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 /* KNI thread scheduling interval */
  49 static long min_scheduling_interval = 100; /* us */
  50 static long max_scheduling_interval = 200; /* us */
  51
  52 #define KNI_DEV_IN_USE_BIT_NUM 0 /* Bit number for device in use */
  53
  54 static int kni_net_id;
  55
  56 struct kni_net {
  57         unsigned long device_in_use; /* device in use flag */
  58         struct mutex kni_kthread_lock;
  59         struct task_struct *kni_kthread;
  60         struct rw_semaphore kni_list_lock;
  61         struct list_head kni_list_head;
  62 };
  63
  64 static int __net_init
  65 kni_init_net(struct net *net)
  66 {
  67 #ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
  68         struct kni_net *knet = net_generic(net, kni_net_id);
  69
  70         memset(knet, 0, sizeof(*knet));
  71 #else
  72         struct kni_net *knet;
  73         int ret;
  74
  75         knet = kzalloc(sizeof(struct kni_net), GFP_KERNEL);
  76         if (!knet) {
  77                 ret = -ENOMEM;
  78                 return ret;
  79         }
  80 #endif
  81
  82         /* Clear the bit of device in use */
  83         clear_bit(KNI_DEV_IN_USE_BIT_NUM, &knet->device_in_use);
  84
  85         mutex_init(&knet->kni_kthread_lock);
  86
  87         init_rwsem(&knet->kni_list_lock);
  88         INIT_LIST_HEAD(&knet->kni_list_head);
  89
  90 #ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
  91         return 0;
  92 #else
  93         ret = net_assign_generic(net, kni_net_id, knet);
  94         if (ret < 0)
  95                 kfree(knet);
  96
  97         return ret;
  98 #endif
  99 }
 100
 101 static void __net_exit
 102 kni_exit_net(struct net *net)
 103 {
 104         struct kni_net *knet __maybe_unused;
 105
 106         knet = net_generic(net, kni_net_id);
 107         mutex_destroy(&knet->kni_kthread_lock);
 108
 109 #ifndef HAVE_SIMPLIFIED_PERNET_OPERATIONS
 110         kfree(knet);
 111 #endif
 112 }
 113
 114 static struct pernet_operations kni_net_ops = {
 115         .init = kni_init_net,
 116         .exit = kni_exit_net,
 117 #ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
 118         .id   = &kni_net_id,
 119         .size = sizeof(struct kni_net),
 120 #endif
 121 };
 122
 123 static int
 124 kni_thread_single(void *data)
 125 {
 126         struct kni_net *knet = data;
 127         int j;
 128         struct kni_dev *dev;
 129
 130         while (!kthread_should_stop()) {
 131                 down_read(&knet->kni_list_lock);
 132                 for (j = 0; j < KNI_RX_LOOP_NUM; j++) {
 133                         list_for_each_entry(dev, &knet->kni_list_head, list) {
 134                                 kni_net_rx(dev);
 135                                 kni_net_poll_resp(dev);
 136                         }
 137                 }
 138                 up_read(&knet->kni_list_lock);
 139                 /* reschedule out for a while */
 140                 usleep_range(min_scheduling_interval, max_scheduling_interval);
 141         }
 142
 143         return 0;
 144 }
 145
 146 static int
 147 kni_thread_multiple(void *param)
 148 {
 149         int j;
 150         struct kni_dev *dev = param;
 151
 152         while (!kthread_should_stop()) {
 153                 for (j = 0; j < KNI_RX_LOOP_NUM; j++) {
 154                         kni_net_rx(dev);
 155                         kni_net_poll_resp(dev);
 156                 }
 157                 usleep_range(min_scheduling_interval, max_scheduling_interval);
 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         if (dev->net_dev) {
 186                 unregister_netdev(dev->net_dev);
 187                 free_netdev(dev->net_dev);
 188         }
 189
 190         kni_net_release_fifo_phy(dev);
 191
 192         return 0;
 193 }
 194
 195 static int
 196 kni_release(struct inode *inode, struct file *file)
 197 {
 198         struct net *net = file->private_data;
 199         struct kni_net *knet = net_generic(net, kni_net_id);
 200         struct kni_dev *dev, *n;
 201
 202         /* Stop kernel thread for single mode */
 203         if (multiple_kthread_on == 0) {
 204                 mutex_lock(&knet->kni_kthread_lock);
 205                 /* Stop kernel thread */
 206                 if (knet->kni_kthread != NULL) {
 207                         kthread_stop(knet->kni_kthread);
 208                         knet->kni_kthread = NULL;
 209                 }
 210                 mutex_unlock(&knet->kni_kthread_lock);
 211         }
 212
 213         down_write(&knet->kni_list_lock);
 214         list_for_each_entry_safe(dev, n, &knet->kni_list_head, list) {
 215                 /* Stop kernel thread for multiple mode */
 216                 if (multiple_kthread_on && dev->pthread != NULL) {
 217                         kthread_stop(dev->pthread);
 218                         dev->pthread = NULL;
 219                 }
 220
 221                 kni_dev_remove(dev);
 222                 list_del(&dev->list);
 223         }
 224         up_write(&knet->kni_list_lock);
 225
 226         /* Clear the bit of device in use */
 227         clear_bit(KNI_DEV_IN_USE_BIT_NUM, &knet->device_in_use);
 228
 229         put_net(net);
 230         pr_debug("/dev/kni closed\n");
 231
 232         return 0;
 233 }
 234
 235 static int
 236 kni_check_param(struct kni_dev *kni, struct rte_kni_device_info *dev)
 237 {
 238         if (!kni || !dev)
 239                 return -1;
 240
 241         /* Check if network name has been used */
 242         if (!strncmp(kni->name, dev->name, RTE_KNI_NAMESIZE)) {
 243                 pr_err("KNI name %s duplicated\n", dev->name);
 244                 return -1;
 245         }
 246
 247         return 0;
 248 }
 249
 250 static int
 251 kni_run_thread(struct kni_net *knet, struct kni_dev *kni, uint8_t force_bind)
 252 {
 253         /**
 254          * Create a new kernel thread for multiple mode, set its core affinity,
 255          * and finally wake it up.
 256          */
 257         if (multiple_kthread_on) {
 258                 kni->pthread = kthread_create(kni_thread_multiple,
 259                         (void *)kni, "kni_%s", kni->name);
 260                 if (IS_ERR(kni->pthread)) {
 261                         kni_dev_remove(kni);
 262                         return -ECANCELED;
 263                 }
 264
 265                 if (force_bind)
 266                         kthread_bind(kni->pthread, kni->core_id);
 267                 wake_up_process(kni->pthread);
 268         } else {
 269                 mutex_lock(&knet->kni_kthread_lock);
 270
 271                 if (knet->kni_kthread == NULL) {
 272                         knet->kni_kthread = kthread_create(kni_thread_single,
 273                                 (void *)knet, "kni_single");
 274                         if (IS_ERR(knet->kni_kthread)) {
 275                                 mutex_unlock(&knet->kni_kthread_lock);
 276                                 kni_dev_remove(kni);
 277                                 return -ECANCELED;
 278                         }
 279
 280                         if (force_bind)
 281                                 kthread_bind(knet->kni_kthread, kni->core_id);
 282                         wake_up_process(knet->kni_kthread);
 283                 }
 284
 285                 mutex_unlock(&knet->kni_kthread_lock);
 286         }
 287
 288         return 0;
 289 }
 290
 291 static int
 292 kni_ioctl_create(struct net *net, uint32_t ioctl_num,
 293                 unsigned long ioctl_param)
 294 {
 295         struct kni_net *knet = net_generic(net, kni_net_id);
 296         int ret;
 297         struct rte_kni_device_info dev_info;
 298         struct net_device *net_dev = NULL;
 299         struct kni_dev *kni, *dev, *n;
 300
 301         pr_info("Creating kni...\n");
 302         /* Check the buffer size, to avoid warning */
 303         if (_IOC_SIZE(ioctl_num) > sizeof(dev_info))
 304                 return -EINVAL;
 305
 306         /* Copy kni info from user space */
 307         if (copy_from_user(&dev_info, (void *)ioctl_param, sizeof(dev_info)))
 308                 return -EFAULT;
 309
 310         /* Check if name is zero-ended */
 311         if (strnlen(dev_info.name, sizeof(dev_info.name)) == sizeof(dev_info.name)) {
 312                 pr_err("kni.name not zero-terminated");
 313                 return -EINVAL;
 314         }
 315
 316         /**
 317          * Check if the cpu core id is valid for binding.
 318          */
 319         if (dev_info.force_bind && !cpu_online(dev_info.core_id)) {
 320                 pr_err("cpu %u is not online\n", dev_info.core_id);
 321                 return -EINVAL;
 322         }
 323
 324         /* Check if it has been created */
 325         down_read(&knet->kni_list_lock);
 326         list_for_each_entry_safe(dev, n, &knet->kni_list_head, list) {
 327                 if (kni_check_param(dev, &dev_info) < 0) {
 328                         up_read(&knet->kni_list_lock);
 329                         return -EINVAL;
 330                 }
 331         }
 332         up_read(&knet->kni_list_lock);
 333
 334         net_dev = alloc_netdev(sizeof(struct kni_dev), dev_info.name,
 335 #ifdef NET_NAME_USER
 336                                                         NET_NAME_USER,
 337 #endif
 338                                                         kni_net_init);
 339         if (net_dev == NULL) {
 340                 pr_err("error allocating device \"%s\"\n", dev_info.name);
 341                 return -EBUSY;
 342         }
 343
 344         dev_net_set(net_dev, net);
 345
 346         kni = netdev_priv(net_dev);
 347
 348         kni->net_dev = net_dev;
 349         kni->core_id = dev_info.core_id;
 350         strncpy(kni->name, dev_info.name, RTE_KNI_NAMESIZE);
 351
 352         /* Translate user space info into kernel space info */
 353         if (dev_info.iova_mode) {
 354 #ifdef HAVE_IOVA_TO_KVA_MAPPING_SUPPORT
 355                 kni->tx_q = iova_to_kva(current, dev_info.tx_phys);
 356                 kni->rx_q = iova_to_kva(current, dev_info.rx_phys);
 357                 kni->alloc_q = iova_to_kva(current, dev_info.alloc_phys);
 358                 kni->free_q = iova_to_kva(current, dev_info.free_phys);
 359
 360                 kni->req_q = iova_to_kva(current, dev_info.req_phys);
 361                 kni->resp_q = iova_to_kva(current, dev_info.resp_phys);
 362                 kni->sync_va = dev_info.sync_va;
 363                 kni->sync_kva = iova_to_kva(current, dev_info.sync_phys);
 364                 kni->usr_tsk = current;
 365                 kni->iova_mode = 1;
 366 #else
 367                 pr_err("KNI module does not support IOVA to VA translation\n");
 368                 return -EINVAL;
 369 #endif
 370         } else {
 371
 372                 kni->tx_q = phys_to_virt(dev_info.tx_phys);
 373                 kni->rx_q = phys_to_virt(dev_info.rx_phys);
 374                 kni->alloc_q = phys_to_virt(dev_info.alloc_phys);
 375                 kni->free_q = phys_to_virt(dev_info.free_phys);
 376
 377                 kni->req_q = phys_to_virt(dev_info.req_phys);
 378                 kni->resp_q = phys_to_virt(dev_info.resp_phys);
 379                 kni->sync_va = dev_info.sync_va;
 380                 kni->sync_kva = phys_to_virt(dev_info.sync_phys);
 381                 kni->iova_mode = 0;
 382         }
 383
 384         kni->mbuf_size = dev_info.mbuf_size;
 385
 386         pr_debug("tx_phys:      0x%016llx, tx_q addr:      0x%p\n",
 387                 (unsigned long long) dev_info.tx_phys, kni->tx_q);
 388         pr_debug("rx_phys:      0x%016llx, rx_q addr:      0x%p\n",
 389                 (unsigned long long) dev_info.rx_phys, kni->rx_q);
 390         pr_debug("alloc_phys:   0x%016llx, alloc_q addr:   0x%p\n",
 391                 (unsigned long long) dev_info.alloc_phys, kni->alloc_q);
 392         pr_debug("free_phys:    0x%016llx, free_q addr:    0x%p\n",
 393                 (unsigned long long) dev_info.free_phys, kni->free_q);
 394         pr_debug("req_phys:     0x%016llx, req_q addr:     0x%p\n",
 395                 (unsigned long long) dev_info.req_phys, kni->req_q);
 396         pr_debug("resp_phys:    0x%016llx, resp_q addr:    0x%p\n",
 397                 (unsigned long long) dev_info.resp_phys, kni->resp_q);
 398         pr_debug("mbuf_size:    %u\n", kni->mbuf_size);
 399
 400         /* if user has provided a valid mac address */
 401         if (is_valid_ether_addr(dev_info.mac_addr))
 402                 memcpy(net_dev->dev_addr, dev_info.mac_addr, ETH_ALEN);
 403         else
 404                 /* Generate random MAC address. */
 405                 eth_random_addr(net_dev->dev_addr);
 406
 407         if (dev_info.mtu)
 408                 net_dev->mtu = dev_info.mtu;
 409 #ifdef HAVE_MAX_MTU_PARAM
 410         net_dev->max_mtu = net_dev->mtu;
 411
 412         if (dev_info.min_mtu)
 413                 net_dev->min_mtu = dev_info.min_mtu;
 414
 415         if (dev_info.max_mtu)
 416                 net_dev->max_mtu = dev_info.max_mtu;
 417 #endif
 418
 419         ret = register_netdev(net_dev);
 420         if (ret) {
 421                 pr_err("error %i registering device \"%s\"\n",
 422                                         ret, dev_info.name);
 423                 kni->net_dev = NULL;
 424                 kni_dev_remove(kni);
 425                 free_netdev(net_dev);
 426                 return -ENODEV;
 427         }
 428
 429         netif_carrier_off(net_dev);
 430
 431         ret = kni_run_thread(knet, kni, dev_info.force_bind);
 432         if (ret != 0)
 433                 return ret;
 434
 435         down_write(&knet->kni_list_lock);
 436         list_add(&kni->list, &knet->kni_list_head);
 437         up_write(&knet->kni_list_lock);
 438
 439         return 0;
 440 }
 441
 442 static int
 443 kni_ioctl_release(struct net *net, uint32_t ioctl_num,
 444                 unsigned long ioctl_param)
 445 {
 446         struct kni_net *knet = net_generic(net, kni_net_id);
 447         int ret = -EINVAL;
 448         struct kni_dev *dev, *n;
 449         struct rte_kni_device_info dev_info;
 450
 451         if (_IOC_SIZE(ioctl_num) > sizeof(dev_info))
 452                 return -EINVAL;
 453
 454         if (copy_from_user(&dev_info, (void *)ioctl_param, sizeof(dev_info)))
 455                 return -EFAULT;
 456
 457         /* Release the network device according to its name */
 458         if (strlen(dev_info.name) == 0)
 459                 return -EINVAL;
 460
 461         down_write(&knet->kni_list_lock);
 462         list_for_each_entry_safe(dev, n, &knet->kni_list_head, list) {
 463                 if (strncmp(dev->name, dev_info.name, RTE_KNI_NAMESIZE) != 0)
 464                         continue;
 465
 466                 if (multiple_kthread_on && dev->pthread != NULL) {
 467                         kthread_stop(dev->pthread);
 468                         dev->pthread = NULL;
 469                 }
 470
 471                 kni_dev_remove(dev);
 472                 list_del(&dev->list);
 473                 ret = 0;
 474                 break;
 475         }
 476         up_write(&knet->kni_list_lock);
 477         pr_info("%s release kni named %s\n",
 478                 (ret == 0 ? "Successfully" : "Unsuccessfully"), dev_info.name);
 479
 480         return ret;
 481 }
 482
 483 static int
 484 kni_ioctl(struct inode *inode, uint32_t ioctl_num, unsigned long ioctl_param)
 485 {
 486         int ret = -EINVAL;
 487         struct net *net = current->nsproxy->net_ns;
 488
 489         pr_debug("IOCTL num=0x%0x param=0x%0lx\n", ioctl_num, ioctl_param);
 490
 491         /*
 492          * Switch according to the ioctl called
 493          */
 494         switch (_IOC_NR(ioctl_num)) {
 495         case _IOC_NR(RTE_KNI_IOCTL_TEST):
 496                 /* For test only, not used */
 497                 break;
 498         case _IOC_NR(RTE_KNI_IOCTL_CREATE):
 499                 ret = kni_ioctl_create(net, ioctl_num, ioctl_param);
 500                 break;
 501         case _IOC_NR(RTE_KNI_IOCTL_RELEASE):
 502                 ret = kni_ioctl_release(net, ioctl_num, ioctl_param);
 503                 break;
 504         default:
 505                 pr_debug("IOCTL default\n");
 506                 break;
 507         }
 508
 509         return ret;
 510 }
 511
 512 static int
 513 kni_compat_ioctl(struct inode *inode, uint32_t ioctl_num,
 514                 unsigned long ioctl_param)
 515 {
 516         /* 32 bits app on 64 bits OS to be supported later */
 517         pr_debug("Not implemented.\n");
 518
 519         return -EINVAL;
 520 }
 521
 522 static const struct file_operations kni_fops = {
 523         .owner = THIS_MODULE,
 524         .open = kni_open,
 525         .release = kni_release,
 526         .unlocked_ioctl = (void *)kni_ioctl,
 527         .compat_ioctl = (void *)kni_compat_ioctl,
 528 };
 529
 530 static struct miscdevice kni_misc = {
 531         .minor = MISC_DYNAMIC_MINOR,
 532         .name = KNI_DEVICE,
 533         .fops = &kni_fops,
 534 };
 535
 536 static int __init
 537 kni_parse_kthread_mode(void)
 538 {
 539         if (!kthread_mode)
 540                 return 0;
 541
 542         if (strcmp(kthread_mode, "single") == 0)
 543                 return 0;
 544         else if (strcmp(kthread_mode, "multiple") == 0)
 545                 multiple_kthread_on = 1;
 546         else
 547                 return -1;
 548
 549         return 0;
 550 }
 551
 552 static int __init
 553 kni_parse_carrier_state(void)
 554 {
 555         if (!carrier) {
 556                 kni_dflt_carrier = 0;
 557                 return 0;
 558         }
 559
 560         if (strcmp(carrier, "off") == 0)
 561                 kni_dflt_carrier = 0;
 562         else if (strcmp(carrier, "on") == 0)
 563                 kni_dflt_carrier = 1;
 564         else
 565                 return -1;
 566
 567         return 0;
 568 }
 569
 570 static int __init
 571 kni_parse_bifurcated_support(void)
 572 {
 573         if (!enable_bifurcated) {
 574                 bifurcated_support = 0;
 575                 return 0;
 576         }
 577
 578         if (strcmp(enable_bifurcated, "on") == 0)
 579                 bifurcated_support = 1;
 580         else
 581                 return -1;
 582
 583         return 0;
 584 }
 585
 586 static int __init
 587 kni_init(void)
 588 {
 589         int rc;
 590
 591         if (kni_parse_kthread_mode() < 0) {
 592                 pr_err("Invalid parameter for kthread_mode\n");
 593                 return -EINVAL;
 594         }
 595
 596         if (multiple_kthread_on == 0)
 597                 pr_debug("Single kernel thread for all KNI devices\n");
 598         else
 599                 pr_debug("Multiple kernel thread mode enabled\n");
 600
 601         if (kni_parse_carrier_state() < 0) {
 602                 pr_err("Invalid parameter for carrier\n");
 603                 return -EINVAL;
 604         }
 605
 606         if (kni_dflt_carrier == 0)
 607                 pr_debug("Default carrier state set to off.\n");
 608         else
 609                 pr_debug("Default carrier state set to on.\n");
 610
 611         if (kni_parse_bifurcated_support() < 0) {
 612                 pr_err("Invalid parameter for bifurcated support\n");
 613                 return -EINVAL;
 614         }
 615         if (bifurcated_support == 1)
 616                 pr_debug("bifurcated support is enabled.\n");
 617
 618         if (min_scheduling_interval < 0 || max_scheduling_interval < 0 ||
 619                 min_scheduling_interval > KNI_KTHREAD_MAX_RESCHEDULE_INTERVAL ||
 620                 max_scheduling_interval > KNI_KTHREAD_MAX_RESCHEDULE_INTERVAL ||
 621                 min_scheduling_interval >= max_scheduling_interval) {
 622                 pr_err("Invalid parameters for scheduling interval\n");
 623                 return -EINVAL;
 624         }
 625
 626 #ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
 627         rc = register_pernet_subsys(&kni_net_ops);
 628 #else
 629         rc = register_pernet_gen_subsys(&kni_net_id, &kni_net_ops);
 630 #endif
 631         if (rc)
 632                 return -EPERM;
 633
 634         rc = misc_register(&kni_misc);
 635         if (rc != 0) {
 636                 pr_err("Misc registration failed\n");
 637                 goto out;
 638         }
 639
 640         /* Configure the lo mode according to the input parameter */
 641         kni_net_config_lo_mode(lo_mode);
 642
 643         return 0;
 644
 645 out:
 646 #ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
 647         unregister_pernet_subsys(&kni_net_ops);
 648 #else
 649         unregister_pernet_gen_subsys(kni_net_id, &kni_net_ops);
 650 #endif
 651         return rc;
 652 }
 653
 654 static void __exit
 655 kni_exit(void)
 656 {
 657         misc_deregister(&kni_misc);
 658 #ifdef HAVE_SIMPLIFIED_PERNET_OPERATIONS
 659         unregister_pernet_subsys(&kni_net_ops);
 660 #else
 661         unregister_pernet_gen_subsys(kni_net_id, &kni_net_ops);
 662 #endif
 663 }
 664
 665 module_init(kni_init);
 666 module_exit(kni_exit);
 667
 668 module_param(lo_mode, charp, 0644);
 669 MODULE_PARM_DESC(lo_mode,
 670 "KNI loopback mode (default=lo_mode_none):\n"
 671 "\t\tlo_mode_none        Kernel loopback disabled\n"
 672 "\t\tlo_mode_fifo        Enable kernel loopback with fifo\n"
 673 "\t\tlo_mode_fifo_skb    Enable kernel loopback with fifo and skb buffer\n"
 674 "\t\t"
 675 );
 676
 677 module_param(kthread_mode, charp, 0644);
 678 MODULE_PARM_DESC(kthread_mode,
 679 "Kernel thread mode (default=single):\n"
 680 "\t\tsingle    Single kernel thread mode enabled.\n"
 681 "\t\tmultiple  Multiple kernel thread mode enabled.\n"
 682 "\t\t"
 683 );
 684
 685 module_param(carrier, charp, 0644);
 686 MODULE_PARM_DESC(carrier,
 687 "Default carrier state for KNI interface (default=off):\n"
 688 "\t\toff   Interfaces will be created with carrier state set to off.\n"
 689 "\t\ton    Interfaces will be created with carrier state set to on.\n"
 690 "\t\t"
 691 );
 692
 693 module_param(enable_bifurcated, charp, 0644);
 694 MODULE_PARM_DESC(enable_bifurcated,
 695 "Enable request processing support for bifurcated drivers, "
 696 "which means releasing rtnl_lock before calling userspace callback and "
 697 "supporting async requests (default=off):\n"
 698 "\t\ton    Enable request processing support for bifurcated drivers.\n"
 699 "\t\t"
 700 );
 701
 702 module_param(min_scheduling_interval, long, 0644);
 703 MODULE_PARM_DESC(min_scheduling_interval,
 704 "KNI thread min scheduling interval (default=100 microseconds)"
 705 );
 706
 707 module_param(max_scheduling_interval, long, 0644);
 708 MODULE_PARM_DESC(max_scheduling_interval,
 709 "KNI thread max scheduling interval (default=200 microseconds)"
 710 );