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