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 <[email protected]>
---
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 9e04166..fd280a6 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 +327,105 @@ 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 (sdata->local->num_sta >= MESH_MAX_PLINKS)
+ return NULL;
- if (insert && sta_info_insert(sta))
+ 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;
+ bool insert = false;
+
+ rcu_read_lock();
+ sta = sta_info_get(sdata, addr);
+ if (!sta) {
+ rcu_read_unlock();
+ /* can't run atomic */
+ sta = mesh_sta_info_alloc(sdata, addr, elems);
+ if (!sta) {
+ rcu_read_lock();
+ return sta;
+ }
+ insert = true;
+ }
+
+ mesh_sta_info_init(sdata, sta, elems, insert);
+
+ if (insert && 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;
@@ -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 9d864ed..227233c 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;
}
--
1.7.10.4
An existing mesh station entry may change its rate
capabilities, so call rate_control_rate_update() to notify
the rate control.
Signed-off-by: Thomas Pedersen <[email protected]>
---
net/mac80211/driver-ops.h | 3 ++-
net/mac80211/mesh_plink.c | 8 +++++++-
2 files changed, 9 insertions(+), 2 deletions(-)
diff --git a/net/mac80211/driver-ops.h b/net/mac80211/driver-ops.h
index 0c07f94..b80d7a3 100644
--- a/net/mac80211/driver-ops.h
+++ b/net/mac80211/driver-ops.h
@@ -569,7 +569,8 @@ static inline void drv_sta_rc_update(struct ieee80211_local *local,
check_sdata_in_driver(sdata);
WARN_ON(changed & IEEE80211_RC_SUPP_RATES_CHANGED &&
- sdata->vif.type != NL80211_IFTYPE_ADHOC);
+ (sdata->vif.type != NL80211_IFTYPE_ADHOC &&
+ sdata->vif.type != NL80211_IFTYPE_MESH_POINT);
trace_drv_sta_rc_update(local, sdata, sta, changed);
if (local->ops->sta_rc_update)
diff --git a/net/mac80211/mesh_plink.c b/net/mac80211/mesh_plink.c
index fd280a6..1500a44 100644
--- a/net/mac80211/mesh_plink.c
+++ b/net/mac80211/mesh_plink.c
@@ -292,7 +292,7 @@ static void mesh_sta_info_init(struct ieee80211_sub_if_data *sdata,
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;
+ u32 rates, basic_rates = 0, changed = 0;
sband = local->hw.wiphy->bands[band];
rates = ieee80211_sta_get_rates(local, elems, band, &basic_rates);
@@ -304,6 +304,8 @@ static void mesh_sta_info_init(struct ieee80211_sub_if_data *sdata,
if (sta->plink_state == NL80211_PLINK_ESTAB)
goto out;
+ if (sta->sta.supp_rates[band] != rates)
+ changed |= IEEE80211_RC_SUPP_RATES_CHANGED;
sta->sta.supp_rates[band] = rates;
if (elems->ht_cap_elem &&
sdata->vif.bss_conf.chandef.width != NL80211_CHAN_WIDTH_20_NOHT)
@@ -322,11 +324,15 @@ static void mesh_sta_info_init(struct ieee80211_sub_if_data *sdata,
~IEEE80211_HT_CAP_SUP_WIDTH_20_40;
ieee80211_ht_oper_to_chandef(sdata->vif.bss_conf.chandef.chan,
elems->ht_operation, &chandef);
+ if (sta->ch_width != chandef.width)
+ changed |= IEEE80211_RC_BW_CHANGED;
sta->ch_width = chandef.width;
}
if (insert)
rate_control_rate_init(sta);
+ else
+ rate_control_rate_update(local, sband, sta, changed);
out:
spin_unlock_bh(&sta->lock);
}
--
1.7.10.4
On Wed, 2013-01-23 at 12:18 -0800, Thomas Pedersen wrote:
> 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().
Applied, I changed it to a bit to make sparse able to prove correctness.
johannes
On Wed, 2013-01-23 at 12:18 -0800, Thomas Pedersen wrote:
> An existing mesh station entry may change its rate
> capabilities, so call rate_control_rate_update() to notify
> the rate control.
Applied, with a fix to make it compile. Tssk Tssk.
johannes