kernel/linux/kni/kni_misc.c

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