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 0238df62bf4516d254d2ece96d4686e4b2882458..a4bfc10b61ddd7872dfa89634f20478be1e2f29a 100644 (file)
--- a/drivers/net/macvtap_main.c
+++ b/drivers/net/macvtap_main.c
@@ -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))

diff --git a/drivers/net/tap.c b/drivers/net/tap.c
index 7d3e8b18f5e603417e7b53c5bcbb81fd40714dc5..71bbf0b6327db4b54b73bf13d42def70a8d3cd64 100644 (file)
--- a/drivers/net/tap.c
+++ b/drivers/net/tap.c
@@ -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;
+
+       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 @@ 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);
+               }
+       }
 }

diff --git a/include/linux/if_tap.h b/include/linux/if_tap.h
index 75031e5d0a65a78b8f2ad7d09ea4599fb4ee9123..362e71c16efb695db52b40f06fb360b00551e845 100644 (file)
--- a/include/linux/if_tap.h
+++ b/include/linux/if_tap.h
@@ -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);