From d9f1f61c0801a73ff36d416a7ede54229b231e1d Mon Sep 17 00:00:00 2001 From: Sainath Grandhi Date: Fri, 10 Feb 2017 16:03:50 -0800 Subject: [PATCH] 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 Signed-off-by: David S. Miller --- drivers/net/macvtap_main.c | 6 +- drivers/net/tap.c | 118 ++++++++++++++++++++++++++++++------- include/linux/if_tap.h | 4 +- 3 files changed, 102 insertions(+), 26 deletions(-) diff --git a/drivers/net/macvtap_main.c b/drivers/net/macvtap_main.c index 0238df62bf45..a4bfc10b61dd 100644 --- 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 7d3e8b18f5e6..71bbf0b6327d 100644 --- 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 75031e5d0a65..362e71c16efb 100644 --- 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); -- 2.20.1