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Message-Id: <20210608040241.10658-3-ryazanov.s.a@gmail.com>
Date: Tue, 8 Jun 2021 07:02:33 +0300
From: Sergey Ryazanov <ryazanov.s.a@...il.com>
To: Loic Poulain <loic.poulain@...aro.org>,
"David S. Miller" <davem@...emloft.net>,
Jakub Kicinski <kuba@...nel.org>
Cc: netdev@...r.kernel.org, linux-wireless@...r.kernel.org
Subject: [PATCH 02/10] wwan_hwsim: add debugfs management interface
wwan_hwsim creates and removes simulated control ports on module loading
and unloading. It would be helpful to be able to create/remove devices
and ports at run-time to trigger wwan port (un-)register actions without
module reloading.
Some simulator objects (e.g. ports) do not have the underling device and
it is not possible to fully manage the simulator via sysfs. wwan_hsim
intend for developers, so implement it as a self-contained debugfs based
management interface.
Signed-off-by: Sergey Ryazanov <ryazanov.s.a@...il.com>
---
drivers/net/wwan/wwan_hwsim.c | 186 +++++++++++++++++++++++++++++++++-
1 file changed, 184 insertions(+), 2 deletions(-)
diff --git a/drivers/net/wwan/wwan_hwsim.c b/drivers/net/wwan/wwan_hwsim.c
index 96d25d7e5bb8..472cae544a2b 100644
--- a/drivers/net/wwan/wwan_hwsim.c
+++ b/drivers/net/wwan/wwan_hwsim.c
@@ -15,6 +15,8 @@
#include <linux/list.h>
#include <linux/skbuff.h>
#include <linux/wwan.h>
+#include <linux/debugfs.h>
+#include <linux/workqueue.h>
static int wwan_hwsim_devsnum = 2;
module_param_named(devices, wwan_hwsim_devsnum, int, 0444);
@@ -22,6 +24,9 @@ MODULE_PARM_DESC(devices, "Number of simulated devices");
static struct class *wwan_hwsim_class;
+static struct dentry *wwan_hwsim_debugfs_topdir;
+static struct dentry *wwan_hwsim_debugfs_devcreate;
+
static DEFINE_SPINLOCK(wwan_hwsim_devs_lock);
static LIST_HEAD(wwan_hwsim_devs);
static unsigned int wwan_hwsim_dev_idx;
@@ -30,6 +35,9 @@ struct wwan_hwsim_dev {
struct list_head list;
unsigned int id;
struct device dev;
+ struct work_struct del_work;
+ struct dentry *debugfs_topdir;
+ struct dentry *debugfs_portcreate;
spinlock_t ports_lock; /* Serialize ports creation/deletion */
unsigned int port_idx;
struct list_head ports;
@@ -40,6 +48,8 @@ struct wwan_hwsim_port {
unsigned int id;
struct wwan_hwsim_dev *dev;
struct wwan_port *wwan;
+ struct work_struct del_work;
+ struct dentry *debugfs_topdir;
enum { /* AT command parser state */
AT_PARSER_WAIT_A,
AT_PARSER_WAIT_T,
@@ -48,6 +58,12 @@ struct wwan_hwsim_port {
} pstate;
};
+static const struct file_operations wwan_hwsim_debugfs_portdestroy_fops;
+static const struct file_operations wwan_hwsim_debugfs_portcreate_fops;
+static const struct file_operations wwan_hwsim_debugfs_devdestroy_fops;
+static void wwan_hwsim_port_del_work(struct work_struct *work);
+static void wwan_hwsim_dev_del_work(struct work_struct *work);
+
static int wwan_hwsim_port_start(struct wwan_port *wport)
{
struct wwan_hwsim_port *port = wwan_port_get_drvdata(wport);
@@ -139,6 +155,7 @@ static const struct wwan_port_ops wwan_hwsim_port_ops = {
static struct wwan_hwsim_port *wwan_hwsim_port_new(struct wwan_hwsim_dev *dev)
{
struct wwan_hwsim_port *port;
+ char name[0x10];
int err;
port = kzalloc(sizeof(*port), GFP_KERNEL);
@@ -159,6 +176,13 @@ static struct wwan_hwsim_port *wwan_hwsim_port_new(struct wwan_hwsim_dev *dev)
goto err_free_port;
}
+ INIT_WORK(&port->del_work, wwan_hwsim_port_del_work);
+
+ snprintf(name, sizeof(name), "port%u", port->id);
+ port->debugfs_topdir = debugfs_create_dir(name, dev->debugfs_topdir);
+ debugfs_create_file("destroy", 0200, port->debugfs_topdir, port,
+ &wwan_hwsim_debugfs_portdestroy_fops);
+
return port;
err_free_port:
@@ -169,10 +193,34 @@ static struct wwan_hwsim_port *wwan_hwsim_port_new(struct wwan_hwsim_dev *dev)
static void wwan_hwsim_port_del(struct wwan_hwsim_port *port)
{
+ debugfs_remove(port->debugfs_topdir);
+
+ /* Make sure that there is no pending deletion work */
+ if (current_work() != &port->del_work)
+ cancel_work_sync(&port->del_work);
+
wwan_remove_port(port->wwan);
kfree(port);
}
+static void wwan_hwsim_port_del_work(struct work_struct *work)
+{
+ struct wwan_hwsim_port *port =
+ container_of(work, typeof(*port), del_work);
+ struct wwan_hwsim_dev *dev = port->dev;
+
+ spin_lock(&dev->ports_lock);
+ if (list_empty(&port->list)) {
+ /* Someone else deleting port at the moment */
+ spin_unlock(&dev->ports_lock);
+ return;
+ }
+ list_del_init(&port->list);
+ spin_unlock(&dev->ports_lock);
+
+ wwan_hwsim_port_del(port);
+}
+
static void wwan_hwsim_dev_release(struct device *sysdev)
{
struct wwan_hwsim_dev *dev = container_of(sysdev, typeof(*dev), dev);
@@ -204,6 +252,17 @@ static struct wwan_hwsim_dev *wwan_hwsim_dev_new(void)
if (err)
goto err_free_dev;
+ INIT_WORK(&dev->del_work, wwan_hwsim_dev_del_work);
+
+ dev->debugfs_topdir = debugfs_create_dir(dev_name(&dev->dev),
+ wwan_hwsim_debugfs_topdir);
+ debugfs_create_file("destroy", 0200, dev->debugfs_topdir, dev,
+ &wwan_hwsim_debugfs_devdestroy_fops);
+ dev->debugfs_portcreate =
+ debugfs_create_file("portcreate", 0200,
+ dev->debugfs_topdir, dev,
+ &wwan_hwsim_debugfs_portcreate_fops);
+
return dev;
err_free_dev:
@@ -214,23 +273,136 @@ static struct wwan_hwsim_dev *wwan_hwsim_dev_new(void)
static void wwan_hwsim_dev_del(struct wwan_hwsim_dev *dev)
{
+ debugfs_remove(dev->debugfs_portcreate); /* Avoid new ports */
+
spin_lock(&dev->ports_lock);
while (!list_empty(&dev->ports)) {
struct wwan_hwsim_port *port;
port = list_first_entry(&dev->ports, struct wwan_hwsim_port,
list);
- list_del(&port->list);
+ list_del_init(&port->list);
spin_unlock(&dev->ports_lock);
wwan_hwsim_port_del(port);
spin_lock(&dev->ports_lock);
}
spin_unlock(&dev->ports_lock);
+ debugfs_remove(dev->debugfs_topdir);
+
+ /* Make sure that there is no pending deletion work */
+ if (current_work() != &dev->del_work)
+ cancel_work_sync(&dev->del_work);
+
device_unregister(&dev->dev);
/* Memory will be freed in the device release callback */
}
+static void wwan_hwsim_dev_del_work(struct work_struct *work)
+{
+ struct wwan_hwsim_dev *dev = container_of(work, typeof(*dev), del_work);
+
+ spin_lock(&wwan_hwsim_devs_lock);
+ if (list_empty(&dev->list)) {
+ /* Someone else deleting device at the moment */
+ spin_unlock(&wwan_hwsim_devs_lock);
+ return;
+ }
+ list_del_init(&dev->list);
+ spin_unlock(&wwan_hwsim_devs_lock);
+
+ wwan_hwsim_dev_del(dev);
+}
+
+static ssize_t wwan_hwsim_debugfs_portdestroy_write(struct file *file,
+ const char __user *usrbuf,
+ size_t count, loff_t *ppos)
+{
+ struct wwan_hwsim_port *port = file->private_data;
+
+ /* We can not delete port here since it will cause a deadlock due to
+ * waiting this callback to finish in the debugfs_remove() call. So,
+ * use workqueue.
+ */
+ schedule_work(&port->del_work);
+
+ return count;
+}
+
+static const struct file_operations wwan_hwsim_debugfs_portdestroy_fops = {
+ .write = wwan_hwsim_debugfs_portdestroy_write,
+ .open = simple_open,
+ .llseek = noop_llseek,
+};
+
+static ssize_t wwan_hwsim_debugfs_portcreate_write(struct file *file,
+ const char __user *usrbuf,
+ size_t count, loff_t *ppos)
+{
+ struct wwan_hwsim_dev *dev = file->private_data;
+ struct wwan_hwsim_port *port;
+
+ port = wwan_hwsim_port_new(dev);
+ if (IS_ERR(port))
+ return PTR_ERR(port);
+
+ spin_lock(&dev->ports_lock);
+ list_add_tail(&port->list, &dev->ports);
+ spin_unlock(&dev->ports_lock);
+
+ return count;
+}
+
+static const struct file_operations wwan_hwsim_debugfs_portcreate_fops = {
+ .write = wwan_hwsim_debugfs_portcreate_write,
+ .open = simple_open,
+ .llseek = noop_llseek,
+};
+
+static ssize_t wwan_hwsim_debugfs_devdestroy_write(struct file *file,
+ const char __user *usrbuf,
+ size_t count, loff_t *ppos)
+{
+ struct wwan_hwsim_dev *dev = file->private_data;
+
+ /* We can not delete device here since it will cause a deadlock due to
+ * waiting this callback to finish in the debugfs_remove() call. So,
+ * use workqueue.
+ */
+ schedule_work(&dev->del_work);
+
+ return count;
+}
+
+static const struct file_operations wwan_hwsim_debugfs_devdestroy_fops = {
+ .write = wwan_hwsim_debugfs_devdestroy_write,
+ .open = simple_open,
+ .llseek = noop_llseek,
+};
+
+static ssize_t wwan_hwsim_debugfs_devcreate_write(struct file *file,
+ const char __user *usrbuf,
+ size_t count, loff_t *ppos)
+{
+ struct wwan_hwsim_dev *dev;
+
+ dev = wwan_hwsim_dev_new();
+ if (IS_ERR(dev))
+ return PTR_ERR(dev);
+
+ spin_lock(&wwan_hwsim_devs_lock);
+ list_add_tail(&dev->list, &wwan_hwsim_devs);
+ spin_unlock(&wwan_hwsim_devs_lock);
+
+ return count;
+}
+
+static const struct file_operations wwan_hwsim_debugfs_devcreate_fops = {
+ .write = wwan_hwsim_debugfs_devcreate_write,
+ .open = simple_open,
+ .llseek = noop_llseek,
+};
+
static int __init wwan_hwsim_init_devs(void)
{
struct wwan_hwsim_dev *dev;
@@ -272,7 +444,7 @@ static void wwan_hwsim_free_devs(void)
while (!list_empty(&wwan_hwsim_devs)) {
dev = list_first_entry(&wwan_hwsim_devs, struct wwan_hwsim_dev,
list);
- list_del(&dev->list);
+ list_del_init(&dev->list);
spin_unlock(&wwan_hwsim_devs_lock);
wwan_hwsim_dev_del(dev);
spin_lock(&wwan_hwsim_devs_lock);
@@ -291,6 +463,12 @@ static int __init wwan_hwsim_init(void)
if (IS_ERR(wwan_hwsim_class))
return PTR_ERR(wwan_hwsim_class);
+ wwan_hwsim_debugfs_topdir = debugfs_create_dir("wwan_hwsim", NULL);
+ wwan_hwsim_debugfs_devcreate =
+ debugfs_create_file("devcreate", 0200,
+ wwan_hwsim_debugfs_topdir, NULL,
+ &wwan_hwsim_debugfs_devcreate_fops);
+
err = wwan_hwsim_init_devs();
if (err)
goto err_clean_devs;
@@ -299,6 +477,7 @@ static int __init wwan_hwsim_init(void)
err_clean_devs:
wwan_hwsim_free_devs();
+ debugfs_remove(wwan_hwsim_debugfs_topdir);
class_destroy(wwan_hwsim_class);
return err;
@@ -306,7 +485,10 @@ static int __init wwan_hwsim_init(void)
static void __exit wwan_hwsim_exit(void)
{
+ debugfs_remove(wwan_hwsim_debugfs_devcreate); /* Avoid new devs */
wwan_hwsim_free_devs();
+ flush_scheduled_work(); /* Wait deletion works completion */
+ debugfs_remove(wwan_hwsim_debugfs_topdir);
class_destroy(wwan_hwsim_class);
}
--
2.26.3
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