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Groups > linux.kernel > #1578876 > unrolled thread

[PATCHv6 0/7] Refactor macvtap to re-use tap functionality by other virtual intefaces

Started bySainath Grandhi <sainath.grandhi@intel.com>
First post2017-02-11 01:10 +0100
Last post2017-02-12 03:10 +0100
Articles 5 — 2 participants

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Contents

  [PATCHv6 0/7] Refactor macvtap to re-use tap functionality by other virtual intefaces Sainath Grandhi <sainath.grandhi@intel.com> - 2017-02-11 01:10 +0100
    [PATCHv6 7/7] ipvtap: IP-VLAN based tap driver Sainath Grandhi <sainath.grandhi@intel.com> - 2017-02-11 01:10 +0100
    [PATCHv6 1/7] tap: Refactoring macvtap.c Sainath Grandhi <sainath.grandhi@intel.com> - 2017-02-11 01:10 +0100
    [PATCHv6 5/7] tap: Extending tap device create/destroy APIs Sainath Grandhi <sainath.grandhi@intel.com> - 2017-02-11 01:10 +0100
    Re: [PATCHv6 0/7] Refactor macvtap to re-use tap functionality by  other virtual intefaces David Miller <davem@davemloft.net> - 2017-02-12 03:10 +0100

#1578876 — [PATCHv6 0/7] Refactor macvtap to re-use tap functionality by other virtual intefaces

FromSainath Grandhi <sainath.grandhi@intel.com>
Date2017-02-11 01:10 +0100
Subject[PATCHv6 0/7] Refactor macvtap to re-use tap functionality by other virtual intefaces
Message-ID<t9tqh-203-3@gated-at.bofh.it>
Tap character devices can be implemented on other virtual interfaces like
ipvlan, similar to macvtap. Source code for tap functionality in macvtap
can be re-used for this purpose.

This patch series splits macvtap source into two modules, macvtap and tap.
This patch series also includes a patch for implementing tap character
device driver based on the IP-VLAN network interface, called ipvtap.

These patches are tested on x86 platform.

Sainath Grandhi (7):
  tap: Refactoring macvtap.c
  tap: Renaming tap related APIs, data structures, macros
  tap: Tap character device creation/destroy API
  tap: Abstract type of virtual interface from tap implementation
  tap: Extending tap device create/destroy APIs
  tap: tap as an independent module
  ipvtap: IP-VLAN based tap driver

 drivers/net/Kconfig              |   20 +
 drivers/net/Makefile             |    2 +
 drivers/net/ipvlan/Makefile      |    1 +
 drivers/net/ipvlan/ipvlan.h      |    7 +
 drivers/net/ipvlan/ipvlan_core.c |    3 +-
 drivers/net/ipvlan/ipvlan_main.c |   27 +-
 drivers/net/ipvlan/ipvtap.c      |  241 +++++++
 drivers/net/macvlan.c            |    2 +-
 drivers/net/macvtap.c            | 1229 ++----------------------------------
 drivers/net/tap.c                | 1285 ++++++++++++++++++++++++++++++++++++++
 drivers/vhost/Kconfig            |    2 +-
 drivers/vhost/net.c              |    3 +-
 include/linux/if_macvlan.h       |   17 +-
 include/linux/if_tap.h           |   75 +++
 14 files changed, 1706 insertions(+), 1208 deletions(-)
 create mode 100644 drivers/net/ipvlan/ipvtap.c
 create mode 100644 drivers/net/tap.c
 create mode 100644 include/linux/if_tap.h

-- 
2.7.4

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#1578877 — [PATCHv6 7/7] ipvtap: IP-VLAN based tap driver

FromSainath Grandhi <sainath.grandhi@intel.com>
Date2017-02-11 01:10 +0100
Subject[PATCHv6 7/7] ipvtap: IP-VLAN based tap driver
Message-ID<t9tqi-203-17@gated-at.bofh.it>
In reply to#1578876
This patch adds a tap character device driver that is based on the
IP-VLAN network interface, called ipvtap. An ipvtap device can be created
in the same way as an ipvlan device, using 'type ipvtap', and then accessed
using the tap user space interface.

Signed-off-by: Sainath Grandhi <sainath.grandhi@intel.com>
---
 drivers/net/Kconfig              |  13 +++
 drivers/net/Makefile             |   1 +
 drivers/net/ipvlan/Makefile      |   1 +
 drivers/net/ipvlan/ipvlan.h      |   7 ++
 drivers/net/ipvlan/ipvlan_core.c |   3 +-
 drivers/net/ipvlan/ipvlan_main.c |  27 +++--
 drivers/net/ipvlan/ipvtap.c      | 241 +++++++++++++++++++++++++++++++++++++++
 7 files changed, 280 insertions(+), 13 deletions(-)
 create mode 100644 drivers/net/ipvlan/ipvtap.c

diff --git a/drivers/net/Kconfig b/drivers/net/Kconfig
index 5763503..823bc2f 100644
--- a/drivers/net/Kconfig
+++ b/drivers/net/Kconfig
@@ -166,6 +166,19 @@ config IPVLAN
       To compile this driver as a module, choose M here: the module
       will be called ipvlan.
 
+config IPVTAP
+	tristate "IP-VLAN based tap driver"
+	depends on IPVLAN
+	depends on INET
+	select TAP
+	---help---
+	  This adds a specialized tap character device driver that is based
+	  on the IP-VLAN network interface, called ipvtap. An ipvtap device
+	  can be added in the same way as a ipvlan device, using 'type
+	  ipvtap', and then be accessed through the tap user space interface.
+
+	  To compile this driver as a module, choose M here: the module
+	  will be called ipvtap.
 
 config VXLAN
        tristate "Virtual eXtensible Local Area Network (VXLAN)"
diff --git a/drivers/net/Makefile b/drivers/net/Makefile
index 7dd86ca..98ed4d9 100644
--- a/drivers/net/Makefile
+++ b/drivers/net/Makefile
@@ -7,6 +7,7 @@
 #
 obj-$(CONFIG_BONDING) += bonding/
 obj-$(CONFIG_IPVLAN) += ipvlan/
+obj-$(CONFIG_IPVTAP) += ipvlan/
 obj-$(CONFIG_DUMMY) += dummy.o
 obj-$(CONFIG_EQUALIZER) += eql.o
 obj-$(CONFIG_IFB) += ifb.o
diff --git a/drivers/net/ipvlan/Makefile b/drivers/net/ipvlan/Makefile
index df79910..8a2c64d 100644
--- a/drivers/net/ipvlan/Makefile
+++ b/drivers/net/ipvlan/Makefile
@@ -3,5 +3,6 @@
 #
 
 obj-$(CONFIG_IPVLAN) += ipvlan.o
+obj-$(CONFIG_IPVTAP) += ipvtap.o
 
 ipvlan-objs := ipvlan_core.o ipvlan_main.o
diff --git a/drivers/net/ipvlan/ipvlan.h b/drivers/net/ipvlan/ipvlan.h
index 406ae4f..800a46c 100644
--- a/drivers/net/ipvlan/ipvlan.h
+++ b/drivers/net/ipvlan/ipvlan.h
@@ -135,4 +135,11 @@ struct sk_buff *ipvlan_l3_rcv(struct net_device *dev, struct sk_buff *skb,
 			      u16 proto);
 unsigned int ipvlan_nf_input(void *priv, struct sk_buff *skb,
 			     const struct nf_hook_state *state);
+void ipvlan_count_rx(const struct ipvl_dev *ipvlan,
+		     unsigned int len, bool success, bool mcast);
+int ipvlan_link_new(struct net *src_net, struct net_device *dev,
+		    struct nlattr *tb[], struct nlattr *data[]);
+void ipvlan_link_delete(struct net_device *dev, struct list_head *head);
+void ipvlan_link_setup(struct net_device *dev);
+int ipvlan_link_register(struct rtnl_link_ops *ops);
 #endif /* __IPVLAN_H */
diff --git a/drivers/net/ipvlan/ipvlan_core.c b/drivers/net/ipvlan/ipvlan_core.c
index 8ae335d..1f3295e 100644
--- a/drivers/net/ipvlan/ipvlan_core.c
+++ b/drivers/net/ipvlan/ipvlan_core.c
@@ -16,7 +16,7 @@ void ipvlan_init_secret(void)
 	net_get_random_once(&ipvlan_jhash_secret, sizeof(ipvlan_jhash_secret));
 }
 
-static void ipvlan_count_rx(const struct ipvl_dev *ipvlan,
+void ipvlan_count_rx(const struct ipvl_dev *ipvlan,
 			    unsigned int len, bool success, bool mcast)
 {
 	if (likely(success)) {
@@ -33,6 +33,7 @@ static void ipvlan_count_rx(const struct ipvl_dev *ipvlan,
 		this_cpu_inc(ipvlan->pcpu_stats->rx_errs);
 	}
 }
+EXPORT_SYMBOL_GPL(ipvlan_count_rx);
 
 static u8 ipvlan_get_v6_hash(const void *iaddr)
 {
diff --git a/drivers/net/ipvlan/ipvlan_main.c b/drivers/net/ipvlan/ipvlan_main.c
index 95b18f4..aa8575c 100644
--- a/drivers/net/ipvlan/ipvlan_main.c
+++ b/drivers/net/ipvlan/ipvlan_main.c
@@ -496,8 +496,8 @@ static int ipvlan_nl_fillinfo(struct sk_buff *skb,
 	return ret;
 }
 
-static int ipvlan_link_new(struct net *src_net, struct net_device *dev,
-			   struct nlattr *tb[], struct nlattr *data[])
+int ipvlan_link_new(struct net *src_net, struct net_device *dev,
+		    struct nlattr *tb[], struct nlattr *data[])
 {
 	struct ipvl_dev *ipvlan = netdev_priv(dev);
 	struct ipvl_port *port;
@@ -594,8 +594,9 @@ static int ipvlan_link_new(struct net *src_net, struct net_device *dev,
 		ipvlan_port_destroy(phy_dev);
 	return err;
 }
+EXPORT_SYMBOL_GPL(ipvlan_link_new);
 
-static void ipvlan_link_delete(struct net_device *dev, struct list_head *head)
+void ipvlan_link_delete(struct net_device *dev, struct list_head *head)
 {
 	struct ipvl_dev *ipvlan = netdev_priv(dev);
 	struct ipvl_addr *addr, *next;
@@ -611,8 +612,9 @@ static void ipvlan_link_delete(struct net_device *dev, struct list_head *head)
 	unregister_netdevice_queue(dev, head);
 	netdev_upper_dev_unlink(ipvlan->phy_dev, dev);
 }
+EXPORT_SYMBOL_GPL(ipvlan_link_delete);
 
-static void ipvlan_link_setup(struct net_device *dev)
+void ipvlan_link_setup(struct net_device *dev)
 {
 	ether_setup(dev);
 
@@ -623,6 +625,7 @@ static void ipvlan_link_setup(struct net_device *dev)
 	dev->header_ops = &ipvlan_header_ops;
 	dev->ethtool_ops = &ipvlan_ethtool_ops;
 }
+EXPORT_SYMBOL_GPL(ipvlan_link_setup);
 
 static const struct nla_policy ipvlan_nl_policy[IFLA_IPVLAN_MAX + 1] =
 {
@@ -633,22 +636,22 @@ static struct rtnl_link_ops ipvlan_link_ops = {
 	.kind		= "ipvlan",
 	.priv_size	= sizeof(struct ipvl_dev),
 
-	.get_size	= ipvlan_nl_getsize,
-	.policy		= ipvlan_nl_policy,
-	.validate	= ipvlan_nl_validate,
-	.fill_info	= ipvlan_nl_fillinfo,
-	.changelink	= ipvlan_nl_changelink,
-	.maxtype	= IFLA_IPVLAN_MAX,
-
 	.setup		= ipvlan_link_setup,
 	.newlink	= ipvlan_link_new,
 	.dellink	= ipvlan_link_delete,
 };
 
-static int ipvlan_link_register(struct rtnl_link_ops *ops)
+int ipvlan_link_register(struct rtnl_link_ops *ops)
 {
+	ops->get_size	= ipvlan_nl_getsize;
+	ops->policy	= ipvlan_nl_policy;
+	ops->validate	= ipvlan_nl_validate;
+	ops->fill_info	= ipvlan_nl_fillinfo;
+	ops->changelink = ipvlan_nl_changelink;
+	ops->maxtype	= IFLA_IPVLAN_MAX;
 	return rtnl_link_register(ops);
 }
+EXPORT_SYMBOL_GPL(ipvlan_link_register);
 
 static int ipvlan_device_event(struct notifier_block *unused,
 			       unsigned long event, void *ptr)
diff --git a/drivers/net/ipvlan/ipvtap.c b/drivers/net/ipvlan/ipvtap.c
new file mode 100644
index 0000000..2b713b6
--- /dev/null
+++ b/drivers/net/ipvlan/ipvtap.c
@@ -0,0 +1,241 @@
+#include <linux/etherdevice.h>
+#include "ipvlan.h"
+#include <linux/if_vlan.h>
+#include <linux/if_tap.h>
+#include <linux/interrupt.h>
+#include <linux/nsproxy.h>
+#include <linux/compat.h>
+#include <linux/if_tun.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/cache.h>
+#include <linux/sched.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+#include <linux/cdev.h>
+#include <linux/idr.h>
+#include <linux/fs.h>
+#include <linux/uio.h>
+
+#include <net/net_namespace.h>
+#include <net/rtnetlink.h>
+#include <net/sock.h>
+#include <linux/virtio_net.h>
+
+#define TUN_OFFLOADS (NETIF_F_HW_CSUM | NETIF_F_TSO_ECN | NETIF_F_TSO | \
+		      NETIF_F_TSO6 | NETIF_F_UFO)
+
+static dev_t ipvtap_major;
+static struct cdev ipvtap_cdev;
+
+static const void *ipvtap_net_namespace(struct device *d)
+{
+	struct net_device *dev = to_net_dev(d->parent);
+	return dev_net(dev);
+}
+
+static struct class ipvtap_class = {
+	 .name = "ipvtap",
+	 .owner = THIS_MODULE,
+	 .ns_type = &net_ns_type_operations,
+	 .namespace = ipvtap_net_namespace,
+};
+
+struct ipvtap_dev {
+	struct ipvl_dev vlan;
+	struct tap_dev	  tap;
+};
+
+static void ipvtap_count_tx_dropped(struct tap_dev *tap)
+{
+	struct ipvtap_dev *vlantap = container_of(tap, struct ipvtap_dev, tap);
+	struct ipvl_dev *vlan = &vlantap->vlan;
+
+	this_cpu_inc(vlan->pcpu_stats->tx_drps);
+}
+
+static void ipvtap_count_rx_dropped(struct tap_dev *tap)
+{
+	struct ipvtap_dev *vlantap = container_of(tap, struct ipvtap_dev, tap);
+	struct ipvl_dev *vlan = &vlantap->vlan;
+
+	ipvlan_count_rx(vlan, 0, 0, 0);
+}
+
+static void ipvtap_update_features(struct tap_dev *tap,
+				   netdev_features_t features)
+{
+	struct ipvtap_dev *vlantap = container_of(tap, struct ipvtap_dev, tap);
+	struct ipvl_dev *vlan = &vlantap->vlan;
+
+	vlan->sfeatures = features;
+	netdev_update_features(vlan->dev);
+}
+
+static int ipvtap_newlink(struct net *src_net,
+			  struct net_device *dev,
+			  struct nlattr *tb[],
+			  struct nlattr *data[])
+{
+	struct ipvtap_dev *vlantap = netdev_priv(dev);
+	int err;
+
+	INIT_LIST_HEAD(&vlantap->tap.queue_list);
+
+	/* Since macvlan supports all offloads by default, make
+	 * tap support all offloads also.
+	 */
+	vlantap->tap.tap_features = TUN_OFFLOADS;
+	vlantap->tap.count_tx_dropped = ipvtap_count_tx_dropped;
+	vlantap->tap.update_features =	ipvtap_update_features;
+	vlantap->tap.count_rx_dropped = ipvtap_count_rx_dropped;
+
+	err = netdev_rx_handler_register(dev, tap_handle_frame, &vlantap->tap);
+	if (err)
+		return err;
+
+	/* Don't put anything that may fail after macvlan_common_newlink
+	 * because we can't undo what it does.
+	 */
+	err =  ipvlan_link_new(src_net, dev, tb, data);
+	if (err) {
+		netdev_rx_handler_unregister(dev);
+		return err;
+	}
+
+	vlantap->tap.dev = vlantap->vlan.dev;
+
+	return err;
+}
+
+static void ipvtap_dellink(struct net_device *dev,
+			   struct list_head *head)
+{
+	struct ipvtap_dev *vlan = netdev_priv(dev);
+
+	netdev_rx_handler_unregister(dev);
+	tap_del_queues(&vlan->tap);
+	ipvlan_link_delete(dev, head);
+}
+
+static void ipvtap_setup(struct net_device *dev)
+{
+	ipvlan_link_setup(dev);
+	dev->tx_queue_len = TUN_READQ_SIZE;
+	dev->priv_flags &= ~IFF_NO_QUEUE;
+}
+
+static struct rtnl_link_ops ipvtap_link_ops __read_mostly = {
+	.kind		= "ipvtap",
+	.setup		= ipvtap_setup,
+	.newlink	= ipvtap_newlink,
+	.dellink	= ipvtap_dellink,
+	.priv_size	= sizeof(struct ipvtap_dev),
+};
+
+static int ipvtap_device_event(struct notifier_block *unused,
+			       unsigned long event, void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+	struct ipvtap_dev *vlantap;
+	struct device *classdev;
+	dev_t devt;
+	int err;
+	char tap_name[IFNAMSIZ];
+
+	if (dev->rtnl_link_ops != &ipvtap_link_ops)
+		return NOTIFY_DONE;
+
+	snprintf(tap_name, IFNAMSIZ, "tap%d", dev->ifindex);
+	vlantap = netdev_priv(dev);
+
+	switch (event) {
+	case NETDEV_REGISTER:
+		/* Create the device node here after the network device has
+		 * been registered but before register_netdevice has
+		 * finished running.
+		 */
+		err = tap_get_minor(ipvtap_major, &vlantap->tap);
+		if (err)
+			return notifier_from_errno(err);
+
+		devt = MKDEV(MAJOR(ipvtap_major), vlantap->tap.minor);
+		classdev = device_create(&ipvtap_class, &dev->dev, devt,
+					 dev, tap_name);
+		if (IS_ERR(classdev)) {
+			tap_free_minor(ipvtap_major, &vlantap->tap);
+			return notifier_from_errno(PTR_ERR(classdev));
+		}
+		err = sysfs_create_link(&dev->dev.kobj, &classdev->kobj,
+					tap_name);
+		if (err)
+			return notifier_from_errno(err);
+		break;
+	case NETDEV_UNREGISTER:
+		/* vlan->minor == 0 if NETDEV_REGISTER above failed */
+		if (vlantap->tap.minor == 0)
+			break;
+		sysfs_remove_link(&dev->dev.kobj, tap_name);
+		devt = MKDEV(MAJOR(ipvtap_major), vlantap->tap.minor);
+		device_destroy(&ipvtap_class, devt);
+		tap_free_minor(ipvtap_major, &vlantap->tap);
+		break;
+	case NETDEV_CHANGE_TX_QUEUE_LEN:
+		if (tap_queue_resize(&vlantap->tap))
+			return NOTIFY_BAD;
+		break;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block ipvtap_notifier_block __read_mostly = {
+	.notifier_call	= ipvtap_device_event,
+};
+
+static int ipvtap_init(void)
+{
+	int err;
+
+	err = tap_create_cdev(&ipvtap_cdev, &ipvtap_major, "ipvtap");
+
+	if (err)
+		goto out1;
+
+	err = class_register(&ipvtap_class);
+	if (err)
+		goto out2;
+
+	err = register_netdevice_notifier(&ipvtap_notifier_block);
+	if (err)
+		goto out3;
+
+	err = ipvlan_link_register(&ipvtap_link_ops);
+	if (err)
+		goto out4;
+
+	return 0;
+
+out4:
+	unregister_netdevice_notifier(&ipvtap_notifier_block);
+out3:
+	class_unregister(&ipvtap_class);
+out2:
+	tap_destroy_cdev(ipvtap_major, &ipvtap_cdev);
+out1:
+	return err;
+}
+module_init(ipvtap_init);
+
+static void ipvtap_exit(void)
+{
+	rtnl_link_unregister(&ipvtap_link_ops);
+	unregister_netdevice_notifier(&ipvtap_notifier_block);
+	class_unregister(&ipvtap_class);
+	tap_destroy_cdev(ipvtap_major, &ipvtap_cdev);
+}
+module_exit(ipvtap_exit);
+MODULE_ALIAS_RTNL_LINK("ipvtap");
+MODULE_AUTHOR("Sainath Grandhi <sainath.grandhi@intel.com>");
+MODULE_LICENSE("GPL");
-- 
2.7.4

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#1578878 — [PATCHv6 1/7] tap: Refactoring macvtap.c

FromSainath Grandhi <sainath.grandhi@intel.com>
Date2017-02-11 01:10 +0100
Subject[PATCHv6 1/7] tap: Refactoring macvtap.c
Message-ID<t9tqi-203-23@gated-at.bofh.it>
In reply to#1578876
macvtap module has code for tap/queue management and link management. This patch splits
the code into macvtap_main.c for link management and tap.c for tap/queue management.
Functionality in tap.c can be re-used for implementing tap on other virtual interfaces.

Signed-off-by: Sainath Grandhi <sainath.grandhi@intel.com>
---
 drivers/net/Makefile             |   2 +
 drivers/net/macvtap_main.c       | 218 +++++++++++++++++++++++++++++++++++++++
 drivers/net/{macvtap.c => tap.c} | 204 ++----------------------------------
 include/linux/if_macvtap.h       |  10 ++
 4 files changed, 238 insertions(+), 196 deletions(-)
 create mode 100644 drivers/net/macvtap_main.c
 rename drivers/net/{macvtap.c => tap.c} (84%)
 create mode 100644 include/linux/if_macvtap.h

diff --git a/drivers/net/Makefile b/drivers/net/Makefile
index 7336cbd..19b03a9 100644
--- a/drivers/net/Makefile
+++ b/drivers/net/Makefile
@@ -29,6 +29,8 @@ obj-$(CONFIG_GTP) += gtp.o
 obj-$(CONFIG_NLMON) += nlmon.o
 obj-$(CONFIG_NET_VRF) += vrf.o
 
+macvtap-objs := macvtap_main.o tap.o
+
 #
 # Networking Drivers
 #
diff --git a/drivers/net/macvtap_main.c b/drivers/net/macvtap_main.c
new file mode 100644
index 0000000..96ffa60
--- /dev/null
+++ b/drivers/net/macvtap_main.c
@@ -0,0 +1,218 @@
+#include <linux/etherdevice.h>
+#include <linux/if_macvlan.h>
+#include <linux/if_macvtap.h>
+#include <linux/if_vlan.h>
+#include <linux/interrupt.h>
+#include <linux/nsproxy.h>
+#include <linux/compat.h>
+#include <linux/if_tun.h>
+#include <linux/module.h>
+#include <linux/skbuff.h>
+#include <linux/cache.h>
+#include <linux/sched.h>
+#include <linux/types.h>
+#include <linux/slab.h>
+#include <linux/wait.h>
+#include <linux/cdev.h>
+#include <linux/idr.h>
+#include <linux/fs.h>
+#include <linux/uio.h>
+
+#include <net/net_namespace.h>
+#include <net/rtnetlink.h>
+#include <net/sock.h>
+#include <linux/virtio_net.h>
+#include <linux/skb_array.h>
+
+/*
+ * Variables for dealing with macvtaps device numbers.
+ */
+static dev_t macvtap_major;
+#define MACVTAP_NUM_DEVS (1U << MINORBITS)
+
+static const void *macvtap_net_namespace(struct device *d)
+{
+	struct net_device *dev = to_net_dev(d->parent);
+	return dev_net(dev);
+}
+
+static struct class macvtap_class = {
+	.name = "macvtap",
+	.owner = THIS_MODULE,
+	.ns_type = &net_ns_type_operations,
+	.namespace = macvtap_net_namespace,
+};
+static struct cdev macvtap_cdev;
+
+#define TUN_OFFLOADS (NETIF_F_HW_CSUM | NETIF_F_TSO_ECN | NETIF_F_TSO | \
+		      NETIF_F_TSO6 | NETIF_F_UFO)
+
+static int macvtap_newlink(struct net *src_net,
+			   struct net_device *dev,
+			   struct nlattr *tb[],
+			   struct nlattr *data[])
+{
+	struct macvlan_dev *vlan = netdev_priv(dev);
+	int err;
+
+	INIT_LIST_HEAD(&vlan->queue_list);
+
+	/* Since macvlan supports all offloads by default, make
+	 * tap support all offloads also.
+	 */
+	vlan->tap_features = TUN_OFFLOADS;
+
+	err = netdev_rx_handler_register(dev, macvtap_handle_frame, vlan);
+	if (err)
+		return err;
+
+	/* Don't put anything that may fail after macvlan_common_newlink
+	 * because we can't undo what it does.
+	 */
+	err = macvlan_common_newlink(src_net, dev, tb, data);
+	if (err) {
+		netdev_rx_handler_unregister(dev);
+		return err;
+	}
+
+	return 0;
+}
+
+static void macvtap_dellink(struct net_device *dev,
+			    struct list_head *head)
+{
+	netdev_rx_handler_unregister(dev);
+	macvtap_del_queues(dev);
+	macvlan_dellink(dev, head);
+}
+
+static void macvtap_setup(struct net_device *dev)
+{
+	macvlan_common_setup(dev);
+	dev->tx_queue_len = TUN_READQ_SIZE;
+}
+
+static struct rtnl_link_ops macvtap_link_ops __read_mostly = {
+	.kind		= "macvtap",
+	.setup		= macvtap_setup,
+	.newlink	= macvtap_newlink,
+	.dellink	= macvtap_dellink,
+};
+
+static int macvtap_device_event(struct notifier_block *unused,
+				unsigned long event, void *ptr)
+{
+	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
+	struct macvlan_dev *vlan;
+	struct device *classdev;
+	dev_t devt;
+	int err;
+	char tap_name[IFNAMSIZ];
+
+	if (dev->rtnl_link_ops != &macvtap_link_ops)
+		return NOTIFY_DONE;
+
+	snprintf(tap_name, IFNAMSIZ, "tap%d", dev->ifindex);
+	vlan = netdev_priv(dev);
+
+	switch (event) {
+	case NETDEV_REGISTER:
+		/* Create the device node here after the network device has
+		 * been registered but before register_netdevice has
+		 * finished running.
+		 */
+		err = macvtap_get_minor(vlan);
+		if (err)
+			return notifier_from_errno(err);
+
+		devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
+		classdev = device_create(&macvtap_class, &dev->dev, devt,
+					 dev, tap_name);
+		if (IS_ERR(classdev)) {
+			macvtap_free_minor(vlan);
+			return notifier_from_errno(PTR_ERR(classdev));
+		}
+		err = sysfs_create_link(&dev->dev.kobj, &classdev->kobj,
+					tap_name);
+		if (err)
+			return notifier_from_errno(err);
+		break;
+	case NETDEV_UNREGISTER:
+		/* vlan->minor == 0 if NETDEV_REGISTER above failed */
+		if (vlan->minor == 0)
+			break;
+		sysfs_remove_link(&dev->dev.kobj, tap_name);
+		devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
+		device_destroy(&macvtap_class, devt);
+		macvtap_free_minor(vlan);
+		break;
+	case NETDEV_CHANGE_TX_QUEUE_LEN:
+		if (macvtap_queue_resize(vlan))
+			return NOTIFY_BAD;
+		break;
+	}
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block macvtap_notifier_block __read_mostly = {
+	.notifier_call	= macvtap_device_event,
+};
+
+extern struct file_operations macvtap_fops;
+static int macvtap_init(void)
+{
+	int err;
+
+	err = alloc_chrdev_region(&macvtap_major, 0,
+				MACVTAP_NUM_DEVS, "macvtap");
+	if (err)
+		goto out1;
+
+	cdev_init(&macvtap_cdev, &macvtap_fops);
+	err = cdev_add(&macvtap_cdev, macvtap_major, MACVTAP_NUM_DEVS);
+	if (err)
+		goto out2;
+
+	err = class_register(&macvtap_class);
+	if (err)
+		goto out3;
+
+	err = register_netdevice_notifier(&macvtap_notifier_block);
+	if (err)
+		goto out4;
+
+	err = macvlan_link_register(&macvtap_link_ops);
+	if (err)
+		goto out5;
+
+	return 0;
+
+out5:
+	unregister_netdevice_notifier(&macvtap_notifier_block);
+out4:
+	class_unregister(&macvtap_class);
+out3:
+	cdev_del(&macvtap_cdev);
+out2:
+	unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
+out1:
+	return err;
+}
+module_init(macvtap_init);
+
+extern struct idr minor_idr;
+static void macvtap_exit(void)
+{
+	rtnl_link_unregister(&macvtap_link_ops);
+	unregister_netdevice_notifier(&macvtap_notifier_block);
+	class_unregister(&macvtap_class);
+	cdev_del(&macvtap_cdev);
+	unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
+	idr_destroy(&minor_idr);
+}
+module_exit(macvtap_exit);
+
+MODULE_ALIAS_RTNL_LINK("macvtap");
+MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
+MODULE_LICENSE("GPL");
diff --git a/drivers/net/macvtap.c b/drivers/net/tap.c
similarity index 84%
rename from drivers/net/macvtap.c
rename to drivers/net/tap.c
index c27011b..6f6228e 100644
--- a/drivers/net/macvtap.c
+++ b/drivers/net/tap.c
@@ -122,33 +122,14 @@ static struct proto macvtap_proto = {
 	.obj_size = sizeof (struct macvtap_queue),
 };
 
-/*
- * Variables for dealing with macvtaps device numbers.
- */
-static dev_t macvtap_major;
 #define MACVTAP_NUM_DEVS (1U << MINORBITS)
 static DEFINE_MUTEX(minor_lock);
-static DEFINE_IDR(minor_idr);
+DEFINE_IDR(minor_idr);
 
 #define GOODCOPY_LEN 128
-static const void *macvtap_net_namespace(struct device *d)
-{
-	struct net_device *dev = to_net_dev(d->parent);
-	return dev_net(dev);
-}
-
-static struct class macvtap_class = {
-	.name = "macvtap",
-	.owner = THIS_MODULE,
-	.ns_type = &net_ns_type_operations,
-	.namespace = macvtap_net_namespace,
-};
-static struct cdev macvtap_cdev;
 
 static const struct proto_ops macvtap_socket_ops;
 
-#define TUN_OFFLOADS (NETIF_F_HW_CSUM | NETIF_F_TSO_ECN | NETIF_F_TSO | \
-		      NETIF_F_TSO6 | NETIF_F_UFO)
 #define RX_OFFLOADS (NETIF_F_GRO | NETIF_F_LRO)
 #define TAP_FEATURES (NETIF_F_GSO | NETIF_F_SG | NETIF_F_FRAGLIST)
 
@@ -332,7 +313,7 @@ static struct macvtap_queue *macvtap_get_queue(struct net_device *dev,
  * that it holds on all queues and safely set the pointer
  * from the queues to NULL.
  */
-static void macvtap_del_queues(struct net_device *dev)
+void macvtap_del_queues(struct net_device *dev)
 {
 	struct macvlan_dev *vlan = netdev_priv(dev);
 	struct macvtap_queue *q, *tmp;
@@ -352,7 +333,7 @@ static void macvtap_del_queues(struct net_device *dev)
 	vlan->numvtaps = MAX_MACVTAP_QUEUES;
 }
 
-static rx_handler_result_t macvtap_handle_frame(struct sk_buff **pskb)
+rx_handler_result_t macvtap_handle_frame(struct sk_buff **pskb)
 {
 	struct sk_buff *skb = *pskb;
 	struct net_device *dev = skb->dev;
@@ -407,7 +388,7 @@ static rx_handler_result_t macvtap_handle_frame(struct sk_buff **pskb)
 		/* If we receive a partial checksum and the tap side
 		 * doesn't support checksum offload, compute the checksum.
 		 * Note: it doesn't matter which checksum feature to
-		 *        check, we either support them all or none.
+		 *	  check, we either support them all or none.
 		 */
 		if (skb->ip_summed == CHECKSUM_PARTIAL &&
 		    !(features & NETIF_F_CSUM_MASK) &&
@@ -428,7 +409,7 @@ static rx_handler_result_t macvtap_handle_frame(struct sk_buff **pskb)
 	return RX_HANDLER_CONSUMED;
 }
 
-static int macvtap_get_minor(struct macvlan_dev *vlan)
+int macvtap_get_minor(struct macvlan_dev *vlan)
 {
 	int retval = -ENOMEM;
 
@@ -444,7 +425,7 @@ static int macvtap_get_minor(struct macvlan_dev *vlan)
 	return retval < 0 ? retval : 0;
 }
 
-static void macvtap_free_minor(struct macvlan_dev *vlan)
+void macvtap_free_minor(struct macvlan_dev *vlan)
 {
 	mutex_lock(&minor_lock);
 	if (vlan->minor) {
@@ -469,59 +450,6 @@ static struct net_device *dev_get_by_macvtap_minor(int minor)
 	return dev;
 }
 
-static int macvtap_newlink(struct net *src_net,
-			   struct net_device *dev,
-			   struct nlattr *tb[],
-			   struct nlattr *data[])
-{
-	struct macvlan_dev *vlan = netdev_priv(dev);
-	int err;
-
-	INIT_LIST_HEAD(&vlan->queue_list);
-
-	/* Since macvlan supports all offloads by default, make
-	 * tap support all offloads also.
-	 */
-	vlan->tap_features = TUN_OFFLOADS;
-
-	err = netdev_rx_handler_register(dev, macvtap_handle_frame, vlan);
-	if (err)
-		return err;
-
-	/* Don't put anything that may fail after macvlan_common_newlink
-	 * because we can't undo what it does.
-	 */
-	err = macvlan_common_newlink(src_net, dev, tb, data);
-	if (err) {
-		netdev_rx_handler_unregister(dev);
-		return err;
-	}
-
-	return 0;
-}
-
-static void macvtap_dellink(struct net_device *dev,
-			    struct list_head *head)
-{
-	netdev_rx_handler_unregister(dev);
-	macvtap_del_queues(dev);
-	macvlan_dellink(dev, head);
-}
-
-static void macvtap_setup(struct net_device *dev)
-{
-	macvlan_common_setup(dev);
-	dev->tx_queue_len = TUN_READQ_SIZE;
-}
-
-static struct rtnl_link_ops macvtap_link_ops __read_mostly = {
-	.kind		= "macvtap",
-	.setup		= macvtap_setup,
-	.newlink	= macvtap_newlink,
-	.dellink	= macvtap_dellink,
-};
-
-
 static void macvtap_sock_write_space(struct sock *sk)
 {
 	wait_queue_head_t *wqueue;
@@ -1169,7 +1097,7 @@ static long macvtap_compat_ioctl(struct file *file, unsigned int cmd,
 }
 #endif
 
-static const struct file_operations macvtap_fops = {
+const struct file_operations macvtap_fops = {
 	.owner		= THIS_MODULE,
 	.open		= macvtap_open,
 	.release	= macvtap_release,
@@ -1235,7 +1163,7 @@ struct socket *macvtap_get_socket(struct file *file)
 }
 EXPORT_SYMBOL_GPL(macvtap_get_socket);
 
-static int macvtap_queue_resize(struct macvlan_dev *vlan)
+int macvtap_queue_resize(struct macvlan_dev *vlan)
 {
 	struct net_device *dev = vlan->dev;
 	struct macvtap_queue *q;
@@ -1256,119 +1184,3 @@ static int macvtap_queue_resize(struct macvlan_dev *vlan)
 	kfree(arrays);
 	return ret;
 }
-
-static int macvtap_device_event(struct notifier_block *unused,
-				unsigned long event, void *ptr)
-{
-	struct net_device *dev = netdev_notifier_info_to_dev(ptr);
-	struct macvlan_dev *vlan;
-	struct device *classdev;
-	dev_t devt;
-	int err;
-	char tap_name[IFNAMSIZ];
-
-	if (dev->rtnl_link_ops != &macvtap_link_ops)
-		return NOTIFY_DONE;
-
-	snprintf(tap_name, IFNAMSIZ, "tap%d", dev->ifindex);
-	vlan = netdev_priv(dev);
-
-	switch (event) {
-	case NETDEV_REGISTER:
-		/* Create the device node here after the network device has
-		 * been registered but before register_netdevice has
-		 * finished running.
-		 */
-		err = macvtap_get_minor(vlan);
-		if (err)
-			return notifier_from_errno(err);
-
-		devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
-		classdev = device_create(&macvtap_class, &dev->dev, devt,
-					 dev, tap_name);
-		if (IS_ERR(classdev)) {
-			macvtap_free_minor(vlan);
-			return notifier_from_errno(PTR_ERR(classdev));
-		}
-		err = sysfs_create_link(&dev->dev.kobj, &classdev->kobj,
-					tap_name);
-		if (err)
-			return notifier_from_errno(err);
-		break;
-	case NETDEV_UNREGISTER:
-		/* vlan->minor == 0 if NETDEV_REGISTER above failed */
-		if (vlan->minor == 0)
-			break;
-		sysfs_remove_link(&dev->dev.kobj, tap_name);
-		devt = MKDEV(MAJOR(macvtap_major), vlan->minor);
-		device_destroy(&macvtap_class, devt);
-		macvtap_free_minor(vlan);
-		break;
-	case NETDEV_CHANGE_TX_QUEUE_LEN:
-		if (macvtap_queue_resize(vlan))
-			return NOTIFY_BAD;
-		break;
-	}
-
-	return NOTIFY_DONE;
-}
-
-static struct notifier_block macvtap_notifier_block __read_mostly = {
-	.notifier_call	= macvtap_device_event,
-};
-
-static int macvtap_init(void)
-{
-	int err;
-
-	err = alloc_chrdev_region(&macvtap_major, 0,
-				MACVTAP_NUM_DEVS, "macvtap");
-	if (err)
-		goto out1;
-
-	cdev_init(&macvtap_cdev, &macvtap_fops);
-	err = cdev_add(&macvtap_cdev, macvtap_major, MACVTAP_NUM_DEVS);
-	if (err)
-		goto out2;
-
-	err = class_register(&macvtap_class);
-	if (err)
-		goto out3;
-
-	err = register_netdevice_notifier(&macvtap_notifier_block);
-	if (err)
-		goto out4;
-
-	err = macvlan_link_register(&macvtap_link_ops);
-	if (err)
-		goto out5;
-
-	return 0;
-
-out5:
-	unregister_netdevice_notifier(&macvtap_notifier_block);
-out4:
-	class_unregister(&macvtap_class);
-out3:
-	cdev_del(&macvtap_cdev);
-out2:
-	unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
-out1:
-	return err;
-}
-module_init(macvtap_init);
-
-static void macvtap_exit(void)
-{
-	rtnl_link_unregister(&macvtap_link_ops);
-	unregister_netdevice_notifier(&macvtap_notifier_block);
-	class_unregister(&macvtap_class);
-	cdev_del(&macvtap_cdev);
-	unregister_chrdev_region(macvtap_major, MACVTAP_NUM_DEVS);
-	idr_destroy(&minor_idr);
-}
-module_exit(macvtap_exit);
-
-MODULE_ALIAS_RTNL_LINK("macvtap");
-MODULE_AUTHOR("Arnd Bergmann <arnd@arndb.de>");
-MODULE_LICENSE("GPL");
diff --git a/include/linux/if_macvtap.h b/include/linux/if_macvtap.h
new file mode 100644
index 0000000..c9bf84b
--- /dev/null
+++ b/include/linux/if_macvtap.h
@@ -0,0 +1,10 @@
+#ifndef _LINUX_IF_MACVTAP_H_
+#define _LINUX_IF_MACVTAP_H_
+
+rx_handler_result_t macvtap_handle_frame(struct sk_buff **pskb);
+void macvtap_del_queues(struct net_device *dev);
+int macvtap_get_minor(struct macvlan_dev *vlan);
+void macvtap_free_minor(struct macvlan_dev *vlan);
+int macvtap_queue_resize(struct macvlan_dev *vlan);
+
+#endif /*_LINUX_IF_MACVTAP_H_*/
-- 
2.7.4

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#1578880 — [PATCHv6 5/7] tap: Extending tap device create/destroy APIs

FromSainath Grandhi <sainath.grandhi@intel.com>
Date2017-02-11 01:10 +0100
Subject[PATCHv6 5/7] tap: Extending tap device create/destroy APIs
Message-ID<t9tqi-203-29@gated-at.bofh.it>
In reply to#1578876
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>
---
 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 0238df6..a4bfc10 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 7d3e8b1..71bbf0b 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 @@ 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);
+		}
+	}
 }
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 @@ 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);
-- 
2.7.4

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#1579149 — Re: [PATCHv6 0/7] Refactor macvtap to re-use tap functionality by other virtual intefaces

FromDavid Miller <davem@davemloft.net>
Date2017-02-12 03:10 +0100
SubjectRe: [PATCHv6 0/7] Refactor macvtap to re-use tap functionality by other virtual intefaces
Message-ID<t9RLY-cs-5@gated-at.bofh.it>
In reply to#1578876
From: Sainath Grandhi <sainath.grandhi@intel.com>
Date: Fri, 10 Feb 2017 16:03:45 -0800

> Tap character devices can be implemented on other virtual interfaces like
> ipvlan, similar to macvtap. Source code for tap functionality in macvtap
> can be re-used for this purpose.
> 
> This patch series splits macvtap source into two modules, macvtap and tap.
> This patch series also includes a patch for implementing tap character
> device driver based on the IP-VLAN network interface, called ipvtap.
> 
> These patches are tested on x86 platform.

Series applied, thanks.

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