Commit e38bad47 authored by Johannes Berg's avatar Johannes Berg Committed by David S. Miller
Browse files

mac80211: make ieee80211_iterate_active_interfaces not need rtnl 



Interface iteration in mac80211 can be done without holding any
locks because I converted it to RCU. Initially, I thought this
wouldn't be needed for ieee80211_iterate_active_interfaces but
it's turning out that multi-BSS AP support can be much simpler
in a driver if ieee80211_iterate_active_interfaces can be called
without holding locks. This converts it to use RCU, it adds a
requirement that the callback it invokes cannot sleep.

Signed-off-by: default avatarJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: default avatarJohn W. Linville <linville@tuxdriver.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 76ee65bf

include/net/mac80211.h

+1 −2
Original line number Diff line number Diff line
@@ -1411,10 +1411,9 @@ void ieee80211_scan_completed(struct ieee80211_hw *hw); 
 *

 * This function iterates over the interfaces associated with a given

 * hardware that are currently active and calls the callback for them.

 * Must be called under RTNL.

 *

 * @hw: the hardware struct of which the interfaces should be iterated over

 * @iterator: the iterator function to call

 * @iterator: the iterator function to call, cannot sleep

 * @data: first argument of the iterator function

 */

void ieee80211_iterate_active_interfaces(struct ieee80211_hw *hw,

net/mac80211/util.c

+4 −3
Original line number Diff line number Diff line
@@ -482,10 +482,9 @@ void ieee80211_iterate_active_interfaces(struct ieee80211_hw *hw, 
	struct ieee80211_local *local = hw_to_local(hw);

	struct ieee80211_sub_if_data *sdata;



	ASSERT_RTNL();

	rcu_read_lock();



	/* we hold the RTNL here so can safely walk the list */

	list_for_each_entry(sdata, &local->interfaces, list) {

	list_for_each_entry_rcu(sdata, &local->interfaces, list) {

		switch (sdata->type) {

		case IEEE80211_IF_TYPE_INVALID:

		case IEEE80211_IF_TYPE_MNTR:
@@ -503,5 +502,7 @@ void ieee80211_iterate_active_interfaces(struct ieee80211_hw *hw, 
			iterator(data, sdata->dev->dev_addr,

				 sdata->dev->ifindex);

	}



	rcu_read_unlock();

}

EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces);

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