/*
 * 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);

/*
 * Each of the three rwsem locks (devices, clients, client_data) protects the
 * xarray of the same name. Specifically it allows the caller to assert that
 * the MARK will/will not be changing under the lock, and for devices and
 * clients, that the value in the xarray is still a valid pointer. Change of
 * the MARK is linked to the object state, so holding the lock and testing the
 * MARK also asserts that the contained object is in a certain state.
 *
 * This is used to build a two stage register/unregister flow where objects
 * can continue to be in the xarray even though they are still in progress to
 * register/unregister.
 *
 * The xarray itself provides additional locking, and restartable iteration,
 * which is also relied on.
 *
 * Locks should not be nested, with the exception of client_data, which is
 * allowed to nest under the read side of the other two locks.
 *
 * The devices_rwsem also protects the device name list, any change or
 * assignment of device name must also hold the write side to guarantee unique
 * names.
 */

/*
 * devices contains devices that have had their names assigned. The
 * devices may not be registered. Users that care about the registration
 * status need to call ib_device_try_get() on the device to ensure it is
 * registered, and keep it registered, for the required duration.
 *
 */
static DEFINE_XARRAY_FLAGS(devices, XA_FLAGS_ALLOC);
static DECLARE_RWSEM(devices_rwsem);
#define DEVICE_REGISTERED XA_MARK_1

static u32 highest_client_id;
#define CLIENT_REGISTERED XA_MARK_1
static DEFINE_XARRAY_FLAGS(clients, XA_FLAGS_ALLOC);
static DECLARE_RWSEM(clients_rwsem);

static void ib_client_put(struct ib_client *client)
{
        if (refcount_dec_and_test(&client->uses))
                complete(&client->uses_zero);
}

/*
 * If client_data is registered then the corresponding client must also still
 * be registered.
 */
#define CLIENT_DATA_REGISTERED XA_MARK_1

unsigned int rdma_dev_net_id;

/*
 * A list of net namespaces is maintained in an xarray. This is necessary
 * because we can't get the locking right using the existing net ns list. We
 * would require a init_net callback after the list is updated.
 */
static DEFINE_XARRAY_FLAGS(rdma_nets, XA_FLAGS_ALLOC);
/*
 * rwsem to protect accessing the rdma_nets xarray entries.
 */
static DECLARE_RWSEM(rdma_nets_rwsem);

bool ib_devices_shared_netns = true;
module_param_named(netns_mode, ib_devices_shared_netns, bool, 0444);
MODULE_PARM_DESC(netns_mode,
                 "Share device among net namespaces; default=1 (shared)");
/**
 * rdma_dev_access_netns() - Return whether an rdma device can be accessed
 *                           from a specified net namespace or not.
 * @dev:        Pointer to rdma device which needs to be checked
 * @net:        Pointer to net namesapce for which access to be checked
 *
 * When the rdma device is in shared mode, it ignores the net namespace.
 * When the rdma device is exclusive to a net namespace, rdma device net
 * namespace is checked against the specified one.
 */
bool rdma_dev_access_netns(const struct ib_device *dev, const struct net *net)
{
        return (ib_devices_shared_netns ||
                net_eq(read_pnet(&dev->coredev.rdma_net), net));
}
EXPORT_SYMBOL(rdma_dev_access_netns);

/*
 * xarray has this behavior where it won't iterate over NULL values stored in
 * allocated arrays.  So we need our own iterator to see all values stored in
 * the array. This does the same thing as xa_for_each except that it also
 * returns NULL valued entries if the array is allocating. Simplified to only
 * work on simple xarrays.
 */
static void *xan_find_marked(struct xarray *xa, unsigned long *indexp,
                             xa_mark_t filter)
{
        XA_STATE(xas, xa, *indexp);
        void *entry;

        rcu_read_lock();
        do {
                entry = xas_find_marked(&xas, ULONG_MAX, filter);
                if (xa_is_zero(entry))
                        break;
        } while (xas_retry(&xas, entry));
        rcu_read_unlock();

        if (entry) {
                *indexp = xas.xa_index;
                if (xa_is_zero(entry))
                        return NULL;
                return entry;
        }
        return XA_ERROR(-ENOENT);
}
#define xan_for_each_marked(xa, index, entry, filter)                          \
        for (index = 0, entry = xan_find_marked(xa, &(index), filter);         \
             !xa_is_err(entry);                                                \
             (index)++, entry = xan_find_marked(xa, &(index), filter))

/* RCU hash table mapping netdevice pointers to struct ib_port_data */
static DEFINE_SPINLOCK(ndev_hash_lock);
static DECLARE_HASHTABLE(ndev_hash, 5);

static void free_netdevs(struct ib_device *ib_dev);
static void ib_unregister_work(struct work_struct *work);
static void __ib_unregister_device(struct ib_device *device);
static int ib_security_change(struct notifier_block *nb, unsigned long event,
                              void *lsm_data);
static void ib_policy_change_task(struct work_struct *work);
static DECLARE_WORK(ib_policy_change_work, ib_policy_change_task);

static void __ibdev_printk(const char *level, const struct ib_device *ibdev,
                           struct va_format *vaf)
{
        if (ibdev && ibdev->dev.parent)
                dev_printk_emit(level[1] - '0',
                                ibdev->dev.parent,
                                "%s %s %s: %pV",
                                dev_driver_string(ibdev->dev.parent),
                                dev_name(ibdev->dev.parent),
                                dev_name(&ibdev->dev),
                                vaf);
        else if (ibdev)
                printk("%s%s: %pV",
                       level, dev_name(&ibdev->dev), vaf);
        else
                printk("%s(NULL ib_device): %pV", level, vaf);
}

void ibdev_printk(const char *level, const struct ib_device *ibdev,
                  const char *format, ...)
{
        struct va_format vaf;
        va_list args;

        va_start(args, format);

        vaf.fmt = format;
        vaf.va = &args;

        __ibdev_printk(level, ibdev, &vaf);

        va_end(args);
}
EXPORT_SYMBOL(ibdev_printk);

#define define_ibdev_printk_level(func, level)                  \
void func(const struct ib_device *ibdev, const char *fmt, ...)  \
{                                                               \
        struct va_format vaf;                                   \
        va_list args;                                           \
                                                                \
        va_start(args, fmt);                                    \
                                                                \
        vaf.fmt = fmt;                                          \
        vaf.va = &args;                                         \
                                                                \
        __ibdev_printk(level, ibdev, &vaf);                     \
                                                                \
        va_end(args);                                           \
}                                                               \
EXPORT_SYMBOL(func);

define_ibdev_printk_level(ibdev_emerg, KERN_EMERG);
define_ibdev_printk_level(ibdev_alert, KERN_ALERT);
define_ibdev_printk_level(ibdev_crit, KERN_CRIT);
define_ibdev_printk_level(ibdev_err, KERN_ERR);
define_ibdev_printk_level(ibdev_warn, KERN_WARNING);
define_ibdev_printk_level(ibdev_notice, KERN_NOTICE);
define_ibdev_printk_level(ibdev_info, KERN_INFO);

static struct notifier_block ibdev_lsm_nb = {
        .notifier_call = ib_security_change,
};

static int rdma_dev_change_netns(struct ib_device *device, struct net *cur_net,
                                 struct net *net);

/* Pointer to the RCU head at the start of the ib_port_data array */
struct ib_port_data_rcu {
        struct rcu_head rcu_head;
        struct ib_port_data pdata[];
};

static void ib_device_check_mandatory(struct ib_device *device)
{
#define IB_MANDATORY_FUNC(x) { offsetof(struct ib_device_ops, x), #x }
        static const struct {
                size_t offset;
                char  *name;
        } mandatory_table[] = {
                IB_MANDATORY_FUNC(query_device),
                IB_MANDATORY_FUNC(query_port),
                IB_MANDATORY_FUNC(alloc_pd),
                IB_MANDATORY_FUNC(dealloc_pd),
                IB_MANDATORY_FUNC(create_qp),
                IB_MANDATORY_FUNC(modify_qp),
                IB_MANDATORY_FUNC(destroy_qp),
                IB_MANDATORY_FUNC(post_send),
                IB_MANDATORY_FUNC(post_recv),
                IB_MANDATORY_FUNC(create_cq),
                IB_MANDATORY_FUNC(destroy_cq),
                IB_MANDATORY_FUNC(poll_cq),
                IB_MANDATORY_FUNC(req_notify_cq),
                IB_MANDATORY_FUNC(get_dma_mr),
                IB_MANDATORY_FUNC(reg_user_mr),
                IB_MANDATORY_FUNC(dereg_mr),
                IB_MANDATORY_FUNC(get_port_immutable)
        };
        int i;

        device->kverbs_provider = true;
        for (i = 0; i < ARRAY_SIZE(mandatory_table); ++i) {
                if (!*(void **) ((void *) &device->ops +
                                 mandatory_table[i].offset)) {
                        device->kverbs_provider = false;
                        break;
                }
        }
}

/*
 * Caller must perform ib_device_put() to return the device reference count
 * when ib_device_get_by_index() returns valid device pointer.
 */
struct ib_device *ib_device_get_by_index(const struct net *net, u32 index)
{
        struct ib_device *device;

        down_read(&devices_rwsem);
        device = xa_load(&devices, index);
        if (device) {
                if (!rdma_dev_access_netns(device, net)) {
                        device = NULL;
                        goto out;
                }

                if (!ib_device_try_get(device))
                        device = NULL;
        }
out:
        up_read(&devices_rwsem);
        return device;
}

/**
 * ib_device_put - Release IB device reference
 * @device: device whose reference to be released
 *
 * ib_device_put() releases reference to the IB device to allow it to be
 * unregistered and eventually free.
 */
void ib_device_put(struct ib_device *device)
{
        if (refcount_dec_and_test(&device->refcount))
                complete(&device->unreg_completion);
}
EXPORT_SYMBOL(ib_device_put);

static struct ib_device *__ib_device_get_by_name(const char *name)
{
        struct ib_device *device;
        unsigned long index;

        xa_for_each (&devices, index, device)
                if (!strcmp(name, dev_name(&device->dev)))
                        return device;

        return NULL;
}

/**
 * ib_device_get_by_name - Find an IB device by name
 * @name: The name to look for
 * @driver_id: The driver ID that must match (RDMA_DRIVER_UNKNOWN matches all)
 *
 * Find and hold an ib_device by its name. The caller must call
 * ib_device_put() on the returned pointer.
 */
struct ib_device *ib_device_get_by_name(const char *name,
                                        enum rdma_driver_id driver_id)
{
        struct ib_device *device;

        down_read(&devices_rwsem);
        device = __ib_device_get_by_name(name);
        if (device && driver_id != RDMA_DRIVER_UNKNOWN &&
            device->ops.driver_id != driver_id)
                device = NULL;

        if (device) {
                if (!ib_device_try_get(device))
                        device = NULL;
        }
        up_read(&devices_rwsem);
        return device;
}
EXPORT_SYMBOL(ib_device_get_by_name);

static int rename_compat_devs(struct ib_device *device)
{
        struct ib_core_device *cdev;
        unsigned long index;
        int ret = 0;

        mutex_lock(&device->compat_devs_mutex);
        xa_for_each (&device->compat_devs, index, cdev) {
                ret = device_rename(&cdev->dev, dev_name(&device->dev));
                if (ret) {
                        dev_warn(&cdev->dev,
                                 "Fail to rename compatdev to new name %s\n",
                                 dev_name(&device->dev));
                        break;
                }
        }
        mutex_unlock(&device->compat_devs_mutex);
        return ret;
}

int ib_device_rename(struct ib_device *ibdev, const char *name)
{
        unsigned long index;
        void *client_data;
        int ret;

        down_write(&devices_rwsem);
        if (!strcmp(name, dev_name(&ibdev->dev))) {
                up_write(&devices_rwsem);
                return 0;
        }

        if (__ib_device_get_by_name(name)) {
                up_write(&devices_rwsem);
                return -EEXIST;
        }

        ret = device_rename(&ibdev->dev, name);
        if (ret) {
                up_write(&devices_rwsem);
                return ret;
        }

        strlcpy(ibdev->name, name, IB_DEVICE_NAME_MAX);
        ret = rename_compat_devs(ibdev);

        downgrade_write(&devices_rwsem);
        down_read(&ibdev->client_data_rwsem);
        xan_for_each_marked(&ibdev->client_data, index, client_data,
                            CLIENT_DATA_REGISTERED) {
                struct ib_client *client = xa_load(&clients, index);

                if (!client || !client->rename)
                        continue;

                client->rename(ibdev, client_data);
        }
        up_read(&ibdev->client_data_rwsem);
        up_read(&devices_rwsem);
        return 0;
}

int ib_device_set_dim(struct ib_device *ibdev, u8 use_dim)
{
        if (use_dim > 1)
                return -EINVAL;
        ibdev->use_cq_dim = use_dim;

        return 0;
}

static int alloc_name(struct ib_device *ibdev, const char *name)
{
        struct ib_device *device;
        unsigned long index;
        struct ida inuse;
        int rc;
        int i;

        lockdep_assert_held_write(&devices_rwsem);
        ida_init(&inuse);
        xa_for_each (&devices, index, device) {
                char buf[IB_DEVICE_NAME_MAX];

                if (sscanf(dev_name(&device->dev), name, &i) != 1)
                        continue;
                if (i < 0 || i >= INT_MAX)
                        continue;
                snprintf(buf, sizeof buf, name, i);
                if (strcmp(buf, dev_name(&device->dev)) != 0)
                        continue;

                rc = ida_alloc_range(&inuse, i, i, GFP_KERNEL);
                if (rc < 0)
                        goto out;
        }

        rc = ida_alloc(&inuse, GFP_KERNEL);
        if (rc < 0)
                goto out;

        rc = dev_set_name(&ibdev->dev, name, rc);
out:
        ida_destroy(&inuse);
        return rc;
}

static void ib_device_release(struct device *device)
{
        struct ib_device *dev = container_of(device, struct ib_device, dev);

        free_netdevs(dev);
        WARN_ON(refcount_read(&dev->refcount));
        if (dev->hw_stats_data)
                ib_device_release_hw_stats(dev->hw_stats_data);
        if (dev->port_data) {
                ib_cache_release_one(dev);
                ib_security_release_port_pkey_list(dev);
                rdma_counter_release(dev);
                kfree_rcu(container_of(dev->port_data, struct ib_port_data_rcu,
                                       pdata[0]),
                          rcu_head);
        }

        mutex_destroy(&dev->unregistration_lock);
        mutex_destroy(&dev->compat_devs_mutex);

        xa_destroy(&dev->compat_devs);
        xa_destroy(&dev->client_data);
        kfree_rcu(dev, rcu_head);
}

static int ib_device_uevent(struct device *device,
                            struct kobj_uevent_env *env)
{
        if (add_uevent_var(env, "NAME=%s", dev_name(device)))
                return -ENOMEM;

        /*
         * It would be nice to pass the node GUID with the event...
         */

        return 0;
}

static const void *net_namespace(struct device *d)
{
        struct ib_core_device *coredev =
                        container_of(d, struct ib_core_device, dev);

        return read_pnet(&coredev->rdma_net);
}

static struct class ib_class = {
        .name    = "infiniband",
        .dev_release = ib_device_release,
        .dev_uevent = ib_device_uevent,
        .ns_type = &net_ns_type_operations,
        .namespace = net_namespace,
};

static void rdma_init_coredev(struct ib_core_device *coredev,
                              struct ib_device *dev, struct net *net)
{
        /* This BUILD_BUG_ON is intended to catch layout change
         * of union of ib_core_device and device.
         * dev must be the first element as ib_core and providers
         * driver uses it. Adding anything in ib_core_device before
         * device will break this assumption.
         */
        BUILD_BUG_ON(offsetof(struct ib_device, coredev.dev) !=
                     offsetof(struct ib_device, dev));

        coredev->dev.class = &ib_class;
        coredev->dev.groups = dev->groups;
        device_initialize(&coredev->dev);
        coredev->owner = dev;
        INIT_LIST_HEAD(&coredev->port_list);
        write_pnet(&coredev->rdma_net, net);
}

/**
 * _ib_alloc_device - allocate an IB device struct
 * @size:size of structure to allocate
 *
 * Low-level drivers should use ib_alloc_device() to allocate &struct
 * ib_device.  @size is the size of the structure to be allocated,
 * including any private data used by the low-level driver.
 * ib_dealloc_device() must be used to free structures allocated with
 * ib_alloc_device().
 */
struct ib_device *_ib_alloc_device(size_t size)
{
        struct ib_device *device;
        unsigned int i;

        if (WARN_ON(size < sizeof(struct ib_device)))
                return NULL;

        device = kzalloc(size, GFP_KERNEL);
        if (!device)
                return NULL;

        if (rdma_restrack_init(device)) {
                kfree(device);
                return NULL;
        }

        rdma_init_coredev(&device->coredev, device, &init_net);

        INIT_LIST_HEAD(&device->event_handler_list);
        spin_lock_init(&device->qp_open_list_lock);
        init_rwsem(&device->event_handler_rwsem);
        mutex_init(&device->unregistration_lock);
        /*
         * client_data needs to be alloc because we don't want our mark to be
         * destroyed if the user stores NULL in the client data.
         */
        xa_init_flags(&device->client_data, XA_FLAGS_ALLOC);
        init_rwsem(&device->client_data_rwsem);
        xa_init_flags(&device->compat_devs, XA_FLAGS_ALLOC);
        mutex_init(&device->compat_devs_mutex);
        init_completion(&device->unreg_completion);
        INIT_WORK(&device->unregistration_work, ib_unregister_work);

        spin_lock_init(&device->cq_pools_lock);
        for (i = 0; i < ARRAY_SIZE(device->cq_pools); i++)
                INIT_LIST_HEAD(&device->cq_pools[i]);

        device->uverbs_cmd_mask =
                BIT_ULL(IB_USER_VERBS_CMD_ALLOC_MW) |
                BIT_ULL(IB_USER_VERBS_CMD_ALLOC_PD) |
                BIT_ULL(IB_USER_VERBS_CMD_ATTACH_MCAST) |
                BIT_ULL(IB_USER_VERBS_CMD_CLOSE_XRCD) |
                BIT_ULL(IB_USER_VERBS_CMD_CREATE_AH) |
                BIT_ULL(IB_USER_VERBS_CMD_CREATE_COMP_CHANNEL) |
                BIT_ULL(IB_USER_VERBS_CMD_CREATE_CQ) |
                BIT_ULL(IB_USER_VERBS_CMD_CREATE_QP) |
                BIT_ULL(IB_USER_VERBS_CMD_CREATE_SRQ) |
                BIT_ULL(IB_USER_VERBS_CMD_CREATE_XSRQ) |
                BIT_ULL(IB_USER_VERBS_CMD_DEALLOC_MW) |
                BIT_ULL(IB_USER_VERBS_CMD_DEALLOC_PD) |
                BIT_ULL(IB_USER_VERBS_CMD_DEREG_MR) |
                BIT_ULL(IB_USER_VERBS_CMD_DESTROY_AH) |
                BIT_ULL(IB_USER_VERBS_CMD_DESTROY_CQ) |
                BIT_ULL(IB_USER_VERBS_CMD_DESTROY_QP) |
                BIT_ULL(IB_USER_VERBS_CMD_DESTROY_SRQ) |
                BIT_ULL(IB_USER_VERBS_CMD_DETACH_MCAST) |
                BIT_ULL(IB_USER_VERBS_CMD_GET_CONTEXT) |
                BIT_ULL(IB_USER_VERBS_CMD_MODIFY_QP) |
                BIT_ULL(IB_USER_VERBS_CMD_MODIFY_SRQ) |
                BIT_ULL(IB_USER_VERBS_CMD_OPEN_QP) |
                BIT_ULL(IB_USER_VERBS_CMD_OPEN_XRCD) |
                BIT_ULL(IB_USER_VERBS_CMD_QUERY_DEVICE) |
                BIT_ULL(IB_USER_VERBS_CMD_QUERY_PORT) |
                BIT_ULL(IB_USER_VERBS_CMD_QUERY_QP) |
                BIT_ULL(IB_USER_VERBS_CMD_QUERY_SRQ) |
                BIT_ULL(IB_USER_VERBS_CMD_REG_MR) |
                BIT_ULL(IB_USER_VERBS_CMD_REREG_MR) |
                BIT_ULL(IB_USER_VERBS_CMD_RESIZE_CQ);
        return device;
}
EXPORT_SYMBOL(_ib_alloc_device);

/**
 * ib_dealloc_device - free an IB device struct
 * @device:structure to free
 *
 * Free a structure allocated with ib_alloc_device().
 */
void ib_dealloc_device(struct ib_device *device)
{
        if (device->ops.dealloc_driver)
                device->ops.dealloc_driver(device);

        /*
         * ib_unregister_driver() requires all devices to remain in the xarray
         * while their ops are callable. The last op we call is dealloc_driver
         * above.  This is needed to create a fence on op callbacks prior to
         * allowing the driver module to unload.
         */
        down_write(&devices_rwsem);
        if (xa_load(&devices, device->index) == device)
                xa_erase(&devices, device->index);
        up_write(&devices_rwsem);

        /* Expedite releasing netdev references */
        free_netdevs(device);

        WARN_ON(!xa_empty(&device->compat_devs));
        WARN_ON(!xa_empty(&device->client_data));
        WARN_ON(refcount_read(&device->refcount));
        rdma_restrack_clean(device);
        /* Balances with device_initialize */
        put_device(&device->dev);
}
EXPORT_SYMBOL(ib_dealloc_device);

/*
 * add_client_context() and remove_client_context() must be safe against
 * parallel calls on the same device - registration/unregistration of both the
 * device and client can be occurring in parallel.
 *
 * The routines need to be a fence, any caller must not return until the add
 * or remove is fully completed.
 */
static int add_client_context(struct ib_device *device,
                              struct ib_client *client)
{
        int ret = 0;

        if (!device->kverbs_provider && !client->no_kverbs_req)
                return 0;

        down_write(&device->client_data_rwsem);
        /*
         * So long as the client is registered hold both the client and device
         * unregistration locks.
         */
        if (!refcount_inc_not_zero(&client->uses))
                goto out_unlock;
        refcount_inc(&device->refcount);

        /*
         * Another caller to add_client_context got here first and has already
         * completely initialized context.
         */
        if (xa_get_mark(&device->client_data, client->client_id,
                    CLIENT_DATA_REGISTERED))
                goto out;

        ret = xa_err(xa_store(&device->client_data, client->client_id, NULL,
                              GFP_KERNEL));
        if (ret)
                goto out;
        downgrade_write(&device->client_data_rwsem);
        if (client->add) {
                if (client->add(device)) {
                        /*
                         * If a client fails to add then the error code is
                         * ignored, but we won't call any more ops on this
                         * client.
                         */
                        xa_erase(&device->client_data, client->client_id);
                        up_read(&device->client_data_rwsem);
                        ib_device_put(device);
                        ib_client_put(client);
                        return 0;
                }
        }

        /* Readers shall not see a client until add has been completed */
        xa_set_mark(&device->client_data, client->client_id,
                    CLIENT_DATA_REGISTERED);
        up_read(&device->client_data_rwsem);
        return 0;

out:
        ib_device_put(device);
        ib_client_put(client);
out_unlock:
        up_write(&device->client_data_rwsem);
        return ret;
}

static void remove_client_context(struct ib_device *device,
                                  unsigned int client_id)
{
        struct ib_client *client;
        void *client_data;

        down_write(&device->client_data_rwsem);
        if (!xa_get_mark(&device->client_data, client_id,
                         CLIENT_DATA_REGISTERED)) {
                up_write(&device->client_data_rwsem);
                return;
        }
        client_data = xa_load(&device->client_data, client_id);
        xa_clear_mark(&device->client_data, client_id, CLIENT_DATA_REGISTERED);
        client = xa_load(&clients, client_id);
        up_write(&device->client_data_rwsem);

        /*
         * Notice we cannot be holding any exclusive locks when calling the
         * remove callback as the remove callback can recurse back into any
         * public functions in this module and thus try for any locks those
         * functions take.
         *
         * For this reason clients and drivers should not call the
         * unregistration functions will holdling any locks.
         */
        if (client->remove)
                client->remove(device, client_data);

        xa_erase(&device->client_data, client_id);
        ib_device_put(device);
        ib_client_put(client);
}

static int alloc_port_data(struct ib_device *device)
{
        struct ib_port_data_rcu *pdata_rcu;
        u32 port;

        if (device->port_data)
                return 0;

        /* This can only be called once the physical port range is defined */
        if (WARN_ON(!device->phys_port_cnt))
                return -EINVAL;

        /* Reserve U32_MAX so the logic to go over all the ports is sane */
        if (WARN_ON(device->phys_port_cnt == U32_MAX))
                return -EINVAL;

        /*
         * device->port_data is indexed directly by the port number to make
         * access to this data as efficient as possible.
         *
         * Therefore port_data is declared as a 1 based array with potential
         * empty slots at the beginning.
         */
        pdata_rcu = kzalloc(struct_size(pdata_rcu, pdata,
                                        rdma_end_port(device) + 1),
                            GFP_KERNEL);
        if (!pdata_rcu)
                return -ENOMEM;
        /*
         * The rcu_head is put in front of the port data array and the stored
         * pointer is adjusted since we never need to see that member until
         * kfree_rcu.
         */
        device->port_data = pdata_rcu->pdata;

        rdma_for_each_port (device, port) {
                struct ib_port_data *pdata = &device->port_data[port];

                pdata->ib_dev = device;
                spin_lock_init(&pdata->pkey_list_lock);
                INIT_LIST_HEAD(&pdata->pkey_list);
                spin_lock_init(&pdata->netdev_lock);
                INIT_HLIST_NODE(&pdata->ndev_hash_link);
        }
        return 0;
}

static int verify_immutable(const struct ib_device *dev, u32 port)
{
        return WARN_ON(!rdma_cap_ib_mad(dev, port) &&
                            rdma_max_mad_size(dev, port) != 0);
}

static int setup_port_data(struct ib_device *device)
{
        u32 port;
        int ret;

        ret = alloc_port_data(device);
        if (ret)
                return ret;

        rdma_for_each_port (device, port) {
                struct ib_port_data *pdata = &device->port_data[port];

                ret = device->ops.get_port_immutable(device, port,
                                                     &pdata->immutable);
                if (ret)
                        return ret;

                if (verify_immutable(device, port))
                        return -EINVAL;
        }
        return 0;
}

/**
 * ib_port_immutable_read() - Read rdma port's immutable data
 * @dev: IB device
 * @port: port number whose immutable data to read. It starts with index 1 and
 *        valid upto including rdma_end_port().
 */
const struct ib_port_immutable*
ib_port_immutable_read(struct ib_device *dev, unsigned int port)
{
        WARN_ON(!rdma_is_port_valid(dev, port));
        return &dev->port_data[port].immutable;
}
EXPORT_SYMBOL(ib_port_immutable_read);

void ib_get_device_fw_str(struct ib_device *dev, char *str)
{
        if (dev->ops.get_dev_fw_str)
                dev->ops.get_dev_fw_str(dev, str);
        else
                str[0] = '\0';
}
EXPORT_SYMBOL(ib_get_device_fw_str);

static void ib_policy_change_task(struct work_struct *work)
{
        struct ib_device *dev;
        unsigned long index;

        down_read(&devices_rwsem);
        xa_for_each_marked (&devices, index, dev, DEVICE_REGISTERED) {
                unsigned int i;

                rdma_for_each_port (dev, i) {
                        u64 sp;
                        ib_get_cached_subnet_prefix(dev, i, &sp);
                        ib_security_cache_change(dev, i, sp);
                }
        }
        up_read(&devices_rwsem);
}

static int ib_security_change(struct notifier_block *nb, unsigned long event,
                              void *lsm_data)
{
        if (event != LSM_POLICY_CHANGE)
                return NOTIFY_DONE;

        schedule_work(&ib_policy_change_work);
        ib_mad_agent_security_change();

        return NOTIFY_OK;
}

static void compatdev_release(struct device *dev)
{
        struct ib_core_device *cdev =
                container_of(dev, struct ib_core_device, dev);

        kfree(cdev);
}

static int add_one_compat_dev(struct ib_device *device,
                              struct rdma_dev_net *rnet)
{
        struct ib_core_device *cdev;
        int ret;

        lockdep_assert_held(&rdma_nets_rwsem);
        if (!ib_devices_shared_netns)
                return 0;

        /*
         * Create and add compat device in all namespaces other than where it
         * is currently bound to.
         */
        if (net_eq(read_pnet(&rnet->net),
                   read_pnet(&device->coredev.rdma_net)))
                return 0;

        /*
         * The first of init_net() or ib_register_device() to take the
         * compat_devs_mutex wins and gets to add the device. Others will wait
         * for completion here.
         */
        mutex_lock(&device->compat_devs_mutex);
        cdev = xa_load(&device->compat_devs, rnet->id);
        if (cdev) {
                ret = 0;
                goto done;
        }
        ret = xa_reserve(&device->compat_devs, rnet->id, GFP_KERNEL);
        if (ret)
                goto done;

        cdev = kzalloc(sizeof(*cdev), GFP_KERNEL);
        if (!cdev) {
                ret = -ENOMEM;
                goto cdev_err;
        }

        cdev->dev.parent = device->dev.parent;
        rdma_init_coredev(cdev, device, read_pnet(&rnet->net));
        cdev->dev.release = compatdev_release;
        ret = dev_set_name(&cdev->dev, "%s", dev_name(&device->dev));
        if (ret)
                goto add_err;

        ret = device_add(&cdev->dev);
        if (ret)
                goto add_err;
        ret = ib_setup_port_attrs(cdev);
        if (ret)
                goto port_err;

        ret = xa_err(xa_store(&device->compat_devs, rnet->id,
                              cdev, GFP_KERNEL));
        if (ret)
                goto insert_err;

        mutex_unlock(&device->compat_devs_mutex);
        return 0;

insert_err:
        ib_free_port_attrs(cdev);
port_err:
        device_del(&cdev->dev);
add_err:
        put_device(&cdev->dev);
cdev_err:
        xa_release(&device->compat_devs, rnet->id);
done:
        mutex_unlock(&device->compat_devs_mutex);
        return ret;
}

static void remove_one_compat_dev(struct ib_device *device, u32 id)
{
        struct ib_core_device *cdev;

        mutex_lock(&device->compat_devs_mutex);
        cdev = xa_erase(&device->compat_devs, id);
        mutex_unlock(&device->compat_devs_mutex);
        if (cdev) {
                ib_free_port_attrs(cdev);
                device_del(&cdev->dev);

                put_device(&cdev->dev);
        }
}

static void remove_compat_devs(struct ib_device *device)
{
        struct ib_core_device *cdev;
        unsigned long index;

        xa_for_each (&device->compat_devs, index, cdev)
                remove_one_compat_dev(device, index);
}

static int add_compat_devs(struct ib_device *device)
{
        struct rdma_dev_net *rnet;
        unsigned long index;
        int ret = 0;

        lockdep_assert_held(&devices_rwsem);

        down_read(&rdma_nets_rwsem);
        xa_for_each (&rdma_nets, index, rnet) {
                ret = add_one_compat_dev(device, rnet);
                if (ret)
                        break;
        }
        up_read(&rdma_nets_rwsem);
        return ret;
}

static void remove_all_compat_devs(void)
{
        struct ib_compat_device *cdev;
        struct ib_device *dev;
        unsigned long index;

        down_read(&devices_rwsem);
        xa_for_each (&devices, index, dev) {
                unsigned long c_index = 0;

                /* Hold nets_rwsem so that any other thread modifying this
                 * system param can sync with this thread.
                 */
                down_read(&rdma_nets_rwsem);
                xa_for_each (&dev->compat_devs, c_index, cdev)
                        remove_one_compat_dev(dev, c_index);
                up_read(&rdma_nets_rwsem);
        }
        up_read(&devices_rwsem);
}

static int add_all_compat_devs(void)
{
        struct rdma_dev_net *rnet;
        struct ib_device *dev;
        unsigned long index;
        int ret = 0;

        down_read(&devices_rwsem);
        xa_for_each_marked (&devices, index, dev, DEVICE_REGISTERED) {
                unsigned long net_index = 0;

                /* Hold nets_rwsem so that any other thread modifying this
                 * system param can sync with this thread.
                 */
                down_read(&rdma_nets_rwsem);
                xa_for_each (&rdma_nets, net_index, rnet) {
                        ret = add_one_compat_dev(dev, rnet);
                        if (ret)
                                break;
                }
                up_read(&rdma_nets_rwsem);
        }
        up_read(&devices_rwsem);
        if (ret)
                remove_all_compat_devs();
        return ret;
}

int rdma_compatdev_set(u8 enable)
{
        struct rdma_dev_net *rnet;
        unsigned long index;
        int ret = 0;

        down_write(&rdma_nets_rwsem);
        if (ib_devices_shared_netns == enable) {
                up_write(&rdma_nets_rwsem);
                return 0;
        }

        /* enable/disable of compat devices is not supported
         * when more than default init_net exists.
         */
        xa_for_each (&rdma_nets, index, rnet) {
                ret++;
                break;
        }
        if (!ret)
                ib_devices_shared_netns = enable;
        up_write(&rdma_nets_rwsem);
        if (ret)
                return -EBUSY;

        if (enable)
                ret = add_all_compat_devs();
        else
                remove_all_compat_devs();
        return ret;
}

static void rdma_dev_exit_net(struct net *net)
{
        struct rdma_dev_net *rnet = rdma_net_to_dev_net(net);
        struct ib_device *dev;
        unsigned long index;
        int ret;

        down_write(&rdma_nets_rwsem);
        /*
         * Prevent the ID from being re-used and hide the id from xa_for_each.
         */
        ret = xa_err(xa_store(&rdma_nets, rnet->id, NULL, GFP_KERNEL));
        WARN_ON(ret);
        up_write(&rdma_nets_rwsem);

        down_read(&devices_rwsem);
        xa_for_each (&devices, index, dev) {
                get_device(&dev->dev);
                /*
                 * Release the devices_rwsem so that pontentially blocking
                 * device_del, doesn't hold the devices_rwsem for too long.
                 */
                up_read(&devices_rwsem);

                remove_one_compat_dev(dev, rnet->id);

                /*
                 * If the real device is in the NS then move it back to init.
                 */
                rdma_dev_change_netns(dev, net, &init_net);

                put_device(&dev->dev);
                down_read(&devices_rwsem);
        }
        up_read(&devices_rwsem);

        rdma_nl_net_exit(rnet);
        xa_erase(&rdma_nets, rnet->id);
}

static __net_init int rdma_dev_init_net(struct net *net)
{
        struct rdma_dev_net *rnet = rdma_net_to_dev_net(net);
        unsigned long index;
        struct ib_device *dev;
        int ret;

        write_pnet(&rnet->net, net);

        ret = rdma_nl_net_init(rnet);
        if (ret)
                return ret;

        /* No need to create any compat devices in default init_net. */
        if (net_eq(net, &init_net))
                return 0;

        ret = xa_alloc(&rdma_nets, &rnet->id, rnet, xa_limit_32b, GFP_KERNEL);
        if (ret) {
                rdma_nl_net_exit(rnet);
                return ret;
        }

        down_read(&devices_rwsem);
        xa_for_each_marked (&devices, index, dev, DEVICE_REGISTERED) {
                /* Hold nets_rwsem so that netlink command cannot change
                 * system configuration for device sharing mode.
                 */
                down_read(&rdma_nets_rwsem);
                ret = add_one_compat_dev(dev, rnet);
                up_read(&rdma_nets_rwsem);
                if (ret)
                        break;
        }
        up_read(&devices_rwsem);

        if (ret)
                rdma_dev_exit_net(net);

        return ret;
}

/*
 * Assign the unique string device name and the unique device index. This is
 * undone by ib_dealloc_device.
 */
static int assign_name(struct ib_device *device, const char *name)
{
        static u32 last_id;
        int ret;

        down_write(&devices_rwsem);
        /* Assign a unique name to the device */
        if (strchr(name, '%'))
                ret = alloc_name(device, name);
        else
                ret = dev_set_name(&device->dev, name);
        if (ret)
                goto out;

        if (__ib_device_get_by_name(dev_name(&device->dev))) {
                ret = -ENFILE;
                goto out;
        }
        strlcpy(device->name, dev_name(&device->dev), IB_DEVICE_NAME_MAX);

        ret = xa_alloc_cyclic(&devices, &device->index, device, xa_limit_31b,
                        &last_id, GFP_KERNEL);
        if (ret > 0)
                ret = 0;

out:
        up_write(&devices_rwsem);
        return ret;
}

/*
 * setup_device() allocates memory and sets up data that requires calling the
 * device ops, this is the only reason these actions are not done during
 * ib_alloc_device. It is undone by ib_dealloc_device().
 */
static int setup_device(struct ib_device *device)
{
        struct ib_udata uhw = {.outlen = 0, .inlen = 0};
        int ret;

        ib_device_check_mandatory(device);

        ret = setup_port_data(device);
        if (ret) {
                dev_warn(&device->dev, "Couldn't create per-port data\n");
                return ret;
        }

        memset(&device->attrs, 0, sizeof(device->attrs));
        ret = device->ops.query_device(device, &device->attrs, &uhw);
        if (ret) {
                dev_warn(&device->dev,
                         "Couldn't query the device attributes\n");
                return ret;
        }

        return 0;
}

static void disable_device(struct ib_device *device)
{
        u32 cid;

        WARN_ON(!refcount_read(&device->refcount));

        down_write(&devices_rwsem);
        xa_clear_mark(&devices, device->index, DEVICE_REGISTERED);
        up_write(&devices_rwsem);

        /*
         * Remove clients in LIFO order, see assign_client_id. This could be
         * more efficient if xarray learns to reverse iterate. Since no new
         * clients can be added to this ib_device past this point we only need
         * the maximum possible client_id value here.
         */
        down_read(&clients_rwsem);
        cid = highest_client_id;
        up_read(&clients_rwsem);
        while (cid) {
                cid--;
                remove_client_context(device, cid);
        }

        ib_cq_pool_cleanup(device);

        /* Pairs with refcount_set in enable_device */
        ib_device_put(device);
        wait_for_completion(&device->unreg_completion);

        /*
         * compat devices must be removed after device refcount drops to zero.
         * Otherwise init_net() may add more compatdevs after removing compat
         * devices and before device is disabled.
         */
        remove_compat_devs(device);
}

/*
 * An enabled device is visible to all clients and to all the public facing
 * APIs that return a device pointer. This always returns with a new get, even
 * if it fails.
 */
static int enable_device_and_get(struct ib_device *device)
{
        struct ib_client *client;
        unsigned long index;
        int ret = 0;

        /*
         * One ref belongs to the xa and the other belongs to this
         * thread. This is needed to guard against parallel unregistration.
         */
        refcount_set(&device->refcount, 2);
        down_write(&devices_rwsem);
        xa_set_mark(&devices, device->index, DEVICE_REGISTERED);

        /*
         * By using downgrade_write() we ensure that no other thread can clear
         * DEVICE_REGISTERED while we are completing the client setup.
         */
        downgrade_write(&devices_rwsem);

        if (device->ops.enable_driver) {
                ret = device->ops.enable_driver(device);
                if (ret)
                        goto out;
        }

        down_read(&clients_rwsem);
        xa_for_each_marked (&clients, index, client, CLIENT_REGISTERED) {
                ret = add_client_context(device, client);
                if (ret)
                        break;
        }
        up_read(&clients_rwsem);
        if (!ret)
                ret = add_compat_devs(device);
out:
        up_read(&devices_rwsem);
        return ret;
}

static void prevent_dealloc_device(struct ib_device *ib_dev)
{
}

/**
 * ib_register_device - Register an IB device with IB core
 * @device: Device to register
 * @name: unique string device name. This may include a '%' which will
 *        cause a unique index to be added to the passed device name.
 * @dma_device: pointer to a DMA-capable device. If %NULL, then the IB
 *              device will be used. In this case the caller should fully
 *              setup the ibdev for DMA. This usually means using dma_virt_ops.
 *
 * Low-level drivers use ib_register_device() to register their
 * devices with the IB core.  All registered clients will receive a
 * callback for each device that is added. @device must be allocated
 * with ib_alloc_device().
 *
 * If the driver uses ops.dealloc_driver and calls any ib_unregister_device()
 * asynchronously then the device pointer may become freed as soon as this
 * function returns.
 */
int ib_register_device(struct ib_device *device, const char *name,
                       struct device *dma_device)
{
        int ret;

        ret = assign_name(device, name);
        if (ret)
                return ret;

        /*
         * If the caller does not provide a DMA capable device then the IB core
         * will set up ib_sge and scatterlist structures that stash the kernel
         * virtual address into the address field.
         */
        WARN_ON(dma_device && !dma_device->dma_parms);
        device->dma_device = dma_device;

        ret = setup_device(device);
        if (ret)
                return ret;

        ret = ib_cache_setup_one(device);
        if (ret) {
                dev_warn(&device->dev,
                         "Couldn't set up InfiniBand P_Key/GID cache\n");
                return ret;
        }

        device->groups[0] = &ib_dev_attr_group;
        device->groups[1] = device->ops.device_group;
        ret = ib_setup_device_attrs(device);
        if (ret)
                goto cache_cleanup;

        ib_device_register_rdmacg(device);

        rdma_counter_init(device);

        /*
         * Ensure that ADD uevent is not fired because it
         * is too early amd device is not initialized yet.
         */
        dev_set_uevent_suppress(&device->dev, true);
        ret = device_add(&device->dev);
        if (ret)
                goto cg_cleanup;

        ret = ib_setup_port_attrs(&device->coredev);
        if (ret) {
                dev_warn(&device->dev,
                         "Couldn't register device with driver model\n");
                goto dev_cleanup;
        }

        ret = enable_device_and_get(device);
        if (ret) {
                void (*dealloc_fn)(struct ib_device *);

                /*
                 * If we hit this error flow then we don't want to
                 * automatically dealloc the device since the caller is
                 * expected to call ib_dealloc_device() after
                 * ib_register_device() fails. This is tricky due to the
                 * possibility for a parallel unregistration along with this
                 * error flow. Since we have a refcount here we know any
                 * parallel flow is stopped in disable_device and will see the
                 * special dealloc_driver pointer, causing the responsibility to
                 * ib_dealloc_device() to revert back to this thread.
                 */
                dealloc_fn = device->ops.dealloc_driver;
                device->ops.dealloc_driver = prevent_dealloc_device;
                ib_device_put(device);
                __ib_unregister_device(device);
                device->ops.dealloc_driver = dealloc_fn;
                dev_set_uevent_suppress(&device->dev, false);
                return ret;
        }
        dev_set_uevent_suppress(&device->dev, false);
        /* Mark for userspace that device is ready */
        kobject_uevent(&device->dev.kobj, KOBJ_ADD);
        ib_device_put(device);

        return 0;

dev_cleanup:
        device_del(&device->dev);
cg_cleanup:
        dev_set_uevent_suppress(&device->dev, false);
        ib_device_unregister_rdmacg(device);
cache_cleanup:
        ib_cache_cleanup_one(device);
        return ret;
}
EXPORT_SYMBOL(ib_register_device);

/* Callers must hold a get on the device. */
static void __ib_unregister_device(struct ib_device *ib_dev)
{
        /*
         * We have a registration lock so that all the calls to unregister are
         * fully fenced, once any unregister returns the device is truely
         * unregistered even if multiple callers are unregistering it at the
         * same time. This also interacts with the registration flow and
         * provides sane semantics if register and unregister are racing.
         */
        mutex_lock(&ib_dev->unregistration_lock);
        if (!refcount_read(&ib_dev->refcount))
                goto out;

        disable_device(ib_dev);

        /* Expedite removing unregistered pointers from the hash table */
        free_netdevs(ib_dev);

        ib_free_port_attrs(&ib_dev->coredev);
        device_del(&ib_dev->dev);
        ib_device_unregister_rdmacg(ib_dev);
        ib_cache_cleanup_one(ib_dev);

        /*
         * Drivers using the new flow may not call ib_dealloc_device except
         * in error unwind prior to registration success.
         */
        if (ib_dev->ops.dealloc_driver &&
            ib_dev->ops.dealloc_driver != prevent_dealloc_device) {
                WARN_ON(kref_read(&ib_dev->dev.kobj.kref) <= 1);
                ib_dealloc_device(ib_dev);
        }
out:
        mutex_unlock(&ib_dev->unregistration_lock);
}

/**
 * ib_unregister_device - Unregister an IB device
 * @ib_dev: The device to unregister
 *
 * Unregister an IB device.  All clients will receive a remove callback.
 *
 * Callers should call this routine only once, and protect against races with
 * registration. Typically it should only be called as part of a remove
 * callback in an implementation of driver core's struct device_driver and
 * related.
 *
 * If ops.dealloc_driver is used then ib_dev will be freed upon return from
 * this function.
 */
void ib_unregister_device(struct ib_device *ib_dev)
{
        get_device(&ib_dev->dev);
        __ib_unregister_device(ib_dev);
        put_device(&ib_dev->dev);
}
EXPORT_SYMBOL(ib_unregister_device);

/**
 * ib_unregister_device_and_put - Unregister a device while holding a 'get'
 * @ib_dev: The device to unregister
 *
 * This is the same as ib_unregister_device(), except it includes an internal
 * ib_device_put() that should match a 'get' obtained by the caller.
 *
 * It is safe to call this routine concurrently from multiple threads while
 * holding the 'get'. When the function returns the device is fully
 * unregistered.
 *
 * Drivers using this flow MUST use the driver_unregister callback to clean up
 * their resources associated with the device and dealloc it.
 */
void ib_unregister_device_and_put(struct ib_device *ib_dev)
{
        WARN_ON(!ib_dev->ops.dealloc_driver);
        get_device(&ib_dev->dev);
        ib_device_put(ib_dev);
        __ib_unregister_device(ib_dev);
        put_device(&ib_dev->dev);
}
EXPORT_SYMBOL(ib_unregister_device_and_put);

/**
 * ib_unregister_driver - Unregister all IB devices for a driver
 * @driver_id: The driver to unregister
 *
 * This implements a fence for device unregistration. It only returns once all
 * devices associated with the driver_id have fully completed their
 * unregistration and returned from ib_unregister_device*().
 *
 * If device's are not yet unregistered it goes ahead and starts unregistering
 * them.
 *
 * This does not block creation of new devices with the given driver_id, that
 * is the responsibility of the caller.
 */
void ib_unregister_driver(enum rdma_driver_id driver_id)
{
        struct ib_device *ib_dev;
        unsigned long index;

        down_read(&devices_rwsem);
        xa_for_each (&devices, index, ib_dev) {
                if (ib_dev->ops.driver_id != driver_id)
                        continue;

                get_device(&ib_dev->dev);
                up_read(&devices_rwsem);

                WARN_ON(!ib_dev->ops.dealloc_driver);
                __ib_unregister_device(ib_dev);

                put_device(&ib_dev->dev);
                down_read(&devices_rwsem);
        }
        up_read(&devices_rwsem);
}
EXPORT_SYMBOL(ib_unregister_driver);

static void ib_unregister_work(struct work_struct *work)
{
        struct ib_device *ib_dev =
                container_of(work, struct ib_device, unregistration_work);

        __ib_unregister_device(ib_dev);
        put_device(&ib_dev->dev);
}

/**
 * ib_unregister_device_queued - Unregister a device using a work queue
 * @ib_dev: The device to unregister
 *
 * This schedules an asynchronous unregistration using a WQ for the device. A
 * driver should use this to avoid holding locks while doing unregistration,
 * such as holding the RTNL lock.
 *
 * Drivers using this API must use ib_unregister_driver before module unload
 * to ensure that all scheduled unregistrations have completed.
 */
void ib_unregister_device_queued(struct ib_device *ib_dev)
{
        WARN_ON(!refcount_read(&ib_dev->refcount));
        WARN_ON(!ib_dev->ops.dealloc_driver);
        get_device(&ib_dev->dev);
        if (!queue_work(system_unbound_wq, &ib_dev->unregistration_work))
                put_device(&ib_dev->dev);
}
EXPORT_SYMBOL(ib_unregister_device_queued);

/*
 * The caller must pass in a device that has the kref held and the refcount
 * released. If the device is in cur_net and still registered then it is moved
 * into net.
 */
static int rdma_dev_change_netns(struct ib_device *device, struct net *cur_net,
                                 struct net *net)
{
        int ret2 = -EINVAL;
        int ret;

        mutex_lock(&device->unregistration_lock);

        /*
         * If a device not under ib_device_get() or if the unregistration_lock
         * is not held, the namespace can be changed, or it can be unregistered.
         * Check again under the lock.
         */
        if (refcount_read(&device->refcount) == 0 ||
            !net_eq(cur_net, read_pnet(&device->coredev.rdma_net))) {
                ret = -ENODEV;
                goto out;
        }

        kobject_uevent(&device->dev.kobj, KOBJ_REMOVE);
        disable_device(device);

        /*
         * At this point no one can be using the device, so it is safe to
         * change the namespace.
         */
        write_pnet(&device->coredev.rdma_net, net);

        down_read(&devices_rwsem);
        /*
         * Currently rdma devices are system wide unique. So the device name
         * is guaranteed free in the new namespace. Publish the new namespace
         * at the sysfs level.
         */
        ret = device_rename(&device->dev, dev_name(&device->dev));
        up_read(&devices_rwsem);
        if (ret) {
                dev_warn(&device->dev,
                         "%s: Couldn't rename device after namespace change\n",
                         __func__);
                /* Try and put things back and re-enable the device */
                write_pnet(&device->coredev.rdma_net, cur_net);
        }

        ret2 = enable_device_and_get(device);
        if (ret2) {
                /*
                 * This shouldn't really happen, but if it does, let the user
                 * retry at later point. So don't disable the device.
                 */
                dev_warn(&device->dev,
                         "%s: Couldn't re-enable device after namespace change\n",
                         __func__);
        }
        kobject_uevent(&device->dev.kobj, KOBJ_ADD);

        ib_device_put(device);
out:
        mutex_unlock(&device->unregistration_lock);
        if (ret)
                return ret;
        return ret2;
}

int ib_device_set_netns_put(struct sk_buff *skb,
                            struct ib_device *dev, u32 ns_fd)
{
        struct net *net;
        int ret;

        net = get_net_ns_by_fd(ns_fd);
        if (IS_ERR(net)) {
                ret = PTR_ERR(net);
                goto net_err;
        }

        if (!netlink_ns_capable(skb, net->user_ns, CAP_NET_ADMIN)) {
                ret = -EPERM;
                goto ns_err;
        }

        /*
         * All the ib_clients, including uverbs, are reset when the namespace is
         * changed and this cannot be blocked waiting for userspace to do
         * something, so disassociation is mandatory.
         */
        if (!dev->ops.disassociate_ucontext || ib_devices_shared_netns) {
                ret = -EOPNOTSUPP;
                goto ns_err;
        }

        get_device(&dev->dev);
        ib_device_put(dev);
        ret = rdma_dev_change_netns(dev, current->nsproxy->net_ns, net);
        put_device(&dev->dev);

        put_net(net);
        return ret;

ns_err:
        put_net(net);
net_err:
        ib_device_put(dev);
        return ret;
}

static struct pernet_operations rdma_dev_net_ops = {
        .init = rdma_dev_init_net,
        .exit = rdma_dev_exit_net,
        .id = &rdma_dev_net_id,
        .size = sizeof(struct rdma_dev_net),
};

static int assign_client_id(struct ib_client *client)
{
        int ret;

        down_write(&clients_rwsem);
        /*
         * The add/remove callbacks must be called in FIFO/LIFO order. To
         * achieve this we assign client_ids so they are sorted in
         * registration order.
         */
        client->client_id = highest_client_id;
        ret = xa_insert(&clients, client->client_id, client, GFP_KERNEL);
        if (ret)
                goto out;

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

out:
        up_write(&clients_rwsem);
        return ret;
}

static void remove_client_id(struct ib_client *client)
{
        down_write(&clients_rwsem);
        xa_erase(&clients, client->client_id);
        for (; highest_client_id; highest_client_id--)
                if (xa_load(&clients, highest_client_id - 1))
                        break;
        up_write(&clients_rwsem);
}

/**
 * ib_register_client - Register an IB client
 * @client:Client to register
 *
 * Upper level users of the IB drivers can use ib_register_client() to
 * register callbacks for IB device addition and removal.  When an IB
 * device is added, each registered client's add method will be called
 * (in the order the clients were registered), and when a device is
 * removed, each client's remove method will be called (in the reverse
 * order that clients were registered).  In addition, when
 * ib_register_client() is called, the client will receive an add
 * callback for all devices already registered.
 */
int ib_register_client(struct ib_client *client)
{
        struct ib_device *device;
        unsigned long index;
        int ret;

        refcount_set(&client->uses, 1);
        init_completion(&client->uses_zero);
        ret = assign_client_id(client);
        if (ret)
                return ret;

        down_read(&devices_rwsem);
        xa_for_each_marked (&devices, index, device, DEVICE_REGISTERED) {
                ret = add_client_context(device, client);
                if (ret) {
                        up_read(&devices_rwsem);
                        ib_unregister_client(client);
                        return ret;
                }
        }
        up_read(&devices_rwsem);
        return 0;
}
EXPORT_SYMBOL(ib_register_client);

/**
 * ib_unregister_client - Unregister an IB client
 * @client:Client to unregister
 *
 * Upper level users use ib_unregister_client() to remove their client
 * registration.  When ib_unregister_client() is called, the client
 * will receive a remove callback for each IB device still registered.
 *
 * This is a full fence, once it returns no client callbacks will be called,
 * or are running in another thread.
 */
void ib_unregister_client(struct ib_client *client)
{
        struct ib_device *device;
        unsigned long index;

        down_write(&clients_rwsem);
        ib_client_put(client);
        xa_clear_mark(&clients, client->client_id, CLIENT_REGISTERED);
        up_write(&clients_rwsem);

        /* We do not want to have locks while calling client->remove() */
        rcu_read_lock();
        xa_for_each (&devices, index, device) {
                if (!ib_device_try_get(device))
                        continue;
                rcu_read_unlock();

                remove_client_context(device, client->client_id);

                ib_device_put(device);
                rcu_read_lock();
        }
        rcu_read_unlock();

        /*
         * remove_client_context() is not a fence, it can return even though a
         * removal is ongoing. Wait until all removals are completed.
         */
        wait_for_completion(&client->uses_zero);
        remove_client_id(client);
}
EXPORT_SYMBOL(ib_unregister_client);

static int __ib_get_global_client_nl_info(const char *client_name,
                                          struct ib_client_nl_info *res)
{
        struct ib_client *client;
        unsigned long index;
        int ret = -ENOENT;

        down_read(&clients_rwsem);
        xa_for_each_marked (&clients, index, client, CLIENT_REGISTERED) {
                if (strcmp(client->name, client_name) != 0)
                        continue;
                if (!client->get_global_nl_info) {
                        ret = -EOPNOTSUPP;
                        break;
                }
                ret = client->get_global_nl_info(res);
                if (WARN_ON(ret == -ENOENT))
                        ret = -EINVAL;
                if (!ret && res->cdev)
                        get_device(res->cdev);
                break;
        }
        up_read(&clients_rwsem);
        return ret;
}

static int __ib_get_client_nl_info(struct ib_device *ibdev,
                                   const char *client_name,
                                   struct ib_client_nl_info *res)
{
        unsigned long index;
        void *client_data;
        int ret = -ENOENT;

        down_read(&ibdev->client_data_rwsem);
        xan_for_each_marked (&ibdev->client_data, index, client_data,
                             CLIENT_DATA_REGISTERED) {
                struct ib_client *client = xa_load(&clients, index);

                if (!client || strcmp(client->name, client_name) != 0)
                        continue;
                if (!client->get_nl_info) {
                        ret = -EOPNOTSUPP;
                        break;
                }
                ret = client->get_nl_info(ibdev, client_data, res);
                if (WARN_ON(ret == -ENOENT))
                        ret = -EINVAL;

                /*
                 * The cdev is guaranteed valid as long as we are inside the
                 * client_data_rwsem as remove_one can't be called. Keep it
                 * valid for the caller.
                 */
                if (!ret && res->cdev)
                        get_device(res->cdev);
                break;
        }
        up_read(&ibdev->client_data_rwsem);

        return ret;
}

/**
 * ib_get_client_nl_info - Fetch the nl_info from a client
 * @ibdev: IB device
 * @client_name: Name of the client
 * @res: Result of the query
 */
int ib_get_client_nl_info(struct ib_device *ibdev, const char *client_name,
                          struct ib_client_nl_info *res)
{
        int ret;

        if (ibdev)
                ret = __ib_get_client_nl_info(ibdev, client_name, res);
        else
                ret = __ib_get_global_client_nl_info(client_name, res);
#ifdef CONFIG_MODULES
        if (ret == -ENOENT) {
                request_module("rdma-client-%s", client_name);
                if (ibdev)
                        ret = __ib_get_client_nl_info(ibdev, client_name, res);
                else
                        ret = __ib_get_global_client_nl_info(client_name, res);
        }
#endif
        if (ret) {
                if (ret == -ENOENT)
                        return -EOPNOTSUPP;
                return ret;
        }

        if (WARN_ON(!res->cdev))
                return -EINVAL;
        return 0;
}

/**
 * ib_set_client_data - Set IB client context
 * @device:Device to set context for
 * @client:Client to set context for
 * @data:Context to set
 *
 * ib_set_client_data() sets client context data that can be retrieved with
 * ib_get_client_data(). This can only be called while the client is
 * registered to the device, once the ib_client remove() callback returns this
 * cannot be called.
 */
void ib_set_client_data(struct ib_device *device, struct ib_client *client,
                        void *data)
{
        void *rc;

        if (WARN_ON(IS_ERR(data)))
                data = NULL;

        rc = xa_store(&device->client_data, client->client_id, data,
                      GFP_KERNEL);
        WARN_ON(xa_is_err(rc));
}
EXPORT_SYMBOL(ib_set_client_data);

/**
 * ib_register_event_handler - Register an IB event handler
 * @event_handler:Handler to register
 *
 * ib_register_event_handler() registers an event handler that will be
 * called back when asynchronous IB events occur (as defined in
 * chapter 11 of the InfiniBand Architecture Specification). This
 * callback occurs in workqueue context.
 */
void ib_register_event_handler(struct ib_event_handler *event_handler)
{
        down_write(&event_handler->device->event_handler_rwsem);
        list_add_tail(&event_handler->list,
                      &event_handler->device->event_handler_list);
        up_write(&event_handler->device->event_handler_rwsem);
}
EXPORT_SYMBOL(ib_register_event_handler);

/**
 * ib_unregister_event_handler - Unregister an event handler
 * @event_handler:Handler to unregister
 *
 * Unregister an event handler registered with
 * ib_register_event_handler().
 */
void ib_unregister_event_handler(struct ib_event_handler *event_handler)
{
        down_write(&event_handler->device->event_handler_rwsem);
        list_del(&event_handler->list);
        up_write(&event_handler->device->event_handler_rwsem);
}
EXPORT_SYMBOL(ib_unregister_event_handler);

void ib_dispatch_event_clients(struct ib_event *event)
{
        struct ib_event_handler *handler;