netlink.c

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/*
 * Copyright (C) 2011 Instituto Nokia de Tecnologia
 *
 * Authors:
 *    Lauro Ramos Venancio <[email protected]>
 *    Aloisio Almeida Jr <[email protected]>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the
 * Free Software Foundation, Inc.,
 * 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
 */

#define pr_fmt(fmt) KBUILD_MODNAME ": %s: " fmt, __func__

#include <net/genetlink.h>
#include <linux/nfc.h>
#include <linux/slab.h>

#include "nfc.h"

static struct genl_multicast_group nfc_genl_event_mcgrp = {
    .name = NFC_GENL_MCAST_EVENT_NAME,
};

static struct genl_family nfc_genl_family = {
    .id = GENL_ID_GENERATE,
    .hdrsize = 0,
    .name = NFC_GENL_NAME,
    .version = NFC_GENL_VERSION,
    .maxattr = NFC_ATTR_MAX,
};

static const struct nla_policy nfc_genl_policy[NFC_ATTR_MAX + 1] = {
    [NFC_ATTR_DEVICE_INDEX] = { .type = NLA_U32 },
    [NFC_ATTR_DEVICE_NAME] = { .type = NLA_STRING,
                .len = NFC_DEVICE_NAME_MAXSIZE },
    [NFC_ATTR_PROTOCOLS] = { .type = NLA_U32 },
    [NFC_ATTR_COMM_MODE] = { .type = NLA_U8 },
    [NFC_ATTR_RF_MODE] = { .type = NLA_U8 },
    [NFC_ATTR_DEVICE_POWERED] = { .type = NLA_U8 },
    [NFC_ATTR_IM_PROTOCOLS] = { .type = NLA_U32 },
    [NFC_ATTR_TM_PROTOCOLS] = { .type = NLA_U32 },
};

static int nfc_genl_send_target(struct sk_buff *msg, struct nfc_target *target,
                struct netlink_callback *cb, int flags)
{
    void *hdr;

    hdr = genlmsg_put(msg, NETLINK_CB(cb->skb).portid, cb->nlh->nlmsg_seq,
              &nfc_genl_family, flags, NFC_CMD_GET_TARGET);
    if (!hdr)
        return -EMSGSIZE;

    genl_dump_check_consistent(cb, hdr, &nfc_genl_family);

    if (nla_put_u32(msg, NFC_ATTR_TARGET_INDEX, target->idx) ||
        nla_put_u32(msg, NFC_ATTR_PROTOCOLS, target->supported_protocols) ||
        nla_put_u16(msg, NFC_ATTR_TARGET_SENS_RES, target->sens_res) ||
        nla_put_u8(msg, NFC_ATTR_TARGET_SEL_RES, target->sel_res))
        goto nla_put_failure;
    if (target->nfcid1_len > 0 &&
        nla_put(msg, NFC_ATTR_TARGET_NFCID1, target->nfcid1_len,
            target->nfcid1))
        goto nla_put_failure;
    if (target->sensb_res_len > 0 &&
        nla_put(msg, NFC_ATTR_TARGET_SENSB_RES, target->sensb_res_len,
            target->sensb_res))
        goto nla_put_failure;
    if (target->sensf_res_len > 0 &&
        nla_put(msg, NFC_ATTR_TARGET_SENSF_RES, target->sensf_res_len,
            target->sensf_res))
        goto nla_put_failure;

    return genlmsg_end(msg, hdr);

nla_put_failure:
    genlmsg_cancel(msg, hdr);
    return -EMSGSIZE;
}

static struct nfc_dev *__get_device_from_cb(struct netlink_callback *cb)
{
    struct nfc_dev *dev;
    int rc;
    u32 idx;

    rc = nlmsg_parse(cb->nlh, GENL_HDRLEN + nfc_genl_family.hdrsize,
             nfc_genl_family.attrbuf,
             nfc_genl_family.maxattr,
             nfc_genl_policy);
    if (rc < 0)
        return ERR_PTR(rc);

    if (!nfc_genl_family.attrbuf[NFC_ATTR_DEVICE_INDEX])
        return ERR_PTR(-EINVAL);

    idx = nla_get_u32(nfc_genl_family.attrbuf[NFC_ATTR_DEVICE_INDEX]);

    dev = nfc_get_device(idx);
    if (!dev)
        return ERR_PTR(-ENODEV);

    return dev;
}

static int nfc_genl_dump_targets(struct sk_buff *skb,
                 struct netlink_callback *cb)
{
    int i = cb->args[0];
    struct nfc_dev *dev = (struct nfc_dev *) cb->args[1];
    int rc;

    if (!dev) {
        dev = __get_device_from_cb(cb);
        if (IS_ERR(dev))
            return PTR_ERR(dev);

        cb->args[1] = (long) dev;
    }

    device_lock(&dev->dev);

    cb->seq = dev->targets_generation;

    while (i < dev->n_targets) {
        rc = nfc_genl_send_target(skb, &dev->targets[i], cb,
                      NLM_F_MULTI);
        if (rc < 0)
            break;

        i++;
    }

    device_unlock(&dev->dev);

    cb->args[0] = i;

    return skb->len;
}

static int nfc_genl_dump_targets_done(struct netlink_callback *cb)
{
    struct nfc_dev *dev = (struct nfc_dev *) cb->args[1];

    if (dev)
        nfc_put_device(dev);

    return 0;
}

int nfc_genl_targets_found(struct nfc_dev *dev)
{
    struct sk_buff *msg;
    void *hdr;

    dev->genl_data.poll_req_portid = 0;

    msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
    if (!msg)
        return -ENOMEM;

    hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
              NFC_EVENT_TARGETS_FOUND);
    if (!hdr)
        goto free_msg;

    if (nla_put_u32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx))
        goto nla_put_failure;

    genlmsg_end(msg, hdr);

    return genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_ATOMIC);

nla_put_failure:
    genlmsg_cancel(msg, hdr);
free_msg:
    nlmsg_free(msg);
    return -EMSGSIZE;
}

int nfc_genl_target_lost(struct nfc_dev *dev, u32 target_idx)
{
    struct sk_buff *msg;
    void *hdr;

    msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
    if (!msg)
        return -ENOMEM;

    hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
              NFC_EVENT_TARGET_LOST);
    if (!hdr)
        goto free_msg;

    if (nla_put_string(msg, NFC_ATTR_DEVICE_NAME, nfc_device_name(dev)) ||
        nla_put_u32(msg, NFC_ATTR_TARGET_INDEX, target_idx))
        goto nla_put_failure;

    genlmsg_end(msg, hdr);

    genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_KERNEL);

    return 0;

nla_put_failure:
    genlmsg_cancel(msg, hdr);
free_msg:
    nlmsg_free(msg);
    return -EMSGSIZE;
}

int nfc_genl_tm_activated(struct nfc_dev *dev, u32 protocol)
{
    struct sk_buff *msg;
    void *hdr;

    msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
    if (!msg)
        return -ENOMEM;

    hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
              NFC_EVENT_TM_ACTIVATED);
    if (!hdr)
        goto free_msg;

    if (nla_put_u32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx))
        goto nla_put_failure;
    if (nla_put_u32(msg, NFC_ATTR_TM_PROTOCOLS, protocol))
        goto nla_put_failure;

    genlmsg_end(msg, hdr);

    genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_KERNEL);

    return 0;

nla_put_failure:
    genlmsg_cancel(msg, hdr);
free_msg:
    nlmsg_free(msg);
    return -EMSGSIZE;
}

int nfc_genl_tm_deactivated(struct nfc_dev *dev)
{
    struct sk_buff *msg;
    void *hdr;

    msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
    if (!msg)
        return -ENOMEM;

    hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
              NFC_EVENT_TM_DEACTIVATED);
    if (!hdr)
        goto free_msg;

    if (nla_put_u32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx))
        goto nla_put_failure;

    genlmsg_end(msg, hdr);

    genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_KERNEL);

    return 0;

nla_put_failure:
    genlmsg_cancel(msg, hdr);
free_msg:
    nlmsg_free(msg);
    return -EMSGSIZE;
}

int nfc_genl_device_added(struct nfc_dev *dev)
{
    struct sk_buff *msg;
    void *hdr;

    msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
    if (!msg)
        return -ENOMEM;

    hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
              NFC_EVENT_DEVICE_ADDED);
    if (!hdr)
        goto free_msg;

    if (nla_put_string(msg, NFC_ATTR_DEVICE_NAME, nfc_device_name(dev)) ||
        nla_put_u32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx) ||
        nla_put_u32(msg, NFC_ATTR_PROTOCOLS, dev->supported_protocols) ||
        nla_put_u8(msg, NFC_ATTR_DEVICE_POWERED, dev->dev_up))
        goto nla_put_failure;

    genlmsg_end(msg, hdr);

    genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_KERNEL);

    return 0;

nla_put_failure:
    genlmsg_cancel(msg, hdr);
free_msg:
    nlmsg_free(msg);
    return -EMSGSIZE;
}

int nfc_genl_device_removed(struct nfc_dev *dev)
{
    struct sk_buff *msg;
    void *hdr;

    msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
    if (!msg)
        return -ENOMEM;

    hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
              NFC_EVENT_DEVICE_REMOVED);
    if (!hdr)
        goto free_msg;

    if (nla_put_u32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx))
        goto nla_put_failure;

    genlmsg_end(msg, hdr);

    genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_KERNEL);

    return 0;

nla_put_failure:
    genlmsg_cancel(msg, hdr);
free_msg:
    nlmsg_free(msg);
    return -EMSGSIZE;
}

static int nfc_genl_send_device(struct sk_buff *msg, struct nfc_dev *dev,
                u32 portid, u32 seq,
                struct netlink_callback *cb,
                int flags)
{
    void *hdr;

    hdr = genlmsg_put(msg, portid, seq, &nfc_genl_family, flags,
              NFC_CMD_GET_DEVICE);
    if (!hdr)
        return -EMSGSIZE;

    if (cb)
        genl_dump_check_consistent(cb, hdr, &nfc_genl_family);

    if (nla_put_string(msg, NFC_ATTR_DEVICE_NAME, nfc_device_name(dev)) ||
        nla_put_u32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx) ||
        nla_put_u32(msg, NFC_ATTR_PROTOCOLS, dev->supported_protocols) ||
        nla_put_u8(msg, NFC_ATTR_DEVICE_POWERED, dev->dev_up))
        goto nla_put_failure;

    return genlmsg_end(msg, hdr);

nla_put_failure:
    genlmsg_cancel(msg, hdr);
    return -EMSGSIZE;
}

static int nfc_genl_dump_devices(struct sk_buff *skb,
                 struct netlink_callback *cb)
{
    struct class_dev_iter *iter = (struct class_dev_iter *) cb->args[0];
    struct nfc_dev *dev = (struct nfc_dev *) cb->args[1];
    bool first_call = false;

    if (!iter) {
        first_call = true;
        iter = kmalloc(sizeof(struct class_dev_iter), GFP_KERNEL);
        if (!iter)
            return -ENOMEM;
        cb->args[0] = (long) iter;
    }

    mutex_lock(&nfc_devlist_mutex);

    cb->seq = nfc_devlist_generation;

    if (first_call) {
        nfc_device_iter_init(iter);
        dev = nfc_device_iter_next(iter);
    }

    while (dev) {
        int rc;

        rc = nfc_genl_send_device(skb, dev, NETLINK_CB(cb->skb).portid,
                      cb->nlh->nlmsg_seq, cb, NLM_F_MULTI);
        if (rc < 0)
            break;

        dev = nfc_device_iter_next(iter);
    }

    mutex_unlock(&nfc_devlist_mutex);

    cb->args[1] = (long) dev;

    return skb->len;
}

static int nfc_genl_dump_devices_done(struct netlink_callback *cb)
{
    struct class_dev_iter *iter = (struct class_dev_iter *) cb->args[0];

    nfc_device_iter_exit(iter);
    kfree(iter);

    return 0;
}

int nfc_genl_dep_link_up_event(struct nfc_dev *dev, u32 target_idx,
                   u8 comm_mode, u8 rf_mode)
{
    struct sk_buff *msg;
    void *hdr;

    pr_debug("DEP link is up\n");

    msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
    if (!msg)
        return -ENOMEM;

    hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0, NFC_CMD_DEP_LINK_UP);
    if (!hdr)
        goto free_msg;

    if (nla_put_u32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx))
        goto nla_put_failure;
    if (rf_mode == NFC_RF_INITIATOR &&
        nla_put_u32(msg, NFC_ATTR_TARGET_INDEX, target_idx))
        goto nla_put_failure;
    if (nla_put_u8(msg, NFC_ATTR_COMM_MODE, comm_mode) ||
        nla_put_u8(msg, NFC_ATTR_RF_MODE, rf_mode))
        goto nla_put_failure;

    genlmsg_end(msg, hdr);

    dev->dep_link_up = true;

    genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_ATOMIC);

    return 0;

nla_put_failure:
    genlmsg_cancel(msg, hdr);
free_msg:
    nlmsg_free(msg);
    return -EMSGSIZE;
}

int nfc_genl_dep_link_down_event(struct nfc_dev *dev)
{
    struct sk_buff *msg;
    void *hdr;

    pr_debug("DEP link is down\n");

    msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_ATOMIC);
    if (!msg)
        return -ENOMEM;

    hdr = genlmsg_put(msg, 0, 0, &nfc_genl_family, 0,
              NFC_CMD_DEP_LINK_DOWN);
    if (!hdr)
        goto free_msg;

    if (nla_put_u32(msg, NFC_ATTR_DEVICE_INDEX, dev->idx))
        goto nla_put_failure;

    genlmsg_end(msg, hdr);

    genlmsg_multicast(msg, 0, nfc_genl_event_mcgrp.id, GFP_ATOMIC);

    return 0;

nla_put_failure:
    genlmsg_cancel(msg, hdr);
free_msg:
    nlmsg_free(msg);
    return -EMSGSIZE;
}

static int nfc_genl_get_device(struct sk_buff *skb, struct genl_info *info)
{
    struct sk_buff *msg;
    struct nfc_dev *dev;
    u32 idx;
    int rc = -ENOBUFS;

    if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
        return -EINVAL;

    idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);

    dev = nfc_get_device(idx);
    if (!dev)
        return -ENODEV;

    msg = nlmsg_new(NLMSG_DEFAULT_SIZE, GFP_KERNEL);
    if (!msg) {
        rc = -ENOMEM;
        goto out_putdev;
    }

    rc = nfc_genl_send_device(msg, dev, info->snd_portid, info->snd_seq,
                  NULL, 0);
    if (rc < 0)
        goto out_free;

    nfc_put_device(dev);

    return genlmsg_reply(msg, info);

out_free:
    nlmsg_free(msg);
out_putdev:
    nfc_put_device(dev);
    return rc;
}

static int nfc_genl_dev_up(struct sk_buff *skb, struct genl_info *info)
{
    struct nfc_dev *dev;
    int rc;
    u32 idx;

    if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
        return -EINVAL;

    idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);

    dev = nfc_get_device(idx);
    if (!dev)
        return -ENODEV;

    rc = nfc_dev_up(dev);

    nfc_put_device(dev);
    return rc;
}

static int nfc_genl_dev_down(struct sk_buff *skb, struct genl_info *info)
{
    struct nfc_dev *dev;
    int rc;
    u32 idx;

    if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
        return -EINVAL;

    idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);

    dev = nfc_get_device(idx);
    if (!dev)
        return -ENODEV;

    rc = nfc_dev_down(dev);

    nfc_put_device(dev);
    return rc;
}

static int nfc_genl_start_poll(struct sk_buff *skb, struct genl_info *info)
{
    struct nfc_dev *dev;
    int rc;
    u32 idx;
    u32 im_protocols = 0, tm_protocols = 0;

    pr_debug("Poll start\n");

    if (!info->attrs[NFC_ATTR_DEVICE_INDEX] ||
        ((!info->attrs[NFC_ATTR_IM_PROTOCOLS] &&
          !info->attrs[NFC_ATTR_PROTOCOLS]) &&
         !info->attrs[NFC_ATTR_TM_PROTOCOLS]))
        return -EINVAL;

    idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);

    if (info->attrs[NFC_ATTR_TM_PROTOCOLS])
        tm_protocols = nla_get_u32(info->attrs[NFC_ATTR_TM_PROTOCOLS]);

    if (info->attrs[NFC_ATTR_IM_PROTOCOLS])
        im_protocols = nla_get_u32(info->attrs[NFC_ATTR_IM_PROTOCOLS]);
    else if (info->attrs[NFC_ATTR_PROTOCOLS])
        im_protocols = nla_get_u32(info->attrs[NFC_ATTR_PROTOCOLS]);

    dev = nfc_get_device(idx);
    if (!dev)
        return -ENODEV;

    mutex_lock(&dev->genl_data.genl_data_mutex);

    rc = nfc_start_poll(dev, im_protocols, tm_protocols);
    if (!rc)
        dev->genl_data.poll_req_portid = info->snd_portid;

    mutex_unlock(&dev->genl_data.genl_data_mutex);

    nfc_put_device(dev);
    return rc;
}

static int nfc_genl_stop_poll(struct sk_buff *skb, struct genl_info *info)
{
    struct nfc_dev *dev;
    int rc;
    u32 idx;

    if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
        return -EINVAL;

    idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);

    dev = nfc_get_device(idx);
    if (!dev)
        return -ENODEV;

    device_lock(&dev->dev);

    if (!dev->polling) {
        device_unlock(&dev->dev);
        return -EINVAL;
    }

    device_unlock(&dev->dev);

    mutex_lock(&dev->genl_data.genl_data_mutex);

    if (dev->genl_data.poll_req_portid != info->snd_portid) {
        rc = -EBUSY;
        goto out;
    }

    rc = nfc_stop_poll(dev);
    dev->genl_data.poll_req_portid = 0;

out:
    mutex_unlock(&dev->genl_data.genl_data_mutex);
    nfc_put_device(dev);
    return rc;
}

static int nfc_genl_dep_link_up(struct sk_buff *skb, struct genl_info *info)
{
    struct nfc_dev *dev;
    int rc, tgt_idx;
    u32 idx;
    u8 comm;

    pr_debug("DEP link up\n");

    if (!info->attrs[NFC_ATTR_DEVICE_INDEX] ||
        !info->attrs[NFC_ATTR_COMM_MODE])
        return -EINVAL;

    idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);
    if (!info->attrs[NFC_ATTR_TARGET_INDEX])
        tgt_idx = NFC_TARGET_IDX_ANY;
    else
        tgt_idx = nla_get_u32(info->attrs[NFC_ATTR_TARGET_INDEX]);

    comm = nla_get_u8(info->attrs[NFC_ATTR_COMM_MODE]);

    if (comm != NFC_COMM_ACTIVE && comm != NFC_COMM_PASSIVE)
        return -EINVAL;

    dev = nfc_get_device(idx);
    if (!dev)
        return -ENODEV;

    rc = nfc_dep_link_up(dev, tgt_idx, comm);

    nfc_put_device(dev);

    return rc;
}

static int nfc_genl_dep_link_down(struct sk_buff *skb, struct genl_info *info)
{
    struct nfc_dev *dev;
    int rc;
    u32 idx;

    if (!info->attrs[NFC_ATTR_DEVICE_INDEX])
        return -EINVAL;

    idx = nla_get_u32(info->attrs[NFC_ATTR_DEVICE_INDEX]);

    dev = nfc_get_device(idx);
    if (!dev)
        return -ENODEV;

    rc = nfc_dep_link_down(dev);

    nfc_put_device(dev);
    return rc;
}

static struct genl_ops nfc_genl_ops[] = {
    {
        .cmd = NFC_CMD_GET_DEVICE,
        .doit = nfc_genl_get_device,
        .dumpit = nfc_genl_dump_devices,
        .done = nfc_genl_dump_devices_done,
        .policy = nfc_genl_policy,
    },
    {
        .cmd = NFC_CMD_DEV_UP,
        .doit = nfc_genl_dev_up,
        .policy = nfc_genl_policy,
    },
    {
        .cmd = NFC_CMD_DEV_DOWN,
        .doit = nfc_genl_dev_down,
        .policy = nfc_genl_policy,
    },
    {
        .cmd = NFC_CMD_START_POLL,
        .doit = nfc_genl_start_poll,
        .policy = nfc_genl_policy,
    },
    {
        .cmd = NFC_CMD_STOP_POLL,
        .doit = nfc_genl_stop_poll,
        .policy = nfc_genl_policy,
    },
    {
        .cmd = NFC_CMD_DEP_LINK_UP,
        .doit = nfc_genl_dep_link_up,
        .policy = nfc_genl_policy,
    },
    {
        .cmd = NFC_CMD_DEP_LINK_DOWN,
        .doit = nfc_genl_dep_link_down,
        .policy = nfc_genl_policy,
    },
    {
        .cmd = NFC_CMD_GET_TARGET,
        .dumpit = nfc_genl_dump_targets,
        .done = nfc_genl_dump_targets_done,
        .policy = nfc_genl_policy,
    },
};


struct urelease_work {
    struct  work_struct w;
    int portid;
};

static void nfc_urelease_event_work(struct work_struct *work)
{
    struct urelease_work *w = container_of(work, struct urelease_work, w);
    struct class_dev_iter iter;
    struct nfc_dev *dev;

    pr_debug("portid %d\n", w->portid);

    mutex_lock(&nfc_devlist_mutex);

    nfc_device_iter_init(&iter);
    dev = nfc_device_iter_next(&iter);

    while (dev) {
        mutex_lock(&dev->genl_data.genl_data_mutex);

        if (dev->genl_data.poll_req_portid == w->portid) {
            nfc_stop_poll(dev);
            dev->genl_data.poll_req_portid = 0;
        }

        mutex_unlock(&dev->genl_data.genl_data_mutex);

        dev = nfc_device_iter_next(&iter);
    }

    nfc_device_iter_exit(&iter);

    mutex_unlock(&nfc_devlist_mutex);

    kfree(w);
}

static int nfc_genl_rcv_nl_event(struct notifier_block *this,
                 unsigned long event, void *ptr)
{
    struct netlink_notify *n = ptr;
    struct urelease_work *w;

    if (event != NETLINK_URELEASE || n->protocol != NETLINK_GENERIC)
        goto out;

    pr_debug("NETLINK_URELEASE event from id %d\n", n->portid);

    w = kmalloc(sizeof(*w), GFP_ATOMIC);
    if (w) {
        INIT_WORK((struct work_struct *) w, nfc_urelease_event_work);
        w->portid = n->portid;
        schedule_work((struct work_struct *) w);
    }

out:
    return NOTIFY_DONE;
}

void nfc_genl_data_init(struct nfc_genl_data *genl_data)
{
    genl_data->poll_req_portid = 0;
    mutex_init(&genl_data->genl_data_mutex);
}

void nfc_genl_data_exit(struct nfc_genl_data *genl_data)
{
    mutex_destroy(&genl_data->genl_data_mutex);
}

static struct notifier_block nl_notifier = {
    .notifier_call  = nfc_genl_rcv_nl_event,
};

int __init nfc_genl_init(void)
{
    int rc;

    rc = genl_register_family_with_ops(&nfc_genl_family, nfc_genl_ops,
                       ARRAY_SIZE(nfc_genl_ops));
    if (rc)
        return rc;

    rc = genl_register_mc_group(&nfc_genl_family, &nfc_genl_event_mcgrp);

    netlink_register_notifier(&nl_notifier);

    return rc;
}

void nfc_genl_exit(void)
{
    netlink_unregister_notifier(&nl_notifier);
    genl_unregister_family(&nfc_genl_family);
}