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nbd: multicast dead link notifications
Provide a mechanism to notify userspace that there's been a link problem on a NBD device. This will allow userspace to re-establish a connection and provide the new socket to the device without disrupting the device. Signed-off-by: Josef Bacik <jbacik@fb.com> Signed-off-by: Jens Axboe <axboe@fb.com>
This commit is contained in:
Josef Bacik
Jens Axboe
parent
b7aa3d3938
commit
799f9a38bc
@ -53,6 +53,7 @@ struct nbd_sock {
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int sent;
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bool dead;
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int fallback_index;
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int cookie;
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};
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struct recv_thread_args {
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@ -61,6 +62,11 @@ struct recv_thread_args {
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int index;
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};
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struct link_dead_args {
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struct work_struct work;
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int index;
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};
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#define NBD_TIMEDOUT 0
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#define NBD_DISCONNECT_REQUESTED 1
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#define NBD_DISCONNECTED 2
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@ -100,6 +106,7 @@ struct nbd_device {
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struct nbd_cmd {
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struct nbd_device *nbd;
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int index;
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int cookie;
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struct completion send_complete;
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};
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@ -120,6 +127,7 @@ static int nbd_dev_dbg_init(struct nbd_device *nbd);
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static void nbd_dev_dbg_close(struct nbd_device *nbd);
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static void nbd_config_put(struct nbd_device *nbd);
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static void nbd_connect_reply(struct genl_info *info, int index);
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static void nbd_dead_link_work(struct work_struct *work);
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static inline struct device *nbd_to_dev(struct nbd_device *nbd)
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{
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@ -152,8 +160,24 @@ static struct device_attribute pid_attr = {
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.show = pid_show,
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};
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static void nbd_mark_nsock_dead(struct nbd_sock *nsock)
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static int nbd_disconnected(struct nbd_config *config)
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{
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return test_bit(NBD_DISCONNECTED, &config->runtime_flags) ||
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test_bit(NBD_DISCONNECT_REQUESTED, &config->runtime_flags);
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}
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static void nbd_mark_nsock_dead(struct nbd_device *nbd, struct nbd_sock *nsock,
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int notify)
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{
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if (!nsock->dead && notify && !nbd_disconnected(nbd->config)) {
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struct link_dead_args *args;
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args = kmalloc(sizeof(struct link_dead_args), GFP_NOIO);
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if (args) {
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INIT_WORK(&args->work, nbd_dead_link_work);
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args->index = nbd->index;
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queue_work(system_wq, &args->work);
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}
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}
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if (!nsock->dead)
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kernel_sock_shutdown(nsock->sock, SHUT_RDWR);
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nsock->dead = true;
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@ -215,8 +239,7 @@ static void sock_shutdown(struct nbd_device *nbd)
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for (i = 0; i < config->num_connections; i++) {
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struct nbd_sock *nsock = config->socks[i];
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mutex_lock(&nsock->tx_lock);
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kernel_sock_shutdown(nsock->sock, SHUT_RDWR);
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nbd_mark_nsock_dead(nsock);
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nbd_mark_nsock_dead(nbd, nsock, 0);
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mutex_unlock(&nsock->tx_lock);
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}
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dev_warn(disk_to_dev(nbd->disk), "shutting down sockets\n");
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@ -248,7 +271,14 @@ static enum blk_eh_timer_return nbd_xmit_timeout(struct request *req,
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struct nbd_sock *nsock =
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config->socks[cmd->index];
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mutex_lock(&nsock->tx_lock);
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nbd_mark_nsock_dead(nsock);
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/* We can have multiple outstanding requests, so
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* we don't want to mark the nsock dead if we've
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* already reconnected with a new socket, so
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* only mark it dead if its the same socket we
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* were sent out on.
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*/
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if (cmd->cookie == nsock->cookie)
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nbd_mark_nsock_dead(nbd, nsock, 1);
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mutex_unlock(&nsock->tx_lock);
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}
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blk_mq_requeue_request(req, true);
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@ -370,6 +400,7 @@ static int nbd_send_cmd(struct nbd_device *nbd, struct nbd_cmd *cmd, int index)
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iov_iter_advance(&from, sent);
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}
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cmd->index = index;
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cmd->cookie = nsock->cookie;
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request.type = htonl(type);
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if (type != NBD_CMD_FLUSH) {
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request.from = cpu_to_be64((u64)blk_rq_pos(req) << 9);
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@ -458,12 +489,6 @@ out:
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return 0;
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}
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static int nbd_disconnected(struct nbd_config *config)
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{
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return test_bit(NBD_DISCONNECTED, &config->runtime_flags) ||
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test_bit(NBD_DISCONNECT_REQUESTED, &config->runtime_flags);
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}
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/* NULL returned = something went wrong, inform userspace */
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static struct nbd_cmd *nbd_read_stat(struct nbd_device *nbd, int index)
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{
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@ -564,7 +589,7 @@ static void recv_work(struct work_struct *work)
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struct nbd_sock *nsock = config->socks[args->index];
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mutex_lock(&nsock->tx_lock);
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nbd_mark_nsock_dead(nsock);
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nbd_mark_nsock_dead(nbd, nsock, 1);
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mutex_unlock(&nsock->tx_lock);
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ret = PTR_ERR(cmd);
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break;
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@ -691,7 +716,7 @@ again:
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if (ret == -EAGAIN) {
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dev_err_ratelimited(disk_to_dev(nbd->disk),
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"Request send failed trying another connection\n");
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nbd_mark_nsock_dead(nsock);
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nbd_mark_nsock_dead(nbd, nsock, 1);
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mutex_unlock(&nsock->tx_lock);
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goto again;
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}
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@ -780,6 +805,7 @@ static int nbd_add_socket(struct nbd_device *nbd, unsigned long arg,
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nsock->sock = sock;
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nsock->pending = NULL;
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nsock->sent = 0;
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nsock->cookie = 0;
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socks[config->num_connections++] = nsock;
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return 0;
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@ -824,6 +850,7 @@ static int nbd_reconnect_socket(struct nbd_device *nbd, unsigned long arg)
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INIT_WORK(&args->work, recv_work);
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args->index = i;
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args->nbd = nbd;
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nsock->cookie++;
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mutex_unlock(&nsock->tx_lock);
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sockfd_put(old);
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@ -1682,6 +1709,10 @@ static const struct genl_ops nbd_connect_genl_ops[] = {
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},
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};
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static const struct genl_multicast_group nbd_mcast_grps[] = {
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{ .name = NBD_GENL_MCAST_GROUP_NAME, },
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};
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static struct genl_family nbd_genl_family __ro_after_init = {
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.hdrsize = 0,
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.name = NBD_GENL_FAMILY_NAME,
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@ -1690,6 +1721,8 @@ static struct genl_family nbd_genl_family __ro_after_init = {
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.ops = nbd_connect_genl_ops,
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.n_ops = ARRAY_SIZE(nbd_connect_genl_ops),
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.maxattr = NBD_ATTR_MAX,
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.mcgrps = nbd_mcast_grps,
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.n_mcgrps = ARRAY_SIZE(nbd_mcast_grps),
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};
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static void nbd_connect_reply(struct genl_info *info, int index)
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@ -1716,6 +1749,38 @@ static void nbd_connect_reply(struct genl_info *info, int index)
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genlmsg_reply(skb, info);
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}
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static void nbd_mcast_index(int index)
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{
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struct sk_buff *skb;
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void *msg_head;
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int ret;
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skb = genlmsg_new(nla_total_size(sizeof(u32)), GFP_KERNEL);
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if (!skb)
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return;
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msg_head = genlmsg_put(skb, 0, 0, &nbd_genl_family, 0,
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NBD_CMD_LINK_DEAD);
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if (!msg_head) {
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nlmsg_free(skb);
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return;
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}
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ret = nla_put_u32(skb, NBD_ATTR_INDEX, index);
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if (ret) {
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nlmsg_free(skb);
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return;
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}
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genlmsg_end(skb, msg_head);
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genlmsg_multicast(&nbd_genl_family, skb, 0, 0, GFP_KERNEL);
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}
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static void nbd_dead_link_work(struct work_struct *work)
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{
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struct link_dead_args *args = container_of(work, struct link_dead_args,
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work);
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nbd_mcast_index(args->index);
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kfree(args);
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}
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static int __init nbd_init(void)
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{
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int i;
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@ -18,8 +18,9 @@
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#ifndef _UAPILINUX_NBD_NETLINK_H
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#define _UAPILINUX_NBD_NETLINK_H
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#define NBD_GENL_FAMILY_NAME "nbd"
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#define NBD_GENL_VERSION 0x1
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#define NBD_GENL_FAMILY_NAME "nbd"
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#define NBD_GENL_VERSION 0x1
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#define NBD_GENL_MCAST_GROUP_NAME "nbd_mc_group"
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/* Configuration policy attributes, used for CONNECT */
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enum {
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@ -63,6 +64,7 @@ enum {
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NBD_CMD_CONNECT,
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NBD_CMD_DISCONNECT,
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NBD_CMD_RECONFIGURE,
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NBD_CMD_LINK_DEAD,
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__NBD_CMD_MAX,
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};
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#define NBD_CMD_MAX (__NBD_CMD_MAX - 1)
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