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Commit d778207b authored by Johannes Berg's avatar Johannes Berg
Browse files

mac80211: optimise synchronize_net() for sta_info_flush 



There's no reason to have one synchronize_net() for each
removed station, refactor the code slightly to have just
a single synchronize_net() for all stations.

Note that this is currently useless as hostapd removes
stations one by one and this coalescing never happens.

Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent c8782078

net/mac80211/sta_info.c

+39 −3
Original line number Diff line number Diff line
@@ -794,7 +794,7 @@ static bool sta_info_cleanup_expire_buffered(struct ieee80211_local *local, 
	return have_buffered;

}



int __must_check __sta_info_destroy(struct sta_info *sta)

static int __must_check __sta_info_destroy_part1(struct sta_info *sta)

{

	struct ieee80211_local *local;

	struct ieee80211_sub_if_data *sdata;
@@ -831,7 +831,23 @@ int __must_check __sta_info_destroy(struct sta_info *sta) 
	    rcu_access_pointer(sdata->u.vlan.sta) == sta)

		RCU_INIT_POINTER(sdata->u.vlan.sta, NULL);



	synchronize_net();

	return 0;

}



static void __sta_info_destroy_part2(struct sta_info *sta)

{

	struct ieee80211_local *local = sta->local;

	struct ieee80211_sub_if_data *sdata = sta->sdata;

	int ret;



	/*

	 * NOTE: This assumes at least synchronize_net() was done

	 *	 after _part1 and before _part2!

	 */



	might_sleep();

	lockdep_assert_held(&local->sta_mtx);



	/* now keys can no longer be reached */

	ieee80211_free_sta_keys(local, sta);
@@ -863,6 +879,18 @@ int __must_check __sta_info_destroy(struct sta_info *sta) 
	ieee80211_recalc_min_chandef(sdata);



	cleanup_single_sta(sta);

}



int __must_check __sta_info_destroy(struct sta_info *sta)

{

	int err = __sta_info_destroy_part1(sta);



	if (err)

		return err;



	synchronize_net();



	__sta_info_destroy_part2(sta);



	return 0;

}
@@ -936,6 +964,7 @@ int sta_info_flush(struct ieee80211_sub_if_data *sdata) 
{

	struct ieee80211_local *local = sdata->local;

	struct sta_info *sta, *tmp;

	LIST_HEAD(free_list);

	int ret = 0;



	might_sleep();
@@ -943,10 +972,17 @@ int sta_info_flush(struct ieee80211_sub_if_data *sdata) 
	mutex_lock(&local->sta_mtx);

	list_for_each_entry_safe(sta, tmp, &local->sta_list, list) {

		if (sdata == sta->sdata) {

			WARN_ON(__sta_info_destroy(sta));

			if (!WARN_ON(__sta_info_destroy_part1(sta)))

				list_add(&sta->free_list, &free_list);

			ret++;

		}

	}



	if (!list_empty(&free_list)) {

		synchronize_net();

		list_for_each_entry_safe(sta, tmp, &free_list, free_list)

			__sta_info_destroy_part2(sta);

	}

	mutex_unlock(&local->sta_mtx);



	return ret;

net/mac80211/sta_info.h

+2 −1
Original line number Diff line number Diff line
@@ -247,6 +247,7 @@ struct ieee80211_tx_latency_stat { 
 * mac80211 is communicating with.

 *

 * @list: global linked list entry

 * @free_list: list entry for keeping track of stations to free

 * @hnext: hash table linked list pointer

 * @local: pointer to the global information

 * @sdata: virtual interface this station belongs to
@@ -329,7 +330,7 @@ struct ieee80211_tx_latency_stat { 
 */

struct sta_info {

	/* General information, mostly static */

	struct list_head list;

	struct list_head list, free_list;

	struct rcu_head rcu_head;

	struct sta_info __rcu *hnext;

	struct ieee80211_local *local;