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tap: Extending tap device create/destroy APIs

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

Signed-off-by: Sainath Grandhi <sainath.grandhi@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
Sainath Grandhi 2017-02-10 16:03:50 -08:00 committed by David S. Miller
parent 6fe3faf867
commit d9f1f61c08
3 changed files with 102 additions and 26 deletions
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6
drivers/net/macvtap_main.c
View File

@ -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))

118
drivers/net/tap.c
View File

@ -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 @@ drop:
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;
mutex_lock(&macvtap_major.minor_lock);
retval = idr_alloc(&macvtap_major.minor_idr, tap, 1, TAP_NUM_DEVS, GFP_KERNEL);
rcu_read_lock();
tap_major = tap_get_major(MAJOR(major));
if (!tap_major) {
retval = -EINVAL;
goto unlock;
}
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 @@ out1:
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);
}
}
}

4
include/linux/if_tap.h
View File

@ -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);