mwifiex: lock main process till reinitialization of vif is over

A crash was detected while changing virtual interface type is in
progress. This was tracked to race condition in accessing bss_priority
table while change is in progress. This patch ensures that main_process
and rx_process works are locked while we change virtual interface.
Signed-off-by: Cathy Luo <cluo@marvell.com>
Signed-off-by: Avinash Patil <patila@marvell.com>
Signed-off-by: Kalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/mwifiex/cfg80211.c

@@ -717,6 +717,9 @@ mwifiex_cfg80211_init_p2p_go(struct mwifiex_private *priv)
 
 static int mwifiex_deinit_priv_params(struct mwifiex_private *priv)
 {
+	struct mwifiex_adapter *adapter = priv->adapter;
+	unsigned long flags;
+
 	priv->mgmt_frame_mask = 0;
 	if (mwifiex_send_cmd(priv, HostCmd_CMD_MGMT_FRAME_REG,
 			     HostCmd_ACT_GEN_SET, 0,
@@ -727,6 +730,25 @@ static int mwifiex_deinit_priv_params(struct mwifiex_private *priv)
 	}
 
 	mwifiex_deauthenticate(priv, NULL);
+
+	spin_lock_irqsave(&adapter->main_proc_lock, flags);
+	adapter->main_locked = true;
+	if (adapter->mwifiex_processing) {
+		spin_unlock_irqrestore(&adapter->main_proc_lock, flags);
+		flush_workqueue(adapter->workqueue);
+	} else {
+		spin_unlock_irqrestore(&adapter->main_proc_lock, flags);
+	}
+
+	spin_lock_irqsave(&adapter->rx_proc_lock, flags);
+	adapter->rx_locked = true;
+	if (adapter->rx_processing) {
+		spin_unlock_irqrestore(&adapter->rx_proc_lock, flags);
+		flush_workqueue(adapter->rx_workqueue);
+	} else {
+	spin_unlock_irqrestore(&adapter->rx_proc_lock, flags);
+	}
+
 	mwifiex_free_priv(priv);
 	priv->wdev.iftype = NL80211_IFTYPE_UNSPECIFIED;
 	priv->bss_mode = NL80211_IFTYPE_UNSPECIFIED;
@@ -740,6 +762,9 @@ mwifiex_init_new_priv_params(struct mwifiex_private *priv,
 			     struct net_device *dev,
 			     enum nl80211_iftype type)
 {
+	struct mwifiex_adapter *adapter = priv->adapter;
+	unsigned long flags;
+
 	mwifiex_init_priv(priv);
 
 	priv->bss_mode = type;
@@ -770,6 +795,14 @@ mwifiex_init_new_priv_params(struct mwifiex_private *priv,
 		return -EOPNOTSUPP;
 	}
 
+	spin_lock_irqsave(&adapter->main_proc_lock, flags);
+	adapter->main_locked = false;
+	spin_unlock_irqrestore(&adapter->main_proc_lock, flags);
+
+	spin_lock_irqsave(&adapter->rx_proc_lock, flags);
+	adapter->rx_locked = false;
+	spin_unlock_irqrestore(&adapter->rx_proc_lock, flags);
+
 	return 0;
 }
 

drivers/net/wireless/mwifiex/main.c

@@ -189,7 +189,7 @@ int mwifiex_main_process(struct mwifiex_adapter *adapter)
 	spin_lock_irqsave(&adapter->main_proc_lock, flags);
 
 	/* Check if already processing */
-	if (adapter->mwifiex_processing) {
+	if (adapter->mwifiex_processing || adapter->main_locked) {
 		adapter->more_task_flag = true;
 		spin_unlock_irqrestore(&adapter->main_proc_lock, flags);
 		goto exit_main_proc;

drivers/net/wireless/mwifiex/main.h

@@ -772,6 +772,7 @@ struct mwifiex_adapter {
 	bool rx_processing;
 	bool delay_main_work;
 	bool rx_locked;
+	bool main_locked;
 	struct mwifiex_bss_prio_tbl bss_prio_tbl[MWIFIEX_MAX_BSS_NUM];
 	/* spin lock for init/shutdown */
 	spinlock_t mwifiex_lock;