diff options
| author | Johannes Berg <johannes@sipsolutions.net> | 2010-01-17 15:49:02 +0100 |
|---|---|---|
| committer | John W. Linville <linville@tuxdriver.com> | 2010-01-19 16:43:09 -0500 |
| commit | 5f2aa25e0e5b221a176ab3d1c51d51da265cb4a7 (patch) | |
| tree | b991f42ad2f5874b6ac3d8fcb1a138e889d70c19 /net/wireless | |
| parent | c57199bc32ebcd914253496486d2e09b1c9a3de0 (diff) | |
| download | linux-5f2aa25e0e5b221a176ab3d1c51d51da265cb4a7.tar.gz | |
cfg80211: rcu-ify rdev and wdev
Future code will need to look up rdev and wdev within atomic sections, but currently we need to lock a mutex for such lookups. Change the list handling for both to be RCU-safe so that we can look them up in rcu sections instead in the future. Signed-off-by: Johannes Berg <johannes@sipsolutions.net> Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'net/wireless')
| -rw-r--r-- | net/wireless/core.c | 26 | ||||
| -rw-r--r-- | net/wireless/core.h | 3 |
2 files changed, 17 insertions, 12 deletions
diff --git a/net/wireless/core.c b/net/wireless/core.c index 20db90246de5..d07f57c906db 100644 --- a/net/wireless/core.c +++ b/net/wireless/core.c @@ -1,7 +1,7 @@ /* * This is the linux wireless configuration interface. * - * Copyright 2006-2009 Johannes Berg <johannes@sipsolutions.net> + * Copyright 2006-2010 Johannes Berg <johannes@sipsolutions.net> */ #include <linux/if.h> @@ -31,15 +31,10 @@ MODULE_AUTHOR("Johannes Berg"); MODULE_LICENSE("GPL"); MODULE_DESCRIPTION("wireless configuration support"); -/* RCU might be appropriate here since we usually - * only read the list, and that can happen quite - * often because we need to do it for each command */ +/* RCU-protected (and cfg80211_mutex for writers) */ LIST_HEAD(cfg80211_rdev_list); int cfg80211_rdev_list_generation; -/* - * This is used to protect the cfg80211_rdev_list - */ DEFINE_MUTEX(cfg80211_mutex); /* for debugfs */ @@ -477,7 +472,7 @@ int wiphy_register(struct wiphy *wiphy) /* set up regulatory info */ wiphy_update_regulatory(wiphy, NL80211_REGDOM_SET_BY_CORE); - list_add(&rdev->list, &cfg80211_rdev_list); + list_add_rcu(&rdev->list, &cfg80211_rdev_list); cfg80211_rdev_list_generation++; mutex_unlock(&cfg80211_mutex); @@ -554,7 +549,8 @@ void wiphy_unregister(struct wiphy *wiphy) * it impossible to find from userspace. */ debugfs_remove_recursive(rdev->wiphy.debugfsdir); - list_del(&rdev->list); + list_del_rcu(&rdev->list); + synchronize_rcu(); /* * Try to grab rdev->mtx. If a command is still in progress, @@ -670,7 +666,7 @@ static int cfg80211_netdev_notifier_call(struct notifier_block * nb, INIT_LIST_HEAD(&wdev->event_list); spin_lock_init(&wdev->event_lock); mutex_lock(&rdev->devlist_mtx); - list_add(&wdev->list, &rdev->netdev_list); + list_add_rcu(&wdev->list, &rdev->netdev_list); rdev->devlist_generation++; /* can only change netns with wiphy */ dev->features |= NETIF_F_NETNS_LOCAL; @@ -782,13 +778,21 @@ static int cfg80211_netdev_notifier_call(struct notifier_block * nb, */ if (!list_empty(&wdev->list)) { sysfs_remove_link(&dev->dev.kobj, "phy80211"); - list_del_init(&wdev->list); + list_del_rcu(&wdev->list); rdev->devlist_generation++; #ifdef CONFIG_CFG80211_WEXT kfree(wdev->wext.keys); #endif } mutex_unlock(&rdev->devlist_mtx); + /* + * synchronise (so that we won't find this netdev + * from other code any more) and then clear the list + * head so that the above code can safely check for + * !list_empty() to avoid double-cleanup. + */ + synchronize_rcu(); + INIT_LIST_HEAD(&wdev->list); break; case NETDEV_PRE_UP: if (!(wdev->wiphy->interface_modes & BIT(wdev->iftype))) diff --git a/net/wireless/core.h b/net/wireless/core.h index 2d6a6b9c0c43..c326a667022a 100644 --- a/net/wireless/core.h +++ b/net/wireless/core.h @@ -1,7 +1,7 @@ /* * Wireless configuration interface internals. * - * Copyright 2006-2009 Johannes Berg <johannes@sipsolutions.net> + * Copyright 2006-2010 Johannes Berg <johannes@sipsolutions.net> */ #ifndef __NET_WIRELESS_CORE_H #define __NET_WIRELESS_CORE_H @@ -48,6 +48,7 @@ struct cfg80211_registered_device { /* associate netdev list */ struct mutex devlist_mtx; + /* protected by devlist_mtx or RCU */ struct list_head netdev_list; int devlist_generation; int opencount; /* also protected by devlist_mtx */ |