Adding upstream version 4.19.249.upstream/4.19.249

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 748 insertions, 0 deletions

diff --git a/drivers/w1/w1_netlink.c b/drivers/w1/w1_netlink.c
new file mode 100644
index 000000000..f2f099cae
--- /dev/null
+++ b/drivers/w1/w1_netlink.c
@@ -0,0 +1,748 @@
+/*
+ * Copyright (c) 2003 Evgeniy Polyakov <zbr@ioremap.net>
+ *
+ * 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.
+ */
+
+#include <linux/slab.h>
+#include <linux/skbuff.h>
+#include <linux/netlink.h>
+#include <linux/connector.h>
+
+#include "w1_internal.h"
+#include "w1_netlink.h"
+
+#if defined(CONFIG_W1_CON) && (defined(CONFIG_CONNECTOR) || (defined(CONFIG_CONNECTOR_MODULE) && defined(CONFIG_W1_MODULE)))
+
+/* Bundle together everything required to process a request in one memory
+ * allocation.
+ */
+struct w1_cb_block {
+	atomic_t refcnt;
+	u32 portid; /* Sending process port ID */
+	/* maximum value for first_cn->len */
+	u16 maxlen;
+	/* pointers to building up the reply message */
+	struct cn_msg *first_cn; /* fixed once the structure is populated */
+	struct cn_msg *cn; /* advances as cn_msg is appeneded */
+	struct w1_netlink_msg *msg; /* advances as w1_netlink_msg is appened */
+	struct w1_netlink_cmd *cmd; /* advances as cmds are appened */
+	struct w1_netlink_msg *cur_msg; /* currently message being processed */
+	/* copy of the original request follows */
+	struct cn_msg request_cn;
+	/* followed by variable length:
+	 * cn_msg, data (w1_netlink_msg and w1_netlink_cmd)
+	 * one or more struct w1_cb_node
+	 * reply first_cn, data (w1_netlink_msg and w1_netlink_cmd)
+	 */
+};
+struct w1_cb_node {
+	struct w1_async_cmd async;
+	/* pointers within w1_cb_block and cn data */
+	struct w1_cb_block *block;
+	struct w1_netlink_msg *msg;
+	struct w1_slave *sl;
+	struct w1_master *dev;
+};
+
+/**
+ * w1_reply_len() - calculate current reply length, compare to maxlen
+ * @block: block to calculate
+ *
+ * Calculates the current message length including possible multiple
+ * cn_msg and data, excludes the first sizeof(struct cn_msg).  Direclty
+ * compariable to maxlen and usable to send the message.
+ */
+static u16 w1_reply_len(struct w1_cb_block *block)
+{
+	if (!block->cn)
+		return 0;
+	return (u8 *)block->cn - (u8 *)block->first_cn + block->cn->len;
+}
+
+static void w1_unref_block(struct w1_cb_block *block)
+{
+	if (atomic_sub_return(1, &block->refcnt) == 0) {
+		u16 len = w1_reply_len(block);
+		if (len) {
+			cn_netlink_send_mult(block->first_cn, len,
+				block->portid, 0, GFP_KERNEL);
+		}
+		kfree(block);
+	}
+}
+
+/**
+ * w1_reply_make_space() - send message if needed to make space
+ * @block: block to make space on
+ * @space: how many bytes requested
+ *
+ * Verify there is enough room left for the caller to add "space" bytes to the
+ * message, if there isn't send the message and reset.
+ */
+static void w1_reply_make_space(struct w1_cb_block *block, u16 space)
+{
+	u16 len = w1_reply_len(block);
+	if (len + space >= block->maxlen) {
+		cn_netlink_send_mult(block->first_cn, len, block->portid, 0, GFP_KERNEL);
+		block->first_cn->len = 0;
+		block->cn = NULL;
+		block->msg = NULL;
+		block->cmd = NULL;
+	}
+}
+
+/* Early send when replies aren't bundled. */
+static void w1_netlink_check_send(struct w1_cb_block *block)
+{
+	if (!(block->request_cn.flags & W1_CN_BUNDLE) && block->cn)
+		w1_reply_make_space(block, block->maxlen);
+}
+
+/**
+ * w1_netlink_setup_msg() - prepare to write block->msg
+ * @block: block to operate on
+ * @ack: determines if cn can be reused
+ *
+ * block->cn will be setup with the correct ack, advancing if needed
+ * block->cn->len does not include space for block->msg
+ * block->msg advances but remains uninitialized
+ */
+static void w1_netlink_setup_msg(struct w1_cb_block *block, u32 ack)
+{
+	if (block->cn && block->cn->ack == ack) {
+		block->msg = (struct w1_netlink_msg *)(block->cn->data + block->cn->len);
+	} else {
+		/* advance or set to data */
+		if (block->cn)
+			block->cn = (struct cn_msg *)(block->cn->data +
+				block->cn->len);
+		else
+			block->cn = block->first_cn;
+
+		memcpy(block->cn, &block->request_cn, sizeof(*block->cn));
+		block->cn->len = 0;
+		block->cn->ack = ack;
+		block->msg = (struct w1_netlink_msg *)block->cn->data;
+	}
+}
+
+/* Append cmd to msg, include cmd->data as well.  This is because
+ * any following data goes with the command and in the case of a read is
+ * the results.
+ */
+static void w1_netlink_queue_cmd(struct w1_cb_block *block,
+	struct w1_netlink_cmd *cmd)
+{
+	u32 space;
+	w1_reply_make_space(block, sizeof(struct cn_msg) +
+		sizeof(struct w1_netlink_msg) + sizeof(*cmd) + cmd->len);
+
+	/* There's a status message sent after each command, so no point
+	 * in trying to bundle this cmd after an existing one, because
+	 * there won't be one.  Allocate and copy over a new cn_msg.
+	 */
+	w1_netlink_setup_msg(block, block->request_cn.seq + 1);
+	memcpy(block->msg, block->cur_msg, sizeof(*block->msg));
+	block->cn->len += sizeof(*block->msg);
+	block->msg->len = 0;
+	block->cmd = (struct w1_netlink_cmd *)(block->msg->data);
+
+	space = sizeof(*cmd) + cmd->len;
+	if (block->cmd != cmd)
+		memcpy(block->cmd, cmd, space);
+	block->cn->len += space;
+	block->msg->len += space;
+}
+
+/* Append req_msg and req_cmd, no other commands and no data from req_cmd are
+ * copied.
+ */
+static void w1_netlink_queue_status(struct w1_cb_block *block,
+	struct w1_netlink_msg *req_msg, struct w1_netlink_cmd *req_cmd,
+	int error)
+{
+	u16 space = sizeof(struct cn_msg) + sizeof(*req_msg) + sizeof(*req_cmd);
+	w1_reply_make_space(block, space);
+	w1_netlink_setup_msg(block, block->request_cn.ack);
+
+	memcpy(block->msg, req_msg, sizeof(*req_msg));
+	block->cn->len += sizeof(*req_msg);
+	block->msg->len = 0;
+	block->msg->status = (u8)-error;
+	if (req_cmd) {
+		struct w1_netlink_cmd *cmd = (struct w1_netlink_cmd *)block->msg->data;
+		memcpy(cmd, req_cmd, sizeof(*cmd));
+		block->cn->len += sizeof(*cmd);
+		block->msg->len += sizeof(*cmd);
+		cmd->len = 0;
+	}
+	w1_netlink_check_send(block);
+}
+
+/**
+ * w1_netlink_send_error() - sends the error message now
+ * @cn: original cn_msg
+ * @msg: original w1_netlink_msg
+ * @portid: where to send it
+ * @error: error status
+ *
+ * Use when a block isn't available to queue the message to and cn, msg
+ * might not be contiguous.
+ */
+static void w1_netlink_send_error(struct cn_msg *cn, struct w1_netlink_msg *msg,
+	int portid, int error)
+{
+	struct {
+		struct cn_msg cn;
+		struct w1_netlink_msg msg;
+	} packet;
+	memcpy(&packet.cn, cn, sizeof(packet.cn));
+	memcpy(&packet.msg, msg, sizeof(packet.msg));
+	packet.cn.len = sizeof(packet.msg);
+	packet.msg.len = 0;
+	packet.msg.status = (u8)-error;
+	cn_netlink_send(&packet.cn, portid, 0, GFP_KERNEL);
+}
+
+/**
+ * w1_netlink_send() - sends w1 netlink notifications
+ * @dev: w1_master the even is associated with or for
+ * @msg: w1_netlink_msg message to be sent
+ *
+ * This are notifications generated from the kernel.
+ */
+void w1_netlink_send(struct w1_master *dev, struct w1_netlink_msg *msg)
+{
+	struct {
+		struct cn_msg cn;
+		struct w1_netlink_msg msg;
+	} packet;
+	memset(&packet, 0, sizeof(packet));
+
+	packet.cn.id.idx = CN_W1_IDX;
+	packet.cn.id.val = CN_W1_VAL;
+
+	packet.cn.seq = dev->seq++;
+	packet.cn.len = sizeof(*msg);
+
+	memcpy(&packet.msg, msg, sizeof(*msg));
+	packet.msg.len = 0;
+
+	cn_netlink_send(&packet.cn, 0, 0, GFP_KERNEL);
+}
+
+static void w1_send_slave(struct w1_master *dev, u64 rn)
+{
+	struct w1_cb_block *block = dev->priv;
+	struct w1_netlink_cmd *cache_cmd = block->cmd;
+	u64 *data;
+
+	w1_reply_make_space(block, sizeof(*data));
+
+	/* Add cmd back if the packet was sent */
+	if (!block->cmd) {
+		cache_cmd->len = 0;
+		w1_netlink_queue_cmd(block, cache_cmd);
+	}
+
+	data = (u64 *)(block->cmd->data + block->cmd->len);
+
+	*data = rn;
+	block->cn->len += sizeof(*data);
+	block->msg->len += sizeof(*data);
+	block->cmd->len += sizeof(*data);
+}
+
+static void w1_found_send_slave(struct w1_master *dev, u64 rn)
+{
+	/* update kernel slave list */
+	w1_slave_found(dev, rn);
+
+	w1_send_slave(dev, rn);
+}
+
+/* Get the current slave list, or search (with or without alarm) */
+static int w1_get_slaves(struct w1_master *dev, struct w1_netlink_cmd *req_cmd)
+{
+	struct w1_slave *sl;
+
+	req_cmd->len = 0;
+	w1_netlink_queue_cmd(dev->priv, req_cmd);
+
+	if (req_cmd->cmd == W1_CMD_LIST_SLAVES) {
+		u64 rn;
+		mutex_lock(&dev->list_mutex);
+		list_for_each_entry(sl, &dev->slist, w1_slave_entry) {
+			memcpy(&rn, &sl->reg_num, sizeof(rn));
+			w1_send_slave(dev, rn);
+		}
+		mutex_unlock(&dev->list_mutex);
+	} else {
+		w1_search_process_cb(dev, req_cmd->cmd == W1_CMD_ALARM_SEARCH ?
+			W1_ALARM_SEARCH : W1_SEARCH, w1_found_send_slave);
+	}
+
+	return 0;
+}
+
+static int w1_process_command_io(struct w1_master *dev,
+	struct w1_netlink_cmd *cmd)
+{
+	int err = 0;
+
+	switch (cmd->cmd) {
+	case W1_CMD_TOUCH:
+		w1_touch_block(dev, cmd->data, cmd->len);
+		w1_netlink_queue_cmd(dev->priv, cmd);
+		break;
+	case W1_CMD_READ:
+		w1_read_block(dev, cmd->data, cmd->len);
+		w1_netlink_queue_cmd(dev->priv, cmd);
+		break;
+	case W1_CMD_WRITE:
+		w1_write_block(dev, cmd->data, cmd->len);
+		break;
+	default:
+		err = -EINVAL;
+		break;
+	}
+
+	return err;
+}
+
+static int w1_process_command_addremove(struct w1_master *dev,
+	struct w1_netlink_cmd *cmd)
+{
+	struct w1_slave *sl;
+	int err = 0;
+	struct w1_reg_num *id;
+
+	if (cmd->len != sizeof(*id))
+		return -EINVAL;
+
+	id = (struct w1_reg_num *)cmd->data;
+
+	sl = w1_slave_search_device(dev, id);
+	switch (cmd->cmd) {
+	case W1_CMD_SLAVE_ADD:
+		if (sl)
+			err = -EINVAL;
+		else
+			err = w1_attach_slave_device(dev, id);
+		break;
+	case W1_CMD_SLAVE_REMOVE:
+		if (sl)
+			w1_slave_detach(sl);
+		else
+			err = -EINVAL;
+		break;
+	default:
+		err = -EINVAL;
+		break;
+	}
+
+	return err;
+}
+
+static int w1_process_command_master(struct w1_master *dev,
+	struct w1_netlink_cmd *req_cmd)
+{
+	int err = -EINVAL;
+
+	/* drop bus_mutex for search (does it's own locking), and add/remove
+	 * which doesn't use the bus
+	 */
+	switch (req_cmd->cmd) {
+	case W1_CMD_SEARCH:
+	case W1_CMD_ALARM_SEARCH:
+	case W1_CMD_LIST_SLAVES:
+		mutex_unlock(&dev->bus_mutex);
+		err = w1_get_slaves(dev, req_cmd);
+		mutex_lock(&dev->bus_mutex);
+		break;
+	case W1_CMD_READ:
+	case W1_CMD_WRITE:
+	case W1_CMD_TOUCH:
+		err = w1_process_command_io(dev, req_cmd);
+		break;
+	case W1_CMD_RESET:
+		err = w1_reset_bus(dev);
+		break;
+	case W1_CMD_SLAVE_ADD:
+	case W1_CMD_SLAVE_REMOVE:
+		mutex_unlock(&dev->bus_mutex);
+		mutex_lock(&dev->mutex);
+		err = w1_process_command_addremove(dev, req_cmd);
+		mutex_unlock(&dev->mutex);
+		mutex_lock(&dev->bus_mutex);
+		break;
+	default:
+		err = -EINVAL;
+		break;
+	}
+
+	return err;
+}
+
+static int w1_process_command_slave(struct w1_slave *sl,
+		struct w1_netlink_cmd *cmd)
+{
+	dev_dbg(&sl->master->dev, "%s: %02x.%012llx.%02x: cmd=%02x, len=%u.\n",
+		__func__, sl->reg_num.family, (unsigned long long)sl->reg_num.id,
+		sl->reg_num.crc, cmd->cmd, cmd->len);
+
+	return w1_process_command_io(sl->master, cmd);
+}
+
+static int w1_process_command_root(struct cn_msg *req_cn, u32 portid)
+{
+	struct w1_master *dev;
+	struct cn_msg *cn;
+	struct w1_netlink_msg *msg;
+	u32 *id;
+
+	cn = kmalloc(PAGE_SIZE, GFP_KERNEL);
+	if (!cn)
+		return -ENOMEM;
+
+	cn->id.idx = CN_W1_IDX;
+	cn->id.val = CN_W1_VAL;
+
+	cn->seq = req_cn->seq;
+	cn->ack = req_cn->seq + 1;
+	cn->len = sizeof(struct w1_netlink_msg);
+	msg = (struct w1_netlink_msg *)cn->data;
+
+	msg->type = W1_LIST_MASTERS;
+	msg->status = 0;
+	msg->len = 0;
+	id = (u32 *)msg->data;
+
+	mutex_lock(&w1_mlock);
+	list_for_each_entry(dev, &w1_masters, w1_master_entry) {
+		if (cn->len + sizeof(*id) > PAGE_SIZE - sizeof(struct cn_msg)) {
+			cn_netlink_send(cn, portid, 0, GFP_KERNEL);
+			cn->len = sizeof(struct w1_netlink_msg);
+			msg->len = 0;
+			id = (u32 *)msg->data;
+		}
+
+		*id = dev->id;
+		msg->len += sizeof(*id);
+		cn->len += sizeof(*id);
+		id++;
+	}
+	cn_netlink_send(cn, portid, 0, GFP_KERNEL);
+	mutex_unlock(&w1_mlock);
+
+	kfree(cn);
+	return 0;
+}
+
+static void w1_process_cb(struct w1_master *dev, struct w1_async_cmd *async_cmd)
+{
+	struct w1_cb_node *node = container_of(async_cmd, struct w1_cb_node,
+		async);
+	u16 mlen = node->msg->len;
+	u16 len;
+	int err = 0;
+	struct w1_slave *sl = node->sl;
+	struct w1_netlink_cmd *cmd = (struct w1_netlink_cmd *)node->msg->data;
+
+	mutex_lock(&dev->bus_mutex);
+	dev->priv = node->block;
+	if (sl && w1_reset_select_slave(sl))
+		err = -ENODEV;
+	node->block->cur_msg = node->msg;
+
+	while (mlen && !err) {
+		if (cmd->len + sizeof(struct w1_netlink_cmd) > mlen) {
+			err = -E2BIG;
+			break;
+		}
+
+		if (sl)
+			err = w1_process_command_slave(sl, cmd);
+		else
+			err = w1_process_command_master(dev, cmd);
+		w1_netlink_check_send(node->block);
+
+		w1_netlink_queue_status(node->block, node->msg, cmd, err);
+		err = 0;
+
+		len = sizeof(*cmd) + cmd->len;
+		cmd = (struct w1_netlink_cmd *)((u8 *)cmd + len);
+		mlen -= len;
+	}
+
+	if (!cmd || err)
+		w1_netlink_queue_status(node->block, node->msg, cmd, err);
+
+	/* ref taken in w1_search_slave or w1_search_master_id when building
+	 * the block
+	 */
+	if (sl)
+		w1_unref_slave(sl);
+	else
+		atomic_dec(&dev->refcnt);
+	dev->priv = NULL;
+	mutex_unlock(&dev->bus_mutex);
+
+	mutex_lock(&dev->list_mutex);
+	list_del(&async_cmd->async_entry);
+	mutex_unlock(&dev->list_mutex);
+
+	w1_unref_block(node->block);
+}
+
+static void w1_list_count_cmds(struct w1_netlink_msg *msg, int *cmd_count,
+	u16 *slave_len)
+{
+	struct w1_netlink_cmd *cmd = (struct w1_netlink_cmd *)msg->data;
+	u16 mlen = msg->len;
+	u16 len;
+	int slave_list = 0;
+	while (mlen) {
+		if (cmd->len + sizeof(struct w1_netlink_cmd) > mlen)
+			break;
+
+		switch (cmd->cmd) {
+		case W1_CMD_SEARCH:
+		case W1_CMD_ALARM_SEARCH:
+		case W1_CMD_LIST_SLAVES:
+			++slave_list;
+		}
+		++*cmd_count;
+		len = sizeof(*cmd) + cmd->len;
+		cmd = (struct w1_netlink_cmd *)((u8 *)cmd + len);
+		mlen -= len;
+	}
+
+	if (slave_list) {
+		struct w1_master *dev = w1_search_master_id(msg->id.mst.id);
+		if (dev) {
+			/* Bytes, and likely an overstimate, and if it isn't
+			 * the results can still be split between packets.
+			 */
+			*slave_len += sizeof(struct w1_reg_num) * slave_list *
+				(dev->slave_count + dev->max_slave_count);
+			/* search incremented it */
+			atomic_dec(&dev->refcnt);
+		}
+	}
+}
+
+static void w1_cn_callback(struct cn_msg *cn, struct netlink_skb_parms *nsp)
+{
+	struct w1_netlink_msg *msg = (struct w1_netlink_msg *)(cn + 1);
+	struct w1_slave *sl;
+	struct w1_master *dev;
+	u16 msg_len;
+	u16 slave_len = 0;
+	int err = 0;
+	struct w1_cb_block *block = NULL;
+	struct w1_cb_node *node = NULL;
+	int node_count = 0;
+	int cmd_count = 0;
+
+	/* If any unknown flag is set let the application know, that way
+	 * applications can detect the absence of features in kernels that
+	 * don't know about them.  http://lwn.net/Articles/587527/
+	 */
+	if (cn->flags & ~(W1_CN_BUNDLE)) {
+		w1_netlink_send_error(cn, msg, nsp->portid, -EINVAL);
+		return;
+	}
+
+	/* Count the number of master or slave commands there are to allocate
+	 * space for one cb_node each.
+	 */
+	msg_len = cn->len;
+	while (msg_len && !err) {
+		if (msg->len + sizeof(struct w1_netlink_msg) > msg_len) {
+			err = -E2BIG;
+			break;
+		}
+
+		/* count messages for nodes and allocate any additional space
+		 * required for slave lists
+		 */
+		if (msg->type == W1_MASTER_CMD || msg->type == W1_SLAVE_CMD) {
+			++node_count;
+			w1_list_count_cmds(msg, &cmd_count, &slave_len);
+		}
+
+		msg_len -= sizeof(struct w1_netlink_msg) + msg->len;
+		msg = (struct w1_netlink_msg *)(((u8 *)msg) +
+			sizeof(struct w1_netlink_msg) + msg->len);
+	}
+	msg = (struct w1_netlink_msg *)(cn + 1);
+	if (node_count) {
+		int size;
+		int reply_size = sizeof(*cn) + cn->len + slave_len;
+		if (cn->flags & W1_CN_BUNDLE) {
+			/* bundling duplicats some of the messages */
+			reply_size += 2 * cmd_count * (sizeof(struct cn_msg) +
+				sizeof(struct w1_netlink_msg) +
+				sizeof(struct w1_netlink_cmd));
+		}
+		reply_size = min(CONNECTOR_MAX_MSG_SIZE, reply_size);
+
+		/* allocate space for the block, a copy of the original message,
+		 * one node per cmd to point into the original message,
+		 * space for replies which is the original message size plus
+		 * space for any list slave data and status messages
+		 * cn->len doesn't include itself which is part of the block
+		 * */
+		size =  /* block + original message */
+			sizeof(struct w1_cb_block) + sizeof(*cn) + cn->len +
+			/* space for nodes */
+			node_count * sizeof(struct w1_cb_node) +
+			/* replies */
+			sizeof(struct cn_msg) + reply_size;
+		block = kzalloc(size, GFP_KERNEL);
+		if (!block) {
+			/* if the system is already out of memory,
+			 * (A) will this work, and (B) would it be better
+			 * to not try?
+			 */
+			w1_netlink_send_error(cn, msg, nsp->portid, -ENOMEM);
+			return;
+		}
+		atomic_set(&block->refcnt, 1);
+		block->portid = nsp->portid;
+		memcpy(&block->request_cn, cn, sizeof(*cn) + cn->len);
+		node = (struct w1_cb_node *)(block->request_cn.data + cn->len);
+
+		/* Sneeky, when not bundling, reply_size is the allocated space
+		 * required for the reply, cn_msg isn't part of maxlen so
+		 * it should be reply_size - sizeof(struct cn_msg), however
+		 * when checking if there is enough space, w1_reply_make_space
+		 * is called with the full message size including cn_msg,
+		 * because it isn't known at that time if an additional cn_msg
+		 * will need to be allocated.  So an extra cn_msg is added
+		 * above in "size".
+		 */
+		block->maxlen = reply_size;
+		block->first_cn = (struct cn_msg *)(node + node_count);
+		memset(block->first_cn, 0, sizeof(*block->first_cn));
+	}
+
+	msg_len = cn->len;
+	while (msg_len && !err) {
+
+		dev = NULL;
+		sl = NULL;
+
+		if (msg->len + sizeof(struct w1_netlink_msg) > msg_len) {
+			err = -E2BIG;
+			break;
+		}
+
+		/* execute on this thread, no need to process later */
+		if (msg->type == W1_LIST_MASTERS) {
+			err = w1_process_command_root(cn, nsp->portid);
+			goto out_cont;
+		}
+
+		/* All following message types require additional data,
+		 * check here before references are taken.
+		 */
+		if (!msg->len) {
+			err = -EPROTO;
+			goto out_cont;
+		}
+
+		/* both search calls take references */
+		if (msg->type == W1_MASTER_CMD) {
+			dev = w1_search_master_id(msg->id.mst.id);
+		} else if (msg->type == W1_SLAVE_CMD) {
+			sl = w1_search_slave((struct w1_reg_num *)msg->id.id);
+			if (sl)
+				dev = sl->master;
+		} else {
+			pr_notice("%s: cn: %x.%x, wrong type: %u, len: %u.\n",
+				__func__, cn->id.idx, cn->id.val,
+				msg->type, msg->len);
+			err = -EPROTO;
+			goto out_cont;
+		}
+
+		if (!dev) {
+			err = -ENODEV;
+			goto out_cont;
+		}
+
+		err = 0;
+
+		atomic_inc(&block->refcnt);
+		node->async.cb = w1_process_cb;
+		node->block = block;
+		node->msg = (struct w1_netlink_msg *)((u8 *)&block->request_cn +
+			(size_t)((u8 *)msg - (u8 *)cn));
+		node->sl = sl;
+		node->dev = dev;
+
+		mutex_lock(&dev->list_mutex);
+		list_add_tail(&node->async.async_entry, &dev->async_list);
+		wake_up_process(dev->thread);
+		mutex_unlock(&dev->list_mutex);
+		++node;
+
+out_cont:
+		/* Can't queue because that modifies block and another
+		 * thread could be processing the messages by now and
+		 * there isn't a lock, send directly.
+		 */
+		if (err)
+			w1_netlink_send_error(cn, msg, nsp->portid, err);
+		msg_len -= sizeof(struct w1_netlink_msg) + msg->len;
+		msg = (struct w1_netlink_msg *)(((u8 *)msg) +
+			sizeof(struct w1_netlink_msg) + msg->len);
+
+		/*
+		 * Let's allow requests for nonexisting devices.
+		 */
+		if (err == -ENODEV)
+			err = 0;
+	}
+	if (block)
+		w1_unref_block(block);
+}
+
+int w1_init_netlink(void)
+{
+	struct cb_id w1_id = {.idx = CN_W1_IDX, .val = CN_W1_VAL};
+
+	return cn_add_callback(&w1_id, "w1", &w1_cn_callback);
+}
+
+void w1_fini_netlink(void)
+{
+	struct cb_id w1_id = {.idx = CN_W1_IDX, .val = CN_W1_VAL};
+
+	cn_del_callback(&w1_id);
+}
+#else
+void w1_netlink_send(struct w1_master *dev, struct w1_netlink_msg *cn)
+{
+}
+
+int w1_init_netlink(void)
+{
+	return 0;
+}
+
+void w1_fini_netlink(void)
+{
+}
+#endif