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net: wwan: common debugfs base dir for wwan device

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This patch set brings in a common debugfs base directory
i.e. /sys/kernel/debugfs/wwan/ in WWAN Subsystem for a
WWAN device instance. So that it avoids driver polluting
debugfs root with unrelated directories & possible name
collusion.

Having a common debugfs base directory for WWAN drivers
eases user to match control devices with debugfs entries.

WWAN Subsystem creates dentry (/sys/kernel/debugfs/wwan)
on module load & removes dentry on module unload.

When driver registers a new wwan device, dentry (wwanX)
is created for WWAN device instance & on driver unregister
dentry is removed.

New API is introduced to return the wwan device instance
dentry so that driver can create debugfs entries under it.

Signed-off-by: M Chetan Kumar <m.chetan.kumar@linux.intel.com>
Reviewed-by: Loic Poulain <loic.poulain@linaro.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
M Chetan Kumar 2021-11-20 21:51:54 +05:30 committed by David S. Miller
parent a9c2cf9e93
commit c480467002
2 changed files with 30 additions and 2 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

30
drivers/net/wwan/wwan_core.c
View File

@ -3,6 +3,7 @@
#include <linux/err.h>
#include <linux/errno.h>
#include <linux/debugfs.h>
#include <linux/fs.h>
#include <linux/init.h>
#include <linux/idr.h>
@ -25,6 +26,7 @@ static DEFINE_IDA(minors); /* minors for WWAN port chardevs */
static DEFINE_IDA(wwan_dev_ids); /* for unique WWAN device IDs */
static struct class *wwan_class;
static int wwan_major;
static struct dentry *wwan_debugfs_dir;
#define to_wwan_dev(d) container_of(d, struct wwan_device, dev)
#define to_wwan_port(d) container_of(d, struct wwan_port, dev)
@ -40,6 +42,7 @@ static int wwan_major;
* @port_id: Current available port ID to pick.
* @ops: wwan device ops
* @ops_ctxt: context to pass to ops
* @debugfs_dir: WWAN device debugfs dir
*/
struct wwan_device {
unsigned int id;
@ -47,6 +50,7 @@ struct wwan_device {
atomic_t port_id;
const struct wwan_ops *ops;
void *ops_ctxt;
struct dentry *debugfs_dir;
};
/**
@ -142,6 +146,18 @@ static struct wwan_device *wwan_dev_get_by_name(const char *name)
return to_wwan_dev(dev);
}
struct dentry *wwan_get_debugfs_dir(struct device *parent)
{
struct wwan_device *wwandev;
wwandev = wwan_dev_get_by_parent(parent);
if (IS_ERR(wwandev))
return ERR_CAST(wwandev);
return wwandev->debugfs_dir;
}
EXPORT_SYMBOL_GPL(wwan_get_debugfs_dir);
/* This function allocates and registers a new WWAN device OR if a WWAN device
* already exist for the given parent, it gets a reference and return it.
* This function is not exported (for now), it is called indirectly via
@ -150,6 +166,7 @@ static struct wwan_device *wwan_dev_get_by_name(const char *name)
static struct wwan_device *wwan_create_dev(struct device *parent)
{
struct wwan_device *wwandev;
const char *wwandev_name;
int err, id;
/* The 'find-alloc-register' operation must be protected against
@ -189,6 +206,10 @@ static struct wwan_device *wwan_create_dev(struct device *parent)
goto done_unlock;
}
wwandev_name = kobject_name(&wwandev->dev.kobj);
wwandev->debugfs_dir = debugfs_create_dir(wwandev_name,
wwan_debugfs_dir);
done_unlock:
mutex_unlock(&wwan_register_lock);
@ -218,10 +239,12 @@ static void wwan_remove_dev(struct wwan_device *wwandev)
else
ret = device_for_each_child(&wwandev->dev, NULL, is_wwan_child);
if (!ret)
if (!ret) {
debugfs_remove_recursive(wwandev->debugfs_dir);
device_unregister(&wwandev->dev);
else
} else {
put_device(&wwandev->dev);
}
mutex_unlock(&wwan_register_lock);
}
@ -1117,6 +1140,8 @@ static int __init wwan_init(void)
goto destroy;
}
wwan_debugfs_dir = debugfs_create_dir("wwan", NULL);
return 0;
destroy:
@ -1128,6 +1153,7 @@ unregister:
static void __exit wwan_exit(void)
{
debugfs_remove_recursive(wwan_debugfs_dir);
__unregister_chrdev(wwan_major, 0, WWAN_MAX_MINORS, "wwan_port");
rtnl_link_unregister(&wwan_rtnl_link_ops);
class_destroy(wwan_class);

2
include/linux/wwan.h
View File

@ -171,4 +171,6 @@ int wwan_register_ops(struct device *parent, const struct wwan_ops *ops,
void wwan_unregister_ops(struct device *parent);
struct dentry *wwan_get_debugfs_dir(struct device *parent);
#endif /* __WWAN_H */