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Date: Thu, 3 Nov 2022 19:08:49 +0800
From: <zhaoping.shu@...iatek.com>
To: <m.chetan.kumar@...el.com>, <linuxwwan@...el.com>,
<loic.poulain@...aro.org>, <ryazanov.s.a@...il.com>,
<johannes@...solutions.net>, <davem@...emloft.net>,
<edumazet@...gle.com>, <kuba@...nel.org>, <pabeni@...hat.com>,
<netdev@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC: <srv_heupstream@...iatek.com>, <haijun.liu@...iatek.com>,
<xiayu.zhang@...iatek.com>, <lambert.wang@...iatek.com>,
Zhaoping Shu <zhaoping.shu@...iatek.com>
Subject: [PATCH RESEND] net: wwan: iosm: Remove unnecessary if_mutex lock
From: Zhaoping Shu <zhaoping.shu@...iatek.com>
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: Zhaoping Shu <zhaoping.shu@...iatek.com>
---
drivers/net/wwan/iosm/iosm_ipc_wwan.c | 42 ++++-----------------------
1 file changed, 6 insertions(+), 36 deletions(-)
diff --git a/drivers/net/wwan/iosm/iosm_ipc_wwan.c b/drivers/net/wwan/iosm/iosm_ipc_wwan.c
index 2f1f8b5d5b59..fa2261697d53 100644
--- a/drivers/net/wwan/iosm/iosm_ipc_wwan.c
+++ b/drivers/net/wwan/iosm/iosm_ipc_wwan.c
@@ -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;
}
@@ -189,26 +178,17 @@ 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,
@@ -222,17 +202,12 @@ 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 = {
@@ -323,12 +298,9 @@ 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;
}
@@ -341,7 +313,5 @@ 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);
}
--
2.17.0
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