Commit f9027f88 authored by Zhaoping Shu's avatar Zhaoping Shu Committed by David S. Miller
Browse files

net: wwan: iosm: Remove unnecessary if_mutex lock 



These WWAN network interface operations (create/delete/open/close)
are already protected by RTNL lock, i.e., wwan_ops.newlink(),
wwan_ops.dellink(), net_device_ops.ndo_open() and
net_device.ndo_stop() are called with RTNL lock held.
Therefore, this patch removes the unnecessary if_mutex.

Signed-off-by: default avatarZhaoping Shu <zhaoping.shu@mediatek.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 668205b9

drivers/net/wwan/iosm/iosm_ipc_wwan.c

+6 −36
Original line number Diff line number Diff line
@@ -40,13 +40,11 @@ struct iosm_netdev_priv { 
 * @ipc_imem:		Pointer to imem data-struct

 * @sub_netlist:	List of active netdevs

 * @dev:		Pointer device structure

 * @if_mutex:		Mutex used for add and remove interface id

 */

struct iosm_wwan {

	struct iosm_imem *ipc_imem;

	struct iosm_netdev_priv __rcu *sub_netlist[IP_MUX_SESSION_END + 1];

	struct device *dev;

	struct mutex if_mutex; /* Mutex used for add and remove interface id */

};



/* Bring-up the wwan net link */
@@ -55,14 +53,11 @@ static int ipc_wwan_link_open(struct net_device *netdev) 
	struct iosm_netdev_priv *priv = wwan_netdev_drvpriv(netdev);

	struct iosm_wwan *ipc_wwan = priv->ipc_wwan;

	int if_id = priv->if_id;

	int ret;



	if (if_id < IP_MUX_SESSION_START ||

	    if_id >= ARRAY_SIZE(ipc_wwan->sub_netlist))

		return -EINVAL;



	mutex_lock(&ipc_wwan->if_mutex);



	/* get channel id */

	priv->ch_id = ipc_imem_sys_wwan_open(ipc_wwan->ipc_imem, if_id);
@@ -70,8 +65,7 @@ static int ipc_wwan_link_open(struct net_device *netdev) 
		dev_err(ipc_wwan->dev,

			"cannot connect wwan0 & id %d to the IPC mem layer",

			if_id);

		ret = -ENODEV;

		goto out;

		return -ENODEV;

	}



	/* enable tx path, DL data may follow */
@@ -80,10 +74,7 @@ static int ipc_wwan_link_open(struct net_device *netdev) 
	dev_dbg(ipc_wwan->dev, "Channel id %d allocated to if_id %d",

		priv->ch_id, priv->if_id);



	ret = 0;

out:

	mutex_unlock(&ipc_wwan->if_mutex);

	return ret;

	return 0;

}



/* Bring-down the wwan net link */
@@ -93,11 +84,9 @@ static int ipc_wwan_link_stop(struct net_device *netdev) 


	netif_stop_queue(netdev);



	mutex_lock(&priv->ipc_wwan->if_mutex);

	ipc_imem_sys_wwan_close(priv->ipc_wwan->ipc_imem, priv->if_id,

				priv->ch_id);

	priv->ch_id = -1;

	mutex_unlock(&priv->ipc_wwan->if_mutex);



	return 0;

}
@@ -190,26 +179,17 @@ static int ipc_wwan_newlink(void *ctxt, struct net_device *dev, 
	priv->netdev = dev;

	priv->ipc_wwan = ipc_wwan;



	mutex_lock(&ipc_wwan->if_mutex);

	if (rcu_access_pointer(ipc_wwan->sub_netlist[if_id])) {

		err = -EBUSY;

		goto out_unlock;

	}

	if (rcu_access_pointer(ipc_wwan->sub_netlist[if_id]))

		return -EBUSY;



	err = register_netdevice(dev);

	if (err)

		goto out_unlock;

		return err;



	rcu_assign_pointer(ipc_wwan->sub_netlist[if_id], priv);

	mutex_unlock(&ipc_wwan->if_mutex);



	netif_device_attach(dev);



	return 0;



out_unlock:

	mutex_unlock(&ipc_wwan->if_mutex);

	return err;

}



static void ipc_wwan_dellink(void *ctxt, struct net_device *dev,
@@ -223,17 +203,12 @@ static void ipc_wwan_dellink(void *ctxt, struct net_device *dev, 
		    if_id >= ARRAY_SIZE(ipc_wwan->sub_netlist)))

		return;



	mutex_lock(&ipc_wwan->if_mutex);



	if (WARN_ON(rcu_access_pointer(ipc_wwan->sub_netlist[if_id]) != priv))

		goto unlock;

		return;



	RCU_INIT_POINTER(ipc_wwan->sub_netlist[if_id], NULL);

	/* unregistering includes synchronize_net() */

	unregister_netdevice_queue(dev, head);



unlock:

	mutex_unlock(&ipc_wwan->if_mutex);

}



static const struct wwan_ops iosm_wwan_ops = {
@@ -324,12 +299,9 @@ struct iosm_wwan *ipc_wwan_init(struct iosm_imem *ipc_imem, struct device *dev) 
	ipc_wwan->dev = dev;

	ipc_wwan->ipc_imem = ipc_imem;



	mutex_init(&ipc_wwan->if_mutex);



	/* WWAN core will create a netdev for the default IP MUX channel */

	if (wwan_register_ops(ipc_wwan->dev, &iosm_wwan_ops, ipc_wwan,

			      IP_MUX_SESSION_DEFAULT)) {

		mutex_destroy(&ipc_wwan->if_mutex);

		kfree(ipc_wwan);

		return NULL;

	}
@@ -342,7 +314,5 @@ void ipc_wwan_deinit(struct iosm_wwan *ipc_wwan) 
	/* This call will remove all child netdev(s) */

	wwan_unregister_ops(ipc_wwan->dev);



	mutex_destroy(&ipc_wwan->if_mutex);



	kfree(ipc_wwan);

}