dma-mapping: don't return errors from dma_set_max_seg_size

[linux.git] / drivers / infiniband / core / device.c

/*
 * 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;
        }

        strscpy(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->subdev_lock);
        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(const 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(const struct device *d)
{
        const 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);

        mutex_init(&device->subdev_lock);
        INIT_LIST_HEAD(&device->subdev_list_head);
        INIT_LIST_HEAD(&device->subdev_list);

        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,
                                        size_add(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;
        }
        strscpy(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)
{
        struct ib_device *sub, *tmp;

        mutex_lock(&ib_dev->subdev_lock);
        list_for_each_entry_safe_reverse(sub, tmp,
                                         &ib_dev->subdev_list_head,
                                         subdev_list) {
                list_del(&sub->subdev_list);
                ib_dev->ops.del_sub_dev(sub);
                ib_device_put(ib_dev);
        }
        mutex_unlock(&ib_dev->subdev_lock);

        /*
         * 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;

        lockdep_assert_held(&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)
                return ret;

        highest_client_id++;
        xa_set_mark(&clients, client->client_id, CLIENT_REGISTERED);
        return 0;
}

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;
        bool need_unreg = false;
        int ret;

        refcount_set(&client->uses, 1);
        init_completion(&client->uses_zero);

        /*
         * The devices_rwsem is held in write mode to ensure that a racing
         * ib_register_device() sees a consisent view of clients and devices.
         */
        down_write(&devices_rwsem);
        down_write(&clients_rwsem);
        ret = assign_client_id(client);
        if (ret)
                goto out;

        need_unreg = true;
        xa_for_each_marked (&devices, index, device, DEVICE_REGISTERED) {
                ret = add_client_context(device, client);
                if (ret)
                        goto out;
        }
        ret = 0;
out:
        up_write(&clients_rwsem);
        up_write(&devices_rwsem);
        if (need_unreg && ret)
                ib_unregister_client(client);
        return ret;
}
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;

        if (!rdma_is_port_valid(ib_dev, port))
                return -EINVAL;

        /*
         * 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;

        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;
        }

        rcu_assign_pointer(pdata->netdev, ndev);
        netdev_put(old_ndev, &pdata->netdev_tracker);
        netdev_hold(ndev, &pdata->netdev_tracker, GFP_ATOMIC);
        spin_unlock_irqrestore(&pdata->netdev_lock, flags);

        add_ndev_hash(pdata);
        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);
                        netdev_put(ndev, &pdata->netdev_tracker);
                }
                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));
                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);
                        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, add_sub_dev);
        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, del_sub_dev);
        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_res_srq_entry);
        SET_DEVICE_OP(dev_ops, fill_res_srq_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);

int ib_add_sub_device(struct ib_device *parent,
                      enum rdma_nl_dev_type type,
                      const char *name)
{
        struct ib_device *sub;
        int ret = 0;

        if (!parent->ops.add_sub_dev || !parent->ops.del_sub_dev)
                return -EOPNOTSUPP;

        if (!ib_device_try_get(parent))
                return -EINVAL;

        sub = parent->ops.add_sub_dev(parent, type, name);
        if (IS_ERR(sub)) {
                ib_device_put(parent);
                return PTR_ERR(sub);
        }

        sub->type = type;
        sub->parent = parent;

        mutex_lock(&parent->subdev_lock);
        list_add_tail(&parent->subdev_list_head, &sub->subdev_list);
        mutex_unlock(&parent->subdev_lock);

        return ret;
}
EXPORT_SYMBOL(ib_add_sub_device);

int ib_del_sub_device_and_put(struct ib_device *sub)
{
        struct ib_device *parent = sub->parent;

        if (!parent)
                return -EOPNOTSUPP;

        mutex_lock(&parent->subdev_lock);
        list_del(&sub->subdev_list);
        mutex_unlock(&parent->subdev_lock);

        ib_device_put(sub);
        parent->ops.del_sub_dev(sub);
        ib_device_put(parent);

        return 0;
}
EXPORT_SYMBOL(ib_del_sub_device_and_put);

#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);
        ret = roce_gid_mgmt_init();
        if (ret) {
                pr_warn("Couldn't init RoCE GID management\n");
                goto err_parent;
        }

        return 0;

err_parent:
        rdma_nl_unregister(RDMA_NL_LS);
        nldev_exit();
        unregister_pernet_device(&rdma_dev_net_ops);
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();
        rdma_nl_unregister(RDMA_NL_LS);
        nldev_exit();
        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);