Commit ebc05ba7 authored by Sainath Grandhi's avatar Sainath Grandhi Committed by David S. Miller
Browse files

tap: Tap character device creation/destroy API 



This patch provides tap device create/destroy APIs in tap.c.

Signed-off-by: default avatarSainath Grandhi <sainath.grandhi@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 635b8c8e

drivers/net/macvtap_main.c

+9 −21
Original line number Diff line number Diff line
@@ -28,7 +28,6 @@ 
 * Variables for dealing with macvtaps device numbers.

 */

static dev_t macvtap_major;

#define MACVTAP_NUM_DEVS (1U << MINORBITS)



static const void *macvtap_net_namespace(struct device *d)

{
@@ -159,57 +158,46 @@ static struct notifier_block macvtap_notifier_block __read_mostly = { 
	.notifier_call	= macvtap_device_event,

};



extern struct file_operations tap_fops;

static int macvtap_init(void)

{

	int err;



	err = alloc_chrdev_region(&macvtap_major, 0,

				MACVTAP_NUM_DEVS, "macvtap");

	if (err)

		goto out1;

	err = tap_create_cdev(&macvtap_cdev, &macvtap_major, "macvtap");



	cdev_init(&macvtap_cdev, &tap_fops);

	err = cdev_add(&macvtap_cdev, macvtap_major, MACVTAP_NUM_DEVS);

	if (err)

		goto out2;

		goto out1;



	err = class_register(&macvtap_class);

	if (err)

		goto out3;

		goto out2;



	err = register_netdevice_notifier(&macvtap_notifier_block);

	if (err)

		goto out4;

		goto out3;



	err = macvlan_link_register(&macvtap_link_ops);

	if (err)

		goto out5;

		goto out4;



	return 0;



out5:

	unregister_netdevice_notifier(&macvtap_notifier_block);

out4:

	class_unregister(&macvtap_class);

	unregister_netdevice_notifier(&macvtap_notifier_block);

out3:

	cdev_del(&macvtap_cdev);

	class_unregister(&macvtap_class);

out2:

	unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);

	tap_destroy_cdev(macvtap_major, &macvtap_cdev);

out1:

	return err;

}

module_init(macvtap_init);



extern struct idr minor_idr;

static void macvtap_exit(void)

{

	rtnl_link_unregister(&macvtap_link_ops);

	unregister_netdevice_notifier(&macvtap_notifier_block);

	class_unregister(&macvtap_class);

	cdev_del(&macvtap_cdev);

	unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);

	idr_destroy(&minor_idr);

	tap_destroy_cdev(macvtap_major, &macvtap_cdev);

}

module_exit(macvtap_exit);

drivers/net/tap.c

+51 −11
Original line number Diff line number Diff line
@@ -123,8 +123,12 @@ static struct proto tap_proto = { 
};



#define TAP_NUM_DEVS (1U << MINORBITS)

static DEFINE_MUTEX(minor_lock);

DEFINE_IDR(minor_idr);

struct major_info {

	dev_t major;

	struct idr minor_idr;

	struct mutex minor_lock;

	const char *device_name;

} macvtap_major;



#define GOODCOPY_LEN 128
@@ -413,26 +417,26 @@ int tap_get_minor(struct macvlan_dev *vlan) 
{

	int retval = -ENOMEM;



	mutex_lock(&minor_lock);

	retval = idr_alloc(&minor_idr, vlan, 1, TAP_NUM_DEVS, GFP_KERNEL);

	mutex_lock(&macvtap_major.minor_lock);

	retval = idr_alloc(&macvtap_major.minor_idr, vlan, 1, TAP_NUM_DEVS, GFP_KERNEL);

	if (retval >= 0) {

		vlan->minor = retval;

	} else if (retval == -ENOSPC) {

		netdev_err(vlan->dev, "Too many tap devices\n");

		retval = -EINVAL;

	}

	mutex_unlock(&minor_lock);

	mutex_unlock(&macvtap_major.minor_lock);

	return retval < 0 ? retval : 0;

}



void tap_free_minor(struct macvlan_dev *vlan)

{

	mutex_lock(&minor_lock);

	mutex_lock(&macvtap_major.minor_lock);

	if (vlan->minor) {

		idr_remove(&minor_idr, vlan->minor);

		idr_remove(&macvtap_major.minor_idr, vlan->minor);

		vlan->minor = 0;

	}

	mutex_unlock(&minor_lock);

	mutex_unlock(&macvtap_major.minor_lock);

}



static struct net_device *dev_get_by_tap_minor(int minor)
@@ -440,13 +444,13 @@ static struct net_device *dev_get_by_tap_minor(int minor) 
	struct net_device *dev = NULL;

	struct macvlan_dev *vlan;



	mutex_lock(&minor_lock);

	vlan = idr_find(&minor_idr, minor);

	mutex_lock(&macvtap_major.minor_lock);

	vlan = idr_find(&macvtap_major.minor_idr, minor);

	if (vlan) {

		dev = vlan->dev;

		dev_hold(dev);

	}

	mutex_unlock(&minor_lock);

	mutex_unlock(&macvtap_major.minor_lock);

	return dev;

}
@@ -1184,3 +1188,39 @@ int tap_queue_resize(struct macvlan_dev *vlan) 
	kfree(arrays);

	return ret;

}



int tap_create_cdev(struct cdev *tap_cdev,

		    dev_t *tap_major, const char *device_name)

{

	int err;



	err = alloc_chrdev_region(tap_major, 0, TAP_NUM_DEVS, device_name);

	if (err)

		goto out1;



	cdev_init(tap_cdev, &tap_fops);

	err = cdev_add(tap_cdev, *tap_major, TAP_NUM_DEVS);

	if (err)

		goto out2;



	macvtap_major.major = MAJOR(*tap_major);



	idr_init(&macvtap_major.minor_idr);

	mutex_init(&macvtap_major.minor_lock);



	macvtap_major.device_name = device_name;



	return 0;



out2:

	unregister_chrdev_region(*tap_major, TAP_NUM_DEVS);

out1:

	return err;

}



void tap_destroy_cdev(dev_t major, struct cdev *tap_cdev)

{

	cdev_del(tap_cdev);

	unregister_chrdev_region(major, TAP_NUM_DEVS);

	idr_destroy(&macvtap_major.minor_idr);

}

include/linux/if_tap.h

+3 −0
Original line number Diff line number Diff line
@@ -19,5 +19,8 @@ void tap_del_queues(struct net_device *dev); 
int tap_get_minor(struct macvlan_dev *vlan);

void tap_free_minor(struct macvlan_dev *vlan);

int tap_queue_resize(struct macvlan_dev *vlan);

int tap_create_cdev(struct cdev *tap_cdev,

		    dev_t *tap_major, const char *device_name);

void tap_destroy_cdev(dev_t major, struct cdev *tap_cdev);



#endif /*_LINUX_IF_TAP_H_*/