[PATCHv3 1/7] tap: Refactoring macvtap.c

From: Sainath Grandhi
Date: Mon Jan 30 2017 - 14:16:23 EST

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@xxxxxxxxx>
---
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@xxxxxxxx>");
+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 4026185..e192d25 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@xxxxxxxx>");
-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