lib/librte_eal/common/eal_common_dev.c

   1 /* SPDX-License-Identifier: BSD-3-Clause
   2  * Copyright(c) 2010-2014 Intel Corporation.
   3  * Copyright(c) 2014 6WIND S.A.
   4  */
   5
   6 #include <stdio.h>
   7 #include <string.h>
   8 #include <inttypes.h>
   9 #include <sys/queue.h>
  10
  11 #include <rte_compat.h>
  12 #include <rte_bus.h>
  13 #include <rte_class.h>
  14 #include <rte_dev.h>
  15 #include <rte_devargs.h>
  16 #include <rte_debug.h>
  17 #include <rte_errno.h>
  18 #include <rte_kvargs.h>
  19 #include <rte_log.h>
  20 #include <rte_spinlock.h>
  21 #include <rte_malloc.h>
  22 #include <rte_string_fns.h>
  23
  24 #include "eal_private.h"
  25 #include "hotplug_mp.h"
  26
  27 /**
  28  * The device event callback description.
  29  *
  30  * It contains callback address to be registered by user application,
  31  * the pointer to the parameters for callback, and the device name.
  32  */
  33 struct dev_event_callback {
  34         TAILQ_ENTRY(dev_event_callback) next; /**< Callbacks list */
  35         rte_dev_event_cb_fn cb_fn;            /**< Callback address */
  36         void *cb_arg;                         /**< Callback parameter */
  37         char *dev_name;  /**< Callback device name, NULL is for all device */
  38         uint32_t active;                      /**< Callback is executing */
  39 };
  40
  41 /** @internal Structure to keep track of registered callbacks */
  42 TAILQ_HEAD(dev_event_cb_list, dev_event_callback);
  43
  44 /* The device event callback list for all registered callbacks. */
  45 static struct dev_event_cb_list dev_event_cbs;
  46
  47 /* spinlock for device callbacks */
  48 static rte_spinlock_t dev_event_lock = RTE_SPINLOCK_INITIALIZER;
  49
  50 struct dev_next_ctx {
  51         struct rte_dev_iterator *it;
  52         const char *bus_str;
  53         const char *cls_str;
  54 };
  55
  56 #define CTX(it, bus_str, cls_str) \
  57         (&(const struct dev_next_ctx){ \
  58                 .it = it, \
  59                 .bus_str = bus_str, \
  60                 .cls_str = cls_str, \
  61         })
  62
  63 #define ITCTX(ptr) \
  64         (((struct dev_next_ctx *)(intptr_t)ptr)->it)
  65
  66 #define BUSCTX(ptr) \
  67         (((struct dev_next_ctx *)(intptr_t)ptr)->bus_str)
  68
  69 #define CLSCTX(ptr) \
  70         (((struct dev_next_ctx *)(intptr_t)ptr)->cls_str)
  71
  72 static int cmp_dev_name(const struct rte_device *dev, const void *_name)
  73 {
  74         const char *name = _name;
  75
  76         return strcmp(dev->name, name);
  77 }
  78
  79 int __rte_experimental
  80 rte_dev_is_probed(const struct rte_device *dev)
  81 {
  82         /* The field driver should be set only when the probe is successful. */
  83         return dev->driver != NULL;
  84 }
  85
  86 int rte_eal_dev_attach(const char *name, const char *devargs)
  87 {
  88         struct rte_bus *bus;
  89
  90         if (name == NULL || devargs == NULL) {
  91                 RTE_LOG(ERR, EAL, "Invalid device or arguments provided\n");
  92                 return -EINVAL;
  93         }
  94
  95         bus = rte_bus_find_by_device_name(name);
  96         if (bus == NULL) {
  97                 RTE_LOG(ERR, EAL, "Unable to find a bus for the device '%s'\n",
  98                         name);
  99                 return -EINVAL;
 100         }
 101         if (strcmp(bus->name, "pci") == 0 || strcmp(bus->name, "vdev") == 0)
 102                 return rte_eal_hotplug_add(bus->name, name, devargs);
 103
 104         RTE_LOG(ERR, EAL,
 105                 "Device attach is only supported for PCI and vdev devices.\n");
 106
 107         return -ENOTSUP;
 108 }
 109
 110 int rte_eal_dev_detach(struct rte_device *dev)
 111 {
 112         struct rte_bus *bus;
 113         int ret;
 114
 115         if (dev == NULL) {
 116                 RTE_LOG(ERR, EAL, "Invalid device provided.\n");
 117                 return -EINVAL;
 118         }
 119
 120         bus = rte_bus_find_by_device(dev);
 121         if (bus == NULL) {
 122                 RTE_LOG(ERR, EAL, "Cannot find bus for device (%s)\n",
 123                         dev->name);
 124                 return -EINVAL;
 125         }
 126
 127         if (bus->unplug == NULL) {
 128                 RTE_LOG(ERR, EAL, "Bus function not supported\n");
 129                 return -ENOTSUP;
 130         }
 131
 132         ret = bus->unplug(dev);
 133         if (ret)
 134                 RTE_LOG(ERR, EAL, "Driver cannot detach the device (%s)\n",
 135                         dev->name);
 136         return ret;
 137 }
 138
 139 /* helper function to build devargs, caller should free the memory */
 140 static int
 141 build_devargs(const char *busname, const char *devname,
 142               const char *drvargs, char **devargs)
 143 {
 144         int length;
 145
 146         length = snprintf(NULL, 0, "%s:%s,%s", busname, devname, drvargs);
 147         if (length < 0)
 148                 return -EINVAL;
 149
 150         *devargs = malloc(length + 1);
 151         if (*devargs == NULL)
 152                 return -ENOMEM;
 153
 154         length = snprintf(*devargs, length + 1, "%s:%s,%s",
 155                         busname, devname, drvargs);
 156         if (length < 0) {
 157                 free(*devargs);
 158                 return -EINVAL;
 159         }
 160
 161         return 0;
 162 }
 163
 164 int
 165 rte_eal_hotplug_add(const char *busname, const char *devname,
 166                     const char *drvargs)
 167 {
 168
 169         char *devargs;
 170         int ret;
 171
 172         ret = build_devargs(busname, devname, drvargs, &devargs);
 173         if (ret != 0)
 174                 return ret;
 175
 176         ret = rte_dev_probe(devargs);
 177         free(devargs);
 178
 179         return ret;
 180 }
 181
 182 /* probe device at local process. */
 183 int
 184 local_dev_probe(const char *devargs, struct rte_device **new_dev)
 185 {
 186         struct rte_device *dev;
 187         struct rte_devargs *da;
 188         int ret;
 189
 190         *new_dev = NULL;
 191         da = calloc(1, sizeof(*da));
 192         if (da == NULL)
 193                 return -ENOMEM;
 194
 195         ret = rte_devargs_parse(da, devargs);
 196         if (ret)
 197                 goto err_devarg;
 198
 199         if (da->bus->plug == NULL) {
 200                 RTE_LOG(ERR, EAL, "Function plug not supported by bus (%s)\n",
 201                         da->bus->name);
 202                 ret = -ENOTSUP;
 203                 goto err_devarg;
 204         }
 205
 206         ret = rte_devargs_insert(da);
 207         if (ret)
 208                 goto err_devarg;
 209
 210         ret = da->bus->scan();
 211         if (ret)
 212                 goto err_devarg;
 213
 214         dev = da->bus->find_device(NULL, cmp_dev_name, da->name);
 215         if (dev == NULL) {
 216                 RTE_LOG(ERR, EAL, "Cannot find device (%s)\n",
 217                         da->name);
 218                 ret = -ENODEV;
 219                 goto err_devarg;
 220         }
 221
 222         ret = dev->bus->plug(dev);
 223         if (ret) {
 224                 if (rte_dev_is_probed(dev)) /* if already succeeded earlier */
 225                         return ret; /* no rollback */
 226                 RTE_LOG(ERR, EAL, "Driver cannot attach the device (%s)\n",
 227                         dev->name);
 228                 goto err_devarg;
 229         }
 230
 231         *new_dev = dev;
 232         return 0;
 233
 234 err_devarg:
 235         if (rte_devargs_remove(da) != 0) {
 236                 free(da->args);
 237                 free(da);
 238         }
 239         return ret;
 240 }
 241
 242 int __rte_experimental
 243 rte_dev_probe(const char *devargs)
 244 {
 245         struct eal_dev_mp_req req;
 246         struct rte_device *dev;
 247         int ret;
 248
 249         memset(&req, 0, sizeof(req));
 250         req.t = EAL_DEV_REQ_TYPE_ATTACH;
 251         strlcpy(req.devargs, devargs, EAL_DEV_MP_DEV_ARGS_MAX_LEN);
 252
 253         if (rte_eal_process_type() != RTE_PROC_PRIMARY) {
 254                 /**
 255                  * If in secondary process, just send IPC request to
 256                  * primary process.
 257                  */
 258                 ret = eal_dev_hotplug_request_to_primary(&req);
 259                 if (ret != 0) {
 260                         RTE_LOG(ERR, EAL,
 261                                 "Failed to send hotplug request to primary\n");
 262                         return -ENOMSG;
 263                 }
 264                 if (req.result != 0)
 265                         RTE_LOG(ERR, EAL,
 266                                 "Failed to hotplug add device\n");
 267                 return req.result;
 268         }
 269
 270         /* attach a shared device from primary start from here: */
 271
 272         /* primary attach the new device itself. */
 273         ret = local_dev_probe(devargs, &dev);
 274
 275         if (ret != 0) {
 276                 RTE_LOG(ERR, EAL,
 277                         "Failed to attach device on primary process\n");
 278
 279                 /**
 280                  * it is possible that secondary process failed to attached a
 281                  * device that primary process have during initialization,
 282                  * so for -EEXIST case, we still need to sync with secondary
 283                  * process.
 284                  */
 285                 if (ret != -EEXIST)
 286                         return ret;
 287         }
 288
 289         /* primary send attach sync request to secondary. */
 290         ret = eal_dev_hotplug_request_to_secondary(&req);
 291
 292         /* if any communication error, we need to rollback. */
 293         if (ret != 0) {
 294                 RTE_LOG(ERR, EAL,
 295                         "Failed to send hotplug add request to secondary\n");
 296                 ret = -ENOMSG;
 297                 goto rollback;
 298         }
 299
 300         /**
 301          * if any secondary failed to attach, we need to consider if rollback
 302          * is necessary.
 303          */
 304         if (req.result != 0) {
 305                 RTE_LOG(ERR, EAL,
 306                         "Failed to attach device on secondary process\n");
 307                 ret = req.result;
 308
 309                 /* for -EEXIST, we don't need to rollback. */
 310                 if (ret == -EEXIST)
 311                         return ret;
 312                 goto rollback;
 313         }
 314
 315         return 0;
 316
 317 rollback:
 318         req.t = EAL_DEV_REQ_TYPE_ATTACH_ROLLBACK;
 319
 320         /* primary send rollback request to secondary. */
 321         if (eal_dev_hotplug_request_to_secondary(&req) != 0)
 322                 RTE_LOG(WARNING, EAL,
 323                         "Failed to rollback device attach on secondary."
 324                         "Devices in secondary may not sync with primary\n");
 325
 326         /* primary rollback itself. */
 327         if (local_dev_remove(dev) != 0)
 328                 RTE_LOG(WARNING, EAL,
 329                         "Failed to rollback device attach on primary."
 330                         "Devices in secondary may not sync with primary\n");
 331
 332         return ret;
 333 }
 334
 335 int
 336 rte_eal_hotplug_remove(const char *busname, const char *devname)
 337 {
 338         struct rte_device *dev;
 339         struct rte_bus *bus;
 340
 341         bus = rte_bus_find_by_name(busname);
 342         if (bus == NULL) {
 343                 RTE_LOG(ERR, EAL, "Cannot find bus (%s)\n", busname);
 344                 return -ENOENT;
 345         }
 346
 347         dev = bus->find_device(NULL, cmp_dev_name, devname);
 348         if (dev == NULL) {
 349                 RTE_LOG(ERR, EAL, "Cannot find plugged device (%s)\n", devname);
 350                 return -EINVAL;
 351         }
 352
 353         return rte_dev_remove(dev);
 354 }
 355
 356 /* remove device at local process. */
 357 int
 358 local_dev_remove(struct rte_device *dev)
 359 {
 360         int ret;
 361
 362         if (dev->bus->unplug == NULL) {
 363                 RTE_LOG(ERR, EAL, "Function unplug not supported by bus (%s)\n",
 364                         dev->bus->name);
 365                 return -ENOTSUP;
 366         }
 367
 368         ret = dev->bus->unplug(dev);
 369         if (ret) {
 370                 RTE_LOG(ERR, EAL, "Driver cannot detach the device (%s)\n",
 371                         dev->name);
 372                 return ret;
 373         }
 374
 375         rte_devargs_remove(dev->devargs);
 376
 377         return 0;
 378 }
 379
 380 int __rte_experimental
 381 rte_dev_remove(struct rte_device *dev)
 382 {
 383         struct eal_dev_mp_req req;
 384         char *devargs;
 385         int ret;
 386
 387         if (!rte_dev_is_probed(dev)) {
 388                 RTE_LOG(ERR, EAL, "Device is not probed\n");
 389                 return -ENOENT;
 390         }
 391
 392         ret = build_devargs(dev->devargs->bus->name, dev->name, "", &devargs);
 393         if (ret != 0)
 394                 return ret;
 395
 396         memset(&req, 0, sizeof(req));
 397         req.t = EAL_DEV_REQ_TYPE_DETACH;
 398         strlcpy(req.devargs, devargs, EAL_DEV_MP_DEV_ARGS_MAX_LEN);
 399         free(devargs);
 400
 401         if (rte_eal_process_type() != RTE_PROC_PRIMARY) {
 402                 /**
 403                  * If in secondary process, just send IPC request to
 404                  * primary process.
 405                  */
 406                 ret = eal_dev_hotplug_request_to_primary(&req);
 407                 if (ret != 0) {
 408                         RTE_LOG(ERR, EAL,
 409                                 "Failed to send hotplug request to primary\n");
 410                         return -ENOMSG;
 411                 }
 412                 if (req.result != 0)
 413                         RTE_LOG(ERR, EAL,
 414                                 "Failed to hotplug remove device\n");
 415                 return req.result;
 416         }
 417
 418         /* detach a device from primary start from here: */
 419
 420         /* primary send detach sync request to secondary */
 421         ret = eal_dev_hotplug_request_to_secondary(&req);
 422
 423         /**
 424          * if communication error, we need to rollback, because it is possible
 425          * part of the secondary processes still detached it successfully.
 426          */
 427         if (ret != 0) {
 428                 RTE_LOG(ERR, EAL,
 429                         "Failed to send device detach request to secondary\n");
 430                 ret = -ENOMSG;
 431                 goto rollback;
 432         }
 433
 434         /**
 435          * if any secondary failed to detach, we need to consider if rollback
 436          * is necessary.
 437          */
 438         if (req.result != 0) {
 439                 RTE_LOG(ERR, EAL,
 440                         "Failed to detach device on secondary process\n");
 441                 ret = req.result;
 442                 /**
 443                  * if -ENOENT, we don't need to rollback, since devices is
 444                  * already detached on secondary process.
 445                  */
 446                 if (ret != -ENOENT)
 447                         goto rollback;
 448         }
 449
 450         /* primary detach the device itself. */
 451         ret = local_dev_remove(dev);
 452
 453         /* if primary failed, still need to consider if rollback is necessary */
 454         if (ret != 0) {
 455                 RTE_LOG(ERR, EAL,
 456                         "Failed to detach device on primary process\n");
 457                 /* if -ENOENT, we don't need to rollback */
 458                 if (ret == -ENOENT)
 459                         return ret;
 460                 goto rollback;
 461         }
 462
 463         return 0;
 464
 465 rollback:
 466         req.t = EAL_DEV_REQ_TYPE_DETACH_ROLLBACK;
 467
 468         /* primary send rollback request to secondary. */
 469         if (eal_dev_hotplug_request_to_secondary(&req) != 0)
 470                 RTE_LOG(WARNING, EAL,
 471                         "Failed to rollback device detach on secondary."
 472                         "Devices in secondary may not sync with primary\n");
 473
 474         return ret;
 475 }
 476
 477 int __rte_experimental
 478 rte_dev_event_callback_register(const char *device_name,
 479                                 rte_dev_event_cb_fn cb_fn,
 480                                 void *cb_arg)
 481 {
 482         struct dev_event_callback *event_cb;
 483         int ret;
 484
 485         if (!cb_fn)
 486                 return -EINVAL;
 487
 488         rte_spinlock_lock(&dev_event_lock);
 489
 490         if (TAILQ_EMPTY(&dev_event_cbs))
 491                 TAILQ_INIT(&dev_event_cbs);
 492
 493         TAILQ_FOREACH(event_cb, &dev_event_cbs, next) {
 494                 if (event_cb->cb_fn == cb_fn && event_cb->cb_arg == cb_arg) {
 495                         if (device_name == NULL && event_cb->dev_name == NULL)
 496                                 break;
 497                         if (device_name == NULL || event_cb->dev_name == NULL)
 498                                 continue;
 499                         if (!strcmp(event_cb->dev_name, device_name))
 500                                 break;
 501                 }
 502         }
 503
 504         /* create a new callback. */
 505         if (event_cb == NULL) {
 506                 event_cb = malloc(sizeof(struct dev_event_callback));
 507                 if (event_cb != NULL) {
 508                         event_cb->cb_fn = cb_fn;
 509                         event_cb->cb_arg = cb_arg;
 510                         event_cb->active = 0;
 511                         if (!device_name) {
 512                                 event_cb->dev_name = NULL;
 513                         } else {
 514                                 event_cb->dev_name = strdup(device_name);
 515                                 if (event_cb->dev_name == NULL) {
 516                                         ret = -ENOMEM;
 517                                         goto error;
 518                                 }
 519                         }
 520                         TAILQ_INSERT_TAIL(&dev_event_cbs, event_cb, next);
 521                 } else {
 522                         RTE_LOG(ERR, EAL,
 523                                 "Failed to allocate memory for device "
 524                                 "event callback.");
 525                         ret = -ENOMEM;
 526                         goto error;
 527                 }
 528         } else {
 529                 RTE_LOG(ERR, EAL,
 530                         "The callback is already exist, no need "
 531                         "to register again.\n");
 532                 ret = -EEXIST;
 533         }
 534
 535         rte_spinlock_unlock(&dev_event_lock);
 536         return 0;
 537 error:
 538         free(event_cb);
 539         rte_spinlock_unlock(&dev_event_lock);
 540         return ret;
 541 }
 542
 543 int __rte_experimental
 544 rte_dev_event_callback_unregister(const char *device_name,
 545                                   rte_dev_event_cb_fn cb_fn,
 546                                   void *cb_arg)
 547 {
 548         int ret = 0;
 549         struct dev_event_callback *event_cb, *next;
 550
 551         if (!cb_fn)
 552                 return -EINVAL;
 553
 554         rte_spinlock_lock(&dev_event_lock);
 555         /*walk through the callbacks and remove all that match. */
 556         for (event_cb = TAILQ_FIRST(&dev_event_cbs); event_cb != NULL;
 557              event_cb = next) {
 558
 559                 next = TAILQ_NEXT(event_cb, next);
 560
 561                 if (device_name != NULL && event_cb->dev_name != NULL) {
 562                         if (!strcmp(event_cb->dev_name, device_name)) {
 563                                 if (event_cb->cb_fn != cb_fn ||
 564                                     (cb_arg != (void *)-1 &&
 565                                     event_cb->cb_arg != cb_arg))
 566                                         continue;
 567                         }
 568                 } else if (device_name != NULL) {
 569                         continue;
 570                 }
 571
 572                 /*
 573                  * if this callback is not executing right now,
 574                  * then remove it.
 575                  */
 576                 if (event_cb->active == 0) {
 577                         TAILQ_REMOVE(&dev_event_cbs, event_cb, next);
 578                         free(event_cb);
 579                         ret++;
 580                 } else {
 581                         continue;
 582                 }
 583         }
 584         rte_spinlock_unlock(&dev_event_lock);
 585         return ret;
 586 }
 587
 588 void __rte_experimental
 589 rte_dev_event_callback_process(const char *device_name,
 590                                enum rte_dev_event_type event)
 591 {
 592         struct dev_event_callback *cb_lst;
 593
 594         if (device_name == NULL)
 595                 return;
 596
 597         rte_spinlock_lock(&dev_event_lock);
 598
 599         TAILQ_FOREACH(cb_lst, &dev_event_cbs, next) {
 600                 if (cb_lst->dev_name) {
 601                         if (strcmp(cb_lst->dev_name, device_name))
 602                                 continue;
 603                 }
 604                 cb_lst->active = 1;
 605                 rte_spinlock_unlock(&dev_event_lock);
 606                 cb_lst->cb_fn(device_name, event,
 607                                 cb_lst->cb_arg);
 608                 rte_spinlock_lock(&dev_event_lock);
 609                 cb_lst->active = 0;
 610         }
 611         rte_spinlock_unlock(&dev_event_lock);
 612 }
 613
 614 __rte_experimental
 615 int
 616 rte_dev_iterator_init(struct rte_dev_iterator *it,
 617                       const char *dev_str)
 618 {
 619         struct rte_devargs devargs;
 620         struct rte_class *cls = NULL;
 621         struct rte_bus *bus = NULL;
 622
 623         /* Having both bus_str and cls_str NULL is illegal,
 624          * marking this iterator as invalid unless
 625          * everything goes well.
 626          */
 627         it->bus_str = NULL;
 628         it->cls_str = NULL;
 629
 630         devargs.data = dev_str;
 631         if (rte_devargs_layers_parse(&devargs, dev_str))
 632                 goto get_out;
 633
 634         bus = devargs.bus;
 635         cls = devargs.cls;
 636         /* The string should have at least
 637          * one layer specified.
 638          */
 639         if (bus == NULL && cls == NULL) {
 640                 RTE_LOG(ERR, EAL,
 641                         "Either bus or class must be specified.\n");
 642                 rte_errno = EINVAL;
 643                 goto get_out;
 644         }
 645         if (bus != NULL && bus->dev_iterate == NULL) {
 646                 RTE_LOG(ERR, EAL, "Bus %s not supported\n", bus->name);
 647                 rte_errno = ENOTSUP;
 648                 goto get_out;
 649         }
 650         if (cls != NULL && cls->dev_iterate == NULL) {
 651                 RTE_LOG(ERR, EAL, "Class %s not supported\n", cls->name);
 652                 rte_errno = ENOTSUP;
 653                 goto get_out;
 654         }
 655         it->bus_str = devargs.bus_str;
 656         it->cls_str = devargs.cls_str;
 657         it->dev_str = dev_str;
 658         it->bus = bus;
 659         it->cls = cls;
 660         it->device = NULL;
 661         it->class_device = NULL;
 662 get_out:
 663         return -rte_errno;
 664 }
 665
 666 static char *
 667 dev_str_sane_copy(const char *str)
 668 {
 669         size_t end;
 670         char *copy;
 671
 672         end = strcspn(str, ",/");
 673         if (str[end] == ',') {
 674                 copy = strdup(&str[end + 1]);
 675         } else {
 676                 /* '/' or '\0' */
 677                 copy = strdup("");
 678         }
 679         if (copy == NULL) {
 680                 rte_errno = ENOMEM;
 681         } else {
 682                 char *slash;
 683
 684                 slash = strchr(copy, '/');
 685                 if (slash != NULL)
 686                         slash[0] = '\0';
 687         }
 688         return copy;
 689 }
 690
 691 static int
 692 class_next_dev_cmp(const struct rte_class *cls,
 693                    const void *ctx)
 694 {
 695         struct rte_dev_iterator *it;
 696         const char *cls_str = NULL;
 697         void *dev;
 698
 699         if (cls->dev_iterate == NULL)
 700                 return 1;
 701         it = ITCTX(ctx);
 702         cls_str = CLSCTX(ctx);
 703         dev = it->class_device;
 704         /* it->cls_str != NULL means a class
 705          * was specified in the devstr.
 706          */
 707         if (it->cls_str != NULL && cls != it->cls)
 708                 return 1;
 709         /* If an error occurred previously,
 710          * no need to test further.
 711          */
 712         if (rte_errno != 0)
 713                 return -1;
 714         dev = cls->dev_iterate(dev, cls_str, it);
 715         it->class_device = dev;
 716         return dev == NULL;
 717 }
 718
 719 static int
 720 bus_next_dev_cmp(const struct rte_bus *bus,
 721                  const void *ctx)
 722 {
 723         struct rte_device *dev = NULL;
 724         struct rte_class *cls = NULL;
 725         struct rte_dev_iterator *it;
 726         const char *bus_str = NULL;
 727
 728         if (bus->dev_iterate == NULL)
 729                 return 1;
 730         it = ITCTX(ctx);
 731         bus_str = BUSCTX(ctx);
 732         dev = it->device;
 733         /* it->bus_str != NULL means a bus
 734          * was specified in the devstr.
 735          */
 736         if (it->bus_str != NULL && bus != it->bus)
 737                 return 1;
 738         /* If an error occurred previously,
 739          * no need to test further.
 740          */
 741         if (rte_errno != 0)
 742                 return -1;
 743         if (it->cls_str == NULL) {
 744                 dev = bus->dev_iterate(dev, bus_str, it);
 745                 goto end;
 746         }
 747         /* cls_str != NULL */
 748         if (dev == NULL) {
 749 next_dev_on_bus:
 750                 dev = bus->dev_iterate(dev, bus_str, it);
 751                 it->device = dev;
 752         }
 753         if (dev == NULL)
 754                 return 1;
 755         if (it->cls != NULL)
 756                 cls = TAILQ_PREV(it->cls, rte_class_list, next);
 757         cls = rte_class_find(cls, class_next_dev_cmp, ctx);
 758         if (cls != NULL) {
 759                 it->cls = cls;
 760                 goto end;
 761         }
 762         goto next_dev_on_bus;
 763 end:
 764         it->device = dev;
 765         return dev == NULL;
 766 }
 767 __rte_experimental
 768 struct rte_device *
 769 rte_dev_iterator_next(struct rte_dev_iterator *it)
 770 {
 771         struct rte_bus *bus = NULL;
 772         int old_errno = rte_errno;
 773         char *bus_str = NULL;
 774         char *cls_str = NULL;
 775
 776         rte_errno = 0;
 777         if (it->bus_str == NULL && it->cls_str == NULL) {
 778                 /* Invalid iterator. */
 779                 rte_errno = EINVAL;
 780                 return NULL;
 781         }
 782         if (it->bus != NULL)
 783                 bus = TAILQ_PREV(it->bus, rte_bus_list, next);
 784         if (it->bus_str != NULL) {
 785                 bus_str = dev_str_sane_copy(it->bus_str);
 786                 if (bus_str == NULL)
 787                         goto out;
 788         }
 789         if (it->cls_str != NULL) {
 790                 cls_str = dev_str_sane_copy(it->cls_str);
 791                 if (cls_str == NULL)
 792                         goto out;
 793         }
 794         while ((bus = rte_bus_find(bus, bus_next_dev_cmp,
 795                                    CTX(it, bus_str, cls_str)))) {
 796                 if (it->device != NULL) {
 797                         it->bus = bus;
 798                         goto out;
 799                 }
 800                 if (it->bus_str != NULL ||
 801                     rte_errno != 0)
 802                         break;
 803         }
 804         if (rte_errno == 0)
 805                 rte_errno = old_errno;
 806 out:
 807         free(bus_str);
 808         free(cls_str);
 809         return it->device;
 810 }