On Tue, 2009-01-20 at 21:30 +0530, Sujith wrote:
> Johannes Berg wrote:
> > cOn Tue, 2009-01-20 at 13:27 +0530, Sujith wrote:
> > > This patch adds a flag to notify drivers to start and
> > > stop beaconing when needed, for example, during a scan run.
> >
> >
> > > + if ((changed & IEEE80211_IFCC_BEACON) &&
> > > + (sdata->vif.type == NL80211_IFTYPE_AP ||
> > > + sdata->vif.type == NL80211_IFTYPE_ADHOC ||
> > > + sdata->vif.type == NL80211_IFTYPE_MESH_POINT)) {
> > > + if (local->sw_scanning || local->hw_scanning)
> > > + conf.enable_beacon = false;
> > > + else
> > > + conf.enable_beacon = true;
> > > + }
> > > +
> >
> > You really just want to do the minimal thing, right? :)
>
> Oh, absolutely :)
:)
> > That won't work when userspace disables the beacon by removing it, for
> > instance, right now drivers won't know when hostapd removed the beacon
> > except that ieee80211_beacon_get will start returning 0... Also, I think
> > a separate change flag would be appropriate, sometimes we might just
> > re-enable the beacon without having changed it, after scanning?
>
> Ok, how about this ?
How about this? Untested still though.
johannes
--- Begin Message ---
- Subject: mac80211: add interface list lock
- From:
- Date: Wed, 21 Jan 2009 12:45:47 +0100
Using only the RTNL has a number of problems, most notably that ieee80211_iterate_active_interfaces() and other interface list traversals cannot be done from the internal workqueue because it needs to be flushed under the RTNL. This patch introduces a new mutex that protects the interface list against modifications. A more detailed explanation is part of the code change. Signed-off-by: Johannes Berg <johannes@xxxxxxxxxxxxxxxx> --- Need this for the scan stuff I'm doing next, but this has the side effect of allowing you to call ieee80211_iterate_active_interfaces() from mac80211's workqueue, which might be interesting. net/mac80211/ieee80211_i.h | 2 ++ net/mac80211/iface.c | 24 ++++++++++++++++++++++++ net/mac80211/main.c | 3 +++ net/mac80211/util.c | 4 ++-- 4 files changed, 31 insertions(+), 2 deletions(-) --- wireless-testing.orig/net/mac80211/ieee80211_i.h 2009-01-21 12:19:47.000000000 +0100 +++ wireless-testing/net/mac80211/ieee80211_i.h 2009-01-21 12:22:02.000000000 +0100 @@ -643,7 +643,9 @@ struct ieee80211_local { struct crypto_blkcipher *wep_rx_tfm; u32 wep_iv; + /* see iface.c */ struct list_head interfaces; + struct mutex iflist_mtx; /* * Key lock, protects sdata's key_list and sta_info's --- wireless-testing.orig/net/mac80211/iface.c 2009-01-21 12:20:40.000000000 +0100 +++ wireless-testing/net/mac80211/iface.c 2009-01-21 12:28:15.000000000 +0100 @@ -21,6 +21,23 @@ #include "mesh.h" #include "led.h" +/** + * DOC: Interface list locking + * + * The interface list in each struct ieee80211_local is protected + * three-fold: + * + * (1) modifications may only be done under the RTNL + * (2) modifications and readers are protected against each other by + * the iflist_mtx. + * (3) modifications are done in an RCU manner so atomic readers + * can traverse the list in RCU-safe blocks. + * + * As a consequence, reads (traversals) of the list can be protected + * by either the RTNL, the iflist_mtx or RCU. + */ + + static int ieee80211_change_mtu(struct net_device *dev, int new_mtu) { int meshhdrlen; @@ -800,7 +817,9 @@ int ieee80211_if_add(struct ieee80211_lo params->mesh_id_len, params->mesh_id); + mutex_lock(&local->iflist_mtx); list_add_tail_rcu(&sdata->list, &local->interfaces); + mutex_unlock(&local->iflist_mtx); if (new_dev) *new_dev = ndev; @@ -816,7 +835,10 @@ void ieee80211_if_remove(struct ieee8021 { ASSERT_RTNL(); + mutex_lock(&sdata->local->iflist_mtx); list_del_rcu(&sdata->list); + mutex_unlock(&sdata->local->iflist_mtx); + synchronize_rcu(); unregister_netdevice(sdata->dev); } @@ -831,8 +853,10 @@ void ieee80211_remove_interfaces(struct ASSERT_RTNL(); + mutex_lock(&local->iflist_mtx); list_for_each_entry_safe(sdata, tmp, &local->interfaces, list) { list_del(&sdata->list); unregister_netdevice(sdata->dev); } + mutex_unlock(&local->iflist_mtx); } --- wireless-testing.orig/net/mac80211/main.c 2009-01-21 12:26:36.000000000 +0100 +++ wireless-testing/net/mac80211/main.c 2009-01-21 12:27:19.000000000 +0100 @@ -718,6 +718,7 @@ struct ieee80211_hw *ieee80211_alloc_hw( local->hw.conf.radio_enabled = true; INIT_LIST_HEAD(&local->interfaces); + mutex_init(&local->iflist_mtx); spin_lock_init(&local->key_lock); @@ -968,6 +969,8 @@ void ieee80211_free_hw(struct ieee80211_ { struct ieee80211_local *local = hw_to_local(hw); + mutex_destroy(&local->iflist_mtx); + wiphy_free(local->hw.wiphy); } EXPORT_SYMBOL(ieee80211_free_hw); --- wireless-testing.orig/net/mac80211/util.c 2009-01-21 12:28:36.000000000 +0100 +++ wireless-testing/net/mac80211/util.c 2009-01-21 12:29:01.000000000 +0100 @@ -459,7 +459,7 @@ void ieee80211_iterate_active_interfaces struct ieee80211_local *local = hw_to_local(hw); struct ieee80211_sub_if_data *sdata; - rtnl_lock(); + mutex_lock(&local->iflist_mtx); list_for_each_entry(sdata, &local->interfaces, list) { switch (sdata->vif.type) { @@ -480,7 +480,7 @@ void ieee80211_iterate_active_interfaces &sdata->vif); } - rtnl_unlock(); + mutex_unlock(&local->iflist_mtx); } EXPORT_SYMBOL_GPL(ieee80211_iterate_active_interfaces);
--- End Message ---
--- Begin Message ---
- Subject: mac80211: Add capability to enable/disable beaconing
- From:
- Date: Wed, 21 Jan 2009 12:45:47 +0100
This patch adds a flag to notify drivers to start and stop beaconing when needed, for example, during a scan run. Signed-off-by: Sujith <Sujith.Manoharan@xxxxxxxxxxx> Signed-off-by: Johannes Berg <johannes@xxxxxxxxxxxxxxxx> --- include/net/mac80211.h | 9 +++++++-- net/mac80211/cfg.c | 5 +++-- net/mac80211/main.c | 42 +++++++++++++++++++++++++++++++++++++++++- net/mac80211/mesh.c | 3 ++- net/mac80211/mlme.c | 3 ++- net/mac80211/scan.c | 18 +++++++++++------- 6 files changed, 66 insertions(+), 14 deletions(-) --- wireless-testing.orig/include/net/mac80211.h 2009-01-21 12:44:02.000000000 +0100 +++ wireless-testing/include/net/mac80211.h 2009-01-21 12:44:16.000000000 +0100 @@ -626,10 +626,12 @@ struct ieee80211_if_init_conf { * @IEEE80211_IFCC_BSSID: The BSSID changed. * @IEEE80211_IFCC_BEACON: The beacon for this interface changed * (currently AP and MESH only), use ieee80211_beacon_get(). + * @IEEE80211_IFCC_BEACON_ENABLED: The enable_beacon value changed. */ enum ieee80211_if_conf_change { - IEEE80211_IFCC_BSSID = BIT(0), - IEEE80211_IFCC_BEACON = BIT(1), + IEEE80211_IFCC_BSSID = BIT(0), + IEEE80211_IFCC_BEACON = BIT(1), + IEEE80211_IFCC_BEACON_ENABLED = BIT(2), }; /** @@ -637,6 +639,8 @@ enum ieee80211_if_conf_change { * * @changed: parameters that have changed, see &enum ieee80211_if_conf_change. * @bssid: BSSID of the network we are associated to/creating. + * @enable_beacon: Indicates whether beacons can be sent. + * This is valid only for AP/IBSS/MESH modes. * * This structure is passed to the config_interface() callback of * &struct ieee80211_hw. @@ -644,6 +648,7 @@ enum ieee80211_if_conf_change { struct ieee80211_if_conf { u32 changed; const u8 *bssid; + bool enable_beacon; }; /** --- wireless-testing.orig/net/mac80211/main.c 2009-01-21 12:44:04.000000000 +0100 +++ wireless-testing/net/mac80211/main.c 2009-01-21 12:44:16.000000000 +0100 @@ -168,7 +168,6 @@ int ieee80211_if_config(struct ieee80211 return 0; memset(&conf, 0, sizeof(conf)); - conf.changed = changed; if (sdata->vif.type == NL80211_IFTYPE_STATION || sdata->vif.type == NL80211_IFTYPE_ADHOC) @@ -183,9 +182,50 @@ int ieee80211_if_config(struct ieee80211 return -EINVAL; } + switch (sdata->vif.type) { + case NL80211_IFTYPE_AP: + case NL80211_IFTYPE_ADHOC: + case NL80211_IFTYPE_MESH_POINT: + break; + default: + /* do not warn to simplify caller in scan.c */ + changed &= ~IEEE80211_IFCC_BEACON_ENABLED; + if (WARN_ON(changed & IEEE80211_IFCC_BEACON)) + return -EINVAL; + changed &= ~IEEE80211_IFCC_BEACON; + break; + } + + if (changed & IEEE80211_IFCC_BEACON_ENABLED) { + if (local->sw_scanning) { + conf.enable_beacon = false; + } else { + /* + * Beacon should be enabled, but AP mode must + * check whether there is a beacon configured. + */ + switch (sdata->vif.type) { + case NL80211_IFTYPE_AP: + conf.enable_beacon = + !!rcu_dereference(sdata->u.ap.beacon); + break; + case NL80211_IFTYPE_ADHOC: + case NL80211_IFTYPE_MESH_POINT: + conf.enable_beacon = true; + break; + default: + /* not reached */ + WARN_ON(1); + break; + } + } + } + if (WARN_ON(!conf.bssid && (changed & IEEE80211_IFCC_BSSID))) return -EINVAL; + conf.changed = changed; + return local->ops->config_interface(local_to_hw(local), &sdata->vif, &conf); } --- wireless-testing.orig/net/mac80211/scan.c 2009-01-21 12:43:32.000000000 +0100 +++ wireless-testing/net/mac80211/scan.c 2009-01-21 12:44:16.000000000 +0100 @@ -20,6 +20,7 @@ #include <linux/wireless.h> #include <linux/if_arp.h> +#include <linux/rtnetlink.h> #include <net/mac80211.h> #include <net/iw_handler.h> @@ -472,8 +473,8 @@ void ieee80211_scan_completed(struct iee netif_addr_unlock(local->mdev); netif_tx_unlock_bh(local->mdev); - rcu_read_lock(); - list_for_each_entry_rcu(sdata, &local->interfaces, list) { + mutex_lock(&local->iflist_mtx); + list_for_each_entry(sdata, &local->interfaces, list) { /* Tell AP we're back */ if (sdata->vif.type == NL80211_IFTYPE_STATION) { if (sdata->u.sta.flags & IEEE80211_STA_ASSOCIATED) { @@ -482,8 +483,10 @@ void ieee80211_scan_completed(struct iee } } else netif_tx_wake_all_queues(sdata->dev); + + ieee80211_if_config(sdata, IEEE80211_IFCC_BEACON_ENABLED); } - rcu_read_unlock(); + mutex_unlock(&local->iflist_mtx); done: ieee80211_mlme_notify_scan_completed(local); @@ -491,7 +494,6 @@ void ieee80211_scan_completed(struct iee } EXPORT_SYMBOL(ieee80211_scan_completed); - void ieee80211_scan_work(struct work_struct *work) { struct ieee80211_local *local = @@ -633,8 +635,10 @@ int ieee80211_start_scan(struct ieee8021 local->sw_scanning = true; - rcu_read_lock(); - list_for_each_entry_rcu(sdata, &local->interfaces, list) { + mutex_lock(&local->iflist_mtx); + list_for_each_entry(sdata, &local->interfaces, list) { + ieee80211_if_config(sdata, IEEE80211_IFCC_BEACON_ENABLED); + if (sdata->vif.type == NL80211_IFTYPE_STATION) { if (sdata->u.sta.flags & IEEE80211_STA_ASSOCIATED) { netif_tx_stop_all_queues(sdata->dev); @@ -643,7 +647,7 @@ int ieee80211_start_scan(struct ieee8021 } else netif_tx_stop_all_queues(sdata->dev); } - rcu_read_unlock(); + mutex_unlock(&local->iflist_mtx); if (ssid) { local->scan_ssid_len = ssid_len; --- wireless-testing.orig/net/mac80211/mesh.c 2009-01-21 12:43:32.000000000 +0100 +++ wireless-testing/net/mac80211/mesh.c 2009-01-21 12:44:16.000000000 +0100 @@ -442,7 +442,8 @@ void ieee80211_start_mesh(struct ieee802 ifmsh->housekeeping = true; queue_work(local->hw.workqueue, &ifmsh->work); - ieee80211_if_config(sdata, IEEE80211_IFCC_BEACON); + ieee80211_if_config(sdata, IEEE80211_IFCC_BEACON | + IEEE80211_IFCC_BEACON_ENABLED); } void ieee80211_stop_mesh(struct ieee80211_sub_if_data *sdata) --- wireless-testing.orig/net/mac80211/mlme.c 2009-01-21 12:43:32.000000000 +0100 +++ wireless-testing/net/mac80211/mlme.c 2009-01-21 12:44:16.000000000 +0100 @@ -1598,7 +1598,8 @@ static int ieee80211_sta_join_ibss(struc ifsta->probe_resp = skb; - ieee80211_if_config(sdata, IEEE80211_IFCC_BEACON); + ieee80211_if_config(sdata, IEEE80211_IFCC_BEACON | + IEEE80211_IFCC_BEACON_ENABLED); rates = 0; --- wireless-testing.orig/net/mac80211/cfg.c 2009-01-21 12:43:32.000000000 +0100 +++ wireless-testing/net/mac80211/cfg.c 2009-01-21 12:44:16.000000000 +0100 @@ -523,7 +523,8 @@ static int ieee80211_config_beacon(struc kfree(old); - return ieee80211_if_config(sdata, IEEE80211_IFCC_BEACON); + return ieee80211_if_config(sdata, IEEE80211_IFCC_BEACON | + IEEE80211_IFCC_BEACON_ENABLED); } static int ieee80211_add_beacon(struct wiphy *wiphy, struct net_device *dev, @@ -583,7 +584,7 @@ static int ieee80211_del_beacon(struct w synchronize_rcu(); kfree(old); - return ieee80211_if_config(sdata, IEEE80211_IFCC_BEACON); + return ieee80211_if_config(sdata, IEEE80211_IFCC_BEACON_ENABLED); } /* Layer 2 Update frame (802.2 Type 1 LLC XID Update response) */
--- End Message ---
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