Linux Audio

Check our new training course

Embedded Linux training

Mar 10-20, 2025, special US time zones
Register
Loading...
v4.17
 
  1/* drivers/net/ifb.c:
  2
  3	The purpose of this driver is to provide a device that allows
  4	for sharing of resources:
  5
  6	1) qdiscs/policies that are per device as opposed to system wide.
  7	ifb allows for a device which can be redirected to thus providing
  8	an impression of sharing.
  9
 10	2) Allows for queueing incoming traffic for shaping instead of
 11	dropping.
 12
 13	The original concept is based on what is known as the IMQ
 14	driver initially written by Martin Devera, later rewritten
 15	by Patrick McHardy and then maintained by Andre Correa.
 16
 17	You need the tc action  mirror or redirect to feed this device
 18       	packets.
 19
 20	This program is free software; you can redistribute it and/or
 21	modify it under the terms of the GNU General Public License
 22	as published by the Free Software Foundation; either version
 23	2 of the License, or (at your option) any later version.
 24
 25  	Authors:	Jamal Hadi Salim (2005)
 26
 27*/
 28
 29
 30#include <linux/module.h>
 31#include <linux/kernel.h>
 32#include <linux/netdevice.h>
 33#include <linux/etherdevice.h>
 34#include <linux/init.h>
 35#include <linux/interrupt.h>
 36#include <linux/moduleparam.h>
 37#include <net/pkt_sched.h>
 38#include <net/net_namespace.h>
 39
 40#define TX_Q_LIMIT    32
 41struct ifb_q_private {
 42	struct net_device	*dev;
 43	struct tasklet_struct   ifb_tasklet;
 44	int			tasklet_pending;
 45	int			txqnum;
 46	struct sk_buff_head     rq;
 47	u64			rx_packets;
 48	u64			rx_bytes;
 49	struct u64_stats_sync	rsync;
 50
 51	struct u64_stats_sync	tsync;
 52	u64			tx_packets;
 53	u64			tx_bytes;
 54	struct sk_buff_head     tq;
 55} ____cacheline_aligned_in_smp;
 56
 57struct ifb_dev_private {
 58	struct ifb_q_private *tx_private;
 59};
 60
 61static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev);
 62static int ifb_open(struct net_device *dev);
 63static int ifb_close(struct net_device *dev);
 64
 65static void ifb_ri_tasklet(unsigned long _txp)
 66{
 67	struct ifb_q_private *txp = (struct ifb_q_private *)_txp;
 68	struct netdev_queue *txq;
 69	struct sk_buff *skb;
 70
 71	txq = netdev_get_tx_queue(txp->dev, txp->txqnum);
 72	skb = skb_peek(&txp->tq);
 73	if (!skb) {
 74		if (!__netif_tx_trylock(txq))
 75			goto resched;
 76		skb_queue_splice_tail_init(&txp->rq, &txp->tq);
 77		__netif_tx_unlock(txq);
 78	}
 79
 80	while ((skb = __skb_dequeue(&txp->tq)) != NULL) {
 81		skb->tc_redirected = 0;
 82		skb->tc_skip_classify = 1;
 83
 84		u64_stats_update_begin(&txp->tsync);
 85		txp->tx_packets++;
 86		txp->tx_bytes += skb->len;
 87		u64_stats_update_end(&txp->tsync);
 88
 89		rcu_read_lock();
 90		skb->dev = dev_get_by_index_rcu(dev_net(txp->dev), skb->skb_iif);
 91		if (!skb->dev) {
 92			rcu_read_unlock();
 93			dev_kfree_skb(skb);
 94			txp->dev->stats.tx_dropped++;
 95			if (skb_queue_len(&txp->tq) != 0)
 96				goto resched;
 97			break;
 98		}
 99		rcu_read_unlock();
100		skb->skb_iif = txp->dev->ifindex;
101
102		if (!skb->tc_from_ingress) {
103			dev_queue_xmit(skb);
104		} else {
105			skb_pull(skb, skb->mac_len);
106			netif_receive_skb(skb);
107		}
108	}
109
110	if (__netif_tx_trylock(txq)) {
111		skb = skb_peek(&txp->rq);
112		if (!skb) {
113			txp->tasklet_pending = 0;
114			if (netif_tx_queue_stopped(txq))
115				netif_tx_wake_queue(txq);
116		} else {
117			__netif_tx_unlock(txq);
118			goto resched;
119		}
120		__netif_tx_unlock(txq);
121	} else {
122resched:
123		txp->tasklet_pending = 1;
124		tasklet_schedule(&txp->ifb_tasklet);
125	}
126
127}
128
129static void ifb_stats64(struct net_device *dev,
130			struct rtnl_link_stats64 *stats)
131{
132	struct ifb_dev_private *dp = netdev_priv(dev);
133	struct ifb_q_private *txp = dp->tx_private;
134	unsigned int start;
135	u64 packets, bytes;
136	int i;
137
138	for (i = 0; i < dev->num_tx_queues; i++,txp++) {
139		do {
140			start = u64_stats_fetch_begin_irq(&txp->rsync);
141			packets = txp->rx_packets;
142			bytes = txp->rx_bytes;
143		} while (u64_stats_fetch_retry_irq(&txp->rsync, start));
144		stats->rx_packets += packets;
145		stats->rx_bytes += bytes;
146
147		do {
148			start = u64_stats_fetch_begin_irq(&txp->tsync);
149			packets = txp->tx_packets;
150			bytes = txp->tx_bytes;
151		} while (u64_stats_fetch_retry_irq(&txp->tsync, start));
152		stats->tx_packets += packets;
153		stats->tx_bytes += bytes;
154	}
155	stats->rx_dropped = dev->stats.rx_dropped;
156	stats->tx_dropped = dev->stats.tx_dropped;
157}
158
159static int ifb_dev_init(struct net_device *dev)
160{
161	struct ifb_dev_private *dp = netdev_priv(dev);
162	struct ifb_q_private *txp;
163	int i;
164
165	txp = kcalloc(dev->num_tx_queues, sizeof(*txp), GFP_KERNEL);
166	if (!txp)
167		return -ENOMEM;
168	dp->tx_private = txp;
169	for (i = 0; i < dev->num_tx_queues; i++,txp++) {
170		txp->txqnum = i;
171		txp->dev = dev;
172		__skb_queue_head_init(&txp->rq);
173		__skb_queue_head_init(&txp->tq);
174		u64_stats_init(&txp->rsync);
175		u64_stats_init(&txp->tsync);
176		tasklet_init(&txp->ifb_tasklet, ifb_ri_tasklet,
177			     (unsigned long)txp);
178		netif_tx_start_queue(netdev_get_tx_queue(dev, i));
179	}
180	return 0;
181}
182
183static const struct net_device_ops ifb_netdev_ops = {
184	.ndo_open	= ifb_open,
185	.ndo_stop	= ifb_close,
186	.ndo_get_stats64 = ifb_stats64,
187	.ndo_start_xmit	= ifb_xmit,
188	.ndo_validate_addr = eth_validate_addr,
189	.ndo_init	= ifb_dev_init,
190};
191
192#define IFB_FEATURES (NETIF_F_HW_CSUM | NETIF_F_SG  | NETIF_F_FRAGLIST	| \
193		      NETIF_F_TSO_ECN | NETIF_F_TSO | NETIF_F_TSO6	| \
194		      NETIF_F_GSO_ENCAP_ALL 				| \
195		      NETIF_F_HIGHDMA | NETIF_F_HW_VLAN_CTAG_TX		| \
196		      NETIF_F_HW_VLAN_STAG_TX)
197
198static void ifb_dev_free(struct net_device *dev)
199{
200	struct ifb_dev_private *dp = netdev_priv(dev);
201	struct ifb_q_private *txp = dp->tx_private;
202	int i;
203
204	for (i = 0; i < dev->num_tx_queues; i++,txp++) {
205		tasklet_kill(&txp->ifb_tasklet);
206		__skb_queue_purge(&txp->rq);
207		__skb_queue_purge(&txp->tq);
208	}
209	kfree(dp->tx_private);
210}
211
212static void ifb_setup(struct net_device *dev)
213{
214	/* Initialize the device structure. */
215	dev->netdev_ops = &ifb_netdev_ops;
216
217	/* Fill in device structure with ethernet-generic values. */
218	ether_setup(dev);
219	dev->tx_queue_len = TX_Q_LIMIT;
220
221	dev->features |= IFB_FEATURES;
222	dev->hw_features |= dev->features;
223	dev->hw_enc_features |= dev->features;
224	dev->vlan_features |= IFB_FEATURES & ~(NETIF_F_HW_VLAN_CTAG_TX |
225					       NETIF_F_HW_VLAN_STAG_TX);
226
227	dev->flags |= IFF_NOARP;
228	dev->flags &= ~IFF_MULTICAST;
229	dev->priv_flags &= ~IFF_TX_SKB_SHARING;
230	netif_keep_dst(dev);
231	eth_hw_addr_random(dev);
232	dev->needs_free_netdev = true;
233	dev->priv_destructor = ifb_dev_free;
234
235	dev->min_mtu = 0;
236	dev->max_mtu = 0;
237}
238
239static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev)
240{
241	struct ifb_dev_private *dp = netdev_priv(dev);
242	struct ifb_q_private *txp = dp->tx_private + skb_get_queue_mapping(skb);
243
244	u64_stats_update_begin(&txp->rsync);
245	txp->rx_packets++;
246	txp->rx_bytes += skb->len;
247	u64_stats_update_end(&txp->rsync);
248
249	if (!skb->tc_redirected || !skb->skb_iif) {
250		dev_kfree_skb(skb);
251		dev->stats.rx_dropped++;
252		return NETDEV_TX_OK;
253	}
254
255	if (skb_queue_len(&txp->rq) >= dev->tx_queue_len)
256		netif_tx_stop_queue(netdev_get_tx_queue(dev, txp->txqnum));
257
258	__skb_queue_tail(&txp->rq, skb);
259	if (!txp->tasklet_pending) {
260		txp->tasklet_pending = 1;
261		tasklet_schedule(&txp->ifb_tasklet);
262	}
263
264	return NETDEV_TX_OK;
265}
266
267static int ifb_close(struct net_device *dev)
268{
269	netif_tx_stop_all_queues(dev);
270	return 0;
271}
272
273static int ifb_open(struct net_device *dev)
274{
275	netif_tx_start_all_queues(dev);
276	return 0;
277}
278
279static int ifb_validate(struct nlattr *tb[], struct nlattr *data[],
280			struct netlink_ext_ack *extack)
281{
282	if (tb[IFLA_ADDRESS]) {
283		if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
284			return -EINVAL;
285		if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
286			return -EADDRNOTAVAIL;
287	}
288	return 0;
289}
290
291static struct rtnl_link_ops ifb_link_ops __read_mostly = {
292	.kind		= "ifb",
293	.priv_size	= sizeof(struct ifb_dev_private),
294	.setup		= ifb_setup,
295	.validate	= ifb_validate,
296};
297
298/* Number of ifb devices to be set up by this module.
299 * Note that these legacy devices have one queue.
300 * Prefer something like : ip link add ifb10 numtxqueues 8 type ifb
301 */
302static int numifbs = 2;
303module_param(numifbs, int, 0);
304MODULE_PARM_DESC(numifbs, "Number of ifb devices");
305
306static int __init ifb_init_one(int index)
307{
308	struct net_device *dev_ifb;
309	int err;
310
311	dev_ifb = alloc_netdev(sizeof(struct ifb_dev_private), "ifb%d",
312			       NET_NAME_UNKNOWN, ifb_setup);
313
314	if (!dev_ifb)
315		return -ENOMEM;
316
317	dev_ifb->rtnl_link_ops = &ifb_link_ops;
318	err = register_netdevice(dev_ifb);
319	if (err < 0)
320		goto err;
321
322	return 0;
323
324err:
325	free_netdev(dev_ifb);
326	return err;
327}
328
329static int __init ifb_init_module(void)
330{
331	int i, err;
332
333	down_write(&pernet_ops_rwsem);
334	rtnl_lock();
335	err = __rtnl_link_register(&ifb_link_ops);
336	if (err < 0)
337		goto out;
338
339	for (i = 0; i < numifbs && !err; i++) {
340		err = ifb_init_one(i);
341		cond_resched();
342	}
343	if (err)
344		__rtnl_link_unregister(&ifb_link_ops);
345
346out:
347	rtnl_unlock();
348	up_write(&pernet_ops_rwsem);
349
350	return err;
351}
352
353static void __exit ifb_cleanup_module(void)
354{
355	rtnl_link_unregister(&ifb_link_ops);
356}
357
358module_init(ifb_init_module);
359module_exit(ifb_cleanup_module);
360MODULE_LICENSE("GPL");
361MODULE_AUTHOR("Jamal Hadi Salim");
362MODULE_ALIAS_RTNL_LINK("ifb");
v5.14.15
  1// SPDX-License-Identifier: GPL-2.0-or-later
  2/* drivers/net/ifb.c:
  3
  4	The purpose of this driver is to provide a device that allows
  5	for sharing of resources:
  6
  7	1) qdiscs/policies that are per device as opposed to system wide.
  8	ifb allows for a device which can be redirected to thus providing
  9	an impression of sharing.
 10
 11	2) Allows for queueing incoming traffic for shaping instead of
 12	dropping.
 13
 14	The original concept is based on what is known as the IMQ
 15	driver initially written by Martin Devera, later rewritten
 16	by Patrick McHardy and then maintained by Andre Correa.
 17
 18	You need the tc action  mirror or redirect to feed this device
 19	packets.
 20
 
 
 
 
 21
 22	Authors:	Jamal Hadi Salim (2005)
 23
 24*/
 25
 26
 27#include <linux/module.h>
 28#include <linux/kernel.h>
 29#include <linux/netdevice.h>
 30#include <linux/etherdevice.h>
 31#include <linux/init.h>
 32#include <linux/interrupt.h>
 33#include <linux/moduleparam.h>
 34#include <net/pkt_sched.h>
 35#include <net/net_namespace.h>
 36
 37#define TX_Q_LIMIT    32
 38struct ifb_q_private {
 39	struct net_device	*dev;
 40	struct tasklet_struct   ifb_tasklet;
 41	int			tasklet_pending;
 42	int			txqnum;
 43	struct sk_buff_head     rq;
 44	u64			rx_packets;
 45	u64			rx_bytes;
 46	struct u64_stats_sync	rsync;
 47
 48	struct u64_stats_sync	tsync;
 49	u64			tx_packets;
 50	u64			tx_bytes;
 51	struct sk_buff_head     tq;
 52} ____cacheline_aligned_in_smp;
 53
 54struct ifb_dev_private {
 55	struct ifb_q_private *tx_private;
 56};
 57
 58static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev);
 59static int ifb_open(struct net_device *dev);
 60static int ifb_close(struct net_device *dev);
 61
 62static void ifb_ri_tasklet(struct tasklet_struct *t)
 63{
 64	struct ifb_q_private *txp = from_tasklet(txp, t, ifb_tasklet);
 65	struct netdev_queue *txq;
 66	struct sk_buff *skb;
 67
 68	txq = netdev_get_tx_queue(txp->dev, txp->txqnum);
 69	skb = skb_peek(&txp->tq);
 70	if (!skb) {
 71		if (!__netif_tx_trylock(txq))
 72			goto resched;
 73		skb_queue_splice_tail_init(&txp->rq, &txp->tq);
 74		__netif_tx_unlock(txq);
 75	}
 76
 77	while ((skb = __skb_dequeue(&txp->tq)) != NULL) {
 78		skb->redirected = 0;
 79		skb->tc_skip_classify = 1;
 80
 81		u64_stats_update_begin(&txp->tsync);
 82		txp->tx_packets++;
 83		txp->tx_bytes += skb->len;
 84		u64_stats_update_end(&txp->tsync);
 85
 86		rcu_read_lock();
 87		skb->dev = dev_get_by_index_rcu(dev_net(txp->dev), skb->skb_iif);
 88		if (!skb->dev) {
 89			rcu_read_unlock();
 90			dev_kfree_skb(skb);
 91			txp->dev->stats.tx_dropped++;
 92			if (skb_queue_len(&txp->tq) != 0)
 93				goto resched;
 94			break;
 95		}
 96		rcu_read_unlock();
 97		skb->skb_iif = txp->dev->ifindex;
 98
 99		if (!skb->from_ingress) {
100			dev_queue_xmit(skb);
101		} else {
102			skb_pull_rcsum(skb, skb->mac_len);
103			netif_receive_skb(skb);
104		}
105	}
106
107	if (__netif_tx_trylock(txq)) {
108		skb = skb_peek(&txp->rq);
109		if (!skb) {
110			txp->tasklet_pending = 0;
111			if (netif_tx_queue_stopped(txq))
112				netif_tx_wake_queue(txq);
113		} else {
114			__netif_tx_unlock(txq);
115			goto resched;
116		}
117		__netif_tx_unlock(txq);
118	} else {
119resched:
120		txp->tasklet_pending = 1;
121		tasklet_schedule(&txp->ifb_tasklet);
122	}
123
124}
125
126static void ifb_stats64(struct net_device *dev,
127			struct rtnl_link_stats64 *stats)
128{
129	struct ifb_dev_private *dp = netdev_priv(dev);
130	struct ifb_q_private *txp = dp->tx_private;
131	unsigned int start;
132	u64 packets, bytes;
133	int i;
134
135	for (i = 0; i < dev->num_tx_queues; i++,txp++) {
136		do {
137			start = u64_stats_fetch_begin_irq(&txp->rsync);
138			packets = txp->rx_packets;
139			bytes = txp->rx_bytes;
140		} while (u64_stats_fetch_retry_irq(&txp->rsync, start));
141		stats->rx_packets += packets;
142		stats->rx_bytes += bytes;
143
144		do {
145			start = u64_stats_fetch_begin_irq(&txp->tsync);
146			packets = txp->tx_packets;
147			bytes = txp->tx_bytes;
148		} while (u64_stats_fetch_retry_irq(&txp->tsync, start));
149		stats->tx_packets += packets;
150		stats->tx_bytes += bytes;
151	}
152	stats->rx_dropped = dev->stats.rx_dropped;
153	stats->tx_dropped = dev->stats.tx_dropped;
154}
155
156static int ifb_dev_init(struct net_device *dev)
157{
158	struct ifb_dev_private *dp = netdev_priv(dev);
159	struct ifb_q_private *txp;
160	int i;
161
162	txp = kcalloc(dev->num_tx_queues, sizeof(*txp), GFP_KERNEL);
163	if (!txp)
164		return -ENOMEM;
165	dp->tx_private = txp;
166	for (i = 0; i < dev->num_tx_queues; i++,txp++) {
167		txp->txqnum = i;
168		txp->dev = dev;
169		__skb_queue_head_init(&txp->rq);
170		__skb_queue_head_init(&txp->tq);
171		u64_stats_init(&txp->rsync);
172		u64_stats_init(&txp->tsync);
173		tasklet_setup(&txp->ifb_tasklet, ifb_ri_tasklet);
 
174		netif_tx_start_queue(netdev_get_tx_queue(dev, i));
175	}
176	return 0;
177}
178
179static const struct net_device_ops ifb_netdev_ops = {
180	.ndo_open	= ifb_open,
181	.ndo_stop	= ifb_close,
182	.ndo_get_stats64 = ifb_stats64,
183	.ndo_start_xmit	= ifb_xmit,
184	.ndo_validate_addr = eth_validate_addr,
185	.ndo_init	= ifb_dev_init,
186};
187
188#define IFB_FEATURES (NETIF_F_HW_CSUM | NETIF_F_SG  | NETIF_F_FRAGLIST	| \
189		      NETIF_F_GSO_SOFTWARE | NETIF_F_GSO_ENCAP_ALL	| \
 
190		      NETIF_F_HIGHDMA | NETIF_F_HW_VLAN_CTAG_TX		| \
191		      NETIF_F_HW_VLAN_STAG_TX)
192
193static void ifb_dev_free(struct net_device *dev)
194{
195	struct ifb_dev_private *dp = netdev_priv(dev);
196	struct ifb_q_private *txp = dp->tx_private;
197	int i;
198
199	for (i = 0; i < dev->num_tx_queues; i++,txp++) {
200		tasklet_kill(&txp->ifb_tasklet);
201		__skb_queue_purge(&txp->rq);
202		__skb_queue_purge(&txp->tq);
203	}
204	kfree(dp->tx_private);
205}
206
207static void ifb_setup(struct net_device *dev)
208{
209	/* Initialize the device structure. */
210	dev->netdev_ops = &ifb_netdev_ops;
211
212	/* Fill in device structure with ethernet-generic values. */
213	ether_setup(dev);
214	dev->tx_queue_len = TX_Q_LIMIT;
215
216	dev->features |= IFB_FEATURES;
217	dev->hw_features |= dev->features;
218	dev->hw_enc_features |= dev->features;
219	dev->vlan_features |= IFB_FEATURES & ~(NETIF_F_HW_VLAN_CTAG_TX |
220					       NETIF_F_HW_VLAN_STAG_TX);
221
222	dev->flags |= IFF_NOARP;
223	dev->flags &= ~IFF_MULTICAST;
224	dev->priv_flags &= ~IFF_TX_SKB_SHARING;
225	netif_keep_dst(dev);
226	eth_hw_addr_random(dev);
227	dev->needs_free_netdev = true;
228	dev->priv_destructor = ifb_dev_free;
229
230	dev->min_mtu = 0;
231	dev->max_mtu = 0;
232}
233
234static netdev_tx_t ifb_xmit(struct sk_buff *skb, struct net_device *dev)
235{
236	struct ifb_dev_private *dp = netdev_priv(dev);
237	struct ifb_q_private *txp = dp->tx_private + skb_get_queue_mapping(skb);
238
239	u64_stats_update_begin(&txp->rsync);
240	txp->rx_packets++;
241	txp->rx_bytes += skb->len;
242	u64_stats_update_end(&txp->rsync);
243
244	if (!skb->redirected || !skb->skb_iif) {
245		dev_kfree_skb(skb);
246		dev->stats.rx_dropped++;
247		return NETDEV_TX_OK;
248	}
249
250	if (skb_queue_len(&txp->rq) >= dev->tx_queue_len)
251		netif_tx_stop_queue(netdev_get_tx_queue(dev, txp->txqnum));
252
253	__skb_queue_tail(&txp->rq, skb);
254	if (!txp->tasklet_pending) {
255		txp->tasklet_pending = 1;
256		tasklet_schedule(&txp->ifb_tasklet);
257	}
258
259	return NETDEV_TX_OK;
260}
261
262static int ifb_close(struct net_device *dev)
263{
264	netif_tx_stop_all_queues(dev);
265	return 0;
266}
267
268static int ifb_open(struct net_device *dev)
269{
270	netif_tx_start_all_queues(dev);
271	return 0;
272}
273
274static int ifb_validate(struct nlattr *tb[], struct nlattr *data[],
275			struct netlink_ext_ack *extack)
276{
277	if (tb[IFLA_ADDRESS]) {
278		if (nla_len(tb[IFLA_ADDRESS]) != ETH_ALEN)
279			return -EINVAL;
280		if (!is_valid_ether_addr(nla_data(tb[IFLA_ADDRESS])))
281			return -EADDRNOTAVAIL;
282	}
283	return 0;
284}
285
286static struct rtnl_link_ops ifb_link_ops __read_mostly = {
287	.kind		= "ifb",
288	.priv_size	= sizeof(struct ifb_dev_private),
289	.setup		= ifb_setup,
290	.validate	= ifb_validate,
291};
292
293/* Number of ifb devices to be set up by this module.
294 * Note that these legacy devices have one queue.
295 * Prefer something like : ip link add ifb10 numtxqueues 8 type ifb
296 */
297static int numifbs = 2;
298module_param(numifbs, int, 0);
299MODULE_PARM_DESC(numifbs, "Number of ifb devices");
300
301static int __init ifb_init_one(int index)
302{
303	struct net_device *dev_ifb;
304	int err;
305
306	dev_ifb = alloc_netdev(sizeof(struct ifb_dev_private), "ifb%d",
307			       NET_NAME_UNKNOWN, ifb_setup);
308
309	if (!dev_ifb)
310		return -ENOMEM;
311
312	dev_ifb->rtnl_link_ops = &ifb_link_ops;
313	err = register_netdevice(dev_ifb);
314	if (err < 0)
315		goto err;
316
317	return 0;
318
319err:
320	free_netdev(dev_ifb);
321	return err;
322}
323
324static int __init ifb_init_module(void)
325{
326	int i, err;
327
328	down_write(&pernet_ops_rwsem);
329	rtnl_lock();
330	err = __rtnl_link_register(&ifb_link_ops);
331	if (err < 0)
332		goto out;
333
334	for (i = 0; i < numifbs && !err; i++) {
335		err = ifb_init_one(i);
336		cond_resched();
337	}
338	if (err)
339		__rtnl_link_unregister(&ifb_link_ops);
340
341out:
342	rtnl_unlock();
343	up_write(&pernet_ops_rwsem);
344
345	return err;
346}
347
348static void __exit ifb_cleanup_module(void)
349{
350	rtnl_link_unregister(&ifb_link_ops);
351}
352
353module_init(ifb_init_module);
354module_exit(ifb_cleanup_module);
355MODULE_LICENSE("GPL");
356MODULE_AUTHOR("Jamal Hadi Salim");
357MODULE_ALIAS_RTNL_LINK("ifb");