xref: /f-stack/dpdk/kernel/linux/kni/kni_misc.c (revision 16d80a6d)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Copyright(c) 2010-2014 Intel Corporation.
4  */
5 
6 #include <linux/version.h>
7 #include <linux/module.h>
8 #include <linux/miscdevice.h>
9 #include <linux/netdevice.h>
10 #include <linux/etherdevice.h>
11 #include <linux/pci.h>
12 #include <linux/kthread.h>
13 #include <linux/rwsem.h>
14 #include <linux/mutex.h>
15 #include <linux/nsproxy.h>
16 #include <net/net_namespace.h>
17 #include <net/netns/generic.h>
18 
19 #include <exec-env/rte_kni_common.h>
20 
21 #include "compat.h"
22 #include "kni_dev.h"
23 
24 MODULE_LICENSE("Dual BSD/GPL");
25 MODULE_AUTHOR("Intel Corporation");
26 MODULE_DESCRIPTION("Kernel Module for managing kni devices");
27 
28 #define KNI_RX_LOOP_NUM 1000
29 
30 #define KNI_MAX_DEVICES 32
31 
32 extern const struct pci_device_id ixgbe_pci_tbl[];
33 extern const struct pci_device_id igb_pci_tbl[];
34 
35 /* loopback mode */
36 static char *lo_mode;
37 
38 /* Kernel thread mode */
39 static char *kthread_mode;
40 static uint32_t multiple_kthread_on;
41 
42 /* Default carrier state for created KNI network interfaces */
43 static char *carrier;
44 uint32_t dflt_carrier;
45 
46 #define KNI_DEV_IN_USE_BIT_NUM 0 /* Bit number for device in use */
47 
48 static int kni_net_id;
49 
50 struct kni_net {
51 	unsigned long device_in_use; /* device in use flag */
52 	struct mutex kni_kthread_lock;
53 	struct task_struct *kni_kthread;
54 	struct rw_semaphore kni_list_lock;
55 	struct list_head kni_list_head;
56 };
57 
58 static int __net_init
59 kni_init_net(struct net *net)
60 {
61 #ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
62 	struct kni_net *knet = net_generic(net, kni_net_id);
63 
64 	memset(knet, 0, sizeof(*knet));
65 #else
66 	struct kni_net *knet;
67 	int ret;
68 
69 	knet = kzalloc(sizeof(struct kni_net), GFP_KERNEL);
70 	if (!knet) {
71 		ret = -ENOMEM;
72 		return ret;
73 	}
74 #endif
75 
76 	/* Clear the bit of device in use */
77 	clear_bit(KNI_DEV_IN_USE_BIT_NUM, &knet->device_in_use);
78 
79 	mutex_init(&knet->kni_kthread_lock);
80 
81 	init_rwsem(&knet->kni_list_lock);
82 	INIT_LIST_HEAD(&knet->kni_list_head);
83 
84 #ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
85 	return 0;
86 #else
87 	ret = net_assign_generic(net, kni_net_id, knet);
88 	if (ret < 0)
89 		kfree(knet);
90 
91 	return ret;
92 #endif
93 }
94 
95 static void __net_exit
96 kni_exit_net(struct net *net)
97 {
98 	struct kni_net *knet __maybe_unused;
99 
100 	knet = net_generic(net, kni_net_id);
101 	mutex_destroy(&knet->kni_kthread_lock);
102 
103 #ifndef HAVE_SIMPLIFIED_PERNET_OPERATIONS
104 	kfree(knet);
105 #endif
106 }
107 
108 static struct pernet_operations kni_net_ops = {
109 	.init = kni_init_net,
110 	.exit = kni_exit_net,
111 #ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
112 	.id   = &kni_net_id,
113 	.size = sizeof(struct kni_net),
114 #endif
115 };
116 
117 static int
118 kni_thread_single(void *data)
119 {
120 	struct kni_net *knet = data;
121 	int j;
122 	struct kni_dev *dev;
123 
124 	while (!kthread_should_stop()) {
125 		down_read(&knet->kni_list_lock);
126 		for (j = 0; j < KNI_RX_LOOP_NUM; j++) {
127 			list_for_each_entry(dev, &knet->kni_list_head, list) {
128 				kni_net_rx(dev);
129 				kni_net_poll_resp(dev);
130 			}
131 		}
132 		up_read(&knet->kni_list_lock);
133 #ifdef RTE_KNI_PREEMPT_DEFAULT
134 		/* reschedule out for a while */
135 		schedule_timeout_interruptible(
136 			usecs_to_jiffies(KNI_KTHREAD_RESCHEDULE_INTERVAL));
137 #endif
138 	}
139 
140 	return 0;
141 }
142 
143 static int
144 kni_thread_multiple(void *param)
145 {
146 	int j;
147 	struct kni_dev *dev = param;
148 
149 	while (!kthread_should_stop()) {
150 		for (j = 0; j < KNI_RX_LOOP_NUM; j++) {
151 			kni_net_rx(dev);
152 			kni_net_poll_resp(dev);
153 		}
154 #ifdef RTE_KNI_PREEMPT_DEFAULT
155 		schedule_timeout_interruptible(
156 			usecs_to_jiffies(KNI_KTHREAD_RESCHEDULE_INTERVAL));
157 #endif
158 	}
159 
160 	return 0;
161 }
162 
163 static int
164 kni_open(struct inode *inode, struct file *file)
165 {
166 	struct net *net = current->nsproxy->net_ns;
167 	struct kni_net *knet = net_generic(net, kni_net_id);
168 
169 	/* kni device can be opened by one user only per netns */
170 	if (test_and_set_bit(KNI_DEV_IN_USE_BIT_NUM, &knet->device_in_use))
171 		return -EBUSY;
172 
173 	file->private_data = get_net(net);
174 	pr_debug("/dev/kni opened\n");
175 
176 	return 0;
177 }
178 
179 static int
180 kni_dev_remove(struct kni_dev *dev)
181 {
182 	if (!dev)
183 		return -ENODEV;
184 
185 #ifdef RTE_KNI_KMOD_ETHTOOL
186 	if (dev->pci_dev) {
187 		if (pci_match_id(ixgbe_pci_tbl, dev->pci_dev))
188 			ixgbe_kni_remove(dev->pci_dev);
189 		else if (pci_match_id(igb_pci_tbl, dev->pci_dev))
190 			igb_kni_remove(dev->pci_dev);
191 	}
192 #endif
193 
194 	if (dev->net_dev) {
195 		unregister_netdev(dev->net_dev);
196 		free_netdev(dev->net_dev);
197 	}
198 
199 	kni_net_release_fifo_phy(dev);
200 
201 	return 0;
202 }
203 
204 static int
205 kni_release(struct inode *inode, struct file *file)
206 {
207 	struct net *net = file->private_data;
208 	struct kni_net *knet = net_generic(net, kni_net_id);
209 	struct kni_dev *dev, *n;
210 
211 	/* Stop kernel thread for single mode */
212 	if (multiple_kthread_on == 0) {
213 		mutex_lock(&knet->kni_kthread_lock);
214 		/* Stop kernel thread */
215 		if (knet->kni_kthread != NULL) {
216 			kthread_stop(knet->kni_kthread);
217 			knet->kni_kthread = NULL;
218 		}
219 		mutex_unlock(&knet->kni_kthread_lock);
220 	}
221 
222 	down_write(&knet->kni_list_lock);
223 	list_for_each_entry_safe(dev, n, &knet->kni_list_head, list) {
224 		/* Stop kernel thread for multiple mode */
225 		if (multiple_kthread_on && dev->pthread != NULL) {
226 			kthread_stop(dev->pthread);
227 			dev->pthread = NULL;
228 		}
229 
230 		kni_dev_remove(dev);
231 		list_del(&dev->list);
232 	}
233 	up_write(&knet->kni_list_lock);
234 
235 	/* Clear the bit of device in use */
236 	clear_bit(KNI_DEV_IN_USE_BIT_NUM, &knet->device_in_use);
237 
238 	put_net(net);
239 	pr_debug("/dev/kni closed\n");
240 
241 	return 0;
242 }
243 
244 static int
245 kni_check_param(struct kni_dev *kni, struct rte_kni_device_info *dev)
246 {
247 	if (!kni || !dev)
248 		return -1;
249 
250 	/* Check if network name has been used */
251 	if (!strncmp(kni->name, dev->name, RTE_KNI_NAMESIZE)) {
252 		pr_err("KNI name %s duplicated\n", dev->name);
253 		return -1;
254 	}
255 
256 	return 0;
257 }
258 
259 static int
260 kni_run_thread(struct kni_net *knet, struct kni_dev *kni, uint8_t force_bind)
261 {
262 	/**
263 	 * Create a new kernel thread for multiple mode, set its core affinity,
264 	 * and finally wake it up.
265 	 */
266 	if (multiple_kthread_on) {
267 		kni->pthread = kthread_create(kni_thread_multiple,
268 			(void *)kni, "kni_%s", kni->name);
269 		if (IS_ERR(kni->pthread)) {
270 			kni_dev_remove(kni);
271 			return -ECANCELED;
272 		}
273 
274 		if (force_bind)
275 			kthread_bind(kni->pthread, kni->core_id);
276 		wake_up_process(kni->pthread);
277 	} else {
278 		mutex_lock(&knet->kni_kthread_lock);
279 
280 		if (knet->kni_kthread == NULL) {
281 			knet->kni_kthread = kthread_create(kni_thread_single,
282 				(void *)knet, "kni_single");
283 			if (IS_ERR(knet->kni_kthread)) {
284 				mutex_unlock(&knet->kni_kthread_lock);
285 				kni_dev_remove(kni);
286 				return -ECANCELED;
287 			}
288 
289 			if (force_bind)
290 				kthread_bind(knet->kni_kthread, kni->core_id);
291 			wake_up_process(knet->kni_kthread);
292 		}
293 
294 		mutex_unlock(&knet->kni_kthread_lock);
295 	}
296 
297 	return 0;
298 }
299 
300 static int
301 kni_ioctl_create(struct net *net, uint32_t ioctl_num,
302 		unsigned long ioctl_param)
303 {
304 	struct kni_net *knet = net_generic(net, kni_net_id);
305 	int ret;
306 	struct rte_kni_device_info dev_info;
307 	struct net_device *net_dev = NULL;
308 	struct kni_dev *kni, *dev, *n;
309 #ifdef RTE_KNI_KMOD_ETHTOOL
310 	struct pci_dev *found_pci = NULL;
311 	struct net_device *lad_dev = NULL;
312 	struct pci_dev *pci = NULL;
313 #endif
314 
315 	pr_info("Creating kni...\n");
316 	/* Check the buffer size, to avoid warning */
317 	if (_IOC_SIZE(ioctl_num) > sizeof(dev_info))
318 		return -EINVAL;
319 
320 	/* Copy kni info from user space */
321 	ret = copy_from_user(&dev_info, (void *)ioctl_param, sizeof(dev_info));
322 	if (ret) {
323 		pr_err("copy_from_user in kni_ioctl_create");
324 		return -EIO;
325 	}
326 
327 	/* Check if name is zero-ended */
328 	if (strnlen(dev_info.name, sizeof(dev_info.name)) == sizeof(dev_info.name)) {
329 		pr_err("kni.name not zero-terminated");
330 		return -EINVAL;
331 	}
332 
333 	/**
334 	 * Check if the cpu core id is valid for binding.
335 	 */
336 	if (dev_info.force_bind && !cpu_online(dev_info.core_id)) {
337 		pr_err("cpu %u is not online\n", dev_info.core_id);
338 		return -EINVAL;
339 	}
340 
341 	/* Check if it has been created */
342 	down_read(&knet->kni_list_lock);
343 	list_for_each_entry_safe(dev, n, &knet->kni_list_head, list) {
344 		if (kni_check_param(dev, &dev_info) < 0) {
345 			up_read(&knet->kni_list_lock);
346 			return -EINVAL;
347 		}
348 	}
349 	up_read(&knet->kni_list_lock);
350 
351 	net_dev = alloc_netdev(sizeof(struct kni_dev), dev_info.name,
352 #ifdef NET_NAME_USER
353 							NET_NAME_USER,
354 #endif
355 							kni_net_init);
356 	if (net_dev == NULL) {
357 		pr_err("error allocating device \"%s\"\n", dev_info.name);
358 		return -EBUSY;
359 	}
360 
361 	dev_net_set(net_dev, net);
362 
363 	kni = netdev_priv(net_dev);
364 
365 	kni->net_dev = net_dev;
366 	kni->group_id = dev_info.group_id;
367 	kni->core_id = dev_info.core_id;
368 	strncpy(kni->name, dev_info.name, RTE_KNI_NAMESIZE);
369 
370 	/* Translate user space info into kernel space info */
371 	kni->tx_q = phys_to_virt(dev_info.tx_phys);
372 	kni->rx_q = phys_to_virt(dev_info.rx_phys);
373 	kni->alloc_q = phys_to_virt(dev_info.alloc_phys);
374 	kni->free_q = phys_to_virt(dev_info.free_phys);
375 
376 	kni->req_q = phys_to_virt(dev_info.req_phys);
377 	kni->resp_q = phys_to_virt(dev_info.resp_phys);
378 	kni->sync_va = dev_info.sync_va;
379 	kni->sync_kva = phys_to_virt(dev_info.sync_phys);
380 
381 	kni->mbuf_size = dev_info.mbuf_size;
382 
383 	pr_debug("tx_phys:      0x%016llx, tx_q addr:      0x%p\n",
384 		(unsigned long long) dev_info.tx_phys, kni->tx_q);
385 	pr_debug("rx_phys:      0x%016llx, rx_q addr:      0x%p\n",
386 		(unsigned long long) dev_info.rx_phys, kni->rx_q);
387 	pr_debug("alloc_phys:   0x%016llx, alloc_q addr:   0x%p\n",
388 		(unsigned long long) dev_info.alloc_phys, kni->alloc_q);
389 	pr_debug("free_phys:    0x%016llx, free_q addr:    0x%p\n",
390 		(unsigned long long) dev_info.free_phys, kni->free_q);
391 	pr_debug("req_phys:     0x%016llx, req_q addr:     0x%p\n",
392 		(unsigned long long) dev_info.req_phys, kni->req_q);
393 	pr_debug("resp_phys:    0x%016llx, resp_q addr:    0x%p\n",
394 		(unsigned long long) dev_info.resp_phys, kni->resp_q);
395 	pr_debug("mbuf_size:    %u\n", kni->mbuf_size);
396 
397 	pr_debug("PCI: %02x:%02x.%02x %04x:%04x\n",
398 					dev_info.bus,
399 					dev_info.devid,
400 					dev_info.function,
401 					dev_info.vendor_id,
402 					dev_info.device_id);
403 #ifdef RTE_KNI_KMOD_ETHTOOL
404 	pci = pci_get_device(dev_info.vendor_id, dev_info.device_id, NULL);
405 
406 	/* Support Ethtool */
407 	while (pci) {
408 		pr_debug("pci_bus: %02x:%02x:%02x\n",
409 					pci->bus->number,
410 					PCI_SLOT(pci->devfn),
411 					PCI_FUNC(pci->devfn));
412 
413 		if ((pci->bus->number == dev_info.bus) &&
414 			(PCI_SLOT(pci->devfn) == dev_info.devid) &&
415 			(PCI_FUNC(pci->devfn) == dev_info.function)) {
416 			found_pci = pci;
417 
418 			if (pci_match_id(ixgbe_pci_tbl, found_pci))
419 				ret = ixgbe_kni_probe(found_pci, &lad_dev);
420 			else if (pci_match_id(igb_pci_tbl, found_pci))
421 				ret = igb_kni_probe(found_pci, &lad_dev);
422 			else
423 				ret = -1;
424 
425 			pr_debug("PCI found: pci=0x%p, lad_dev=0x%p\n",
426 							pci, lad_dev);
427 			if (ret == 0) {
428 				kni->lad_dev = lad_dev;
429 				kni_set_ethtool_ops(kni->net_dev);
430 			} else {
431 				pr_err("Device not supported by ethtool");
432 				kni->lad_dev = NULL;
433 			}
434 
435 			kni->pci_dev = found_pci;
436 			kni->device_id = dev_info.device_id;
437 			break;
438 		}
439 		pci = pci_get_device(dev_info.vendor_id,
440 				dev_info.device_id, pci);
441 	}
442 	if (pci)
443 		pci_dev_put(pci);
444 #endif
445 
446 	if (kni->lad_dev)
447 		ether_addr_copy(net_dev->dev_addr, kni->lad_dev->dev_addr);
448 	else {
449 		/* if user has provided a valid mac address */
450 		if (is_valid_ether_addr(dev_info.mac_addr))
451 			memcpy(net_dev->dev_addr, dev_info.mac_addr, ETH_ALEN);
452 		else
453 			/*
454 			 * Generate random mac address. eth_random_addr() is the
455 			 * newer version of generating mac address in kernel.
456 			 */
457 			random_ether_addr(net_dev->dev_addr);
458 	}
459 
460 	if (dev_info.mtu)
461 		net_dev->mtu = dev_info.mtu;
462 
463 	ret = register_netdev(net_dev);
464 	if (ret) {
465 		pr_err("error %i registering device \"%s\"\n",
466 					ret, dev_info.name);
467 		kni->net_dev = NULL;
468 		kni_dev_remove(kni);
469 		free_netdev(net_dev);
470 		return -ENODEV;
471 	}
472 
473 	netif_carrier_off(net_dev);
474 
475 	ret = kni_run_thread(knet, kni, dev_info.force_bind);
476 	if (ret != 0)
477 		return ret;
478 
479 	down_write(&knet->kni_list_lock);
480 	list_add(&kni->list, &knet->kni_list_head);
481 	up_write(&knet->kni_list_lock);
482 
483 	return 0;
484 }
485 
486 static int
487 kni_ioctl_release(struct net *net, uint32_t ioctl_num,
488 		unsigned long ioctl_param)
489 {
490 	struct kni_net *knet = net_generic(net, kni_net_id);
491 	int ret = -EINVAL;
492 	struct kni_dev *dev, *n;
493 	struct rte_kni_device_info dev_info;
494 
495 	if (_IOC_SIZE(ioctl_num) > sizeof(dev_info))
496 		return -EINVAL;
497 
498 	ret = copy_from_user(&dev_info, (void *)ioctl_param, sizeof(dev_info));
499 	if (ret) {
500 		pr_err("copy_from_user in kni_ioctl_release");
501 		return -EIO;
502 	}
503 
504 	/* Release the network device according to its name */
505 	if (strlen(dev_info.name) == 0)
506 		return ret;
507 
508 	down_write(&knet->kni_list_lock);
509 	list_for_each_entry_safe(dev, n, &knet->kni_list_head, list) {
510 		if (strncmp(dev->name, dev_info.name, RTE_KNI_NAMESIZE) != 0)
511 			continue;
512 
513 		if (multiple_kthread_on && dev->pthread != NULL) {
514 			kthread_stop(dev->pthread);
515 			dev->pthread = NULL;
516 		}
517 
518 		kni_dev_remove(dev);
519 		list_del(&dev->list);
520 		ret = 0;
521 		break;
522 	}
523 	up_write(&knet->kni_list_lock);
524 	pr_info("%s release kni named %s\n",
525 		(ret == 0 ? "Successfully" : "Unsuccessfully"), dev_info.name);
526 
527 	return ret;
528 }
529 
530 static int
531 kni_ioctl(struct inode *inode, uint32_t ioctl_num, unsigned long ioctl_param)
532 {
533 	int ret = -EINVAL;
534 	struct net *net = current->nsproxy->net_ns;
535 
536 	pr_debug("IOCTL num=0x%0x param=0x%0lx\n", ioctl_num, ioctl_param);
537 
538 	/*
539 	 * Switch according to the ioctl called
540 	 */
541 	switch (_IOC_NR(ioctl_num)) {
542 	case _IOC_NR(RTE_KNI_IOCTL_TEST):
543 		/* For test only, not used */
544 		break;
545 	case _IOC_NR(RTE_KNI_IOCTL_CREATE):
546 		ret = kni_ioctl_create(net, ioctl_num, ioctl_param);
547 		break;
548 	case _IOC_NR(RTE_KNI_IOCTL_RELEASE):
549 		ret = kni_ioctl_release(net, ioctl_num, ioctl_param);
550 		break;
551 	default:
552 		pr_debug("IOCTL default\n");
553 		break;
554 	}
555 
556 	return ret;
557 }
558 
559 static int
560 kni_compat_ioctl(struct inode *inode, uint32_t ioctl_num,
561 		unsigned long ioctl_param)
562 {
563 	/* 32 bits app on 64 bits OS to be supported later */
564 	pr_debug("Not implemented.\n");
565 
566 	return -EINVAL;
567 }
568 
569 static const struct file_operations kni_fops = {
570 	.owner = THIS_MODULE,
571 	.open = kni_open,
572 	.release = kni_release,
573 	.unlocked_ioctl = (void *)kni_ioctl,
574 	.compat_ioctl = (void *)kni_compat_ioctl,
575 };
576 
577 static struct miscdevice kni_misc = {
578 	.minor = MISC_DYNAMIC_MINOR,
579 	.name = KNI_DEVICE,
580 	.fops = &kni_fops,
581 };
582 
583 static int __init
584 kni_parse_kthread_mode(void)
585 {
586 	if (!kthread_mode)
587 		return 0;
588 
589 	if (strcmp(kthread_mode, "single") == 0)
590 		return 0;
591 	else if (strcmp(kthread_mode, "multiple") == 0)
592 		multiple_kthread_on = 1;
593 	else
594 		return -1;
595 
596 	return 0;
597 }
598 
599 static int __init
600 kni_parse_carrier_state(void)
601 {
602 	if (!carrier) {
603 		dflt_carrier = 0;
604 		return 0;
605 	}
606 
607 	if (strcmp(carrier, "off") == 0)
608 		dflt_carrier = 0;
609 	else if (strcmp(carrier, "on") == 0)
610 		dflt_carrier = 1;
611 	else
612 		return -1;
613 
614 	return 0;
615 }
616 
617 static int __init
618 kni_init(void)
619 {
620 	int rc;
621 
622 	if (kni_parse_kthread_mode() < 0) {
623 		pr_err("Invalid parameter for kthread_mode\n");
624 		return -EINVAL;
625 	}
626 
627 	if (multiple_kthread_on == 0)
628 		pr_debug("Single kernel thread for all KNI devices\n");
629 	else
630 		pr_debug("Multiple kernel thread mode enabled\n");
631 
632 	if (kni_parse_carrier_state() < 0) {
633 		pr_err("Invalid parameter for carrier\n");
634 		return -EINVAL;
635 	}
636 
637 	if (dflt_carrier == 0)
638 		pr_debug("Default carrier state set to off.\n");
639 	else
640 		pr_debug("Default carrier state set to on.\n");
641 
642 #ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
643 	rc = register_pernet_subsys(&kni_net_ops);
644 #else
645 	rc = register_pernet_gen_subsys(&kni_net_id, &kni_net_ops);
646 #endif
647 	if (rc)
648 		return -EPERM;
649 
650 	rc = misc_register(&kni_misc);
651 	if (rc != 0) {
652 		pr_err("Misc registration failed\n");
653 		goto out;
654 	}
655 
656 	/* Configure the lo mode according to the input parameter */
657 	kni_net_config_lo_mode(lo_mode);
658 
659 	return 0;
660 
661 out:
662 #ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
663 	unregister_pernet_subsys(&kni_net_ops);
664 #else
665 	unregister_pernet_gen_subsys(kni_net_id, &kni_net_ops);
666 #endif
667 	return rc;
668 }
669 
670 static void __exit
671 kni_exit(void)
672 {
673 	misc_deregister(&kni_misc);
674 #ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
675 	unregister_pernet_subsys(&kni_net_ops);
676 #else
677 	unregister_pernet_gen_subsys(kni_net_id, &kni_net_ops);
678 #endif
679 }
680 
681 module_init(kni_init);
682 module_exit(kni_exit);
683 
684 module_param(lo_mode, charp, 0644);
685 MODULE_PARM_DESC(lo_mode,
686 "KNI loopback mode (default=lo_mode_none):\n"
687 "\t\tlo_mode_none        Kernel loopback disabled\n"
688 "\t\tlo_mode_fifo        Enable kernel loopback with fifo\n"
689 "\t\tlo_mode_fifo_skb    Enable kernel loopback with fifo and skb buffer\n"
690 "\t\t"
691 );
692 
693 module_param(kthread_mode, charp, 0644);
694 MODULE_PARM_DESC(kthread_mode,
695 "Kernel thread mode (default=single):\n"
696 "\t\tsingle    Single kernel thread mode enabled.\n"
697 "\t\tmultiple  Multiple kernel thread mode enabled.\n"
698 "\t\t"
699 );
700 
701 module_param(carrier, charp, 0644);
702 MODULE_PARM_DESC(carrier,
703 "Default carrier state for KNI interface (default=off):\n"
704 "\t\toff   Interfaces will be created with carrier state set to off.\n"
705 "\t\ton    Interfaces will be created with carrier state set to on.\n"
706 "\t\t"
707 );
708