From mboxrd@z Thu Jan 1 00:00:00 1970 Return-path: Received: from crystal.sipsolutions.net ([195.210.38.204]:52508 "EHLO sipsolutions.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1758016AbXK1N1F (ORCPT ); Wed, 28 Nov 2007 08:27:05 -0500 Subject: [PATCH] mac80211: make ieee80211_iterate_active_interfaces not need rtnl From: Johannes Berg To: John Linville Cc: Michael Wu , linux-wireless Content-Type: text/plain Date: Wed, 28 Nov 2007 10:55:32 +0100 Message-Id: <1196243733.6058.117.camel@johannes.berg> (sfid-20071128_132710_226273_17F224E5) Mime-Version: 1.0 Sender: linux-wireless-owner@vger.kernel.org List-ID: 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: Johannes Berg --- include/net/mac80211.h | 3 +-- net/mac80211/util.c | 7 ++++--- 2 files changed, 5 insertions(+), 5 deletions(-) --- everything.orig/include/net/mac80211.h 2007-11-28 01:24:04.030767632 +0100 +++ everything/include/net/mac80211.h 2007-11-28 10:51:18.718922797 +0100 @@ -1408,10 +1408,9 @@ void ieee80211_scan_completed(struct iee * * 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, --- everything.orig/net/mac80211/util.c 2007-11-28 01:24:24.310766384 +0100 +++ everything/net/mac80211/util.c 2007-11-28 01:26:40.510763509 +0100 @@ -482,10 +482,9 @@ void ieee80211_iterate_active_interfaces 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: @@ -504,5 +503,7 @@ void ieee80211_iterate_active_interfaces iterator(data, sdata->dev->dev_addr, sdata->dev->ifindex); } + + rcu_read_unlock(); } EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces);