereference it in the RX path to see
if a received frame actually matches the interface
that is scanning. This is just preparations, making
the pointer __rcu.

Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent d811b3d5

net/mac80211/ieee80211_i.h

+1 −1
Original line number Diff line number Diff line
@@ -972,7 +972,7 @@ struct ieee80211_local { 
	unsigned long leave_oper_channel_time;

	enum mac80211_scan_state next_scan_state;

	struct delayed_work scan_work;

	struct ieee80211_sub_if_data *scan_sdata;

	struct ieee80211_sub_if_data __rcu *scan_sdata;

	enum nl80211_channel_type _oper_channel_type;

	struct ieee80211_channel *oper_channel, *csa_channel;

net/mac80211/iface.c

+5 −4
Original line number Diff line number Diff line
@@ -112,10 +112,11 @@ static u32 __ieee80211_recalc_idle(struct ieee80211_local *local) 
		}

	}



	if (local->scan_sdata &&

	    !(local->hw.flags & IEEE80211_HW_SCAN_WHILE_IDLE)) {

	sdata = rcu_dereference_protected(local->scan_sdata,

					  lockdep_is_held(&local->mtx));

	if (sdata && !(local->hw.flags & IEEE80211_HW_SCAN_WHILE_IDLE)) {

		scanning = true;

		local->scan_sdata->vif.bss_conf.idle = false;

		sdata->vif.bss_conf.idle = false;

	}



	list_for_each_entry(sdata, &local->interfaces, list) {
@@ -628,7 +629,7 @@ static void ieee80211_do_stop(struct ieee80211_sub_if_data *sdata, 


	clear_bit(SDATA_STATE_RUNNING, &sdata->state);



	if (local->scan_sdata == sdata)

	if (rcu_access_pointer(local->scan_sdata) == sdata)

		ieee80211_scan_cancel(local);



	/*

net/mac80211/scan.c

+24 −9
Original line number Diff line number Diff line
@@ -293,7 +293,13 @@ static void __ieee80211_scan_completed(struct ieee80211_hw *hw, bool aborted, 
		return;



	if (was_hw_scan && !aborted && ieee80211_prep_hw_scan(local)) {

		int rc = drv_hw_scan(local, local->scan_sdata, local->hw_scan_req);

		int rc;



		rc = drv_hw_scan(local,

			rcu_dereference_protected(local->scan_sdata,

						  lockdep_is_held(&local->mtx)),

			local->hw_scan_req);



		if (rc == 0)

			return;

	}
@@ -394,7 +400,10 @@ void ieee80211_run_deferred_scan(struct ieee80211_local *local) 
	if (!local->scan_req || local->scanning)

		return;



	if (!ieee80211_can_scan(local, local->scan_sdata))

	if (!ieee80211_can_scan(local,

				rcu_dereference_protected(

					local->scan_sdata,

					lockdep_is_held(&local->mtx))))

		return;



	ieee80211_queue_delayed_work(&local->hw, &local->scan_work,
@@ -405,9 +414,12 @@ static void ieee80211_scan_state_send_probe(struct ieee80211_local *local, 
					    unsigned long *next_delay)

{

	int i;

	struct ieee80211_sub_if_data *sdata = local->scan_sdata;

	struct ieee80211_sub_if_data *sdata;

	enum ieee80211_band band = local->hw.conf.channel->band;



	sdata = rcu_dereference_protected(local->scan_sdata,

					  lockdep_is_held(&local->mtx));;



	for (i = 0; i < local->scan_req->n_ssids; i++)

		ieee80211_send_probe_req(

			sdata, NULL,
@@ -439,7 +451,7 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, 
	if (!ieee80211_can_scan(local, sdata)) {

		/* wait for the work to finish/time out */

		local->scan_req = req;

		local->scan_sdata = sdata;

		rcu_assign_pointer(local->scan_sdata, sdata);

		return 0;

	}
@@ -473,7 +485,7 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, 
	}



	local->scan_req = req;

	local->scan_sdata = sdata;

	rcu_assign_pointer(local->scan_sdata, sdata);



	if (local->ops->hw_scan) {

		__set_bit(SCAN_HW_SCANNING, &local->scanning);
@@ -533,7 +545,7 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata, 
		ieee80211_recalc_idle(local);



		local->scan_req = NULL;

		local->scan_sdata = NULL;

		rcu_assign_pointer(local->scan_sdata, NULL);

	}



	return rc;
@@ -720,7 +732,8 @@ void ieee80211_scan_work(struct work_struct *work) 


	mutex_lock(&local->mtx);



	sdata = local->scan_sdata;

	sdata = rcu_dereference_protected(local->scan_sdata,

					  lockdep_is_held(&local->mtx));



	/* When scanning on-channel, the first-callback means completed. */

	if (test_bit(SCAN_ONCHANNEL_SCANNING, &local->scanning)) {
@@ -741,7 +754,7 @@ void ieee80211_scan_work(struct work_struct *work) 
		int rc;



		local->scan_req = NULL;

		local->scan_sdata = NULL;

		rcu_assign_pointer(local->scan_sdata, NULL);



		rc = __ieee80211_start_scan(sdata, req);

		if (rc) {
@@ -893,7 +906,9 @@ void ieee80211_scan_cancel(struct ieee80211_local *local) 


	if (test_bit(SCAN_HW_SCANNING, &local->scanning)) {

		if (local->ops->cancel_hw_scan)

			drv_cancel_hw_scan(local, local->scan_sdata);

			drv_cancel_hw_scan(local,

				rcu_dereference_protected(local->scan_sdata,

						lockdep_is_held(&local->mtx)));

		goto out;

	}