New upstream version 18.11-rc3
[deb_dpdk.git] / lib / librte_eal / common / eal_common_dev.c
index e251275..1fdc9ab 100644 (file)
@@ -1,35 +1,6 @@
-/*-
- *   BSD LICENSE
- *
- *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
- *   Copyright(c) 2014 6WIND S.A.
- *   All rights reserved.
- *
- *   Redistribution and use in source and binary forms, with or without
- *   modification, are permitted provided that the following conditions
- *   are met:
- *
- *     * Redistributions of source code must retain the above copyright
- *       notice, this list of conditions and the following disclaimer.
- *     * Redistributions in binary form must reproduce the above copyright
- *       notice, this list of conditions and the following disclaimer in
- *       the documentation and/or other materials provided with the
- *       distribution.
- *     * Neither the name of Intel Corporation nor the names of its
- *       contributors may be used to endorse or promote products derived
- *       from this software without specific prior written permission.
- *
- *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
- *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
- *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
- *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
- *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
- *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
- *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
- *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
- *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
- *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
- *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
+/* SPDX-License-Identifier: BSD-3-Clause
+ * Copyright(c) 2010-2014 Intel Corporation.
+ * Copyright(c) 2014 6WIND S.A.
  */
 
 #include <stdio.h>
 #include <inttypes.h>
 #include <sys/queue.h>
 
+#include <rte_compat.h>
 #include <rte_bus.h>
+#include <rte_class.h>
 #include <rte_dev.h>
 #include <rte_devargs.h>
 #include <rte_debug.h>
+#include <rte_errno.h>
+#include <rte_kvargs.h>
 #include <rte_log.h>
+#include <rte_spinlock.h>
+#include <rte_malloc.h>
+#include <rte_string_fns.h>
 
 #include "eal_private.h"
+#include "hotplug_mp.h"
 
-static int cmp_detached_dev_name(const struct rte_device *dev,
-       const void *_name)
-{
-       const char *name = _name;
+/**
+ * The device event callback description.
+ *
+ * It contains callback address to be registered by user application,
+ * the pointer to the parameters for callback, and the device name.
+ */
+struct dev_event_callback {
+       TAILQ_ENTRY(dev_event_callback) next; /**< Callbacks list */
+       rte_dev_event_cb_fn cb_fn;            /**< Callback address */
+       void *cb_arg;                         /**< Callback parameter */
+       char *dev_name;  /**< Callback device name, NULL is for all device */
+       uint32_t active;                      /**< Callback is executing */
+};
 
-       /* skip attached devices */
-       if (dev->driver != NULL)
-               return 1;
+/** @internal Structure to keep track of registered callbacks */
+TAILQ_HEAD(dev_event_cb_list, dev_event_callback);
 
-       return strcmp(dev->name, name);
-}
+/* The device event callback list for all registered callbacks. */
+static struct dev_event_cb_list dev_event_cbs;
+
+/* spinlock for device callbacks */
+static rte_spinlock_t dev_event_lock = RTE_SPINLOCK_INITIALIZER;
+
+struct dev_next_ctx {
+       struct rte_dev_iterator *it;
+       const char *bus_str;
+       const char *cls_str;
+};
+
+#define CTX(it, bus_str, cls_str) \
+       (&(const struct dev_next_ctx){ \
+               .it = it, \
+               .bus_str = bus_str, \
+               .cls_str = cls_str, \
+       })
+
+#define ITCTX(ptr) \
+       (((struct dev_next_ctx *)(intptr_t)ptr)->it)
+
+#define BUSCTX(ptr) \
+       (((struct dev_next_ctx *)(intptr_t)ptr)->bus_str)
+
+#define CLSCTX(ptr) \
+       (((struct dev_next_ctx *)(intptr_t)ptr)->cls_str)
 
 static int cmp_dev_name(const struct rte_device *dev, const void *_name)
 {
@@ -64,183 +76,681 @@ static int cmp_dev_name(const struct rte_device *dev, const void *_name)
        return strcmp(dev->name, name);
 }
 
-int rte_eal_dev_attach(const char *name, const char *devargs)
+int __rte_experimental
+rte_dev_is_probed(const struct rte_device *dev)
 {
-       struct rte_bus *bus;
-       int ret;
+       /* The field driver should be set only when the probe is successful. */
+       return dev->driver != NULL;
+}
 
-       if (name == NULL || devargs == NULL) {
-               RTE_LOG(ERR, EAL, "Invalid device or arguments provided\n");
+/* helper function to build devargs, caller should free the memory */
+static int
+build_devargs(const char *busname, const char *devname,
+             const char *drvargs, char **devargs)
+{
+       int length;
+
+       length = snprintf(NULL, 0, "%s:%s,%s", busname, devname, drvargs);
+       if (length < 0)
                return -EINVAL;
-       }
 
-       bus = rte_bus_find_by_device_name(name);
-       if (bus == NULL) {
-               RTE_LOG(ERR, EAL, "Unable to find a bus for the device '%s'\n",
-                       name);
+       *devargs = malloc(length + 1);
+       if (*devargs == NULL)
+               return -ENOMEM;
+
+       length = snprintf(*devargs, length + 1, "%s:%s,%s",
+                       busname, devname, drvargs);
+       if (length < 0) {
+               free(*devargs);
                return -EINVAL;
        }
-       if (strcmp(bus->name, "pci") == 0)
-               return rte_eal_hotplug_add("pci", name, devargs);
-       if (strcmp(bus->name, "vdev") != 0) {
-               RTE_LOG(ERR, EAL, "Device attach is only supported for PCI and vdev devices.\n");
-               return -ENOTSUP;
-       }
 
-       /*
-        * If we haven't found a bus device the user meant to "hotplug" a
-        * virtual device instead.
-        */
-       ret = rte_vdev_init(name, devargs);
-       if (ret)
-               RTE_LOG(ERR, EAL, "Driver cannot attach the device (%s)\n",
-                       name);
-       return ret;
+       return 0;
 }
 
-int rte_eal_dev_detach(struct rte_device *dev)
+int
+rte_eal_hotplug_add(const char *busname, const char *devname,
+                   const char *drvargs)
 {
-       struct rte_bus *bus;
+
+       char *devargs;
        int ret;
 
-       if (dev == NULL) {
-               RTE_LOG(ERR, EAL, "Invalid device provided.\n");
-               return -EINVAL;
-       }
+       ret = build_devargs(busname, devname, drvargs, &devargs);
+       if (ret != 0)
+               return ret;
 
-       bus = rte_bus_find_by_device(dev);
-       if (bus == NULL) {
-               RTE_LOG(ERR, EAL, "Cannot find bus for device (%s)\n",
-                       dev->name);
-               return -EINVAL;
-       }
-
-       if (bus->unplug == NULL) {
-               RTE_LOG(ERR, EAL, "Bus function not supported\n");
-               return -ENOTSUP;
-       }
+       ret = rte_dev_probe(devargs);
+       free(devargs);
 
-       ret = bus->unplug(dev);
-       if (ret)
-               RTE_LOG(ERR, EAL, "Driver cannot detach the device (%s)\n",
-                       dev->name);
        return ret;
 }
 
-static char *
-full_dev_name(const char *bus, const char *dev, const char *args)
-{
-       char *name;
-       size_t len;
-
-       len = snprintf(NULL, 0, "%s:%s,%s", bus, dev, args) + 1;
-       name = calloc(1, len);
-       if (name == NULL) {
-               RTE_LOG(ERR, EAL, "Could not allocate full device name\n");
-               return NULL;
-       }
-       snprintf(name, len, "%s:%s,%s", bus, dev, args);
-       return name;
-}
-
-int rte_eal_hotplug_add(const char *busname, const char *devname,
-                       const char *devargs)
+/* probe device at local process. */
+int
+local_dev_probe(const char *devargs, struct rte_device **new_dev)
 {
-       struct rte_bus *bus;
        struct rte_device *dev;
        struct rte_devargs *da;
-       char *name;
        int ret;
 
-       bus = rte_bus_find_by_name(busname);
-       if (bus == NULL) {
-               RTE_LOG(ERR, EAL, "Cannot find bus (%s)\n", busname);
-               return -ENOENT;
-       }
-
-       if (bus->plug == NULL) {
-               RTE_LOG(ERR, EAL, "Function plug not supported by bus (%s)\n",
-                       bus->name);
-               return -ENOTSUP;
-       }
-
-       name = full_dev_name(busname, devname, devargs);
-       if (name == NULL)
-               return -ENOMEM;
-
+       *new_dev = NULL;
        da = calloc(1, sizeof(*da));
-       if (da == NULL) {
-               ret = -ENOMEM;
-               goto err_name;
-       }
+       if (da == NULL)
+               return -ENOMEM;
 
-       ret = rte_eal_devargs_parse(name, da);
+       ret = rte_devargs_parse(da, devargs);
        if (ret)
                goto err_devarg;
 
-       ret = rte_eal_devargs_insert(da);
+       if (da->bus->plug == NULL) {
+               RTE_LOG(ERR, EAL, "Function plug not supported by bus (%s)\n",
+                       da->bus->name);
+               ret = -ENOTSUP;
+               goto err_devarg;
+       }
+
+       ret = rte_devargs_insert(&da);
        if (ret)
                goto err_devarg;
 
-       ret = bus->scan();
+       /* the rte_devargs will be referenced in the matching rte_device */
+       ret = da->bus->scan();
        if (ret)
                goto err_devarg;
 
-       dev = bus->find_device(NULL, cmp_detached_dev_name, devname);
+       dev = da->bus->find_device(NULL, cmp_dev_name, da->name);
        if (dev == NULL) {
-               RTE_LOG(ERR, EAL, "Cannot find unplugged device (%s)\n",
-                       devname);
+               RTE_LOG(ERR, EAL, "Cannot find device (%s)\n",
+                       da->name);
                ret = -ENODEV;
                goto err_devarg;
        }
 
-       ret = bus->plug(dev);
+       ret = dev->bus->plug(dev);
        if (ret) {
+               if (rte_dev_is_probed(dev)) /* if already succeeded earlier */
+                       return ret; /* no rollback */
                RTE_LOG(ERR, EAL, "Driver cannot attach the device (%s)\n",
                        dev->name);
                goto err_devarg;
        }
-       free(name);
+
+       *new_dev = dev;
        return 0;
 
 err_devarg:
-       if (rte_eal_devargs_remove(busname, devname)) {
+       if (rte_devargs_remove(da) != 0) {
                free(da->args);
                free(da);
        }
-err_name:
-       free(name);
        return ret;
 }
 
-int rte_eal_hotplug_remove(const char *busname, const char *devname)
+int
+rte_dev_probe(const char *devargs)
 {
-       struct rte_bus *bus;
+       struct eal_dev_mp_req req;
        struct rte_device *dev;
        int ret;
 
+       memset(&req, 0, sizeof(req));
+       req.t = EAL_DEV_REQ_TYPE_ATTACH;
+       strlcpy(req.devargs, devargs, EAL_DEV_MP_DEV_ARGS_MAX_LEN);
+
+       if (rte_eal_process_type() != RTE_PROC_PRIMARY) {
+               /**
+                * If in secondary process, just send IPC request to
+                * primary process.
+                */
+               ret = eal_dev_hotplug_request_to_primary(&req);
+               if (ret != 0) {
+                       RTE_LOG(ERR, EAL,
+                               "Failed to send hotplug request to primary\n");
+                       return -ENOMSG;
+               }
+               if (req.result != 0)
+                       RTE_LOG(ERR, EAL,
+                               "Failed to hotplug add device\n");
+               return req.result;
+       }
+
+       /* attach a shared device from primary start from here: */
+
+       /* primary attach the new device itself. */
+       ret = local_dev_probe(devargs, &dev);
+
+       if (ret != 0) {
+               RTE_LOG(ERR, EAL,
+                       "Failed to attach device on primary process\n");
+
+               /**
+                * it is possible that secondary process failed to attached a
+                * device that primary process have during initialization,
+                * so for -EEXIST case, we still need to sync with secondary
+                * process.
+                */
+               if (ret != -EEXIST)
+                       return ret;
+       }
+
+       /* primary send attach sync request to secondary. */
+       ret = eal_dev_hotplug_request_to_secondary(&req);
+
+       /* if any communication error, we need to rollback. */
+       if (ret != 0) {
+               RTE_LOG(ERR, EAL,
+                       "Failed to send hotplug add request to secondary\n");
+               ret = -ENOMSG;
+               goto rollback;
+       }
+
+       /**
+        * if any secondary failed to attach, we need to consider if rollback
+        * is necessary.
+        */
+       if (req.result != 0) {
+               RTE_LOG(ERR, EAL,
+                       "Failed to attach device on secondary process\n");
+               ret = req.result;
+
+               /* for -EEXIST, we don't need to rollback. */
+               if (ret == -EEXIST)
+                       return ret;
+               goto rollback;
+       }
+
+       return 0;
+
+rollback:
+       req.t = EAL_DEV_REQ_TYPE_ATTACH_ROLLBACK;
+
+       /* primary send rollback request to secondary. */
+       if (eal_dev_hotplug_request_to_secondary(&req) != 0)
+               RTE_LOG(WARNING, EAL,
+                       "Failed to rollback device attach on secondary."
+                       "Devices in secondary may not sync with primary\n");
+
+       /* primary rollback itself. */
+       if (local_dev_remove(dev) != 0)
+               RTE_LOG(WARNING, EAL,
+                       "Failed to rollback device attach on primary."
+                       "Devices in secondary may not sync with primary\n");
+
+       return ret;
+}
+
+int
+rte_eal_hotplug_remove(const char *busname, const char *devname)
+{
+       struct rte_device *dev;
+       struct rte_bus *bus;
+
        bus = rte_bus_find_by_name(busname);
        if (bus == NULL) {
                RTE_LOG(ERR, EAL, "Cannot find bus (%s)\n", busname);
                return -ENOENT;
        }
 
-       if (bus->unplug == NULL) {
-               RTE_LOG(ERR, EAL, "Function unplug not supported by bus (%s)\n",
-                       bus->name);
-               return -ENOTSUP;
-       }
-
        dev = bus->find_device(NULL, cmp_dev_name, devname);
        if (dev == NULL) {
                RTE_LOG(ERR, EAL, "Cannot find plugged device (%s)\n", devname);
                return -EINVAL;
        }
 
-       ret = bus->unplug(dev);
-       if (ret)
+       return rte_dev_remove(dev);
+}
+
+/* remove device at local process. */
+int
+local_dev_remove(struct rte_device *dev)
+{
+       int ret;
+
+       if (dev->bus->unplug == NULL) {
+               RTE_LOG(ERR, EAL, "Function unplug not supported by bus (%s)\n",
+                       dev->bus->name);
+               return -ENOTSUP;
+       }
+
+       ret = dev->bus->unplug(dev);
+       if (ret) {
                RTE_LOG(ERR, EAL, "Driver cannot detach the device (%s)\n",
                        dev->name);
-       rte_eal_devargs_remove(busname, devname);
+               return ret;
+       }
+
+       return 0;
+}
+
+int
+rte_dev_remove(struct rte_device *dev)
+{
+       struct eal_dev_mp_req req;
+       char *devargs;
+       int ret;
+
+       if (!rte_dev_is_probed(dev)) {
+               RTE_LOG(ERR, EAL, "Device is not probed\n");
+               return -ENOENT;
+       }
+
+       ret = build_devargs(dev->bus->name, dev->name, "", &devargs);
+       if (ret != 0)
+               return ret;
+
+       memset(&req, 0, sizeof(req));
+       req.t = EAL_DEV_REQ_TYPE_DETACH;
+       strlcpy(req.devargs, devargs, EAL_DEV_MP_DEV_ARGS_MAX_LEN);
+       free(devargs);
+
+       if (rte_eal_process_type() != RTE_PROC_PRIMARY) {
+               /**
+                * If in secondary process, just send IPC request to
+                * primary process.
+                */
+               ret = eal_dev_hotplug_request_to_primary(&req);
+               if (ret != 0) {
+                       RTE_LOG(ERR, EAL,
+                               "Failed to send hotplug request to primary\n");
+                       return -ENOMSG;
+               }
+               if (req.result != 0)
+                       RTE_LOG(ERR, EAL,
+                               "Failed to hotplug remove device\n");
+               return req.result;
+       }
+
+       /* detach a device from primary start from here: */
+
+       /* primary send detach sync request to secondary */
+       ret = eal_dev_hotplug_request_to_secondary(&req);
+
+       /**
+        * if communication error, we need to rollback, because it is possible
+        * part of the secondary processes still detached it successfully.
+        */
+       if (ret != 0) {
+               RTE_LOG(ERR, EAL,
+                       "Failed to send device detach request to secondary\n");
+               ret = -ENOMSG;
+               goto rollback;
+       }
+
+       /**
+        * if any secondary failed to detach, we need to consider if rollback
+        * is necessary.
+        */
+       if (req.result != 0) {
+               RTE_LOG(ERR, EAL,
+                       "Failed to detach device on secondary process\n");
+               ret = req.result;
+               /**
+                * if -ENOENT, we don't need to rollback, since devices is
+                * already detached on secondary process.
+                */
+               if (ret != -ENOENT)
+                       goto rollback;
+       }
+
+       /* primary detach the device itself. */
+       ret = local_dev_remove(dev);
+
+       /* if primary failed, still need to consider if rollback is necessary */
+       if (ret != 0) {
+               RTE_LOG(ERR, EAL,
+                       "Failed to detach device on primary process\n");
+               /* if -ENOENT, we don't need to rollback */
+               if (ret == -ENOENT)
+                       return ret;
+               goto rollback;
+       }
+
+       return 0;
+
+rollback:
+       req.t = EAL_DEV_REQ_TYPE_DETACH_ROLLBACK;
+
+       /* primary send rollback request to secondary. */
+       if (eal_dev_hotplug_request_to_secondary(&req) != 0)
+               RTE_LOG(WARNING, EAL,
+                       "Failed to rollback device detach on secondary."
+                       "Devices in secondary may not sync with primary\n");
+
        return ret;
 }
+
+int __rte_experimental
+rte_dev_event_callback_register(const char *device_name,
+                               rte_dev_event_cb_fn cb_fn,
+                               void *cb_arg)
+{
+       struct dev_event_callback *event_cb;
+       int ret;
+
+       if (!cb_fn)
+               return -EINVAL;
+
+       rte_spinlock_lock(&dev_event_lock);
+
+       if (TAILQ_EMPTY(&dev_event_cbs))
+               TAILQ_INIT(&dev_event_cbs);
+
+       TAILQ_FOREACH(event_cb, &dev_event_cbs, next) {
+               if (event_cb->cb_fn == cb_fn && event_cb->cb_arg == cb_arg) {
+                       if (device_name == NULL && event_cb->dev_name == NULL)
+                               break;
+                       if (device_name == NULL || event_cb->dev_name == NULL)
+                               continue;
+                       if (!strcmp(event_cb->dev_name, device_name))
+                               break;
+               }
+       }
+
+       /* create a new callback. */
+       if (event_cb == NULL) {
+               event_cb = malloc(sizeof(struct dev_event_callback));
+               if (event_cb != NULL) {
+                       event_cb->cb_fn = cb_fn;
+                       event_cb->cb_arg = cb_arg;
+                       event_cb->active = 0;
+                       if (!device_name) {
+                               event_cb->dev_name = NULL;
+                       } else {
+                               event_cb->dev_name = strdup(device_name);
+                               if (event_cb->dev_name == NULL) {
+                                       ret = -ENOMEM;
+                                       goto error;
+                               }
+                       }
+                       TAILQ_INSERT_TAIL(&dev_event_cbs, event_cb, next);
+               } else {
+                       RTE_LOG(ERR, EAL,
+                               "Failed to allocate memory for device "
+                               "event callback.");
+                       ret = -ENOMEM;
+                       goto error;
+               }
+       } else {
+               RTE_LOG(ERR, EAL,
+                       "The callback is already exist, no need "
+                       "to register again.\n");
+               ret = -EEXIST;
+       }
+
+       rte_spinlock_unlock(&dev_event_lock);
+       return 0;
+error:
+       free(event_cb);
+       rte_spinlock_unlock(&dev_event_lock);
+       return ret;
+}
+
+int __rte_experimental
+rte_dev_event_callback_unregister(const char *device_name,
+                                 rte_dev_event_cb_fn cb_fn,
+                                 void *cb_arg)
+{
+       int ret = 0;
+       struct dev_event_callback *event_cb, *next;
+
+       if (!cb_fn)
+               return -EINVAL;
+
+       rte_spinlock_lock(&dev_event_lock);
+       /*walk through the callbacks and remove all that match. */
+       for (event_cb = TAILQ_FIRST(&dev_event_cbs); event_cb != NULL;
+            event_cb = next) {
+
+               next = TAILQ_NEXT(event_cb, next);
+
+               if (device_name != NULL && event_cb->dev_name != NULL) {
+                       if (!strcmp(event_cb->dev_name, device_name)) {
+                               if (event_cb->cb_fn != cb_fn ||
+                                   (cb_arg != (void *)-1 &&
+                                   event_cb->cb_arg != cb_arg))
+                                       continue;
+                       }
+               } else if (device_name != NULL) {
+                       continue;
+               }
+
+               /*
+                * if this callback is not executing right now,
+                * then remove it.
+                */
+               if (event_cb->active == 0) {
+                       TAILQ_REMOVE(&dev_event_cbs, event_cb, next);
+                       free(event_cb);
+                       ret++;
+               } else {
+                       continue;
+               }
+       }
+       rte_spinlock_unlock(&dev_event_lock);
+       return ret;
+}
+
+void __rte_experimental
+rte_dev_event_callback_process(const char *device_name,
+                              enum rte_dev_event_type event)
+{
+       struct dev_event_callback *cb_lst;
+
+       if (device_name == NULL)
+               return;
+
+       rte_spinlock_lock(&dev_event_lock);
+
+       TAILQ_FOREACH(cb_lst, &dev_event_cbs, next) {
+               if (cb_lst->dev_name) {
+                       if (strcmp(cb_lst->dev_name, device_name))
+                               continue;
+               }
+               cb_lst->active = 1;
+               rte_spinlock_unlock(&dev_event_lock);
+               cb_lst->cb_fn(device_name, event,
+                               cb_lst->cb_arg);
+               rte_spinlock_lock(&dev_event_lock);
+               cb_lst->active = 0;
+       }
+       rte_spinlock_unlock(&dev_event_lock);
+}
+
+__rte_experimental
+int
+rte_dev_iterator_init(struct rte_dev_iterator *it,
+                     const char *dev_str)
+{
+       struct rte_devargs devargs;
+       struct rte_class *cls = NULL;
+       struct rte_bus *bus = NULL;
+
+       /* Having both bus_str and cls_str NULL is illegal,
+        * marking this iterator as invalid unless
+        * everything goes well.
+        */
+       it->bus_str = NULL;
+       it->cls_str = NULL;
+
+       devargs.data = dev_str;
+       if (rte_devargs_layers_parse(&devargs, dev_str))
+               goto get_out;
+
+       bus = devargs.bus;
+       cls = devargs.cls;
+       /* The string should have at least
+        * one layer specified.
+        */
+       if (bus == NULL && cls == NULL) {
+               RTE_LOG(ERR, EAL,
+                       "Either bus or class must be specified.\n");
+               rte_errno = EINVAL;
+               goto get_out;
+       }
+       if (bus != NULL && bus->dev_iterate == NULL) {
+               RTE_LOG(ERR, EAL, "Bus %s not supported\n", bus->name);
+               rte_errno = ENOTSUP;
+               goto get_out;
+       }
+       if (cls != NULL && cls->dev_iterate == NULL) {
+               RTE_LOG(ERR, EAL, "Class %s not supported\n", cls->name);
+               rte_errno = ENOTSUP;
+               goto get_out;
+       }
+       it->bus_str = devargs.bus_str;
+       it->cls_str = devargs.cls_str;
+       it->dev_str = dev_str;
+       it->bus = bus;
+       it->cls = cls;
+       it->device = NULL;
+       it->class_device = NULL;
+get_out:
+       return -rte_errno;
+}
+
+static char *
+dev_str_sane_copy(const char *str)
+{
+       size_t end;
+       char *copy;
+
+       end = strcspn(str, ",/");
+       if (str[end] == ',') {
+               copy = strdup(&str[end + 1]);
+       } else {
+               /* '/' or '\0' */
+               copy = strdup("");
+       }
+       if (copy == NULL) {
+               rte_errno = ENOMEM;
+       } else {
+               char *slash;
+
+               slash = strchr(copy, '/');
+               if (slash != NULL)
+                       slash[0] = '\0';
+       }
+       return copy;
+}
+
+static int
+class_next_dev_cmp(const struct rte_class *cls,
+                  const void *ctx)
+{
+       struct rte_dev_iterator *it;
+       const char *cls_str = NULL;
+       void *dev;
+
+       if (cls->dev_iterate == NULL)
+               return 1;
+       it = ITCTX(ctx);
+       cls_str = CLSCTX(ctx);
+       dev = it->class_device;
+       /* it->cls_str != NULL means a class
+        * was specified in the devstr.
+        */
+       if (it->cls_str != NULL && cls != it->cls)
+               return 1;
+       /* If an error occurred previously,
+        * no need to test further.
+        */
+       if (rte_errno != 0)
+               return -1;
+       dev = cls->dev_iterate(dev, cls_str, it);
+       it->class_device = dev;
+       return dev == NULL;
+}
+
+static int
+bus_next_dev_cmp(const struct rte_bus *bus,
+                const void *ctx)
+{
+       struct rte_device *dev = NULL;
+       struct rte_class *cls = NULL;
+       struct rte_dev_iterator *it;
+       const char *bus_str = NULL;
+
+       if (bus->dev_iterate == NULL)
+               return 1;
+       it = ITCTX(ctx);
+       bus_str = BUSCTX(ctx);
+       dev = it->device;
+       /* it->bus_str != NULL means a bus
+        * was specified in the devstr.
+        */
+       if (it->bus_str != NULL && bus != it->bus)
+               return 1;
+       /* If an error occurred previously,
+        * no need to test further.
+        */
+       if (rte_errno != 0)
+               return -1;
+       if (it->cls_str == NULL) {
+               dev = bus->dev_iterate(dev, bus_str, it);
+               goto end;
+       }
+       /* cls_str != NULL */
+       if (dev == NULL) {
+next_dev_on_bus:
+               dev = bus->dev_iterate(dev, bus_str, it);
+               it->device = dev;
+       }
+       if (dev == NULL)
+               return 1;
+       if (it->cls != NULL)
+               cls = TAILQ_PREV(it->cls, rte_class_list, next);
+       cls = rte_class_find(cls, class_next_dev_cmp, ctx);
+       if (cls != NULL) {
+               it->cls = cls;
+               goto end;
+       }
+       goto next_dev_on_bus;
+end:
+       it->device = dev;
+       return dev == NULL;
+}
+__rte_experimental
+struct rte_device *
+rte_dev_iterator_next(struct rte_dev_iterator *it)
+{
+       struct rte_bus *bus = NULL;
+       int old_errno = rte_errno;
+       char *bus_str = NULL;
+       char *cls_str = NULL;
+
+       rte_errno = 0;
+       if (it->bus_str == NULL && it->cls_str == NULL) {
+               /* Invalid iterator. */
+               rte_errno = EINVAL;
+               return NULL;
+       }
+       if (it->bus != NULL)
+               bus = TAILQ_PREV(it->bus, rte_bus_list, next);
+       if (it->bus_str != NULL) {
+               bus_str = dev_str_sane_copy(it->bus_str);
+               if (bus_str == NULL)
+                       goto out;
+       }
+       if (it->cls_str != NULL) {
+               cls_str = dev_str_sane_copy(it->cls_str);
+               if (cls_str == NULL)
+                       goto out;
+       }
+       while ((bus = rte_bus_find(bus, bus_next_dev_cmp,
+                                  CTX(it, bus_str, cls_str)))) {
+               if (it->device != NULL) {
+                       it->bus = bus;
+                       goto out;
+               }
+               if (it->bus_str != NULL ||
+                   rte_errno != 0)
+                       break;
+       }
+       if (rte_errno == 0)
+               rte_errno = old_errno;
+out:
+       free(bus_str);
+       free(cls_str);
+       return it->device;
+}