OSCL-LXR linux-6.0.1/​drivers/​infiniband/​core/​device.c	Source navigation Diff markup Identifier search General search
	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 /*
  * Copyright (c) 2004 Topspin Communications.  All rights reserved.
  * Copyright (c) 2005 Sun Microsystems, Inc. All rights reserved.
  *
  * This software is available to you under a choice of one of two
  * licenses.  You may choose to be licensed under the terms of the GNU
  * General Public License (GPL) Version 2, available from the file
  * COPYING in the main directory of this source tree, or the
  * OpenIB.org BSD license below:
  *
  *     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.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
  * SOFTWARE.
  */
 
 #include <linux/module.h>
 #include <linux/string.h>
 #include <linux/errno.h>
 #include <linux/kernel.h>
 #include <linux/slab.h>
 #include <linux/init.h>
 #include <linux/netdevice.h>
 #include <net/net_namespace.h>
 #include <linux/security.h>
 #include <linux/notifier.h>
 #include <linux/hashtable.h>
 #include <rdma/rdma_netlink.h>
 #include <rdma/ib_addr.h>
 #include <rdma/ib_cache.h>
 #include <rdma/rdma_counter.h>
 
 #include "core_priv.h"
 #include "restrack.h"
 
 MODULE_AUTHOR("Roland Dreier");
 MODULE_DESCRIPTION("core kernel InfiniBand API");
 MODULE_LICENSE("Dual BSD/GPL");
 
 struct workqueue_struct *ib_comp_wq;
 struct workqueue_struct *ib_comp_unbound_wq;
 struct workqueue_struct *ib_wq;
 EXPORT_SYMBOL_GPL(ib_wq);
 static struct workqueue_struct *ib_unreg_wq;
 
 /*
  * Each of the three rwsem locks (devices, clients, client_data) protects the
  * xarray of the same name. Specifically it allows the caller to assert that
  * the MARK will/will not be changing under the lock, and for devices and
  * clients, that the value in the xarray is still a valid pointer. Change of
  * the MARK is linked to the object state, so holding the lock and testing the
  * MARK also asserts that the contained object is in a certain state.
  *
  * This is used to build a two stage register/unregister flow where objects
  * can continue to be in the xarray even though they are still in progress to
  * register/unregister.
  *
  * The xarray itself provides additional locking, and restartable iteration,
  * which is also relied on.
  *
  * Locks should not be nested, with the exception of client_data, which is
  * allowed to nest under the read side of the other two locks.
  *
  * The devices_rwsem also protects the device name list, any change or
  * assignment of device name must also hold the write side to guarantee unique
  * names.
  */
 
 /*
  * devices contains devices that have had their names assigned. The
  * devices may not be registered. Users that care about the registration
  * status need to call ib_device_try_get() on the device to ensure it is
  * registered, and keep it registered, for the required duration.
  *
  */
 static DEFINE_XARRAY_FLAGS(devices, XA_FLAGS_ALLOC);
 static DECLARE_RWSEM(devices_rwsem);
 #define DEVICE_REGISTERED XA_MARK_1
 
 static u32 highest_client_id;
 #define CLIENT_REGISTERED XA_MARK_1
 static DEFINE_XARRAY_FLAGS(clients, XA_FLAGS_ALLOC);
 static DECLARE_RWSEM(clients_rwsem);
 
 static void ib_client_put(struct ib_client *client)
 {
     if (refcount_dec_and_test(&client->uses))
         complete(&client->uses_zero);
 }
 
 /*
  * If client_data is registered then the corresponding client must also still
  * be registered.
  */
 #define CLIENT_DATA_REGISTERED XA_MARK_1
 
 unsigned int rdma_dev_net_id;
 
 /*
  * A list of net namespaces is maintained in an xarray. This is necessary
  * because we can't get the locking right using the existing net ns list. We
  * would require a init_net callback after the list is updated.
  */
 static DEFINE_XARRAY_FLAGS(rdma_nets, XA_FLAGS_ALLOC);
 /*
  * rwsem to protect accessing the rdma_nets xarray entries.
  */
 static DECLARE_RWSEM(rdma_nets_rwsem);
 
 bool ib_devices_shared_netns = true;
 module_param_named(netns_mode, ib_devices_shared_netns, bool, 0444);
 MODULE_PARM_DESC(netns_mode,
          "Share device among net namespaces; default=1 (shared)");
 /**
  * rdma_dev_access_netns() - Return whether an rdma device can be accessed
  *               from a specified net namespace or not.
  * @dev:    Pointer to rdma device which needs to be checked
  * @net:    Pointer to net namesapce for which access to be checked
  *
  * When the rdma device is in shared mode, it ignores the net namespace.
  * When the rdma device is exclusive to a net namespace, rdma device net
  * namespace is checked against the specified one.
  */
 bool rdma_dev_access_netns(const struct ib_device *dev, const struct net *net)
 {
     return (ib_devices_shared_netns ||
         net_eq(read_pnet(&dev->coredev.rdma_net), net));
 }
 EXPORT_SYMBOL(rdma_dev_access_netns);
 
 /*
  * xarray has this behavior where it won't iterate over NULL values stored in
  * allocated arrays.  So we need our own iterator to see all values stored in
  * the array. This does the same thing as xa_for_each except that it also
  * returns NULL valued entries if the array is allocating. Simplified to only
  * work on simple xarrays.
  */
 static void *xan_find_marked(struct xarray *xa, unsigned long *indexp,
                  xa_mark_t filter)
 {
     XA_STATE(xas, xa, *indexp);
     void *entry;
 
     rcu_read_lock();
     do {
         entry = xas_find_marked(&xas, ULONG_MAX, filter);
         if (xa_is_zero(entry))
             break;
     } while (xas_retry(&xas, entry));
     rcu_read_unlock();
 
     if (entry) {
         *indexp = xas.xa_index;
         if (xa_is_zero(entry))
             return NULL;
         return entry;
     }
     return XA_ERROR(-ENOENT);
 }
 #define xan_for_each_marked(xa, index, entry, filter)                          \
     for (index = 0, entry = xan_find_marked(xa, &(index), filter);         \
          !xa_is_err(entry);                                                \
          (index)++, entry = xan_find_marked(xa, &(index), filter))
 
 /* RCU hash table mapping netdevice pointers to struct ib_port_data */
 static DEFINE_SPINLOCK(ndev_hash_lock);
 static DECLARE_HASHTABLE(ndev_hash, 5);
 
 static void free_netdevs(struct ib_device *ib_dev);
 static void ib_unregister_work(struct work_struct *work);
 static void __ib_unregister_device(struct ib_device *device);
 static int ib_security_change(struct notifier_block *nb, unsigned long event,
                   void *lsm_data);
 static void ib_policy_change_task(struct work_struct *work);
 static DECLARE_WORK(ib_policy_change_work, ib_policy_change_task);
 
 static void __ibdev_printk(const char *level, const struct ib_device *ibdev,
                struct va_format *vaf)
 {
     if (ibdev && ibdev->dev.parent)
         dev_printk_emit(level[1] - '0',
                 ibdev->dev.parent,
                 "%s %s %s: %pV",
                 dev_driver_string(ibdev->dev.parent),
                 dev_name(ibdev->dev.parent),
                 dev_name(&ibdev->dev),
                 vaf);
     else if (ibdev)
         printk("%s%s: %pV",
                level, dev_name(&ibdev->dev), vaf);
     else
         printk("%s(NULL ib_device): %pV", level, vaf);
 }
 
 void ibdev_printk(const char *level, const struct ib_device *ibdev,
           const char *format, ...)
 {
     struct va_format vaf;
     va_list args;
 
     va_start(args, format);
 
     vaf.fmt = format;
     vaf.va = &args;
 
     __ibdev_printk(level, ibdev, &vaf);
 
     va_end(args);
 }
 EXPORT_SYMBOL(ibdev_printk);
 
 #define define_ibdev_printk_level(func, level)                  \
 void func(const struct ib_device *ibdev, const char *fmt, ...)  \
 {                                                               \
     struct va_format vaf;                                   \
     va_list args;                                           \
                                 \
     va_start(args, fmt);                                    \
                                 \
     vaf.fmt = fmt;                                          \
     vaf.va = &args;                                         \
                                 \
     __ibdev_printk(level, ibdev, &vaf);                     \
                                 \
     va_end(args);                                           \
 }                                                               \
 EXPORT_SYMBOL(func);
 
 define_ibdev_printk_level(ibdev_emerg, KERN_EMERG);
 define_ibdev_printk_level(ibdev_alert, KERN_ALERT);
 define_ibdev_printk_level(ibdev_crit, KERN_CRIT);
 define_ibdev_printk_level(ibdev_err, KERN_ERR);
 define_ibdev_printk_level(ibdev_warn, KERN_WARNING);
 define_ibdev_printk_level(ibdev_notice, KERN_NOTICE);
 define_ibdev_printk_level(ibdev_info, KERN_INFO);
 
 static struct notifier_block ibdev_lsm_nb = {
     .notifier_call = ib_security_change,
 };
 
 static int rdma_dev_change_netns(struct ib_device *device, struct net *cur_net,
                  struct net *net);
 
 /* Pointer to the RCU head at the start of the ib_port_data array */
 struct ib_port_data_rcu {
     struct rcu_head rcu_head;
     struct ib_port_data pdata[];
 };
 
 static void ib_device_check_mandatory(struct ib_device *device)
 {
 #define IB_MANDATORY_FUNC(x) { offsetof(struct ib_device_ops, x), #x }
     static const struct {
         size_t offset;
         char  *name;
     } mandatory_table[] = {
         IB_MANDATORY_FUNC(query_device),
         IB_MANDATORY_FUNC(query_port),
         IB_MANDATORY_FUNC(alloc_pd),
         IB_MANDATORY_FUNC(dealloc_pd),
         IB_MANDATORY_FUNC(create_qp),
         IB_MANDATORY_FUNC(modify_qp),
         IB_MANDATORY_FUNC(destroy_qp),
         IB_MANDATORY_FUNC(post_send),
         IB_MANDATORY_FUNC(post_recv),
         IB_MANDATORY_FUNC(create_cq),
         IB_MANDATORY_FUNC(destroy_cq),
         IB_MANDATORY_FUNC(poll_cq),
         IB_MANDATORY_FUNC(req_notify_cq),
         IB_MANDATORY_FUNC(get_dma_mr),
         IB_MANDATORY_FUNC(reg_user_mr),
         IB_MANDATORY_FUNC(dereg_mr),
         IB_MANDATORY_FUNC(get_port_immutable)
     };
     int i;
 
     device->kverbs_provider = true;
     for (i = 0; i < ARRAY_SIZE(mandatory_table); ++i) {
         if (!*(void **) ((void *) &device->ops +
                  mandatory_table[i].offset)) {
             device->kverbs_provider = false;
             break;
         }
     }
 }
 
 /*
  * Caller must perform ib_device_put() to return the device reference count
  * when ib_device_get_by_index() returns valid device pointer.
  */
 struct ib_device *ib_device_get_by_index(const struct net *net, u32 index)
 {
     struct ib_device *device;
 
     down_read(&devices_rwsem);
     device = xa_load(&devices, index);
     if (device) {
         if (!rdma_dev_access_netns(device, net)) {
             device = NULL;
             goto out;
         }
 
         if (!ib_device_try_get(device))
             device = NULL;
     }
 out:
     up_read(&devices_rwsem);
     return device;
 }
 
 /**
  * ib_device_put - Release IB device reference
  * @device: device whose reference to be released
  *
  * ib_device_put() releases reference to the IB device to allow it to be
  * unregistered and eventually free.
  */
 void ib_device_put(struct ib_device *device)
 {
     if (refcount_dec_and_test(&device->refcount))
         complete(&device->unreg_completion);
 }
 EXPORT_SYMBOL(ib_device_put);
 
 static struct ib_device *__ib_device_get_by_name(const char *name)
 {
     struct ib_device *device;
     unsigned long index;
 
     xa_for_each (&devices, index, device)
         if (!strcmp(name, dev_name(&device->dev)))
             return device;
 
     return NULL;
 }
 
 /**
  * ib_device_get_by_name - Find an IB device by name
  * @name: The name to look for
  * @driver_id: The driver ID that must match (RDMA_DRIVER_UNKNOWN matches all)
  *
  * Find and hold an ib_device by its name. The caller must call
  * ib_device_put() on the returned pointer.
  */
 struct ib_device *ib_device_get_by_name(const char *name,
                     enum rdma_driver_id driver_id)
 {
     struct ib_device *device;
 
     down_read(&devices_rwsem);
     device = __ib_device_get_by_name(name);
     if (device && driver_id != RDMA_DRIVER_UNKNOWN &&
         device->ops.driver_id != driver_id)
         device = NULL;
 
     if (device) {
         if (!ib_device_try_get(device))
             device = NULL;
     }
     up_read(&devices_rwsem);
     return device;
 }
 EXPORT_SYMBOL(ib_device_get_by_name);
 
 static int rename_compat_devs(struct ib_device *device)
 {
     struct ib_core_device *cdev;
     unsigned long index;
     int ret = 0;
 
     mutex_lock(&device->compat_devs_mutex);
     xa_for_each (&device->compat_devs, index, cdev) {
         ret = device_rename(&cdev->dev, dev_name(&device->dev));
         if (ret) {
             dev_warn(&cdev->dev,
                  "Fail to rename compatdev to new name %s\n",
                  dev_name(&device->dev));
             break;
         }
     }
     mutex_unlock(&device->compat_devs_mutex);
     return ret;
 }
 
 int ib_device_rename(struct ib_device *ibdev, const char *name)
 {
     unsigned long index;
     void *client_data;
     int ret;
 
     down_write(&devices_rwsem);
     if (!strcmp(name, dev_name(&ibdev->dev))) {
         up_write(&devices_rwsem);
         return 0;
     }
 
     if (__ib_device_get_by_name(name)) {
         up_write(&devices_rwsem);
         return -EEXIST;
     }
 
     ret = device_rename(&ibdev->dev, name);
     if (ret) {
         up_write(&devices_rwsem);
         return ret;
     }
 
     strlcpy(ibdev->name, name, IB_DEVICE_NAME_MAX);
     ret = rename_compat_devs(ibdev);
 
     downgrade_write(&devices_rwsem);
     down_read(&ibdev->client_data_rwsem);
     xan_for_each_marked(&ibdev->client_data, index, client_data,
                 CLIENT_DATA_REGISTERED) {
         struct ib_client *client = xa_load(&clients, index);
 
         if (!client || !client->rename)
             continue;
 
         client->rename(ibdev, client_data);
     }
     up_read(&ibdev->client_data_rwsem);
     up_read(&devices_rwsem);
     return 0;
 }
 
 int ib_device_set_dim(struct ib_device *ibdev, u8 use_dim)
 {
     if (use_dim > 1)
         return -EINVAL;
     ibdev->use_cq_dim = use_dim;
 
     return 0;
 }
 
 static int alloc_name(struct ib_device *ibdev, const char *name)
 {
     struct ib_device *device;
     unsigned long index;
     struct ida inuse;
     int rc;
     int i;
 
     lockdep_assert_held_write(&devices_rwsem);
     ida_init(&inuse);
     xa_for_each (&devices, index, device) {
         char buf[IB_DEVICE_NAME_MAX];
 
         if (sscanf(dev_name(&device->dev), name, &i) != 1)
             continue;
         if (i < 0 || i >= INT_MAX)
             continue;
         snprintf(buf, sizeof buf, name, i);
         if (strcmp(buf, dev_name(&device->dev)) != 0)
             continue;
 
         rc = ida_alloc_range(&inuse, i, i, GFP_KERNEL);
         if (rc < 0)
             goto out;
     }
 
     rc = ida_alloc(&inuse, GFP_KERNEL);
     if (rc < 0)
         goto out;
 
     rc = dev_set_name(&ibdev->dev, name, rc);
 out:
     ida_destroy(&inuse);
     return rc;
 }
 
 static void ib_device_release(struct device *device)
 {
     struct ib_device *dev = container_of(device, struct ib_device, dev);
 
     free_netdevs(dev);
     WARN_ON(refcount_read(&dev->refcount));
     if (dev->hw_stats_data)
         ib_device_release_hw_stats(dev->hw_stats_data);
     if (dev->port_data) {
         ib_cache_release_one(dev);
         ib_security_release_port_pkey_list(dev);
         rdma_counter_release(dev);
         kfree_rcu(container_of(dev->port_data, struct ib_port_data_rcu,
                        pdata[0]),
               rcu_head);
     }
 
     mutex_destroy(&dev->unregistration_lock);
     mutex_destroy(&dev->compat_devs_mutex);
 
     xa_destroy(&dev->compat_devs);
     xa_destroy(&dev->client_data);
     kfree_rcu(dev, rcu_head);
 }
 
 static int ib_device_uevent(struct device *device,
                 struct kobj_uevent_env *env)
 {
     if (add_uevent_var(env, "NAME=%s", dev_name(device)))
         return -ENOMEM;
 
     /*
      * It would be nice to pass the node GUID with the event...
      */
 
     return 0;
 }
 
 static const void *net_namespace(struct device *d)
 {
     struct ib_core_device *coredev =
             container_of(d, struct ib_core_device, dev);
 
     return read_pnet(&coredev->rdma_net);
 }
 
 static struct class ib_class = {
     .name    = "infiniband",
     .dev_release = ib_device_release,
     .dev_uevent = ib_device_uevent,
     .ns_type = &net_ns_type_operations,
     .namespace = net_namespace,
 };
 
 static void rdma_init_coredev(struct ib_core_device *coredev,
                   struct ib_device *dev, struct net *net)
 {
     /* This BUILD_BUG_ON is intended to catch layout change
      * of union of ib_core_device and device.
      * dev must be the first element as ib_core and providers
      * driver uses it. Adding anything in ib_core_device before
      * device will break this assumption.
      */
     BUILD_BUG_ON(offsetof(struct ib_device, coredev.dev) !=
              offsetof(struct ib_device, dev));
 
     coredev->dev.class = &ib_class;
     coredev->dev.groups = dev->groups;
     device_initialize(&coredev->dev);
     coredev->owner = dev;
     INIT_LIST_HEAD(&coredev->port_list);
     write_pnet(&coredev->rdma_net, net);
 }
 
 /**
  * _ib_alloc_device - allocate an IB device struct
  * @size:size of structure to allocate
  *
  * Low-level drivers should use ib_alloc_device() to allocate &struct
  * ib_device.  @size is the size of the structure to be allocated,
  * including any private data used by the low-level driver.
  * ib_dealloc_device() must be used to free structures allocated with
  * ib_alloc_device().
  */
 struct ib_device *_ib_alloc_device(size_t size)
 {
     struct ib_device *device;
     unsigned int i;
 
     if (WARN_ON(size < sizeof(struct ib_device)))
         return NULL;
 
     device = kzalloc(size, GFP_KERNEL);
     if (!device)
         return NULL;
 
     if (rdma_restrack_init(device)) {
         kfree(device);
         return NULL;
     }
 
     rdma_init_coredev(&device->coredev, device, &init_net);
 
     INIT_LIST_HEAD(&device->event_handler_list);
     spin_lock_init(&device->qp_open_list_lock);
     init_rwsem(&device->event_handler_rwsem);
     mutex_init(&device->unregistration_lock);
     /*
      * client_data needs to be alloc because we don't want our mark to be
      * destroyed if the user stores NULL in the client data.
      */
     xa_init_flags(&device->client_data, XA_FLAGS_ALLOC);
     init_rwsem(&device->client_data_rwsem);
     xa_init_flags(&device->compat_devs, XA_FLAGS_ALLOC);
     mutex_init(&device->compat_devs_mutex);
     init_completion(&device->unreg_completion);
     INIT_WORK(&device->unregistration_work, ib_unregister_work);
 
     spin_lock_init(&device->cq_pools_lock);
     for (i = 0; i < ARRAY_SIZE(device->cq_pools); i++)
         INIT_LIST_HEAD(&device->cq_pools[i]);
 
     rwlock_init(&device->cache_lock);
 
     device->uverbs_cmd_mask =
         BIT_ULL(IB_USER_VERBS_CMD_ALLOC_MW) |
         BIT_ULL(IB_USER_VERBS_CMD_ALLOC_PD) |
         BIT_ULL(IB_USER_VERBS_CMD_ATTACH_MCAST) |
         BIT_ULL(IB_USER_VERBS_CMD_CLOSE_XRCD) |
         BIT_ULL(IB_USER_VERBS_CMD_CREATE_AH) |
         BIT_ULL(IB_USER_VERBS_CMD_CREATE_COMP_CHANNEL) |
         BIT_ULL(IB_USER_VERBS_CMD_CREATE_CQ) |
         BIT_ULL(IB_USER_VERBS_CMD_CREATE_QP) |
         BIT_ULL(IB_USER_VERBS_CMD_CREATE_SRQ) |
         BIT_ULL(IB_USER_VERBS_CMD_CREATE_XSRQ) |
         BIT_ULL(IB_USER_VERBS_CMD_DEALLOC_MW) |
         BIT_ULL(IB_USER_VERBS_CMD_DEALLOC_PD) |
         BIT_ULL(IB_USER_VERBS_CMD_DEREG_MR) |
         BIT_ULL(IB_USER_VERBS_CMD_DESTROY_AH) |
         BIT_ULL(IB_USER_VERBS_CMD_DESTROY_CQ) |
         BIT_ULL(IB_USER_VERBS_CMD_DESTROY_QP) |
         BIT_ULL(IB_USER_VERBS_CMD_DESTROY_SRQ) |
         BIT_ULL(IB_USER_VERBS_CMD_DETACH_MCAST) |
         BIT_ULL(IB_USER_VERBS_CMD_GET_CONTEXT) |
         BIT_ULL(IB_USER_VERBS_CMD_MODIFY_QP) |
         BIT_ULL(IB_USER_VERBS_CMD_MODIFY_SRQ) |
         BIT_ULL(IB_USER_VERBS_CMD_OPEN_QP) |
         BIT_ULL(IB_USER_VERBS_CMD_OPEN_XRCD) |
         BIT_ULL(IB_USER_VERBS_CMD_QUERY_DEVICE) |
         BIT_ULL(IB_USER_VERBS_CMD_QUERY_PORT) |
         BIT_ULL(IB_USER_VERBS_CMD_QUERY_QP) |
         BIT_ULL(IB_USER_VERBS_CMD_QUERY_SRQ) |
         BIT_ULL(IB_USER_VERBS_CMD_REG_MR) |
         BIT_ULL(IB_USER_VERBS_CMD_REREG_MR) |
         BIT_ULL(IB_USER_VERBS_CMD_RESIZE_CQ);
     return device;
 }
 EXPORT_SYMBOL(_ib_alloc_device);
 
 /**
  * ib_dealloc_device - free an IB device struct
  * @device:structure to free
  *
  * Free a structure allocated with ib_alloc_device().
  */
 void ib_dealloc_device(struct ib_device *device)
 {
     if (device->ops.dealloc_driver)
         device->ops.dealloc_driver(device);
 
     /*
      * ib_unregister_driver() requires all devices to remain in the xarray
      * while their ops are callable. The last op we call is dealloc_driver
      * above.  This is needed to create a fence on op callbacks prior to
      * allowing the driver module to unload.
      */
     down_write(&devices_rwsem);
     if (xa_load(&devices, device->index) == device)
         xa_erase(&devices, device->index);
     up_write(&devices_rwsem);
 
     /* Expedite releasing netdev references */
     free_netdevs(device);
 
     WARN_ON(!xa_empty(&device->compat_devs));
     WARN_ON(!xa_empty(&device->client_data));
     WARN_ON(refcount_read(&device->refcount));
     rdma_restrack_clean(device);
     /* Balances with device_initialize */
     put_device(&device->dev);
 }
 EXPORT_SYMBOL(ib_dealloc_device);
 
 /*
  * add_client_context() and remove_client_context() must be safe against
  * parallel calls on the same device - registration/unregistration of both the
  * device and client can be occurring in parallel.
  *
  * The routines need to be a fence, any caller must not return until the add
  * or remove is fully completed.
  */
 static int add_client_context(struct ib_device *device,
                   struct ib_client *client)
 {
     int ret = 0;
 
     if (!device->kverbs_provider && !client->no_kverbs_req)
         return 0;
 
     down_write(&device->client_data_rwsem);
     /*
      * So long as the client is registered hold both the client and device
      * unregistration locks.
      */
     if (!refcount_inc_not_zero(&client->uses))
         goto out_unlock;
     refcount_inc(&device->refcount);
 
     /*
      * Another caller to add_client_context got here first and has already
      * completely initialized context.
      */
     if (xa_get_mark(&device->client_data, client->client_id,
             CLIENT_DATA_REGISTERED))
         goto out;
 
     ret = xa_err(xa_store(&device->client_data, client->client_id, NULL,
                   GFP_KERNEL));
     if (ret)
         goto out;
     downgrade_write(&device->client_data_rwsem);
     if (client->add) {
         if (client->add(device)) {
             /*
              * If a client fails to add then the error code is
              * ignored, but we won't call any more ops on this
              * client.
              */
             xa_erase(&device->client_data, client->client_id);
             up_read(&device->client_data_rwsem);
             ib_device_put(device);
             ib_client_put(client);
             return 0;
         }
     }
 
     /* Readers shall not see a client until add has been completed */
     xa_set_mark(&device->client_data, client->client_id,
             CLIENT_DATA_REGISTERED);
     up_read(&device->client_data_rwsem);
     return 0;
 
 out:
     ib_device_put(device);
     ib_client_put(client);
 out_unlock:
     up_write(&device->client_data_rwsem);
     return ret;
 }
 
 static void remove_client_context(struct ib_device *device,
                   unsigned int client_id)
 {
     struct ib_client *client;
     void *client_data;
 
     down_write(&device->client_data_rwsem);
     if (!xa_get_mark(&device->client_data, client_id,
              CLIENT_DATA_REGISTERED)) {
         up_write(&device->client_data_rwsem);
         return;
     }
     client_data = xa_load(&device->client_data, client_id);
     xa_clear_mark(&device->client_data, client_id, CLIENT_DATA_REGISTERED);
     client = xa_load(&clients, client_id);
     up_write(&device->client_data_rwsem);
 
     /*
      * Notice we cannot be holding any exclusive locks when calling the
      * remove callback as the remove callback can recurse back into any
      * public functions in this module and thus try for any locks those
      * functions take.
      *
      * For this reason clients and drivers should not call the
      * unregistration functions will holdling any locks.
      */
     if (client->remove)
         client->remove(device, client_data);
 
     xa_erase(&device->client_data, client_id);
     ib_device_put(device);
     ib_client_put(client);
 }
 
 static int alloc_port_data(struct ib_device *device)
 {
     struct ib_port_data_rcu *pdata_rcu;
     u32 port;
 
     if (device->port_data)
         return 0;
 
     /* This can only be called once the physical port range is defined */
     if (WARN_ON(!device->phys_port_cnt))
         return -EINVAL;
 
     /* Reserve U32_MAX so the logic to go over all the ports is sane */
     if (WARN_ON(device->phys_port_cnt == U32_MAX))
         return -EINVAL;
 
     /*
      * device->port_data is indexed directly by the port number to make
      * access to this data as efficient as possible.
      *
      * Therefore port_data is declared as a 1 based array with potential
      * empty slots at the beginning.
      */
     pdata_rcu = kzalloc(struct_size(pdata_rcu, pdata,
                     rdma_end_port(device) + 1),
                 GFP_KERNEL);
     if (!pdata_rcu)
         return -ENOMEM;
     /*
      * The rcu_head is put in front of the port data array and the stored
      * pointer is adjusted since we never need to see that member until
      * kfree_rcu.
      */
     device->port_data = pdata_rcu->pdata;
 
     rdma_for_each_port (device, port) {
         struct ib_port_data *pdata = &device->port_data[port];
 
         pdata->ib_dev = device;
         spin_lock_init(&pdata->pkey_list_lock);
         INIT_LIST_HEAD(&pdata->pkey_list);
         spin_lock_init(&pdata->netdev_lock);
         INIT_HLIST_NODE(&pdata->ndev_hash_link);
     }
     return 0;
 }
 
 static int verify_immutable(const struct ib_device *dev, u32 port)
 {
     return WARN_ON(!rdma_cap_ib_mad(dev, port) &&
                 rdma_max_mad_size(dev, port) != 0);
 }
 
 static int setup_port_data(struct ib_device *device)
 {
     u32 port;
     int ret;
 
     ret = alloc_port_data(device);
     if (ret)
         return ret;
 
     rdma_for_each_port (device, port) {
         struct ib_port_data *pdata = &device->port_data[port];
 
         ret = device->ops.get_port_immutable(device, port,
                              &pdata->immutable);
         if (ret)
             return ret;
 
         if (verify_immutable(device, port))
             return -EINVAL;
     }
     return 0;
 }
 
 /**
  * ib_port_immutable_read() - Read rdma port's immutable data
  * @dev: IB device
  * @port: port number whose immutable data to read. It starts with index 1 and
  *        valid upto including rdma_end_port().
  */
 const struct ib_port_immutable*
 ib_port_immutable_read(struct ib_device *dev, unsigned int port)
 {
     WARN_ON(!rdma_is_port_valid(dev, port));
     return &dev->port_data[port].immutable;
 }
 EXPORT_SYMBOL(ib_port_immutable_read);
 
 void ib_get_device_fw_str(struct ib_device *dev, char *str)
 {
     if (dev->ops.get_dev_fw_str)
         dev->ops.get_dev_fw_str(dev, str);
     else
         str[0] = '\0';
 }
 EXPORT_SYMBOL(ib_get_device_fw_str);
 
 static void ib_policy_change_task(struct work_struct *work)
 {
     struct ib_device *dev;
     unsigned long index;
 
     down_read(&devices_rwsem);
     xa_for_each_marked (&devices, index, dev, DEVICE_REGISTERED) {
         unsigned int i;
 
         rdma_for_each_port (dev, i) {
             u64 sp;
             ib_get_cached_subnet_prefix(dev, i, &sp);
             ib_security_cache_change(dev, i, sp);
         }
     }
     up_read(&devices_rwsem);
 }
 
 static int ib_security_change(struct notifier_block *nb, unsigned long event,
                   void *lsm_data)
 {
     if (event != LSM_POLICY_CHANGE)
         return NOTIFY_DONE;
 
     schedule_work(&ib_policy_change_work);
     ib_mad_agent_security_change();
 
     return NOTIFY_OK;
 }
 
 static void compatdev_release(struct device *dev)
 {
     struct ib_core_device *cdev =
         container_of(dev, struct ib_core_device, dev);
 
     kfree(cdev);
 }
 
 static int add_one_compat_dev(struct ib_device *device,
                   struct rdma_dev_net *rnet)
 {
     struct ib_core_device *cdev;
     int ret;
 
     lockdep_assert_held(&rdma_nets_rwsem);
     if (!ib_devices_shared_netns)
         return 0;
 
     /*
      * Create and add compat device in all namespaces other than where it
      * is currently bound to.
      */
     if (net_eq(read_pnet(&rnet->net),
            read_pnet(&device->coredev.rdma_net)))
         return 0;
 
     /*
      * The first of init_net() or ib_register_device() to take the
      * compat_devs_mutex wins and gets to add the device. Others will wait
      * for completion here.
      */
     mutex_lock(&device->compat_devs_mutex);
     cdev = xa_load(&device->compat_devs, rnet->id);
     if (cdev) {
         ret = 0;
         goto done;
     }
     ret = xa_reserve(&device->compat_devs, rnet->id, GFP_KERNEL);
     if (ret)
         goto done;
 
     cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
     if (!cdev) {
         ret = -ENOMEM;
         goto cdev_err;
     }
 
     cdev->dev.parent = device->dev.parent;
     rdma_init_coredev(cdev, device, read_pnet(&rnet->net));
     cdev->dev.release = compatdev_release;
     ret = dev_set_name(&cdev->dev, "%s", dev_name(&device->dev));
     if (ret)
         goto add_err;
 
     ret = device_add(&cdev->dev);
     if (ret)
         goto add_err;
     ret = ib_setup_port_attrs(cdev);
     if (ret)
         goto port_err;
 
     ret = xa_err(xa_store(&device->compat_devs, rnet->id,
                   cdev, GFP_KERNEL));
     if (ret)
         goto insert_err;
 
     mutex_unlock(&device->compat_devs_mutex);
     return 0;
 
 insert_err:
     ib_free_port_attrs(cdev);
 port_err:
     device_del(&cdev->dev);
 add_err:
     put_device(&cdev->dev);
 cdev_err:
     xa_release(&device->compat_devs, rnet->id);
 done:
     mutex_unlock(&device->compat_devs_mutex);
     return ret;
 }
 
 static void remove_one_compat_dev(struct ib_device *device, u32 id)
 {
     struct ib_core_device *cdev;
 
     mutex_lock(&device->compat_devs_mutex);
     cdev = xa_erase(&device->compat_devs, id);
     mutex_unlock(&device->compat_devs_mutex);
     if (cdev) {
         ib_free_port_attrs(cdev);
         device_del(&cdev->dev);
         put_device(&cdev->dev);
     }
 }
 
 static void remove_compat_devs(struct ib_device *device)
 {
     struct ib_core_device *cdev;
     unsigned long index;
 
     xa_for_each (&device->compat_devs, index, cdev)
         remove_one_compat_dev(device, index);
 }
 
 static int add_compat_devs(struct ib_device *device)
 {
     struct rdma_dev_net *rnet;
     unsigned long index;
     int ret = 0;
 
     lockdep_assert_held(&devices_rwsem);
 
     down_read(&rdma_nets_rwsem);
     xa_for_each (&rdma_nets, index, rnet) {
         ret = add_one_compat_dev(device, rnet);
         if (ret)
             break;
     }
     up_read(&rdma_nets_rwsem);
     return ret;
 }
 
 static void remove_all_compat_devs(void)
 {
     struct ib_compat_device *cdev;
     struct ib_device *dev;
     unsigned long index;
 
     down_read(&devices_rwsem);
     xa_for_each (&devices, index, dev) {
         unsigned long c_index = 0;
 
         /* Hold nets_rwsem so that any other thread modifying this
          * system param can sync with this thread.
          */
         down_read(&rdma_nets_rwsem);
         xa_for_each (&dev->compat_devs, c_index, cdev)
             remove_one_compat_dev(dev, c_index);
         up_read(&rdma_nets_rwsem);
     }
     up_read(&devices_rwsem);
 }
 
 static int add_all_compat_devs(void)
 {
     struct rdma_dev_net *rnet;
     struct ib_device *dev;
     unsigned long index;
     int ret = 0;
 
     down_read(&devices_rwsem);
     xa_for_each_marked (&devices, index, dev, DEVICE_REGISTERED) {
         unsigned long net_index = 0;
 
         /* Hold nets_rwsem so that any other thread modifying this
          * system param can sync with this thread.
          */
         down_read(&rdma_nets_rwsem);
         xa_for_each (&rdma_nets, net_index, rnet) {
             ret = add_one_compat_dev(dev, rnet);
             if (ret)
                 break;
         }
         up_read(&rdma_nets_rwsem);
     }
     up_read(&devices_rwsem);
     if (ret)
         remove_all_compat_devs();
     return ret;
 }
 
 int rdma_compatdev_set(u8 enable)
 {
     struct rdma_dev_net *rnet;
     unsigned long index;
     int ret = 0;
 
     down_write(&rdma_nets_rwsem);
     if (ib_devices_shared_netns == enable) {
         up_write(&rdma_nets_rwsem);
         return 0;
     }
 
     /* enable/disable of compat devices is not supported
      * when more than default init_net exists.
      */
     xa_for_each (&rdma_nets, index, rnet) {
         ret++;
         break;
     }
     if (!ret)
         ib_devices_shared_netns = enable;
     up_write(&rdma_nets_rwsem);
     if (ret)
         return -EBUSY;
 
     if (enable)
         ret = add_all_compat_devs();
     else
         remove_all_compat_devs();
     return ret;
 }
 
 static void rdma_dev_exit_net(struct net *net)
 {
     struct rdma_dev_net *rnet = rdma_net_to_dev_net(net);
     struct ib_device *dev;
     unsigned long index;
     int ret;
 
     down_write(&rdma_nets_rwsem);
     /*
      * Prevent the ID from being re-used and hide the id from xa_for_each.
      */
     ret = xa_err(xa_store(&rdma_nets, rnet->id, NULL, GFP_KERNEL));
     WARN_ON(ret);
     up_write(&rdma_nets_rwsem);
 
     down_read(&devices_rwsem);
     xa_for_each (&devices, index, dev) {
         get_device(&dev->dev);
         /*
          * Release the devices_rwsem so that pontentially blocking
          * device_del, doesn't hold the devices_rwsem for too long.
          */
         up_read(&devices_rwsem);
 
         remove_one_compat_dev(dev, rnet->id);
 
         /*
          * If the real device is in the NS then move it back to init.
          */
         rdma_dev_change_netns(dev, net, &init_net);
 
         put_device(&dev->dev);
         down_read(&devices_rwsem);
     }
     up_read(&devices_rwsem);
 
     rdma_nl_net_exit(rnet);
     xa_erase(&rdma_nets, rnet->id);
 }
 
 static __net_init int rdma_dev_init_net(struct net *net)
 {
     struct rdma_dev_net *rnet = rdma_net_to_dev_net(net);
     unsigned long index;
     struct ib_device *dev;
     int ret;
 
     write_pnet(&rnet->net, net);
 
     ret = rdma_nl_net_init(rnet);
     if (ret)
         return ret;
 
     /* No need to create any compat devices in default init_net. */
     if (net_eq(net, &init_net))
         return 0;
 
     ret = xa_alloc(&rdma_nets, &rnet->id, rnet, xa_limit_32b, GFP_KERNEL);
     if (ret) {
         rdma_nl_net_exit(rnet);
         return ret;
     }
 
     down_read(&devices_rwsem);
     xa_for_each_marked (&devices, index, dev, DEVICE_REGISTERED) {
         /* Hold nets_rwsem so that netlink command cannot change
          * system configuration for device sharing mode.
          */
         down_read(&rdma_nets_rwsem);
         ret = add_one_compat_dev(dev, rnet);
         up_read(&rdma_nets_rwsem);
         if (ret)
             break;
     }
     up_read(&devices_rwsem);
 
     if (ret)
         rdma_dev_exit_net(net);
 
     return ret;
 }
 
 /*
  * Assign the unique string device name and the unique device index. This is
  * undone by ib_dealloc_device.
  */
 static int assign_name(struct ib_device *device, const char *name)
 {
     static u32 last_id;
     int ret;
 
     down_write(&devices_rwsem);
     /* Assign a unique name to the device */
     if (strchr(name, '%'))
         ret = alloc_name(device, name);
     else
         ret = dev_set_name(&device->dev, name);
     if (ret)
         goto out;
 
     if (__ib_device_get_by_name(dev_name(&device->dev))) {
         ret = -ENFILE;
         goto out;
     }
     strlcpy(device->name, dev_name(&device->dev), IB_DEVICE_NAME_MAX);
 
     ret = xa_alloc_cyclic(&devices, &device->index, device, xa_limit_31b,
             &last_id, GFP_KERNEL);
     if (ret > 0)
         ret = 0;
 
 out:
     up_write(&devices_rwsem);
     return ret;
 }
 
 /*
  * setup_device() allocates memory and sets up data that requires calling the
  * device ops, this is the only reason these actions are not done during
  * ib_alloc_device. It is undone by ib_dealloc_device().
  */
 static int setup_device(struct ib_device *device)
 {
     struct ib_udata uhw = {.outlen = 0, .inlen = 0};
     int ret;
 
     ib_device_check_mandatory(device);
 
     ret = setup_port_data(device);
     if (ret) {
         dev_warn(&device->dev, "Couldn't create per-port data\n");
         return ret;
     }
 
     memset(&device->attrs, 0, sizeof(device->attrs));
     ret = device->ops.query_device(device, &device->attrs, &uhw);
     if (ret) {
         dev_warn(&device->dev,
              "Couldn't query the device attributes\n");
         return ret;
     }
 
     return 0;
 }
 
 static void disable_device(struct ib_device *device)
 {
     u32 cid;
 
     WARN_ON(!refcount_read(&device->refcount));
 
     down_write(&devices_rwsem);
     xa_clear_mark(&devices, device->index, DEVICE_REGISTERED);
     up_write(&devices_rwsem);
 
     /*
      * Remove clients in LIFO order, see assign_client_id. This could be
      * more efficient if xarray learns to reverse iterate. Since no new
      * clients can be added to this ib_device past this point we only need
      * the maximum possible client_id value here.
      */
     down_read(&clients_rwsem);
     cid = highest_client_id;
     up_read(&clients_rwsem);
     while (cid) {
         cid--;
         remove_client_context(device, cid);
     }
 
     ib_cq_pool_cleanup(device);
 
     /* Pairs with refcount_set in enable_device */
     ib_device_put(device);
     wait_for_completion(&device->unreg_completion);
 
     /*
      * compat devices must be removed after device refcount drops to zero.
      * Otherwise init_net() may add more compatdevs after removing compat
      * devices and before device is disabled.
      */
     remove_compat_devs(device);
 }
 
 /*
  * An enabled device is visible to all clients and to all the public facing
  * APIs that return a device pointer. This always returns with a new get, even
  * if it fails.
  */
 static int enable_device_and_get(struct ib_device *device)
 {
     struct ib_client *client;
     unsigned long index;
     int ret = 0;
 
     /*
      * One ref belongs to the xa and the other belongs to this
      * thread. This is needed to guard against parallel unregistration.
      */
     refcount_set(&device->refcount, 2);
     down_write(&devices_rwsem);
     xa_set_mark(&devices, device->index, DEVICE_REGISTERED);
 
     /*
      * By using downgrade_write() we ensure that no other thread can clear
      * DEVICE_REGISTERED while we are completing the client setup.
      */
     downgrade_write(&devices_rwsem);
 
     if (device->ops.enable_driver) {
         ret = device->ops.enable_driver(device);
         if (ret)
             goto out;
     }
 
     down_read(&clients_rwsem);
     xa_for_each_marked (&clients, index, client, CLIENT_REGISTERED) {
         ret = add_client_context(device, client);
         if (ret)
             break;
     }
     up_read(&clients_rwsem);
     if (!ret)
         ret = add_compat_devs(device);
 out:
     up_read(&devices_rwsem);
     return ret;
 }
 
 static void prevent_dealloc_device(struct ib_device *ib_dev)
 {
 }
 
 /**
  * ib_register_device - Register an IB device with IB core
  * @device: Device to register
  * @name: unique string device name. This may include a '%' which will
  *    cause a unique index to be added to the passed device name.
  * @dma_device: pointer to a DMA-capable device. If %NULL, then the IB
  *          device will be used. In this case the caller should fully
  *      setup the ibdev for DMA. This usually means using dma_virt_ops.
  *
  * Low-level drivers use ib_register_device() to register their
  * devices with the IB core.  All registered clients will receive a
  * callback for each device that is added. @device must be allocated
  * with ib_alloc_device().
  *
  * If the driver uses ops.dealloc_driver and calls any ib_unregister_device()
  * asynchronously then the device pointer may become freed as soon as this
  * function returns.
  */
 int ib_register_device(struct ib_device *device, const char *name,
                struct device *dma_device)
 {
     int ret;
 
     ret = assign_name(device, name);
     if (ret)
         return ret;
 
     /*
      * If the caller does not provide a DMA capable device then the IB core
      * will set up ib_sge and scatterlist structures that stash the kernel
      * virtual address into the address field.
      */
     WARN_ON(dma_device && !dma_device->dma_parms);
     device->dma_device = dma_device;
 
     ret = setup_device(device);
     if (ret)
         return ret;
 
     ret = ib_cache_setup_one(device);
     if (ret) {
         dev_warn(&device->dev,
              "Couldn't set up InfiniBand P_Key/GID cache\n");
         return ret;
     }
 
     device->groups[0] = &ib_dev_attr_group;
     device->groups[1] = device->ops.device_group;
     ret = ib_setup_device_attrs(device);
     if (ret)
         goto cache_cleanup;
 
     ib_device_register_rdmacg(device);
 
     rdma_counter_init(device);
 
     /*
      * Ensure that ADD uevent is not fired because it
      * is too early amd device is not initialized yet.
      */
     dev_set_uevent_suppress(&device->dev, true);
     ret = device_add(&device->dev);
     if (ret)
         goto cg_cleanup;
 
     ret = ib_setup_port_attrs(&device->coredev);
     if (ret) {
         dev_warn(&device->dev,
              "Couldn't register device with driver model\n");
         goto dev_cleanup;
     }
 
     ret = enable_device_and_get(device);
     if (ret) {
         void (*dealloc_fn)(struct ib_device *);
 
         /*
          * If we hit this error flow then we don't want to
          * automatically dealloc the device since the caller is
          * expected to call ib_dealloc_device() after
          * ib_register_device() fails. This is tricky due to the
          * possibility for a parallel unregistration along with this
          * error flow. Since we have a refcount here we know any
          * parallel flow is stopped in disable_device and will see the
          * special dealloc_driver pointer, causing the responsibility to
          * ib_dealloc_device() to revert back to this thread.
          */
         dealloc_fn = device->ops.dealloc_driver;
         device->ops.dealloc_driver = prevent_dealloc_device;
         ib_device_put(device);
         __ib_unregister_device(device);
         device->ops.dealloc_driver = dealloc_fn;
         dev_set_uevent_suppress(&device->dev, false);
         return ret;
     }
     dev_set_uevent_suppress(&device->dev, false);
     /* Mark for userspace that device is ready */
     kobject_uevent(&device->dev.kobj, KOBJ_ADD);
     ib_device_put(device);
 
     return 0;
 
 dev_cleanup:
     device_del(&device->dev);
 cg_cleanup:
     dev_set_uevent_suppress(&device->dev, false);
     ib_device_unregister_rdmacg(device);
 cache_cleanup:
     ib_cache_cleanup_one(device);
     return ret;
 }
 EXPORT_SYMBOL(ib_register_device);
 
 /* Callers must hold a get on the device. */
 static void __ib_unregister_device(struct ib_device *ib_dev)
 {
     /*
      * We have a registration lock so that all the calls to unregister are
      * fully fenced, once any unregister returns the device is truely
      * unregistered even if multiple callers are unregistering it at the
      * same time. This also interacts with the registration flow and
      * provides sane semantics if register and unregister are racing.
      */
     mutex_lock(&ib_dev->unregistration_lock);
     if (!refcount_read(&ib_dev->refcount))
         goto out;
 
     disable_device(ib_dev);
 
     /* Expedite removing unregistered pointers from the hash table */
     free_netdevs(ib_dev);
 
     ib_free_port_attrs(&ib_dev->coredev);
     device_del(&ib_dev->dev);
     ib_device_unregister_rdmacg(ib_dev);
     ib_cache_cleanup_one(ib_dev);
 
     /*
      * Drivers using the new flow may not call ib_dealloc_device except
      * in error unwind prior to registration success.
      */
     if (ib_dev->ops.dealloc_driver &&
         ib_dev->ops.dealloc_driver != prevent_dealloc_device) {
         WARN_ON(kref_read(&ib_dev->dev.kobj.kref) <= 1);
         ib_dealloc_device(ib_dev);
     }
 out:
     mutex_unlock(&ib_dev->unregistration_lock);
 }
 
 /**
  * ib_unregister_device - Unregister an IB device
  * @ib_dev: The device to unregister
  *
  * Unregister an IB device.  All clients will receive a remove callback.
  *
  * Callers should call this routine only once, and protect against races with
  * registration. Typically it should only be called as part of a remove
  * callback in an implementation of driver core's struct device_driver and
  * related.
  *
  * If ops.dealloc_driver is used then ib_dev will be freed upon return from
  * this function.
  */
 void ib_unregister_device(struct ib_device *ib_dev)
 {
     get_device(&ib_dev->dev);
     __ib_unregister_device(ib_dev);
     put_device(&ib_dev->dev);
 }
 EXPORT_SYMBOL(ib_unregister_device);
 
 /**
  * ib_unregister_device_and_put - Unregister a device while holding a 'get'
  * @ib_dev: The device to unregister
  *
  * This is the same as ib_unregister_device(), except it includes an internal
  * ib_device_put() that should match a 'get' obtained by the caller.
  *
  * It is safe to call this routine concurrently from multiple threads while
  * holding the 'get'. When the function returns the device is fully
  * unregistered.
  *
  * Drivers using this flow MUST use the driver_unregister callback to clean up
  * their resources associated with the device and dealloc it.
  */
 void ib_unregister_device_and_put(struct ib_device *ib_dev)
 {
     WARN_ON(!ib_dev->ops.dealloc_driver);
     get_device(&ib_dev->dev);
     ib_device_put(ib_dev);
     __ib_unregister_device(ib_dev);
     put_device(&ib_dev->dev);
 }
 EXPORT_SYMBOL(ib_unregister_device_and_put);
 
 /**
  * ib_unregister_driver - Unregister all IB devices for a driver
  * @driver_id: The driver to unregister
  *
  * This implements a fence for device unregistration. It only returns once all
  * devices associated with the driver_id have fully completed their
  * unregistration and returned from ib_unregister_device*().
  *
  * If device's are not yet unregistered it goes ahead and starts unregistering
  * them.
  *
  * This does not block creation of new devices with the given driver_id, that
  * is the responsibility of the caller.
  */
 void ib_unregister_driver(enum rdma_driver_id driver_id)
 {
     struct ib_device *ib_dev;
     unsigned long index;
 
     down_read(&devices_rwsem);
     xa_for_each (&devices, index, ib_dev) {
         if (ib_dev->ops.driver_id != driver_id)
             continue;
 
         get_device(&ib_dev->dev);
         up_read(&devices_rwsem);
 
         WARN_ON(!ib_dev->ops.dealloc_driver);
         __ib_unregister_device(ib_dev);
 
         put_device(&ib_dev->dev);
         down_read(&devices_rwsem);
     }
     up_read(&devices_rwsem);
 }
 EXPORT_SYMBOL(ib_unregister_driver);
 
 static void ib_unregister_work(struct work_struct *work)
 {
     struct ib_device *ib_dev =
         container_of(work, struct ib_device, unregistration_work);
 
     __ib_unregister_device(ib_dev);
     put_device(&ib_dev->dev);
 }
 
 /**
  * ib_unregister_device_queued - Unregister a device using a work queue
  * @ib_dev: The device to unregister
  *
  * This schedules an asynchronous unregistration using a WQ for the device. A
  * driver should use this to avoid holding locks while doing unregistration,
  * such as holding the RTNL lock.
  *
  * Drivers using this API must use ib_unregister_driver before module unload
  * to ensure that all scheduled unregistrations have completed.
  */
 void ib_unregister_device_queued(struct ib_device *ib_dev)
 {
     WARN_ON(!refcount_read(&ib_dev->refcount));
     WARN_ON(!ib_dev->ops.dealloc_driver);
     get_device(&ib_dev->dev);
     if (!queue_work(ib_unreg_wq, &ib_dev->unregistration_work))
         put_device(&ib_dev->dev);
 }
 EXPORT_SYMBOL(ib_unregister_device_queued);
 
 /*
  * The caller must pass in a device that has the kref held and the refcount
  * released. If the device is in cur_net and still registered then it is moved
  * into net.
  */
 static int rdma_dev_change_netns(struct ib_device *device, struct net *cur_net,
                  struct net *net)
 {
     int ret2 = -EINVAL;
     int ret;
 
     mutex_lock(&device->unregistration_lock);
 
     /*
      * If a device not under ib_device_get() or if the unregistration_lock
      * is not held, the namespace can be changed, or it can be unregistered.
      * Check again under the lock.
      */
     if (refcount_read(&device->refcount) == 0 ||
         !net_eq(cur_net, read_pnet(&device->coredev.rdma_net))) {
         ret = -ENODEV;
         goto out;
     }
 
     kobject_uevent(&device->dev.kobj, KOBJ_REMOVE);
     disable_device(device);
 
     /*
      * At this point no one can be using the device, so it is safe to
      * change the namespace.
      */
     write_pnet(&device->coredev.rdma_net, net);
 
     down_read(&devices_rwsem);
     /*
      * Currently rdma devices are system wide unique. So the device name
      * is guaranteed free in the new namespace. Publish the new namespace
      * at the sysfs level.
      */
     ret = device_rename(&device->dev, dev_name(&device->dev));
     up_read(&devices_rwsem);
     if (ret) {
         dev_warn(&device->dev,
              "%s: Couldn't rename device after namespace change\n",
              __func__);
         /* Try and put things back and re-enable the device */
         write_pnet(&device->coredev.rdma_net, cur_net);
     }
 
     ret2 = enable_device_and_get(device);
     if (ret2) {
         /*
          * This shouldn't really happen, but if it does, let the user
          * retry at later point. So don't disable the device.
          */
         dev_warn(&device->dev,
              "%s: Couldn't re-enable device after namespace change\n",
              __func__);
     }
     kobject_uevent(&device->dev.kobj, KOBJ_ADD);
 
     ib_device_put(device);
 out:
     mutex_unlock(&device->unregistration_lock);
     if (ret)
         return ret;
     return ret2;
 }
 
 int ib_device_set_netns_put(struct sk_buff *skb,
                 struct ib_device *dev, u32 ns_fd)
 {
     struct net *net;
     int ret;
 
     net = get_net_ns_by_fd(ns_fd);
     if (IS_ERR(net)) {
         ret = PTR_ERR(net);
         goto net_err;
     }
 
     if (!netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN)) {
         ret = -EPERM;
         goto ns_err;
     }
 
     /*
      * All the ib_clients, including uverbs, are reset when the namespace is
      * changed and this cannot be blocked waiting for userspace to do
      * something, so disassociation is mandatory.
      */
     if (!dev->ops.disassociate_ucontext || ib_devices_shared_netns) {
         ret = -EOPNOTSUPP;
         goto ns_err;
     }
 
     get_device(&dev->dev);
     ib_device_put(dev);
     ret = rdma_dev_change_netns(dev, current->nsproxy->net_ns, net);
     put_device(&dev->dev);
 
     put_net(net);
     return ret;
 
 ns_err:
     put_net(net);
 net_err:
     ib_device_put(dev);
     return ret;
 }
 
 static struct pernet_operations rdma_dev_net_ops = {
     .init = rdma_dev_init_net,
     .exit = rdma_dev_exit_net,
     .id = &rdma_dev_net_id,
     .size = sizeof(struct rdma_dev_net),
 };
 
 static int assign_client_id(struct ib_client *client)
 {
     int ret;
 
     down_write(&clients_rwsem);
     /*
      * The add/remove callbacks must be called in FIFO/LIFO order. To
      * achieve this we assign client_ids so they are sorted in
      * registration order.
      */
     client->client_id = highest_client_id;
     ret = xa_insert(&clients, client->client_id, client, GFP_KERNEL);
     if (ret)
         goto out;
 
     highest_client_id++;
     xa_set_mark(&clients, client->client_id, CLIENT_REGISTERED);
 
 out:
     up_write(&clients_rwsem);
     return ret;
 }
 
 static void remove_client_id(struct ib_client *client)
 {
     down_write(&clients_rwsem);
     xa_erase(&clients, client->client_id);
     for (; highest_client_id; highest_client_id--)
         if (xa_load(&clients, highest_client_id - 1))
             break;
     up_write(&clients_rwsem);
 }
 
 /**
  * ib_register_client - Register an IB client
  * @client:Client to register
  *
  * Upper level users of the IB drivers can use ib_register_client() to
  * register callbacks for IB device addition and removal.  When an IB
  * device is added, each registered client's add method will be called
  * (in the order the clients were registered), and when a device is
  * removed, each client's remove method will be called (in the reverse
  * order that clients were registered).  In addition, when
  * ib_register_client() is called, the client will receive an add
  * callback for all devices already registered.
  */
 int ib_register_client(struct ib_client *client)
 {
     struct ib_device *device;
     unsigned long index;
     int ret;
 
     refcount_set(&client->uses, 1);
     init_completion(&client->uses_zero);
     ret = assign_client_id(client);
     if (ret)
         return ret;
 
     down_read(&devices_rwsem);
     xa_for_each_marked (&devices, index, device, DEVICE_REGISTERED) {
         ret = add_client_context(device, client);
         if (ret) {
             up_read(&devices_rwsem);
             ib_unregister_client(client);
             return ret;
         }
     }
     up_read(&devices_rwsem);
     return 0;
 }
 EXPORT_SYMBOL(ib_register_client);
 
 /**
  * ib_unregister_client - Unregister an IB client
  * @client:Client to unregister
  *
  * Upper level users use ib_unregister_client() to remove their client
  * registration.  When ib_unregister_client() is called, the client
  * will receive a remove callback for each IB device still registered.
  *
  * This is a full fence, once it returns no client callbacks will be called,
  * or are running in another thread.
  */
 void ib_unregister_client(struct ib_client *client)
 {
     struct ib_device *device;
     unsigned long index;
 
     down_write(&clients_rwsem);
     ib_client_put(client);
     xa_clear_mark(&clients, client->client_id, CLIENT_REGISTERED);
     up_write(&clients_rwsem);
 
     /* We do not want to have locks while calling client->remove() */
     rcu_read_lock();
     xa_for_each (&devices, index, device) {
         if (!ib_device_try_get(device))
             continue;
         rcu_read_unlock();
 
         remove_client_context(device, client->client_id);
 
         ib_device_put(device);
         rcu_read_lock();
     }
     rcu_read_unlock();
 
     /*
      * remove_client_context() is not a fence, it can return even though a
      * removal is ongoing. Wait until all removals are completed.
      */
     wait_for_completion(&client->uses_zero);
     remove_client_id(client);
 }
 EXPORT_SYMBOL(ib_unregister_client);
 
 static int __ib_get_global_client_nl_info(const char *client_name,
                       struct ib_client_nl_info *res)
 {
     struct ib_client *client;
     unsigned long index;
     int ret = -ENOENT;
 
     down_read(&clients_rwsem);
     xa_for_each_marked (&clients, index, client, CLIENT_REGISTERED) {
         if (strcmp(client->name, client_name) != 0)
             continue;
         if (!client->get_global_nl_info) {
             ret = -EOPNOTSUPP;
             break;
         }
         ret = client->get_global_nl_info(res);
         if (WARN_ON(ret == -ENOENT))
             ret = -EINVAL;
         if (!ret && res->cdev)
             get_device(res->cdev);
         break;
     }
     up_read(&clients_rwsem);
     return ret;
 }
 
 static int __ib_get_client_nl_info(struct ib_device *ibdev,
                    const char *client_name,
                    struct ib_client_nl_info *res)
 {
     unsigned long index;
     void *client_data;
     int ret = -ENOENT;
 
     down_read(&ibdev->client_data_rwsem);
     xan_for_each_marked (&ibdev->client_data, index, client_data,
                  CLIENT_DATA_REGISTERED) {
         struct ib_client *client = xa_load(&clients, index);
 
         if (!client || strcmp(client->name, client_name) != 0)
             continue;
         if (!client->get_nl_info) {
             ret = -EOPNOTSUPP;
             break;
         }
         ret = client->get_nl_info(ibdev, client_data, res);
         if (WARN_ON(ret == -ENOENT))
             ret = -EINVAL;
 
         /*
          * The cdev is guaranteed valid as long as we are inside the
          * client_data_rwsem as remove_one can't be called. Keep it
          * valid for the caller.
          */
         if (!ret && res->cdev)
             get_device(res->cdev);
         break;
     }
     up_read(&ibdev->client_data_rwsem);
 
     return ret;
 }
 
 /**
  * ib_get_client_nl_info - Fetch the nl_info from a client
  * @ibdev: IB device
  * @client_name: Name of the client
  * @res: Result of the query
  */
 int ib_get_client_nl_info(struct ib_device *ibdev, const char *client_name,
               struct ib_client_nl_info *res)
 {
     int ret;
 
     if (ibdev)
         ret = __ib_get_client_nl_info(ibdev, client_name, res);
     else
         ret = __ib_get_global_client_nl_info(client_name, res);
 #ifdef CONFIG_MODULES
     if (ret == -ENOENT) {
         request_module("rdma-client-%s", client_name);
         if (ibdev)
             ret = __ib_get_client_nl_info(ibdev, client_name, res);
         else
             ret = __ib_get_global_client_nl_info(client_name, res);
     }
 #endif
     if (ret) {
         if (ret == -ENOENT)
             return -EOPNOTSUPP;
         return ret;
     }
 
     if (WARN_ON(!res->cdev))
         return -EINVAL;
     return 0;
 }
 
 /**
  * ib_set_client_data - Set IB client context
  * @device:Device to set context for
  * @client:Client to set context for
  * @data:Context to set
  *
  * ib_set_client_data() sets client context data that can be retrieved with
  * ib_get_client_data(). This can only be called while the client is
  * registered to the device, once the ib_client remove() callback returns this
  * cannot be called.
  */
 void ib_set_client_data(struct ib_device *device, struct ib_client *client,
             void *data)
 {
     void *rc;
 
     if (WARN_ON(IS_ERR(data)))
         data = NULL;
 
     rc = xa_store(&device->client_data, client->client_id, data,
               GFP_KERNEL);
     WARN_ON(xa_is_err(rc));
 }
 EXPORT_SYMBOL(ib_set_client_data);
 
 /**
  * ib_register_event_handler - Register an IB event handler
  * @event_handler:Handler to register
  *
  * ib_register_event_handler() registers an event handler that will be
  * called back when asynchronous IB events occur (as defined in
  * chapter 11 of the InfiniBand Architecture Specification). This
  * callback occurs in workqueue context.
  */
 void ib_register_event_handler(struct ib_event_handler *event_handler)
 {
     down_write(&event_handler->device->event_handler_rwsem);
     list_add_tail(&event_handler->list,
               &event_handler->device->event_handler_list);
     up_write(&event_handler->device->event_handler_rwsem);
 }
 EXPORT_SYMBOL(ib_register_event_handler);
 
 /**
  * ib_unregister_event_handler - Unregister an event handler
  * @event_handler:Handler to unregister
  *
  * Unregister an event handler registered with
  * ib_register_event_handler().
  */
 void ib_unregister_event_handler(struct ib_event_handler *event_handler)
 {
     down_write(&event_handler->device->event_handler_rwsem);
     list_del(&event_handler->list);
     up_write(&event_handler->device->event_handler_rwsem);
 }
 EXPORT_SYMBOL(ib_unregister_event_handler);
 
 void ib_dispatch_event_clients(struct ib_event *event)
 {
     struct ib_event_handler *handler;
 
     down_read(&event->device->event_handler_rwsem);
 
     list_for_each_entry(handler, &event->device->event_handler_list, list)
         handler->handler(handler, event);
 
     up_read(&event->device->event_handler_rwsem);
 }
 
 static int iw_query_port(struct ib_device *device,
                u32 port_num,
                struct ib_port_attr *port_attr)
 {
     struct in_device *inetdev;
     struct net_device *netdev;
 
     memset(port_attr, 0, sizeof(*port_attr));
 
     netdev = ib_device_get_netdev(device, port_num);
     if (!netdev)
         return -ENODEV;
 
     port_attr->max_mtu = IB_MTU_4096;
     port_attr->active_mtu = ib_mtu_int_to_enum(netdev->mtu);
 
     if (!netif_carrier_ok(netdev)) {
         port_attr->state = IB_PORT_DOWN;
         port_attr->phys_state = IB_PORT_PHYS_STATE_DISABLED;
     } else {
         rcu_read_lock();
         inetdev = __in_dev_get_rcu(netdev);
 
         if (inetdev && inetdev->ifa_list) {
             port_attr->state = IB_PORT_ACTIVE;
             port_attr->phys_state = IB_PORT_PHYS_STATE_LINK_UP;
         } else {
             port_attr->state = IB_PORT_INIT;
             port_attr->phys_state =
                 IB_PORT_PHYS_STATE_PORT_CONFIGURATION_TRAINING;
         }
 
         rcu_read_unlock();
     }
 
     dev_put(netdev);
     return device->ops.query_port(device, port_num, port_attr);
 }
 
 static int __ib_query_port(struct ib_device *device,
                u32 port_num,
                struct ib_port_attr *port_attr)
 {
     int err;
 
     memset(port_attr, 0, sizeof(*port_attr));
 
     err = device->ops.query_port(device, port_num, port_attr);
     if (err || port_attr->subnet_prefix)
         return err;
 
     if (rdma_port_get_link_layer(device, port_num) !=
         IB_LINK_LAYER_INFINIBAND)
         return 0;
 
     ib_get_cached_subnet_prefix(device, port_num,
                     &port_attr->subnet_prefix);
     return 0;
 }
 
 /**
  * ib_query_port - Query IB port attributes
  * @device:Device to query
  * @port_num:Port number to query
  * @port_attr:Port attributes
  *
  * ib_query_port() returns the attributes of a port through the
  * @port_attr pointer.
  */
 int ib_query_port(struct ib_device *device,
           u32 port_num,
           struct ib_port_attr *port_attr)
 {
     if (!rdma_is_port_valid(device, port_num))
         return -EINVAL;
 
     if (rdma_protocol_iwarp(device, port_num))
         return iw_query_port(device, port_num, port_attr);
     else
         return __ib_query_port(device, port_num, port_attr);
 }
 EXPORT_SYMBOL(ib_query_port);
 
 static void add_ndev_hash(struct ib_port_data *pdata)
 {
     unsigned long flags;
 
     might_sleep();
 
     spin_lock_irqsave(&ndev_hash_lock, flags);
     if (hash_hashed(&pdata->ndev_hash_link)) {
         hash_del_rcu(&pdata->ndev_hash_link);
         spin_unlock_irqrestore(&ndev_hash_lock, flags);
         /*
          * We cannot do hash_add_rcu after a hash_del_rcu until the
          * grace period
          */
         synchronize_rcu();
         spin_lock_irqsave(&ndev_hash_lock, flags);
     }
     if (pdata->netdev)
         hash_add_rcu(ndev_hash, &pdata->ndev_hash_link,
                  (uintptr_t)pdata->netdev);
     spin_unlock_irqrestore(&ndev_hash_lock, flags);
 }
 
 /**
  * ib_device_set_netdev - Associate the ib_dev with an underlying net_device
  * @ib_dev: Device to modify
  * @ndev: net_device to affiliate, may be NULL
  * @port: IB port the net_device is connected to
  *
  * Drivers should use this to link the ib_device to a netdev so the netdev
  * shows up in interfaces like ib_enum_roce_netdev. Only one netdev may be
  * affiliated with any port.
  *
  * The caller must ensure that the given ndev is not unregistered or
  * unregistering, and that either the ib_device is unregistered or
  * ib_device_set_netdev() is called with NULL when the ndev sends a
  * NETDEV_UNREGISTER event.
  */
 int ib_device_set_netdev(struct ib_device *ib_dev, struct net_device *ndev,
              u32 port)
 {
     struct net_device *old_ndev;
     struct ib_port_data *pdata;
     unsigned long flags;
     int ret;
 
     /*
      * Drivers wish to call this before ib_register_driver, so we have to
      * setup the port data early.
      */
     ret = alloc_port_data(ib_dev);
     if (ret)
         return ret;
 
     if (!rdma_is_port_valid(ib_dev, port))
         return -EINVAL;
 
     pdata = &ib_dev->port_data[port];
     spin_lock_irqsave(&pdata->netdev_lock, flags);
     old_ndev = rcu_dereference_protected(
         pdata->netdev, lockdep_is_held(&pdata->netdev_lock));
     if (old_ndev == ndev) {
         spin_unlock_irqrestore(&pdata->netdev_lock, flags);
         return 0;
     }
 
     if (ndev)
         dev_hold(ndev);
     rcu_assign_pointer(pdata->netdev, ndev);
     spin_unlock_irqrestore(&pdata->netdev_lock, flags);
 
     add_ndev_hash(pdata);
     if (old_ndev)
         dev_put(old_ndev);
 
     return 0;
 }
 EXPORT_SYMBOL(ib_device_set_netdev);
 
 static void free_netdevs(struct ib_device *ib_dev)
 {
     unsigned long flags;
     u32 port;
 
     if (!ib_dev->port_data)
         return;
 
     rdma_for_each_port (ib_dev, port) {
         struct ib_port_data *pdata = &ib_dev->port_data[port];
         struct net_device *ndev;
 
         spin_lock_irqsave(&pdata->netdev_lock, flags);
         ndev = rcu_dereference_protected(
             pdata->netdev, lockdep_is_held(&pdata->netdev_lock));
         if (ndev) {
             spin_lock(&ndev_hash_lock);
             hash_del_rcu(&pdata->ndev_hash_link);
             spin_unlock(&ndev_hash_lock);
 
             /*
              * If this is the last dev_put there is still a
              * synchronize_rcu before the netdev is kfreed, so we
              * can continue to rely on unlocked pointer
              * comparisons after the put
              */
             rcu_assign_pointer(pdata->netdev, NULL);
             dev_put(ndev);
         }
         spin_unlock_irqrestore(&pdata->netdev_lock, flags);
     }
 }
 
 struct net_device *ib_device_get_netdev(struct ib_device *ib_dev,
                     u32 port)
 {
     struct ib_port_data *pdata;
     struct net_device *res;
 
     if (!rdma_is_port_valid(ib_dev, port))
         return NULL;
 
     pdata = &ib_dev->port_data[port];
 
     /*
      * New drivers should use ib_device_set_netdev() not the legacy
      * get_netdev().
      */
     if (ib_dev->ops.get_netdev)
         res = ib_dev->ops.get_netdev(ib_dev, port);
     else {
         spin_lock(&pdata->netdev_lock);
         res = rcu_dereference_protected(
             pdata->netdev, lockdep_is_held(&pdata->netdev_lock));
         if (res)
             dev_hold(res);
         spin_unlock(&pdata->netdev_lock);
     }
 
     /*
      * If we are starting to unregister expedite things by preventing
      * propagation of an unregistering netdev.
      */
     if (res && res->reg_state != NETREG_REGISTERED) {
         dev_put(res);
         return NULL;
     }
 
     return res;
 }
 
 /**
  * ib_device_get_by_netdev - Find an IB device associated with a netdev
  * @ndev: netdev to locate
  * @driver_id: The driver ID that must match (RDMA_DRIVER_UNKNOWN matches all)
  *
  * Find and hold an ib_device that is associated with a netdev via
  * ib_device_set_netdev(). The caller must call ib_device_put() on the
  * returned pointer.
  */
 struct ib_device *ib_device_get_by_netdev(struct net_device *ndev,
                       enum rdma_driver_id driver_id)
 {
     struct ib_device *res = NULL;
     struct ib_port_data *cur;
 
     rcu_read_lock();
     hash_for_each_possible_rcu (ndev_hash, cur, ndev_hash_link,
                     (uintptr_t)ndev) {
         if (rcu_access_pointer(cur->netdev) == ndev &&
             (driver_id == RDMA_DRIVER_UNKNOWN ||
              cur->ib_dev->ops.driver_id == driver_id) &&
             ib_device_try_get(cur->ib_dev)) {
             res = cur->ib_dev;
             break;
         }
     }
     rcu_read_unlock();
 
     return res;
 }
 EXPORT_SYMBOL(ib_device_get_by_netdev);
 
 /**
  * ib_enum_roce_netdev - enumerate all RoCE ports
  * @ib_dev : IB device we want to query
  * @filter: Should we call the callback?
  * @filter_cookie: Cookie passed to filter
  * @cb: Callback to call for each found RoCE ports
  * @cookie: Cookie passed back to the callback
  *
  * Enumerates all of the physical RoCE ports of ib_dev
  * which are related to netdevice and calls callback() on each
  * device for which filter() function returns non zero.
  */
 void ib_enum_roce_netdev(struct ib_device *ib_dev,
              roce_netdev_filter filter,
              void *filter_cookie,
              roce_netdev_callback cb,
              void *cookie)
 {
     u32 port;
 
     rdma_for_each_port (ib_dev, port)
         if (rdma_protocol_roce(ib_dev, port)) {
             struct net_device *idev =
                 ib_device_get_netdev(ib_dev, port);
 
             if (filter(ib_dev, port, idev, filter_cookie))
                 cb(ib_dev, port, idev, cookie);
 
             if (idev)
                 dev_put(idev);
         }
 }
 
 /**
  * ib_enum_all_roce_netdevs - enumerate all RoCE devices
  * @filter: Should we call the callback?
  * @filter_cookie: Cookie passed to filter
  * @cb: Callback to call for each found RoCE ports
  * @cookie: Cookie passed back to the callback
  *
  * Enumerates all RoCE devices' physical ports which are related
  * to netdevices and calls callback() on each device for which
  * filter() function returns non zero.
  */
 void ib_enum_all_roce_netdevs(roce_netdev_filter filter,
                   void *filter_cookie,
                   roce_netdev_callback cb,
                   void *cookie)
 {
     struct ib_device *dev;
     unsigned long index;
 
     down_read(&devices_rwsem);
     xa_for_each_marked (&devices, index, dev, DEVICE_REGISTERED)
         ib_enum_roce_netdev(dev, filter, filter_cookie, cb, cookie);
     up_read(&devices_rwsem);
 }
 
 /*
  * ib_enum_all_devs - enumerate all ib_devices
  * @cb: Callback to call for each found ib_device
  *
  * Enumerates all ib_devices and calls callback() on each device.
  */
 int ib_enum_all_devs(nldev_callback nldev_cb, struct sk_buff *skb,
              struct netlink_callback *cb)
 {
     unsigned long index;
     struct ib_device *dev;
     unsigned int idx = 0;
     int ret = 0;
 
     down_read(&devices_rwsem);
     xa_for_each_marked (&devices, index, dev, DEVICE_REGISTERED) {
         if (!rdma_dev_access_netns(dev, sock_net(skb->sk)))
             continue;
 
         ret = nldev_cb(dev, skb, cb, idx);
         if (ret)
             break;
         idx++;
     }
     up_read(&devices_rwsem);
     return ret;
 }
 
 /**
  * ib_query_pkey - Get P_Key table entry
  * @device:Device to query
  * @port_num:Port number to query
  * @index:P_Key table index to query
  * @pkey:Returned P_Key
  *
  * ib_query_pkey() fetches the specified P_Key table entry.
  */
 int ib_query_pkey(struct ib_device *device,
           u32 port_num, u16 index, u16 *pkey)
 {
     if (!rdma_is_port_valid(device, port_num))
         return -EINVAL;
 
     if (!device->ops.query_pkey)
         return -EOPNOTSUPP;
 
     return device->ops.query_pkey(device, port_num, index, pkey);
 }
 EXPORT_SYMBOL(ib_query_pkey);
 
 /**
  * ib_modify_device - Change IB device attributes
  * @device:Device to modify
  * @device_modify_mask:Mask of attributes to change
  * @device_modify:New attribute values
  *
  * ib_modify_device() changes a device's attributes as specified by
  * the @device_modify_mask and @device_modify structure.
  */
 int ib_modify_device(struct ib_device *device,
              int device_modify_mask,
              struct ib_device_modify *device_modify)
 {
     if (!device->ops.modify_device)
         return -EOPNOTSUPP;
 
     return device->ops.modify_device(device, device_modify_mask,
                      device_modify);
 }
 EXPORT_SYMBOL(ib_modify_device);
 
 /**
  * ib_modify_port - Modifies the attributes for the specified port.
  * @device: The device to modify.
  * @port_num: The number of the port to modify.
  * @port_modify_mask: Mask used to specify which attributes of the port
  *   to change.
  * @port_modify: New attribute values for the port.
  *
  * ib_modify_port() changes a port's attributes as specified by the
  * @port_modify_mask and @port_modify structure.
  */
 int ib_modify_port(struct ib_device *device,
            u32 port_num, int port_modify_mask,
            struct ib_port_modify *port_modify)
 {
     int rc;
 
     if (!rdma_is_port_valid(device, port_num))
         return -EINVAL;
 
     if (device->ops.modify_port)
         rc = device->ops.modify_port(device, port_num,
                          port_modify_mask,
                          port_modify);
     else if (rdma_protocol_roce(device, port_num) &&
          ((port_modify->set_port_cap_mask & ~IB_PORT_CM_SUP) == 0 ||
           (port_modify->clr_port_cap_mask & ~IB_PORT_CM_SUP) == 0))
         rc = 0;
     else
         rc = -EOPNOTSUPP;
     return rc;
 }
 EXPORT_SYMBOL(ib_modify_port);
 
 /**
  * ib_find_gid - Returns the port number and GID table index where
  *   a specified GID value occurs. Its searches only for IB link layer.
  * @device: The device to query.
  * @gid: The GID value to search for.
  * @port_num: The port number of the device where the GID value was found.
  * @index: The index into the GID table where the GID was found.  This
  *   parameter may be NULL.
  */
 int ib_find_gid(struct ib_device *device, union ib_gid *gid,
         u32 *port_num, u16 *index)
 {
     union ib_gid tmp_gid;
     u32 port;
     int ret, i;
 
     rdma_for_each_port (device, port) {
         if (!rdma_protocol_ib(device, port))
             continue;
 
         for (i = 0; i < device->port_data[port].immutable.gid_tbl_len;
              ++i) {
             ret = rdma_query_gid(device, port, i, &tmp_gid);
             if (ret)
                 continue;
 
             if (!memcmp(&tmp_gid, gid, sizeof *gid)) {
                 *port_num = port;
                 if (index)
                     *index = i;
                 return 0;
             }
         }
     }
 
     return -ENOENT;
 }
 EXPORT_SYMBOL(ib_find_gid);
 
 /**
  * ib_find_pkey - Returns the PKey table index where a specified
  *   PKey value occurs.
  * @device: The device to query.
  * @port_num: The port number of the device to search for the PKey.
  * @pkey: The PKey value to search for.
  * @index: The index into the PKey table where the PKey was found.
  */
 int ib_find_pkey(struct ib_device *device,
          u32 port_num, u16 pkey, u16 *index)
 {
     int ret, i;
     u16 tmp_pkey;
     int partial_ix = -1;
 
     for (i = 0; i < device->port_data[port_num].immutable.pkey_tbl_len;
          ++i) {
         ret = ib_query_pkey(device, port_num, i, &tmp_pkey);
         if (ret)
             return ret;
         if ((pkey & 0x7fff) == (tmp_pkey & 0x7fff)) {
             /* if there is full-member pkey take it.*/
             if (tmp_pkey & 0x8000) {
                 *index = i;
                 return 0;
             }
             if (partial_ix < 0)
                 partial_ix = i;
         }
     }
 
     /*no full-member, if exists take the limited*/
     if (partial_ix >= 0) {
         *index = partial_ix;
         return 0;
     }
     return -ENOENT;
 }
 EXPORT_SYMBOL(ib_find_pkey);
 
 /**
  * ib_get_net_dev_by_params() - Return the appropriate net_dev
  * for a received CM request
  * @dev:    An RDMA device on which the request has been received.
  * @port:   Port number on the RDMA device.
  * @pkey:   The Pkey the request came on.
  * @gid:    A GID that the net_dev uses to communicate.
  * @addr:   Contains the IP address that the request specified as its
  *      destination.
  *
  */
 struct net_device *ib_get_net_dev_by_params(struct ib_device *dev,
                         u32 port,
                         u16 pkey,
                         const union ib_gid *gid,
                         const struct sockaddr *addr)
 {
     struct net_device *net_dev = NULL;
     unsigned long index;
     void *client_data;
 
     if (!rdma_protocol_ib(dev, port))
         return NULL;
 
     /*
      * Holding the read side guarantees that the client will not become
      * unregistered while we are calling get_net_dev_by_params()
      */
     down_read(&dev->client_data_rwsem);
     xan_for_each_marked (&dev->client_data, index, client_data,
                  CLIENT_DATA_REGISTERED) {
         struct ib_client *client = xa_load(&clients, index);
 
         if (!client || !client->get_net_dev_by_params)
             continue;
 
         net_dev = client->get_net_dev_by_params(dev, port, pkey, gid,
                             addr, client_data);
         if (net_dev)
             break;
     }
     up_read(&dev->client_data_rwsem);
 
     return net_dev;
 }
 EXPORT_SYMBOL(ib_get_net_dev_by_params);
 
 void ib_set_device_ops(struct ib_device *dev, const struct ib_device_ops *ops)
 {
     struct ib_device_ops *dev_ops = &dev->ops;
 #define SET_DEVICE_OP(ptr, name)                                               \
     do {                                                                   \
         if (ops->name)                                                 \
             if (!((ptr)->name))                    \
                 (ptr)->name = ops->name;                       \
     } while (0)
 
 #define SET_OBJ_SIZE(ptr, name) SET_DEVICE_OP(ptr, size_##name)
 
     if (ops->driver_id != RDMA_DRIVER_UNKNOWN) {
         WARN_ON(dev_ops->driver_id != RDMA_DRIVER_UNKNOWN &&
             dev_ops->driver_id != ops->driver_id);
         dev_ops->driver_id = ops->driver_id;
     }
     if (ops->owner) {
         WARN_ON(dev_ops->owner && dev_ops->owner != ops->owner);
         dev_ops->owner = ops->owner;
     }
     if (ops->uverbs_abi_ver)
         dev_ops->uverbs_abi_ver = ops->uverbs_abi_ver;
 
     dev_ops->uverbs_no_driver_id_binding |=
         ops->uverbs_no_driver_id_binding;
 
     SET_DEVICE_OP(dev_ops, add_gid);
     SET_DEVICE_OP(dev_ops, advise_mr);
     SET_DEVICE_OP(dev_ops, alloc_dm);
     SET_DEVICE_OP(dev_ops, alloc_hw_device_stats);
     SET_DEVICE_OP(dev_ops, alloc_hw_port_stats);
     SET_DEVICE_OP(dev_ops, alloc_mr);
     SET_DEVICE_OP(dev_ops, alloc_mr_integrity);
     SET_DEVICE_OP(dev_ops, alloc_mw);
     SET_DEVICE_OP(dev_ops, alloc_pd);
     SET_DEVICE_OP(dev_ops, alloc_rdma_netdev);
     SET_DEVICE_OP(dev_ops, alloc_ucontext);
     SET_DEVICE_OP(dev_ops, alloc_xrcd);
     SET_DEVICE_OP(dev_ops, attach_mcast);
     SET_DEVICE_OP(dev_ops, check_mr_status);
     SET_DEVICE_OP(dev_ops, counter_alloc_stats);
     SET_DEVICE_OP(dev_ops, counter_bind_qp);
     SET_DEVICE_OP(dev_ops, counter_dealloc);
     SET_DEVICE_OP(dev_ops, counter_unbind_qp);
     SET_DEVICE_OP(dev_ops, counter_update_stats);
     SET_DEVICE_OP(dev_ops, create_ah);
     SET_DEVICE_OP(dev_ops, create_counters);
     SET_DEVICE_OP(dev_ops, create_cq);
     SET_DEVICE_OP(dev_ops, create_flow);
     SET_DEVICE_OP(dev_ops, create_qp);
     SET_DEVICE_OP(dev_ops, create_rwq_ind_table);
     SET_DEVICE_OP(dev_ops, create_srq);
     SET_DEVICE_OP(dev_ops, create_user_ah);
     SET_DEVICE_OP(dev_ops, create_wq);
     SET_DEVICE_OP(dev_ops, dealloc_dm);
     SET_DEVICE_OP(dev_ops, dealloc_driver);
     SET_DEVICE_OP(dev_ops, dealloc_mw);
     SET_DEVICE_OP(dev_ops, dealloc_pd);
     SET_DEVICE_OP(dev_ops, dealloc_ucontext);
     SET_DEVICE_OP(dev_ops, dealloc_xrcd);
     SET_DEVICE_OP(dev_ops, del_gid);
     SET_DEVICE_OP(dev_ops, dereg_mr);
     SET_DEVICE_OP(dev_ops, destroy_ah);
     SET_DEVICE_OP(dev_ops, destroy_counters);
     SET_DEVICE_OP(dev_ops, destroy_cq);
     SET_DEVICE_OP(dev_ops, destroy_flow);
     SET_DEVICE_OP(dev_ops, destroy_flow_action);
     SET_DEVICE_OP(dev_ops, destroy_qp);
     SET_DEVICE_OP(dev_ops, destroy_rwq_ind_table);
     SET_DEVICE_OP(dev_ops, destroy_srq);
     SET_DEVICE_OP(dev_ops, destroy_wq);
     SET_DEVICE_OP(dev_ops, device_group);
     SET_DEVICE_OP(dev_ops, detach_mcast);
     SET_DEVICE_OP(dev_ops, disassociate_ucontext);
     SET_DEVICE_OP(dev_ops, drain_rq);
     SET_DEVICE_OP(dev_ops, drain_sq);
     SET_DEVICE_OP(dev_ops, enable_driver);
     SET_DEVICE_OP(dev_ops, fill_res_cm_id_entry);
     SET_DEVICE_OP(dev_ops, fill_res_cq_entry);
     SET_DEVICE_OP(dev_ops, fill_res_cq_entry_raw);
     SET_DEVICE_OP(dev_ops, fill_res_mr_entry);
     SET_DEVICE_OP(dev_ops, fill_res_mr_entry_raw);
     SET_DEVICE_OP(dev_ops, fill_res_qp_entry);
     SET_DEVICE_OP(dev_ops, fill_res_qp_entry_raw);
     SET_DEVICE_OP(dev_ops, fill_stat_mr_entry);
     SET_DEVICE_OP(dev_ops, get_dev_fw_str);
     SET_DEVICE_OP(dev_ops, get_dma_mr);
     SET_DEVICE_OP(dev_ops, get_hw_stats);
     SET_DEVICE_OP(dev_ops, get_link_layer);
     SET_DEVICE_OP(dev_ops, get_netdev);
     SET_DEVICE_OP(dev_ops, get_numa_node);
     SET_DEVICE_OP(dev_ops, get_port_immutable);
     SET_DEVICE_OP(dev_ops, get_vector_affinity);
     SET_DEVICE_OP(dev_ops, get_vf_config);
     SET_DEVICE_OP(dev_ops, get_vf_guid);
     SET_DEVICE_OP(dev_ops, get_vf_stats);
     SET_DEVICE_OP(dev_ops, iw_accept);
     SET_DEVICE_OP(dev_ops, iw_add_ref);
     SET_DEVICE_OP(dev_ops, iw_connect);
     SET_DEVICE_OP(dev_ops, iw_create_listen);
     SET_DEVICE_OP(dev_ops, iw_destroy_listen);
     SET_DEVICE_OP(dev_ops, iw_get_qp);
     SET_DEVICE_OP(dev_ops, iw_reject);
     SET_DEVICE_OP(dev_ops, iw_rem_ref);
     SET_DEVICE_OP(dev_ops, map_mr_sg);
     SET_DEVICE_OP(dev_ops, map_mr_sg_pi);
     SET_DEVICE_OP(dev_ops, mmap);
     SET_DEVICE_OP(dev_ops, mmap_free);
     SET_DEVICE_OP(dev_ops, modify_ah);
     SET_DEVICE_OP(dev_ops, modify_cq);
     SET_DEVICE_OP(dev_ops, modify_device);
     SET_DEVICE_OP(dev_ops, modify_hw_stat);
     SET_DEVICE_OP(dev_ops, modify_port);
     SET_DEVICE_OP(dev_ops, modify_qp);
     SET_DEVICE_OP(dev_ops, modify_srq);
     SET_DEVICE_OP(dev_ops, modify_wq);
     SET_DEVICE_OP(dev_ops, peek_cq);
     SET_DEVICE_OP(dev_ops, poll_cq);
     SET_DEVICE_OP(dev_ops, port_groups);
     SET_DEVICE_OP(dev_ops, post_recv);
     SET_DEVICE_OP(dev_ops, post_send);
     SET_DEVICE_OP(dev_ops, post_srq_recv);
     SET_DEVICE_OP(dev_ops, process_mad);
     SET_DEVICE_OP(dev_ops, query_ah);
     SET_DEVICE_OP(dev_ops, query_device);
     SET_DEVICE_OP(dev_ops, query_gid);
     SET_DEVICE_OP(dev_ops, query_pkey);
     SET_DEVICE_OP(dev_ops, query_port);
     SET_DEVICE_OP(dev_ops, query_qp);
     SET_DEVICE_OP(dev_ops, query_srq);
     SET_DEVICE_OP(dev_ops, query_ucontext);
     SET_DEVICE_OP(dev_ops, rdma_netdev_get_params);
     SET_DEVICE_OP(dev_ops, read_counters);
     SET_DEVICE_OP(dev_ops, reg_dm_mr);
     SET_DEVICE_OP(dev_ops, reg_user_mr);
     SET_DEVICE_OP(dev_ops, reg_user_mr_dmabuf);
     SET_DEVICE_OP(dev_ops, req_notify_cq);
     SET_DEVICE_OP(dev_ops, rereg_user_mr);
     SET_DEVICE_OP(dev_ops, resize_cq);
     SET_DEVICE_OP(dev_ops, set_vf_guid);
     SET_DEVICE_OP(dev_ops, set_vf_link_state);
 
     SET_OBJ_SIZE(dev_ops, ib_ah);
     SET_OBJ_SIZE(dev_ops, ib_counters);
     SET_OBJ_SIZE(dev_ops, ib_cq);
     SET_OBJ_SIZE(dev_ops, ib_mw);
     SET_OBJ_SIZE(dev_ops, ib_pd);
     SET_OBJ_SIZE(dev_ops, ib_qp);
     SET_OBJ_SIZE(dev_ops, ib_rwq_ind_table);
     SET_OBJ_SIZE(dev_ops, ib_srq);
     SET_OBJ_SIZE(dev_ops, ib_ucontext);
     SET_OBJ_SIZE(dev_ops, ib_xrcd);
 }
 EXPORT_SYMBOL(ib_set_device_ops);
 
 #ifdef CONFIG_INFINIBAND_VIRT_DMA
 int ib_dma_virt_map_sg(struct ib_device *dev, struct scatterlist *sg, int nents)
 {
     struct scatterlist *s;
     int i;
 
     for_each_sg(sg, s, nents, i) {
         sg_dma_address(s) = (uintptr_t)sg_virt(s);
         sg_dma_len(s) = s->length;
     }
     return nents;
 }
 EXPORT_SYMBOL(ib_dma_virt_map_sg);
 #endif /* CONFIG_INFINIBAND_VIRT_DMA */
 
 static const struct rdma_nl_cbs ibnl_ls_cb_table[RDMA_NL_LS_NUM_OPS] = {
     [RDMA_NL_LS_OP_RESOLVE] = {
         .doit = ib_nl_handle_resolve_resp,
         .flags = RDMA_NL_ADMIN_PERM,
     },
     [RDMA_NL_LS_OP_SET_TIMEOUT] = {
         .doit = ib_nl_handle_set_timeout,
         .flags = RDMA_NL_ADMIN_PERM,
     },
     [RDMA_NL_LS_OP_IP_RESOLVE] = {
         .doit = ib_nl_handle_ip_res_resp,
         .flags = RDMA_NL_ADMIN_PERM,
     },
 };
 
 static int __init ib_core_init(void)
 {
     int ret = -ENOMEM;
 
     ib_wq = alloc_workqueue("infiniband", 0, 0);
     if (!ib_wq)
         return -ENOMEM;
 
     ib_unreg_wq = alloc_workqueue("ib-unreg-wq", WQ_UNBOUND,
                       WQ_UNBOUND_MAX_ACTIVE);
     if (!ib_unreg_wq)
         goto err;
 
     ib_comp_wq = alloc_workqueue("ib-comp-wq",
             WQ_HIGHPRI | WQ_MEM_RECLAIM | WQ_SYSFS, 0);
     if (!ib_comp_wq)
         goto err_unbound;
 
     ib_comp_unbound_wq =
         alloc_workqueue("ib-comp-unb-wq",
                 WQ_UNBOUND | WQ_HIGHPRI | WQ_MEM_RECLAIM |
                 WQ_SYSFS, WQ_UNBOUND_MAX_ACTIVE);
     if (!ib_comp_unbound_wq)
         goto err_comp;
 
     ret = class_register(&ib_class);
     if (ret) {
         pr_warn("Couldn't create InfiniBand device class\n");
         goto err_comp_unbound;
     }
 
     rdma_nl_init();
 
     ret = addr_init();
     if (ret) {
         pr_warn("Couldn't init IB address resolution\n");
         goto err_ibnl;
     }
 
     ret = ib_mad_init();
     if (ret) {
         pr_warn("Couldn't init IB MAD\n");
         goto err_addr;
     }
 
     ret = ib_sa_init();
     if (ret) {
         pr_warn("Couldn't init SA\n");
         goto err_mad;
     }
 
     ret = register_blocking_lsm_notifier(&ibdev_lsm_nb);
     if (ret) {
         pr_warn("Couldn't register LSM notifier. ret %d\n", ret);
         goto err_sa;
     }
 
     ret = register_pernet_device(&rdma_dev_net_ops);
     if (ret) {
         pr_warn("Couldn't init compat dev. ret %d\n", ret);
         goto err_compat;
     }
 
     nldev_init();
     rdma_nl_register(RDMA_NL_LS, ibnl_ls_cb_table);
     roce_gid_mgmt_init();
 
     return 0;
 
 err_compat:
     unregister_blocking_lsm_notifier(&ibdev_lsm_nb);
 err_sa:
     ib_sa_cleanup();
 err_mad:
     ib_mad_cleanup();
 err_addr:
     addr_cleanup();
 err_ibnl:
     class_unregister(&ib_class);
 err_comp_unbound:
     destroy_workqueue(ib_comp_unbound_wq);
 err_comp:
     destroy_workqueue(ib_comp_wq);
 err_unbound:
     destroy_workqueue(ib_unreg_wq);
 err:
     destroy_workqueue(ib_wq);
     return ret;
 }
 
 static void __exit ib_core_cleanup(void)
 {
     roce_gid_mgmt_cleanup();
     nldev_exit();
     rdma_nl_unregister(RDMA_NL_LS);
     unregister_pernet_device(&rdma_dev_net_ops);
     unregister_blocking_lsm_notifier(&ibdev_lsm_nb);
     ib_sa_cleanup();
     ib_mad_cleanup();
     addr_cleanup();
     rdma_nl_exit();
     class_unregister(&ib_class);
     destroy_workqueue(ib_comp_unbound_wq);
     destroy_workqueue(ib_comp_wq);
     /* Make sure that any pending umem accounting work is done. */
     destroy_workqueue(ib_wq);
     destroy_workqueue(ib_unreg_wq);
     WARN_ON(!xa_empty(&clients));
     WARN_ON(!xa_empty(&devices));
 }
 
 MODULE_ALIAS_RDMA_NETLINK(RDMA_NL_LS, 4);
 
 /* ib core relies on netdev stack to first register net_ns_type_operations
  * ns kobject type before ib_core initialization.
  */
 fs_initcall(ib_core_init);
 module_exit(ib_core_cleanup);