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Commit d9f1f61c authored by Sainath Grandhi's avatar Sainath Grandhi Committed by David S. Miller
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tap: Extending tap device create/destroy APIs 



Extending tap APIs get/free_minor and create/destroy_cdev to handle more than one
type of virtual interface.

Signed-off-by: default avatarSainath Grandhi <sainath.grandhi@intel.com>
Signed-off-by: default avatarDavid S. Miller <davem@davemloft.net>
parent 6fe3faf8

drivers/net/macvtap_main.c

+3 −3
Original line number Diff line number Diff line
@@ -163,7 +163,7 @@ static int macvtap_device_event(struct notifier_block *unused, 
		 * been registered but before register_netdevice has

		 * finished running.

		 */

		err = tap_get_minor(&vlantap->tap);

		err = tap_get_minor(macvtap_major, &vlantap->tap);

		if (err)

			return notifier_from_errno(err);
@@ -171,7 +171,7 @@ static int macvtap_device_event(struct notifier_block *unused, 
		classdev = device_create(&macvtap_class, &dev->dev, devt,

					 dev, tap_name);

		if (IS_ERR(classdev)) {

			tap_free_minor(&vlantap->tap);

			tap_free_minor(macvtap_major, &vlantap->tap);

			return notifier_from_errno(PTR_ERR(classdev));

		}

		err = sysfs_create_link(&dev->dev.kobj, &classdev->kobj,
@@ -186,7 +186,7 @@ static int macvtap_device_event(struct notifier_block *unused, 
		sysfs_remove_link(&dev->dev.kobj, tap_name);

		devt = MKDEV(MAJOR(macvtap_major), vlantap->tap.minor);

		device_destroy(&macvtap_class, devt);

		tap_free_minor(&vlantap->tap);

		tap_free_minor(macvtap_major, &vlantap->tap);

		break;

	case NETDEV_CHANGE_TX_QUEUE_LEN:

		if (tap_queue_resize(&vlantap->tap))

drivers/net/tap.c

+97 −21
Original line number Diff line number Diff line
@@ -99,12 +99,17 @@ static struct proto tap_proto = { 
};



#define TAP_NUM_DEVS (1U << MINORBITS)



static LIST_HEAD(major_list);



struct major_info {

	struct rcu_head rcu;

	dev_t major;

	struct idr minor_idr;

	struct mutex minor_lock;

	const char *device_name;

} macvtap_major;

	struct list_head next;

};



#define GOODCOPY_LEN 128
@@ -385,44 +390,89 @@ rx_handler_result_t tap_handle_frame(struct sk_buff **pskb) 
	return RX_HANDLER_CONSUMED;

}



int tap_get_minor(struct tap_dev *tap)

static struct major_info *tap_get_major(int major)

{

	struct major_info *tap_major;



	list_for_each_entry_rcu(tap_major, &major_list, next) {

		if (tap_major->major == major)

			return tap_major;

	}



	return NULL;

}



int tap_get_minor(dev_t major, struct tap_dev *tap)

{

	int retval = -ENOMEM;

	struct major_info *tap_major;



	rcu_read_lock();

	tap_major = tap_get_major(MAJOR(major));

	if (!tap_major) {

		retval = -EINVAL;

		goto unlock;

	}



	mutex_lock(&macvtap_major.minor_lock);

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

	mutex_lock(&tap_major->minor_lock);

	retval = idr_alloc(&tap_major->minor_idr, tap, 1, TAP_NUM_DEVS, GFP_KERNEL);

	if (retval >= 0) {

		tap->minor = retval;

	} else if (retval == -ENOSPC) {

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

		retval = -EINVAL;

	}

	mutex_unlock(&macvtap_major.minor_lock);

	mutex_unlock(&tap_major->minor_lock);



unlock:

	rcu_read_unlock();

	return retval < 0 ? retval : 0;

}



void tap_free_minor(struct tap_dev *tap)

void tap_free_minor(dev_t major, struct tap_dev *tap)

{

	mutex_lock(&macvtap_major.minor_lock);

	struct major_info *tap_major;



	rcu_read_lock();

	tap_major = tap_get_major(MAJOR(major));

	if (!tap_major) {

		goto unlock;

	}



	mutex_lock(&tap_major->minor_lock);

	if (tap->minor) {

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

		idr_remove(&tap_major->minor_idr, tap->minor);

		tap->minor = 0;

	}

	mutex_unlock(&macvtap_major.minor_lock);

	mutex_unlock(&tap_major->minor_lock);



unlock:

	rcu_read_unlock();

}



static struct tap_dev *dev_get_by_tap_minor(int minor)

static struct tap_dev *dev_get_by_tap_file(int major, int minor)

{

	struct net_device *dev = NULL;

	struct tap_dev *tap;

	struct major_info *tap_major;



	mutex_lock(&macvtap_major.minor_lock);

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

	rcu_read_lock();

	tap_major = tap_get_major(major);

	if (!tap_major) {

		tap = NULL;

		goto unlock;

	}



	mutex_lock(&tap_major->minor_lock);

	tap = idr_find(&tap_major->minor_idr, minor);

	if (tap) {

		dev = tap->dev;

		dev_hold(dev);

	}

	mutex_unlock(&macvtap_major.minor_lock);

	mutex_unlock(&tap_major->minor_lock);



unlock:

	rcu_read_unlock();

	return tap;

}
@@ -454,7 +504,7 @@ static int tap_open(struct inode *inode, struct file *file) 
	int err = -ENODEV;



	rtnl_lock();

	tap = dev_get_by_tap_minor(iminor(inode));

	tap = dev_get_by_tap_file(imajor(inode), iminor(inode));

	if (!tap)

		goto err;
@@ -1161,6 +1211,25 @@ int tap_queue_resize(struct tap_dev *tap) 
	return ret;

}



static int tap_list_add(dev_t major, const char *device_name)

{

	struct major_info *tap_major;



	tap_major = kzalloc(sizeof(*tap_major), GFP_ATOMIC);

	if (!tap_major)

		return -ENOMEM;



	tap_major->major = MAJOR(major);



	idr_init(&tap_major->minor_idr);

	mutex_init(&tap_major->minor_lock);



	tap_major->device_name = device_name;



	list_add_tail_rcu(&tap_major->next, &major_list);

	return 0;

}



int tap_create_cdev(struct cdev *tap_cdev,

		    dev_t *tap_major, const char *device_name)

{
@@ -1175,15 +1244,14 @@ int tap_create_cdev(struct cdev *tap_cdev, 
	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;

	err =  tap_list_add(*tap_major, device_name);

	if (err)

		goto out3;



	return 0;



out3:

	cdev_del(tap_cdev);

out2:

	unregister_chrdev_region(*tap_major, TAP_NUM_DEVS);

out1:
@@ -1192,7 +1260,15 @@ int tap_create_cdev(struct cdev *tap_cdev, 


void tap_destroy_cdev(dev_t major, struct cdev *tap_cdev)

{

	struct major_info *tap_major, *tmp;



	cdev_del(tap_cdev);

	unregister_chrdev_region(major, TAP_NUM_DEVS);

	idr_destroy(&macvtap_major.minor_idr);

	list_for_each_entry_safe(tap_major, tmp, &major_list, next) {

		if (tap_major->major == MAJOR(major)) {

			idr_destroy(&tap_major->minor_idr);

			list_del_rcu(&tap_major->next);

			kfree_rcu(tap_major, rcu);

		}

	}

}

include/linux/if_tap.h

+2 −2
Original line number Diff line number Diff line
@@ -65,8 +65,8 @@ struct tap_queue { 


rx_handler_result_t tap_handle_frame(struct sk_buff **pskb);

void tap_del_queues(struct tap_dev *tap);

int tap_get_minor(struct tap_dev *tap);

void tap_free_minor(struct tap_dev *tap);

int tap_get_minor(dev_t major, struct tap_dev *tap);

void tap_free_minor(dev_t major, struct tap_dev *tap);

int tap_queue_resize(struct tap_dev *tap);

int tap_create_cdev(struct cdev *tap_cdev,

		    dev_t *tap_major, const char *device_name);