Commit 48bf6bed authored by Bob Copeland's avatar Bob Copeland Committed by Johannes Berg
Browse files

mac80211: introduce plink lock for plink fields 



The mesh plink code uses sta->lock to serialize access to the
plink state fields between the peer link state machine and the
peer link timer.  Some paths (e.g. those involving
mps_qos_null_tx()) unfortunately hold this spinlock across
frame tx, which is soon to be disallowed.  Add a new spinlock
just for plink access.

Signed-off-by: default avatarBob Copeland <me@bobcopeland.com>
Signed-off-by: default avatarJohannes Berg <johannes.berg@intel.com>
parent 388f9976

net/mac80211/mesh_plink.c

+20 −17
Original line number Diff line number Diff line
@@ -72,10 +72,11 @@ static bool rssi_threshold_check(struct ieee80211_sub_if_data *sdata, 
 *

 * @sta: mesh peer link to restart

 *

 * Locking: this function must be called holding sta->lock

 * Locking: this function must be called holding sta->plink_lock

 */

static inline void mesh_plink_fsm_restart(struct sta_info *sta)

{

	lockdep_assert_held(&sta->plink_lock);

	sta->plink_state = NL80211_PLINK_LISTEN;

	sta->llid = sta->plid = sta->reason = 0;

	sta->plink_retries = 0;
@@ -213,13 +214,15 @@ static u32 mesh_set_ht_prot_mode(struct ieee80211_sub_if_data *sdata) 
 * All mesh paths with this peer as next hop will be flushed

 * Returns beacon changed flag if the beacon content changed.

 *

 * Locking: the caller must hold sta->lock

 * Locking: the caller must hold sta->plink_lock

 */

static u32 __mesh_plink_deactivate(struct sta_info *sta)

{

	struct ieee80211_sub_if_data *sdata = sta->sdata;

	u32 changed = 0;



	lockdep_assert_held(&sta->plink_lock);



	if (sta->plink_state == NL80211_PLINK_ESTAB)

		changed = mesh_plink_dec_estab_count(sdata);

	sta->plink_state = NL80211_PLINK_BLOCKED;
@@ -244,13 +247,13 @@ u32 mesh_plink_deactivate(struct sta_info *sta) 
	struct ieee80211_sub_if_data *sdata = sta->sdata;

	u32 changed;



	spin_lock_bh(&sta->lock);

	spin_lock_bh(&sta->plink_lock);

	changed = __mesh_plink_deactivate(sta);

	sta->reason = WLAN_REASON_MESH_PEER_CANCELED;

	mesh_plink_frame_tx(sdata, WLAN_SP_MESH_PEERING_CLOSE,

			    sta->sta.addr, sta->llid, sta->plid,

			    sta->reason);

	spin_unlock_bh(&sta->lock);

	spin_unlock_bh(&sta->plink_lock);



	return changed;

}
@@ -387,7 +390,7 @@ static void mesh_sta_info_init(struct ieee80211_sub_if_data *sdata, 
	sband = local->hw.wiphy->bands[band];

	rates = ieee80211_sta_get_rates(sdata, elems, band, &basic_rates);



	spin_lock_bh(&sta->lock);

	spin_lock_bh(&sta->plink_lock);

	sta->last_rx = jiffies;



	/* rates and capabilities don't change during peering */
@@ -419,7 +422,7 @@ static void mesh_sta_info_init(struct ieee80211_sub_if_data *sdata, 
	else

		rate_control_rate_update(local, sband, sta, changed);

out:

	spin_unlock_bh(&sta->lock);

	spin_unlock_bh(&sta->plink_lock);

}



static struct sta_info *
@@ -552,7 +555,7 @@ static void mesh_plink_timer(unsigned long data) 
	if (sta->sdata->local->quiescing)

		return;



	spin_lock_bh(&sta->lock);

	spin_lock_bh(&sta->plink_lock);



	/* If a timer fires just before a state transition on another CPU,

	 * we may have already extended the timeout and changed state by the
@@ -563,7 +566,7 @@ static void mesh_plink_timer(unsigned long data) 
		mpl_dbg(sta->sdata,

			"Ignoring timer for %pM in state %s (timer adjusted)",

			sta->sta.addr, mplstates[sta->plink_state]);

		spin_unlock_bh(&sta->lock);

		spin_unlock_bh(&sta->plink_lock);

		return;

	}
@@ -573,7 +576,7 @@ static void mesh_plink_timer(unsigned long data) 
		mpl_dbg(sta->sdata,

			"Ignoring timer for %pM in state %s (timer deleted)",

			sta->sta.addr, mplstates[sta->plink_state]);

		spin_unlock_bh(&sta->lock);

		spin_unlock_bh(&sta->plink_lock);

		return;

	}
@@ -619,7 +622,7 @@ static void mesh_plink_timer(unsigned long data) 
	default:

		break;

	}

	spin_unlock_bh(&sta->lock);

	spin_unlock_bh(&sta->plink_lock);

	if (action)

		mesh_plink_frame_tx(sdata, action, sta->sta.addr,

				    sta->llid, sta->plid, reason);
@@ -674,16 +677,16 @@ u32 mesh_plink_open(struct sta_info *sta) 
	if (!test_sta_flag(sta, WLAN_STA_AUTH))

		return 0;



	spin_lock_bh(&sta->lock);

	spin_lock_bh(&sta->plink_lock);

	sta->llid = mesh_get_new_llid(sdata);

	if (sta->plink_state != NL80211_PLINK_LISTEN &&

	    sta->plink_state != NL80211_PLINK_BLOCKED) {

		spin_unlock_bh(&sta->lock);

		spin_unlock_bh(&sta->plink_lock);

		return 0;

	}

	sta->plink_state = NL80211_PLINK_OPN_SNT;

	mesh_plink_timer_set(sta, sdata->u.mesh.mshcfg.dot11MeshRetryTimeout);

	spin_unlock_bh(&sta->lock);

	spin_unlock_bh(&sta->plink_lock);

	mpl_dbg(sdata,

		"Mesh plink: starting establishment with %pM\n",

		sta->sta.addr);
@@ -700,10 +703,10 @@ u32 mesh_plink_block(struct sta_info *sta) 
{

	u32 changed;



	spin_lock_bh(&sta->lock);

	spin_lock_bh(&sta->plink_lock);

	changed = __mesh_plink_deactivate(sta);

	sta->plink_state = NL80211_PLINK_BLOCKED;

	spin_unlock_bh(&sta->lock);

	spin_unlock_bh(&sta->plink_lock);



	return changed;

}
@@ -758,7 +761,7 @@ static u32 mesh_plink_fsm(struct ieee80211_sub_if_data *sdata, 
	mpl_dbg(sdata, "peer %pM in state %s got event %s\n", sta->sta.addr,

		mplstates[sta->plink_state], mplevents[event]);



	spin_lock_bh(&sta->lock);

	spin_lock_bh(&sta->plink_lock);

	switch (sta->plink_state) {

	case NL80211_PLINK_LISTEN:

		switch (event) {
@@ -872,7 +875,7 @@ static u32 mesh_plink_fsm(struct ieee80211_sub_if_data *sdata, 
		 */

		break;

	}

	spin_unlock_bh(&sta->lock);

	spin_unlock_bh(&sta->plink_lock);

	if (action) {

		mesh_plink_frame_tx(sdata, action, sta->sta.addr,

				    sta->llid, sta->plid, sta->reason);

net/mac80211/sta_info.c

+1 −0
Original line number Diff line number Diff line
@@ -295,6 +295,7 @@ struct sta_info *sta_info_alloc(struct ieee80211_sub_if_data *sdata, 
	INIT_WORK(&sta->ampdu_mlme.work, ieee80211_ba_session_work);

	mutex_init(&sta->ampdu_mlme.mtx);

#ifdef CONFIG_MAC80211_MESH

	spin_lock_init(&sta->plink_lock);

	if (ieee80211_vif_is_mesh(&sdata->vif) &&

	    !sdata->u.mesh.user_mpm)

		init_timer(&sta->plink_timer);

net/mac80211/sta_info.h

+4 −1
Original line number Diff line number Diff line
@@ -299,6 +299,7 @@ struct sta_ampdu_mlme { 
 * @tid_seq: per-TID sequence numbers for sending to this STA

 * @ampdu_mlme: A-MPDU state machine state

 * @timer_to_tid: identity mapping to ID timers

 * @plink_lock: serialize access to plink fields

 * @llid: Local link ID

 * @plid: Peer link ID

 * @reason: Cancel reason on PLINK_HOLDING state
@@ -422,9 +423,10 @@ struct sta_info { 


#ifdef CONFIG_MAC80211_MESH

	/*

	 * Mesh peer link attributes

	 * Mesh peer link attributes, protected by plink_lock.

	 * TODO: move to a sub-structure that is referenced with pointer?

	 */

	spinlock_t plink_lock;

	u16 llid;

	u16 plid;

	u16 reason;
@@ -432,6 +434,7 @@ struct sta_info { 
	enum nl80211_plink_state plink_state;

	u32 plink_timeout;

	struct timer_list plink_timer;



	s64 t_offset;

	s64 t_offset_setpoint;

	/* mesh power save */

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