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: Sainath Grandhi <sainath.grandhi@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
diff --git a/drivers/net/macvtap_main.c b/drivers/net/macvtap_main.c
index 0238df62..a4bfc10 100644
--- a/drivers/net/macvtap_main.c
+++ b/drivers/net/macvtap_main.c
@@ -163,7 +163,7 @@
* 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 @@
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 @@
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))
diff --git a/drivers/net/tap.c b/drivers/net/tap.c
index 7d3e8b1..71bbf0b 100644
--- a/drivers/net/tap.c
+++ b/drivers/net/tap.c
@@ -99,12 +99,17 @@
};
#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 @@
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 @@
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 @@
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 @@
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 @@
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);
+ }
+ }
}
diff --git a/include/linux/if_tap.h b/include/linux/if_tap.h
index 75031e5..362e71c 100644
--- a/include/linux/if_tap.h
+++ b/include/linux/if_tap.h
@@ -65,8 +65,8 @@
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);