From 296fcba3ba1b8888aa8f5211de1e25a78b47aeee Mon Sep 17 00:00:00 2001 From: Thomas Pedersen Date: Wed, 23 Jan 2013 12:18:12 -0800 Subject: [PATCH] mac80211: clean up mesh sta allocation warning This refactoring fixes a "scheduling while atomic" warning when allocating a mesh station entry while holding the RCU read lock. Fix this by creating a new function mesh_sta_info_get(), which correctly handles the locking and returns under RCU. Also move some unnecessarily #ifdefed mesh station init code from sta_info_alloc() to __mesh_sta_info_alloc(). Signed-off-by: Thomas Pedersen [change code flow to make sparse happy] Signed-off-by: Johannes Berg --- net/mac80211/mesh_plink.c | 158 ++++++++++++++++++++++++++++------------------ net/mac80211/sta_info.c | 5 -- 2 files changed, 95 insertions(+), 68 deletions(-) diff --git a/net/mac80211/mesh_plink.c b/net/mac80211/mesh_plink.c index 9e0416696a83..ef92d2705851 100644 --- a/net/mac80211/mesh_plink.c +++ b/net/mac80211/mesh_plink.c @@ -55,30 +55,6 @@ static inline void mesh_plink_fsm_restart(struct sta_info *sta) sta->plink_retries = 0; } -/* - * Allocate mesh sta entry and insert into station table - */ -static struct sta_info *mesh_plink_alloc(struct ieee80211_sub_if_data *sdata, - u8 *hw_addr) -{ - struct sta_info *sta; - - if (sdata->local->num_sta >= MESH_MAX_PLINKS) - return NULL; - - sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL); - if (!sta) - return NULL; - - sta_info_pre_move_state(sta, IEEE80211_STA_AUTH); - sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC); - sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED); - - set_sta_flag(sta, WLAN_STA_WME); - - return sta; -} - /** * mesh_set_ht_prot_mode - set correct HT protection mode * @@ -309,52 +285,24 @@ free: return err; } -/** - * mesh_peer_init - initialize new mesh peer and return resulting sta_info - * - * @sdata: local meshif - * @addr: peer's address - * @elems: IEs from beacon or mesh peering frame - * - * call under RCU - */ -static struct sta_info *mesh_peer_init(struct ieee80211_sub_if_data *sdata, - u8 *addr, - struct ieee802_11_elems *elems) +static void mesh_sta_info_init(struct ieee80211_sub_if_data *sdata, + struct sta_info *sta, + struct ieee802_11_elems *elems, bool insert) { struct ieee80211_local *local = sdata->local; enum ieee80211_band band = ieee80211_get_sdata_band(sdata); struct ieee80211_supported_band *sband; u32 rates, basic_rates = 0; - struct sta_info *sta; - bool insert = false; sband = local->hw.wiphy->bands[band]; rates = ieee80211_sta_get_rates(local, elems, band, &basic_rates); - sta = sta_info_get(sdata, addr); - if (!sta) { - /* Userspace handles peer allocation when security is enabled */ - if (sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED) { - cfg80211_notify_new_peer_candidate(sdata->dev, addr, - elems->ie_start, - elems->total_len, - GFP_ATOMIC); - return NULL; - } - - sta = mesh_plink_alloc(sdata, addr); - if (!sta) - return NULL; - insert = true; - } - spin_lock_bh(&sta->lock); sta->last_rx = jiffies; - if (sta->plink_state == NL80211_PLINK_ESTAB) { - spin_unlock_bh(&sta->lock); - return sta; - } + + /* rates and capabilities don't change during peering */ + if (sta->plink_state == NL80211_PLINK_ESTAB) + goto out; sta->sta.supp_rates[band] = rates; if (elems->ht_cap_elem && @@ -379,22 +327,104 @@ static struct sta_info *mesh_peer_init(struct ieee80211_sub_if_data *sdata, if (insert) rate_control_rate_init(sta); +out: spin_unlock_bh(&sta->lock); +} + +static struct sta_info * +__mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *hw_addr) +{ + struct sta_info *sta; - if (insert && sta_info_insert(sta)) + if (sdata->local->num_sta >= MESH_MAX_PLINKS) return NULL; + sta = sta_info_alloc(sdata, hw_addr, GFP_KERNEL); + if (!sta) + return NULL; + + sta->plink_state = NL80211_PLINK_LISTEN; + init_timer(&sta->plink_timer); + + sta_info_pre_move_state(sta, IEEE80211_STA_AUTH); + sta_info_pre_move_state(sta, IEEE80211_STA_ASSOC); + sta_info_pre_move_state(sta, IEEE80211_STA_AUTHORIZED); + + set_sta_flag(sta, WLAN_STA_WME); + + return sta; +} + +static struct sta_info * +mesh_sta_info_alloc(struct ieee80211_sub_if_data *sdata, u8 *addr, + struct ieee802_11_elems *elems) +{ + struct sta_info *sta = NULL; + + /* Userspace handles peer allocation when security is enabled */ + if (sdata->u.mesh.security & IEEE80211_MESH_SEC_AUTHED) + cfg80211_notify_new_peer_candidate(sdata->dev, addr, + elems->ie_start, + elems->total_len, + GFP_KERNEL); + else + sta = __mesh_sta_info_alloc(sdata, addr); + return sta; } +/* + * mesh_sta_info_get - return mesh sta info entry for @addr. + * + * @sdata: local meshif + * @addr: peer's address + * @elems: IEs from beacon or mesh peering frame. + * + * Return existing or newly allocated sta_info under RCU read lock. + * (re)initialize with given IEs. + */ +static struct sta_info * +mesh_sta_info_get(struct ieee80211_sub_if_data *sdata, + u8 *addr, struct ieee802_11_elems *elems) __acquires(RCU) +{ + struct sta_info *sta = NULL; + + rcu_read_lock(); + sta = sta_info_get(sdata, addr); + if (sta) { + mesh_sta_info_init(sdata, sta, elems, false); + } else { + rcu_read_unlock(); + /* can't run atomic */ + sta = mesh_sta_info_alloc(sdata, addr, elems); + if (!sta) { + rcu_read_lock(); + return NULL; + } + + if (sta_info_insert_rcu(sta)) + return NULL; + } + + return sta; +} + +/* + * mesh_neighbour_update - update or initialize new mesh neighbor. + * + * @sdata: local meshif + * @addr: peer's address + * @elems: IEs from beacon or mesh peering frame + * + * Initiates peering if appropriate. + */ void mesh_neighbour_update(struct ieee80211_sub_if_data *sdata, u8 *hw_addr, struct ieee802_11_elems *elems) { struct sta_info *sta; - rcu_read_lock(); - sta = mesh_peer_init(sdata, hw_addr, elems); + sta = mesh_sta_info_get(sdata, hw_addr, elems); if (!sta) goto out; @@ -632,6 +662,7 @@ void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_m (ftype == WLAN_SP_MESH_PEERING_CLOSE && ie_len == 8)) memcpy(&llid, PLINK_GET_PLID(elems.peering), 2); + /* WARNING: Only for sta pointer, is dropped & re-acquired */ rcu_read_lock(); sta = sta_info_get(sdata, mgmt->sa); @@ -735,8 +766,9 @@ void mesh_rx_plink_frame(struct ieee80211_sub_if_data *sdata, struct ieee80211_m } if (event == OPN_ACPT) { + rcu_read_unlock(); /* allocate sta entry if necessary and update info */ - sta = mesh_peer_init(sdata, mgmt->sa, &elems); + sta = mesh_sta_info_get(sdata, mgmt->sa, &elems); if (!sta) { mpl_dbg(sdata, "Mesh plink: failed to init peer!\n"); rcu_read_unlock(); diff --git a/net/mac80211/sta_info.c b/net/mac80211/sta_info.c index 9d864ed5f3da..227233c3ff7f 100644 --- a/net/mac80211/sta_info.c +++ b/net/mac80211/sta_info.c @@ -380,11 +380,6 @@ struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata, sta_dbg(sdata, "Allocated STA %pM\n", sta->sta.addr); -#ifdef CONFIG_MAC80211_MESH - sta->plink_state = NL80211_PLINK_LISTEN; - init_timer(&sta->plink_timer); -#endif - return sta; } -- 2.11.0