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Message-Id: <20231214212443.3638210-2-dw@davidwei.uk>
Date: Thu, 14 Dec 2023 13:24:40 -0800
From: David Wei <dw@...idwei.uk>
To: Jakub Kicinski <kuba@...nel.org>,
Jiri Pirko <jiri@...nulli.us>,
Sabrina Dubroca <sd@...asysnail.net>,
netdev@...r.kernel.org
Cc: "David S. Miller" <davem@...emloft.net>,
Eric Dumazet <edumazet@...gle.com>,
Paolo Abeni <pabeni@...hat.com>
Subject: [PATCH net-next v3 1/4] netdevsim: allow two netdevsim ports to be connected
Add a debugfs file in
/sys/kernel/debug/netdevsim/netdevsimN/ports/A/peer
Writing "M B" to this file will link port A of netdevsim N with port B of
netdevsim M.
Reading this file will return the linked netdevsim id and port, if any.
Signed-off-by: David Wei <dw@...idwei.uk>
---
drivers/net/netdevsim/bus.c | 17 ++++++
drivers/net/netdevsim/dev.c | 88 +++++++++++++++++++++++++++++++
drivers/net/netdevsim/netdev.c | 6 +++
drivers/net/netdevsim/netdevsim.h | 3 ++
4 files changed, 114 insertions(+)
diff --git a/drivers/net/netdevsim/bus.c b/drivers/net/netdevsim/bus.c
index bcbc1e19edde..1ef95661a3f5 100644
--- a/drivers/net/netdevsim/bus.c
+++ b/drivers/net/netdevsim/bus.c
@@ -323,6 +323,23 @@ static struct device_driver nsim_driver = {
.owner = THIS_MODULE,
};
+struct nsim_bus_dev *nsim_bus_dev_get(unsigned int id)
+{
+ struct nsim_bus_dev *nsim_bus_dev;
+
+ mutex_lock(&nsim_bus_dev_list_lock);
+ list_for_each_entry(nsim_bus_dev, &nsim_bus_dev_list, list) {
+ if (nsim_bus_dev->dev.id == id) {
+ get_device(&nsim_bus_dev->dev);
+ mutex_unlock(&nsim_bus_dev_list_lock);
+ return nsim_bus_dev;
+ }
+ }
+ mutex_unlock(&nsim_bus_dev_list_lock);
+
+ return NULL;
+}
+
int nsim_bus_init(void)
{
int err;
diff --git a/drivers/net/netdevsim/dev.c b/drivers/net/netdevsim/dev.c
index b4d3b9cde8bd..034145ba1861 100644
--- a/drivers/net/netdevsim/dev.c
+++ b/drivers/net/netdevsim/dev.c
@@ -388,6 +388,91 @@ static const struct file_operations nsim_dev_rate_parent_fops = {
.owner = THIS_MODULE,
};
+static ssize_t nsim_dev_peer_read(struct file *file, char __user *data,
+ size_t count, loff_t *ppos)
+{
+ struct nsim_dev_port *nsim_dev_port;
+ struct netdevsim *peer;
+ unsigned int id, port;
+ char buf[23];
+ ssize_t len;
+
+ nsim_dev_port = file->private_data;
+ rcu_read_lock();
+ peer = rcu_dereference(nsim_dev_port->ns->peer);
+ if (!peer) {
+ rcu_read_unlock();
+ return 0;
+ }
+
+ id = peer->nsim_bus_dev->dev.id;
+ port = peer->nsim_dev_port->port_index;
+ len = scnprintf(buf, sizeof(buf), "%u %u\n", id, port);
+
+ rcu_read_unlock();
+ return simple_read_from_buffer(data, count, ppos, buf, len);
+}
+
+static ssize_t nsim_dev_peer_write(struct file *file,
+ const char __user *data,
+ size_t count, loff_t *ppos)
+{
+ struct nsim_dev_port *nsim_dev_port, *peer_dev_port;
+ struct nsim_bus_dev *peer_bus_dev;
+ struct nsim_dev *peer_dev;
+ unsigned int id, port;
+ char buf[22];
+ ssize_t ret;
+
+ if (count >= sizeof(buf))
+ return -ENOSPC;
+
+ ret = copy_from_user(buf, data, count);
+ if (ret)
+ return -EFAULT;
+ buf[count] = '\0';
+
+ ret = sscanf(buf, "%u %u", &id, &port);
+ if (ret != 2) {
+ pr_err("Format for adding a peer is \"id port\" (uint uint)");
+ return -EINVAL;
+ }
+
+ /* invalid netdevsim id */
+ peer_bus_dev = nsim_bus_dev_get(id);
+ if (!peer_bus_dev)
+ return -EINVAL;
+
+ ret = -EINVAL;
+ /* cannot link to self */
+ nsim_dev_port = file->private_data;
+ if (nsim_dev_port->ns->nsim_bus_dev == peer_bus_dev &&
+ nsim_dev_port->port_index == port)
+ goto out;
+
+ peer_dev = dev_get_drvdata(&peer_bus_dev->dev);
+ list_for_each_entry(peer_dev_port, &peer_dev->port_list, list) {
+ if (peer_dev_port->port_index != port)
+ continue;
+ rcu_assign_pointer(nsim_dev_port->ns->peer, peer_dev_port->ns);
+ rcu_assign_pointer(peer_dev_port->ns->peer, nsim_dev_port->ns);
+ ret = count;
+ goto out;
+ }
+
+out:
+ put_device(&peer_bus_dev->dev);
+ return ret;
+}
+
+static const struct file_operations nsim_dev_peer_fops = {
+ .open = simple_open,
+ .read = nsim_dev_peer_read,
+ .write = nsim_dev_peer_write,
+ .llseek = generic_file_llseek,
+ .owner = THIS_MODULE,
+};
+
static int nsim_dev_port_debugfs_init(struct nsim_dev *nsim_dev,
struct nsim_dev_port *nsim_dev_port)
{
@@ -418,6 +503,9 @@ static int nsim_dev_port_debugfs_init(struct nsim_dev *nsim_dev,
}
debugfs_create_symlink("dev", nsim_dev_port->ddir, dev_link_name);
+ debugfs_create_file("peer", 0600, nsim_dev_port->ddir,
+ nsim_dev_port, &nsim_dev_peer_fops);
+
return 0;
}
diff --git a/drivers/net/netdevsim/netdev.c b/drivers/net/netdevsim/netdev.c
index aecaf5f44374..e290c54b0e70 100644
--- a/drivers/net/netdevsim/netdev.c
+++ b/drivers/net/netdevsim/netdev.c
@@ -388,6 +388,7 @@ nsim_create(struct nsim_dev *nsim_dev, struct nsim_dev_port *nsim_dev_port)
ns->nsim_dev = nsim_dev;
ns->nsim_dev_port = nsim_dev_port;
ns->nsim_bus_dev = nsim_dev->nsim_bus_dev;
+ RCU_INIT_POINTER(ns->peer, NULL);
SET_NETDEV_DEV(dev, &ns->nsim_bus_dev->dev);
SET_NETDEV_DEVLINK_PORT(dev, &nsim_dev_port->devlink_port);
nsim_ethtool_init(ns);
@@ -407,9 +408,14 @@ nsim_create(struct nsim_dev *nsim_dev, struct nsim_dev_port *nsim_dev_port)
void nsim_destroy(struct netdevsim *ns)
{
struct net_device *dev = ns->netdev;
+ struct netdevsim *peer;
rtnl_lock();
+ peer = rtnl_dereference(ns->peer);
+ RCU_INIT_POINTER(ns->peer, NULL);
unregister_netdevice(dev);
+ if (peer)
+ RCU_INIT_POINTER(peer->peer, NULL);
if (nsim_dev_port_is_pf(ns->nsim_dev_port)) {
nsim_macsec_teardown(ns);
nsim_ipsec_teardown(ns);
diff --git a/drivers/net/netdevsim/netdevsim.h b/drivers/net/netdevsim/netdevsim.h
index 028c825b86db..61ac3a80cf9a 100644
--- a/drivers/net/netdevsim/netdevsim.h
+++ b/drivers/net/netdevsim/netdevsim.h
@@ -125,6 +125,7 @@ struct netdevsim {
} udp_ports;
struct nsim_ethtool ethtool;
+ struct netdevsim __rcu *peer;
};
struct netdevsim *
@@ -415,5 +416,7 @@ struct nsim_bus_dev {
bool init;
};
+struct nsim_bus_dev *nsim_bus_dev_get(unsigned int id);
+
int nsim_bus_init(void);
void nsim_bus_exit(void);
--
2.39.3
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