iwlwifi: fix and add missing sta_lock usage

There are a few places where sta_lock is used, but the
station information protected by it is accessed outside
of the lock. Address this in two ways, if the access
won't sleep then just move the access into the lock, if
the access can sleep then copy the needed station
information to the stack to be accessed without risk of
it changing while access in progress.

Additionally, a number of other places access station
station information without holding the sta_lock, fix
those as well.

Signed-off-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 34 insertions, 7 deletions

diff --git a/drivers/net/wireless/iwlwifi/iwl-agn-tx.c b/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
index 18b15466fce..52bec104046 100644
--- a/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
+++ b/drivers/net/wireless/iwlwifi/iwl-agn-tx.c
@@ -595,11 +595,17 @@ int iwlagn_tx_skb(struct iwl_priv *priv, struct sk_buff *skb)
 	}
 
 	txq_id = get_queue_from_ac(skb_get_queue_mapping(skb));
+
+	/* irqs already disabled/saved above when locking priv->lock */
+	spin_lock(&priv->sta_lock);
+
 	if (ieee80211_is_data_qos(fc)) {
 		qc = ieee80211_get_qos_ctl(hdr);
 		tid = qc[0] & IEEE80211_QOS_CTL_TID_MASK;
-		if (unlikely(tid >= MAX_TID_COUNT))
+		if (WARN_ON_ONCE(tid >= MAX_TID_COUNT)) {
+			spin_unlock(&priv->sta_lock);
 			goto drop_unlock;
+		}
 		seq_number = priv->stations[sta_id].tid[tid].seq_number;
 		seq_number &= IEEE80211_SCTL_SEQ;
 		hdr->seq_ctrl = hdr->seq_ctrl &
@@ -617,11 +623,18 @@ int iwlagn_tx_skb(struct iwl_priv *priv, struct sk_buff *skb)
 	swq_id = txq->swq_id;
 	q = &txq->q;
 
-	if (unlikely(iwl_queue_space(q) < q->high_mark))
+	if (unlikely(iwl_queue_space(q) < q->high_mark)) {
+		spin_unlock(&priv->sta_lock);
 		goto drop_unlock;
+	}
 
-	if (ieee80211_is_data_qos(fc))
+	if (ieee80211_is_data_qos(fc)) {
 		priv->stations[sta_id].tid[tid].tfds_in_queue++;
+		if (!ieee80211_has_morefrags(fc))
+			priv->stations[sta_id].tid[tid].seq_number = seq_number;
+	}
+
+	spin_unlock(&priv->sta_lock);
 
 	/* Set up driver data for this TFD */
 	memset(&(txq->txb[q->write_ptr]), 0, sizeof(struct iwl_tx_info));
@@ -700,8 +713,6 @@ int iwlagn_tx_skb(struct iwl_priv *priv, struct sk_buff *skb)
 
 	if (!ieee80211_has_morefrags(hdr->frame_control)) {
 		txq->need_update = 1;
-		if (qc)
-			priv->stations[sta_id].tid[tid].seq_number = seq_number;
 	} else {
 		wait_write_ptr = 1;
 		txq->need_update = 0;
@@ -1006,6 +1017,8 @@ int iwlagn_tx_agg_start(struct iwl_priv *priv, struct ieee80211_vif *vif,
 	if (ret)
 		return ret;
 
+	spin_lock_irqsave(&priv->sta_lock, flags);
+	tid_data = &priv->stations[sta_id].tid[tid];
 	if (tid_data->tfds_in_queue == 0) {
 		IWL_DEBUG_HT(priv, "HW queue is empty\n");
 		tid_data->agg.state = IWL_AGG_ON;
@@ -1015,6 +1028,7 @@ int iwlagn_tx_agg_start(struct iwl_priv *priv, struct ieee80211_vif *vif,
 			     tid_data->tfds_in_queue);
 		tid_data->agg.state = IWL_EMPTYING_HW_QUEUE_ADDBA;
 	}
+	spin_unlock_irqrestore(&priv->sta_lock, flags);
 	return ret;
 }
 
@@ -1037,11 +1051,14 @@ int iwlagn_tx_agg_stop(struct iwl_priv *priv, struct ieee80211_vif *vif,
 		return -ENXIO;
 	}
 
+	spin_lock_irqsave(&priv->sta_lock, flags);
+
 	if (priv->stations[sta_id].tid[tid].agg.state ==
 				IWL_EMPTYING_HW_QUEUE_ADDBA) {
 		IWL_DEBUG_HT(priv, "AGG stop before setup done\n");
 		ieee80211_stop_tx_ba_cb_irqsafe(vif, sta->addr, tid);
 		priv->stations[sta_id].tid[tid].agg.state = IWL_AGG_OFF;
+		spin_unlock_irqrestore(&priv->sta_lock, flags);
 		return 0;
 	}
 
@@ -1059,13 +1076,17 @@ int iwlagn_tx_agg_stop(struct iwl_priv *priv, struct ieee80211_vif *vif,
 		IWL_DEBUG_HT(priv, "Stopping a non empty AGG HW QUEUE\n");
 		priv->stations[sta_id].tid[tid].agg.state =
 				IWL_EMPTYING_HW_QUEUE_DELBA;
+		spin_unlock_irqrestore(&priv->sta_lock, flags);
 		return 0;
 	}
 
 	IWL_DEBUG_HT(priv, "HW queue is empty\n");
 	priv->stations[sta_id].tid[tid].agg.state = IWL_AGG_OFF;
 
-	spin_lock_irqsave(&priv->lock, flags);
+	/* do not restore/save irqs */
+	spin_unlock(&priv->sta_lock);
+	spin_lock(&priv->lock);
+
 	/*
 	 * the only reason this call can fail is queue number out of range,
 	 * which can happen if uCode is reloaded and all the station
@@ -1089,6 +1110,8 @@ int iwlagn_txq_check_empty(struct iwl_priv *priv,
 	u8 *addr = priv->stations[sta_id].sta.sta.addr;
 	struct iwl_tid_data *tid_data = &priv->stations[sta_id].tid[tid];
 
+	WARN_ON(!spin_is_locked(&priv->sta_lock));
+
 	switch (priv->stations[sta_id].tid[tid].agg.state) {
 	case IWL_EMPTYING_HW_QUEUE_DELBA:
 		/* We are reclaiming the last packet of the */
@@ -1113,6 +1136,7 @@ int iwlagn_txq_check_empty(struct iwl_priv *priv,
 		}
 		break;
 	}
+
 	return 0;
 }
 
@@ -1276,6 +1300,7 @@ void iwlagn_rx_reply_compressed_ba(struct iwl_priv *priv,
 	int index;
 	int sta_id;
 	int tid;
+	unsigned long flags;
 
 	/* "flow" corresponds to Tx queue */
 	u16 scd_flow = le16_to_cpu(ba_resp->scd_flow);
@@ -1298,7 +1323,7 @@ void iwlagn_rx_reply_compressed_ba(struct iwl_priv *priv,
 	/* Find index just before block-ack window */
 	index = iwl_queue_dec_wrap(ba_resp_scd_ssn & 0xff, txq->q.n_bd);
 
-	/* TODO: Need to get this copy more safely - now good for debug */
+	spin_lock_irqsave(&priv->sta_lock, flags);
 
 	IWL_DEBUG_TX_REPLY(priv, "REPLY_COMPRESSED_BA [%d] Received from %pM, "
 			   "sta_id = %d\n",
@@ -1334,4 +1359,6 @@ void iwlagn_rx_reply_compressed_ba(struct iwl_priv *priv,
 
 		iwlagn_txq_check_empty(priv, sta_id, tid, scd_flow);
 	}
+
+	spin_unlock_irqrestore(&priv->sta_lock, flags);
 }