fs/smb/server/connection.c - third_party/kernel - Git at Google

 // SPDX-License-Identifier: GPL-2.0-or-later
 /*
  *   Copyright (C) 2016 Namjae Jeon <namjae.jeon@protocolfreedom.org>
  *   Copyright (C) 2018 Samsung Electronics Co., Ltd.
  */

 #include <linux/mutex.h>
 #include <linux/freezer.h>
 #include <linux/module.h>

 #include "server.h"
 #include "smb_common.h"
 #include "mgmt/ksmbd_ida.h"
 #include "connection.h"
 #include "transport_tcp.h"
 #include "transport_rdma.h"

 static DEFINE_MUTEX(init_lock);

 static struct ksmbd_conn_ops default_conn_ops;

 LIST_HEAD(conn_list);
 DECLARE_RWSEM(conn_list_lock);

 /**
  * ksmbd_conn_free() - free resources of the connection instance
  *
  * @conn:	connection instance to be cleand up
  *
  * During the thread termination, the corresponding conn instance
  * resources(sock/memory) are released and finally the conn object is freed.
  */
 void ksmbd_conn_free(struct ksmbd_conn *conn)
 {
 	down_write(&conn_list_lock);
 	list_del(&conn->conns_list);
 	up_write(&conn_list_lock);

 	xa_destroy(&conn->sessions);
 	kvfree(conn->request_buf);
 	kfree(conn->preauth_info);
 	if (atomic_dec_and_test(&conn->refcnt))
 		kfree(conn);
 }

 /**
  * ksmbd_conn_alloc() - initialize a new connection instance
  *
  * Return:	ksmbd_conn struct on success, otherwise NULL
  */
 struct ksmbd_conn *ksmbd_conn_alloc(void)
 {
 	struct ksmbd_conn *conn;

 	conn = kzalloc(sizeof(struct ksmbd_conn), GFP_KERNEL);
 	if (!conn)
 		return NULL;

 	conn->need_neg = true;
 	ksmbd_conn_set_new(conn);
 	conn->local_nls = load_nls("utf8");
 	if (!conn->local_nls)
 		conn->local_nls = load_nls_default();
 	if (IS_ENABLED(CONFIG_UNICODE))
 		conn->um = utf8_load(UNICODE_AGE(12, 1, 0));
 	else
 		conn->um = ERR_PTR(-EOPNOTSUPP);
 	if (IS_ERR(conn->um))
 		conn->um = NULL;
 	atomic_set(&conn->req_running, 0);
 	atomic_set(&conn->r_count, 0);
 	atomic_set(&conn->refcnt, 1);
 	conn->total_credits = 1;
 	conn->outstanding_credits = 0;

 	init_waitqueue_head(&conn->req_running_q);
 	init_waitqueue_head(&conn->r_count_q);
 	INIT_LIST_HEAD(&conn->conns_list);
 	INIT_LIST_HEAD(&conn->requests);
 	INIT_LIST_HEAD(&conn->async_requests);
 	spin_lock_init(&conn->request_lock);
 	spin_lock_init(&conn->credits_lock);
 	ida_init(&conn->async_ida);
 	xa_init(&conn->sessions);

 	spin_lock_init(&conn->llist_lock);
 	INIT_LIST_HEAD(&conn->lock_list);

 	init_rwsem(&conn->session_lock);

 	down_write(&conn_list_lock);
 	list_add(&conn->conns_list, &conn_list);
 	up_write(&conn_list_lock);
 	return conn;
 }

 bool ksmbd_conn_lookup_dialect(struct ksmbd_conn *c)
 {
 	struct ksmbd_conn *t;
 	bool ret = false;

 	down_read(&conn_list_lock);
 	list_for_each_entry(t, &conn_list, conns_list) {
 		if (memcmp(t->ClientGUID, c->ClientGUID, SMB2_CLIENT_GUID_SIZE))
 			continue;

 		ret = true;
 		break;
 	}
 	up_read(&conn_list_lock);
 	return ret;
 }

 void ksmbd_conn_enqueue_request(struct ksmbd_work *work)
 {
 	struct ksmbd_conn *conn = work->conn;
 	struct list_head *requests_queue = NULL;

 	if (conn->ops->get_cmd_val(work) != SMB2_CANCEL_HE)
 		requests_queue = &conn->requests;

 	atomic_inc(&conn->req_running);
 	if (requests_queue) {
 		spin_lock(&conn->request_lock);
 		list_add_tail(&work->request_entry, requests_queue);
 		spin_unlock(&conn->request_lock);
 	}
 }

 void ksmbd_conn_try_dequeue_request(struct ksmbd_work *work)
 {
 	struct ksmbd_conn *conn = work->conn;

 	atomic_dec(&conn->req_running);
 	if (waitqueue_active(&conn->req_running_q))
 		wake_up(&conn->req_running_q);

 	if (list_empty(&work->request_entry) &&
 	    list_empty(&work->async_request_entry))
 		return;

 	spin_lock(&conn->request_lock);
 	list_del_init(&work->request_entry);
 	spin_unlock(&conn->request_lock);
 	if (work->asynchronous)
 		release_async_work(work);

 	wake_up_all(&conn->req_running_q);
 }

 void ksmbd_conn_lock(struct ksmbd_conn *conn)
 {
 	mutex_lock(&conn->srv_mutex);
 }

 void ksmbd_conn_unlock(struct ksmbd_conn *conn)
 {
 	mutex_unlock(&conn->srv_mutex);
 }

 void ksmbd_all_conn_set_status(u64 sess_id, u32 status)
 {
 	struct ksmbd_conn *conn;

 	down_read(&conn_list_lock);
 	list_for_each_entry(conn, &conn_list, conns_list) {
 		if (conn->binding || xa_load(&conn->sessions, sess_id))
 			WRITE_ONCE(conn->status, status);
 	}
 	up_read(&conn_list_lock);
 }

 void ksmbd_conn_wait_idle(struct ksmbd_conn *conn)
 {
 	wait_event(conn->req_running_q, atomic_read(&conn->req_running) < 2);
 }

 int ksmbd_conn_wait_idle_sess_id(struct ksmbd_conn *curr_conn, u64 sess_id)
 {
 	struct ksmbd_conn *conn;
 	int rc, retry_count = 0, max_timeout = 120;
 	int rcount = 1;

 retry_idle:
 	if (retry_count >= max_timeout)
 		return -EIO;

 	down_read(&conn_list_lock);
 	list_for_each_entry(conn, &conn_list, conns_list) {
 		if (conn->binding || xa_load(&conn->sessions, sess_id)) {
 			if (conn == curr_conn)
 				rcount = 2;
 			if (atomic_read(&conn->req_running) >= rcount) {
 				rc = wait_event_timeout(conn->req_running_q,
 					atomic_read(&conn->req_running) < rcount,
 					HZ);
 				if (!rc) {
 					up_read(&conn_list_lock);
 					retry_count++;
 					goto retry_idle;
 				}
 			}
 		}
 	}
 	up_read(&conn_list_lock);

 	return 0;
 }

 int ksmbd_conn_write(struct ksmbd_work *work)
 {
 	struct ksmbd_conn *conn = work->conn;
 	int sent;

 	if (!work->response_buf) {
 		pr_err("NULL response header\n");
 		return -EINVAL;
 	}

 	if (work->send_no_response)
 		return 0;

 	if (!work->iov_idx)
 		return -EINVAL;

 	ksmbd_conn_lock(conn);
 	sent = conn->transport->ops->writev(conn->transport, work->iov,
 			work->iov_cnt,
 			get_rfc1002_len(work->iov[0].iov_base) + 4,
 			work->need_invalidate_rkey,
 			work->remote_key);
 	ksmbd_conn_unlock(conn);

 	if (sent < 0) {
 		pr_err("Failed to send message: %d\n", sent);
 		return sent;
 	}

 	return 0;
 }

 int ksmbd_conn_rdma_read(struct ksmbd_conn *conn,
 			 void *buf, unsigned int buflen,
 			 struct smb2_buffer_desc_v1 *desc,
 			 unsigned int desc_len)
 {
 	int ret = -EINVAL;

 	if (conn->transport->ops->rdma_read)
 		ret = conn->transport->ops->rdma_read(conn->transport,
 						      buf, buflen,
 						      desc, desc_len);
 	return ret;
 }

 int ksmbd_conn_rdma_write(struct ksmbd_conn *conn,
 			  void *buf, unsigned int buflen,
 			  struct smb2_buffer_desc_v1 *desc,
 			  unsigned int desc_len)
 {
 	int ret = -EINVAL;

 	if (conn->transport->ops->rdma_write)
 		ret = conn->transport->ops->rdma_write(conn->transport,
 						       buf, buflen,
 						       desc, desc_len);
 	return ret;
 }

 bool ksmbd_conn_alive(struct ksmbd_conn *conn)
 {
 	if (!ksmbd_server_running())
 		return false;

 	if (ksmbd_conn_exiting(conn))
 		return false;

 	if (kthread_should_stop())
 		return false;

 	if (atomic_read(&conn->stats.open_files_count) > 0)
 		return true;

 	/*
 	 * Stop current session if the time that get last request from client
 	 * is bigger than deadtime user configured and opening file count is
 	 * zero.
 	 */
 	if (server_conf.deadtime > 0 &&
 	    time_after(jiffies, conn->last_active + server_conf.deadtime)) {
 		ksmbd_debug(CONN, "No response from client in %lu minutes\n",
 			    server_conf.deadtime / SMB_ECHO_INTERVAL);
 		return false;
 	}
 	return true;
 }

 #define SMB1_MIN_SUPPORTED_HEADER_SIZE (sizeof(struct smb_hdr))
 #define SMB2_MIN_SUPPORTED_HEADER_SIZE (sizeof(struct smb2_hdr) + 4)

 /**
  * ksmbd_conn_handler_loop() - session thread to listen on new smb requests
  * @p:		connection instance
  *
  * One thread each per connection
  *
  * Return:	0 on success
  */
 int ksmbd_conn_handler_loop(void *p)
 {
 	struct ksmbd_conn *conn = (struct ksmbd_conn *)p;
 	struct ksmbd_transport *t = conn->transport;
 	unsigned int pdu_size, max_allowed_pdu_size, max_req;
 	char hdr_buf[4] = {0,};
 	int size;

 	mutex_init(&conn->srv_mutex);
 	__module_get(THIS_MODULE);

 	if (t->ops->prepare && t->ops->prepare(t))
 		goto out;

 	max_req = server_conf.max_inflight_req;
 	conn->last_active = jiffies;
 	set_freezable();
 	while (ksmbd_conn_alive(conn)) {
 		if (try_to_freeze())
 			continue;

 		kvfree(conn->request_buf);
 		conn->request_buf = NULL;

 recheck:
 		if (atomic_read(&conn->req_running) + 1 > max_req) {
 			wait_event_interruptible(conn->req_running_q,
 				atomic_read(&conn->req_running) < max_req);
 			goto recheck;
 		}

 		size = t->ops->read(t, hdr_buf, sizeof(hdr_buf), -1);
 		if (size != sizeof(hdr_buf))
 			break;

 		pdu_size = get_rfc1002_len(hdr_buf);
 		ksmbd_debug(CONN, "RFC1002 header %u bytes\n", pdu_size);

 		if (ksmbd_conn_good(conn))
 			max_allowed_pdu_size =
 				SMB3_MAX_MSGSIZE + conn->vals->max_write_size;
 		else
 			max_allowed_pdu_size = SMB3_MAX_MSGSIZE;

 		if (pdu_size > max_allowed_pdu_size) {
 			pr_err_ratelimited("PDU length(%u) exceeded maximum allowed pdu size(%u) on connection(%d)\n",
 					pdu_size, max_allowed_pdu_size,
 					READ_ONCE(conn->status));
 			break;
 		}

 		/*
 		 * Check maximum pdu size(0x00FFFFFF).
 		 */
 		if (pdu_size > MAX_STREAM_PROT_LEN)
 			break;

 		if (pdu_size < SMB1_MIN_SUPPORTED_HEADER_SIZE)
 			break;

 		/* 4 for rfc1002 length field */
 		/* 1 for implied bcc[0] */
 		size = pdu_size + 4 + 1;
 		conn->request_buf = kvmalloc(size, GFP_KERNEL);
 		if (!conn->request_buf)
 			break;

 		memcpy(conn->request_buf, hdr_buf, sizeof(hdr_buf));

 		/*
 		 * We already read 4 bytes to find out PDU size, now
 		 * read in PDU
 		 */
 		size = t->ops->read(t, conn->request_buf + 4, pdu_size, 2);
 		if (size < 0) {
 			pr_err("sock_read failed: %d\n", size);
 			break;
 		}

 		if (size != pdu_size) {
 			pr_err("PDU error. Read: %d, Expected: %d\n",
 			       size, pdu_size);
 			continue;
 		}

 		if (!ksmbd_smb_request(conn))
 			break;

 		if (((struct smb2_hdr *)smb2_get_msg(conn->request_buf))->ProtocolId ==
 		    SMB2_PROTO_NUMBER) {
 			if (pdu_size < SMB2_MIN_SUPPORTED_HEADER_SIZE)
 				break;
 		}

 		if (!default_conn_ops.process_fn) {
 			pr_err("No connection request callback\n");
 			break;
 		}

 		if (default_conn_ops.process_fn(conn)) {
 			pr_err("Cannot handle request\n");
 			break;
 		}
 	}

 out:
 	ksmbd_conn_set_releasing(conn);
 	/* Wait till all reference dropped to the Server object*/
 	wait_event(conn->r_count_q, atomic_read(&conn->r_count) == 0);

 	if (IS_ENABLED(CONFIG_UNICODE))
 		utf8_unload(conn->um);
 	unload_nls(conn->local_nls);
 	if (default_conn_ops.terminate_fn)
 		default_conn_ops.terminate_fn(conn);
 	t->ops->disconnect(t);
 	module_put(THIS_MODULE);
 	return 0;
 }

 void ksmbd_conn_init_server_callbacks(struct ksmbd_conn_ops *ops)
 {
 	default_conn_ops.process_fn = ops->process_fn;
 	default_conn_ops.terminate_fn = ops->terminate_fn;
 }

 void ksmbd_conn_r_count_inc(struct ksmbd_conn *conn)
 {
 	atomic_inc(&conn->r_count);
 }

 void ksmbd_conn_r_count_dec(struct ksmbd_conn *conn)
 {
 	/*
 	 * Checking waitqueue to dropping pending requests on
 	 * disconnection. waitqueue_active is safe because it
 	 * uses atomic operation for condition.
 	 */
 	atomic_inc(&conn->refcnt);
 	if (!atomic_dec_return(&conn->r_count) && waitqueue_active(&conn->r_count_q))
 		wake_up(&conn->r_count_q);

 	if (atomic_dec_and_test(&conn->refcnt))
 		kfree(conn);
 }

 int ksmbd_conn_transport_init(void)
 {
 	int ret;

 	mutex_lock(&init_lock);
 	ret = ksmbd_tcp_init();
 	if (ret) {
 		pr_err("Failed to init TCP subsystem: %d\n", ret);
 		goto out;
 	}

 	ret = ksmbd_rdma_init();
 	if (ret) {
 		pr_err("Failed to init RDMA subsystem: %d\n", ret);
 		goto out;
 	}
 out:
 	mutex_unlock(&init_lock);
 	return ret;
 }

 static void stop_sessions(void)
 {
 	struct ksmbd_conn *conn;
 	struct ksmbd_transport *t;

 again:
 	down_read(&conn_list_lock);
 	list_for_each_entry(conn, &conn_list, conns_list) {
 		t = conn->transport;
 		ksmbd_conn_set_exiting(conn);
 		if (t->ops->shutdown) {
 			up_read(&conn_list_lock);
 			t->ops->shutdown(t);
 			down_read(&conn_list_lock);
 		}
 	}
 	up_read(&conn_list_lock);

 	if (!list_empty(&conn_list)) {
 		schedule_timeout_interruptible(HZ / 10); /* 100ms */
 		goto again;
 	}
 }

 void ksmbd_conn_transport_destroy(void)
 {
 	mutex_lock(&init_lock);
 	ksmbd_tcp_destroy();
 	ksmbd_rdma_destroy();
 	stop_sessions();
 	mutex_unlock(&init_lock);
 }
	// SPDX-License-Identifier: GPL-2.0-or-later
	/*
	* Copyright (C) 2016 Namjae Jeon <namjae.jeon@protocolfreedom.org>
	* Copyright (C) 2018 Samsung Electronics Co., Ltd.
	*/

	#include <linux/mutex.h>
	#include <linux/freezer.h>
	#include <linux/module.h>

	#include "server.h"
	#include "smb_common.h"
	#include "mgmt/ksmbd_ida.h"
	#include "connection.h"
	#include "transport_tcp.h"
	#include "transport_rdma.h"

	static DEFINE_MUTEX(init_lock);

	static struct ksmbd_conn_ops default_conn_ops;

	LIST_HEAD(conn_list);
	DECLARE_RWSEM(conn_list_lock);

	/**
	* ksmbd_conn_free() - free resources of the connection instance
	*
	* @conn: connection instance to be cleand up
	*
	* During the thread termination, the corresponding conn instance
	* resources(sock/memory) are released and finally the conn object is freed.
	*/
	void ksmbd_conn_free(struct ksmbd_conn *conn)
	{
	down_write(&conn_list_lock);
	list_del(&conn->conns_list);
	up_write(&conn_list_lock);

	xa_destroy(&conn->sessions);
	kvfree(conn->request_buf);
	kfree(conn->preauth_info);
	if (atomic_dec_and_test(&conn->refcnt))
	kfree(conn);
	}

	/**
	* ksmbd_conn_alloc() - initialize a new connection instance
	*
	* Return: ksmbd_conn struct on success, otherwise NULL
	*/
	struct ksmbd_conn *ksmbd_conn_alloc(void)
	{
	struct ksmbd_conn *conn;

	conn = kzalloc(sizeof(struct ksmbd_conn), GFP_KERNEL);
	if (!conn)
	return NULL;

	conn->need_neg = true;
	ksmbd_conn_set_new(conn);
	conn->local_nls = load_nls("utf8");
	if (!conn->local_nls)
	conn->local_nls = load_nls_default();
	if (IS_ENABLED(CONFIG_UNICODE))
	conn->um = utf8_load(UNICODE_AGE(12, 1, 0));
	else
	conn->um = ERR_PTR(-EOPNOTSUPP);
	if (IS_ERR(conn->um))
	conn->um = NULL;
	atomic_set(&conn->req_running, 0);
	atomic_set(&conn->r_count, 0);
	atomic_set(&conn->refcnt, 1);
	conn->total_credits = 1;
	conn->outstanding_credits = 0;

	init_waitqueue_head(&conn->req_running_q);
	init_waitqueue_head(&conn->r_count_q);
	INIT_LIST_HEAD(&conn->conns_list);
	INIT_LIST_HEAD(&conn->requests);
	INIT_LIST_HEAD(&conn->async_requests);
	spin_lock_init(&conn->request_lock);
	spin_lock_init(&conn->credits_lock);
	ida_init(&conn->async_ida);
	xa_init(&conn->sessions);

	spin_lock_init(&conn->llist_lock);
	INIT_LIST_HEAD(&conn->lock_list);

	init_rwsem(&conn->session_lock);

	down_write(&conn_list_lock);
	list_add(&conn->conns_list, &conn_list);
	up_write(&conn_list_lock);
	return conn;
	}

	bool ksmbd_conn_lookup_dialect(struct ksmbd_conn *c)
	{
	struct ksmbd_conn *t;
	bool ret = false;

	down_read(&conn_list_lock);
	list_for_each_entry(t, &conn_list, conns_list) {
	if (memcmp(t->ClientGUID, c->ClientGUID, SMB2_CLIENT_GUID_SIZE))
	continue;

	ret = true;
	break;
	}
	up_read(&conn_list_lock);
	return ret;
	}

	void ksmbd_conn_enqueue_request(struct ksmbd_work *work)
	{
	struct ksmbd_conn *conn = work->conn;
	struct list_head *requests_queue = NULL;

	if (conn->ops->get_cmd_val(work) != SMB2_CANCEL_HE)
	requests_queue = &conn->requests;

	atomic_inc(&conn->req_running);
	if (requests_queue) {
	spin_lock(&conn->request_lock);
	list_add_tail(&work->request_entry, requests_queue);
	spin_unlock(&conn->request_lock);
	}
	}

	void ksmbd_conn_try_dequeue_request(struct ksmbd_work *work)
	{
	struct ksmbd_conn *conn = work->conn;

	atomic_dec(&conn->req_running);
	if (waitqueue_active(&conn->req_running_q))
	wake_up(&conn->req_running_q);

	if (list_empty(&work->request_entry) &&
	list_empty(&work->async_request_entry))
	return;

	spin_lock(&conn->request_lock);
	list_del_init(&work->request_entry);
	spin_unlock(&conn->request_lock);
	if (work->asynchronous)
	release_async_work(work);

	wake_up_all(&conn->req_running_q);
	}

	void ksmbd_conn_lock(struct ksmbd_conn *conn)
	{
	mutex_lock(&conn->srv_mutex);
	}

	void ksmbd_conn_unlock(struct ksmbd_conn *conn)
	{
	mutex_unlock(&conn->srv_mutex);
	}

	void ksmbd_all_conn_set_status(u64 sess_id, u32 status)
	{
	struct ksmbd_conn *conn;

	down_read(&conn_list_lock);
	list_for_each_entry(conn, &conn_list, conns_list) {
	if (conn->binding \|\| xa_load(&conn->sessions, sess_id))
	WRITE_ONCE(conn->status, status);
	}
	up_read(&conn_list_lock);
	}

	void ksmbd_conn_wait_idle(struct ksmbd_conn *conn)
	{
	wait_event(conn->req_running_q, atomic_read(&conn->req_running) < 2);
	}

	int ksmbd_conn_wait_idle_sess_id(struct ksmbd_conn *curr_conn, u64 sess_id)
	{
	struct ksmbd_conn *conn;
	int rc, retry_count = 0, max_timeout = 120;
	int rcount = 1;

	retry_idle:
	if (retry_count >= max_timeout)
	return -EIO;

	down_read(&conn_list_lock);
	list_for_each_entry(conn, &conn_list, conns_list) {
	if (conn->binding \|\| xa_load(&conn->sessions, sess_id)) {
	if (conn == curr_conn)
	rcount = 2;
	if (atomic_read(&conn->req_running) >= rcount) {
	rc = wait_event_timeout(conn->req_running_q,
	atomic_read(&conn->req_running) < rcount,
	HZ);
	if (!rc) {
	up_read(&conn_list_lock);
	retry_count++;
	goto retry_idle;
	}
	}
	}
	}
	up_read(&conn_list_lock);

	return 0;
	}

	int ksmbd_conn_write(struct ksmbd_work *work)
	{
	struct ksmbd_conn *conn = work->conn;
	int sent;

	if (!work->response_buf) {
	pr_err("NULL response header\n");
	return -EINVAL;
	}

	if (work->send_no_response)
	return 0;

	if (!work->iov_idx)
	return -EINVAL;

	ksmbd_conn_lock(conn);
	sent = conn->transport->ops->writev(conn->transport, work->iov,
	work->iov_cnt,
	get_rfc1002_len(work->iov[0].iov_base) + 4,
	work->need_invalidate_rkey,
	work->remote_key);
	ksmbd_conn_unlock(conn);

	if (sent < 0) {
	pr_err("Failed to send message: %d\n", sent);
	return sent;
	}

	return 0;
	}

	int ksmbd_conn_rdma_read(struct ksmbd_conn *conn,
	void *buf, unsigned int buflen,
	struct smb2_buffer_desc_v1 *desc,
	unsigned int desc_len)
	{
	int ret = -EINVAL;

	if (conn->transport->ops->rdma_read)
	ret = conn->transport->ops->rdma_read(conn->transport,
	buf, buflen,
	desc, desc_len);
	return ret;
	}

	int ksmbd_conn_rdma_write(struct ksmbd_conn *conn,
	void *buf, unsigned int buflen,
	struct smb2_buffer_desc_v1 *desc,
	unsigned int desc_len)
	{
	int ret = -EINVAL;

	if (conn->transport->ops->rdma_write)
	ret = conn->transport->ops->rdma_write(conn->transport,
	buf, buflen,
	desc, desc_len);
	return ret;
	}

	bool ksmbd_conn_alive(struct ksmbd_conn *conn)
	{
	if (!ksmbd_server_running())
	return false;

	if (ksmbd_conn_exiting(conn))
	return false;

	if (kthread_should_stop())
	return false;

	if (atomic_read(&conn->stats.open_files_count) > 0)
	return true;

	/*
	* Stop current session if the time that get last request from client
	* is bigger than deadtime user configured and opening file count is
	* zero.
	*/
	if (server_conf.deadtime > 0 &&
	time_after(jiffies, conn->last_active + server_conf.deadtime)) {
	ksmbd_debug(CONN, "No response from client in %lu minutes\n",
	server_conf.deadtime / SMB_ECHO_INTERVAL);
	return false;
	}
	return true;
	}

	#define SMB1_MIN_SUPPORTED_HEADER_SIZE (sizeof(struct smb_hdr))
	#define SMB2_MIN_SUPPORTED_HEADER_SIZE (sizeof(struct smb2_hdr) + 4)

	/**
	* ksmbd_conn_handler_loop() - session thread to listen on new smb requests
	* @p: connection instance
	*
	* One thread each per connection
	*
	* Return: 0 on success
	*/
	int ksmbd_conn_handler_loop(void *p)
	{
	struct ksmbd_conn conn = (struct ksmbd_conn )p;
	struct ksmbd_transport *t = conn->transport;
	unsigned int pdu_size, max_allowed_pdu_size, max_req;
	char hdr_buf[4] = {0,};
	int size;

	mutex_init(&conn->srv_mutex);
	__module_get(THIS_MODULE);

	if (t->ops->prepare && t->ops->prepare(t))
	goto out;

	max_req = server_conf.max_inflight_req;
	conn->last_active = jiffies;
	set_freezable();
	while (ksmbd_conn_alive(conn)) {
	if (try_to_freeze())
	continue;

	kvfree(conn->request_buf);
	conn->request_buf = NULL;

	recheck:
	if (atomic_read(&conn->req_running) + 1 > max_req) {
	wait_event_interruptible(conn->req_running_q,
	atomic_read(&conn->req_running) < max_req);
	goto recheck;
	}

	size = t->ops->read(t, hdr_buf, sizeof(hdr_buf), -1);
	if (size != sizeof(hdr_buf))
	break;

	pdu_size = get_rfc1002_len(hdr_buf);
	ksmbd_debug(CONN, "RFC1002 header %u bytes\n", pdu_size);

	if (ksmbd_conn_good(conn))
	max_allowed_pdu_size =
	SMB3_MAX_MSGSIZE + conn->vals->max_write_size;
	else
	max_allowed_pdu_size = SMB3_MAX_MSGSIZE;

	if (pdu_size > max_allowed_pdu_size) {
	pr_err_ratelimited("PDU length(%u) exceeded maximum allowed pdu size(%u) on connection(%d)\n",
	pdu_size, max_allowed_pdu_size,
	READ_ONCE(conn->status));
	break;
	}

	/*
	* Check maximum pdu size(0x00FFFFFF).
	*/
	if (pdu_size > MAX_STREAM_PROT_LEN)
	break;

	if (pdu_size < SMB1_MIN_SUPPORTED_HEADER_SIZE)
	break;

	/* 4 for rfc1002 length field */
	/* 1 for implied bcc[0] */
	size = pdu_size + 4 + 1;
	conn->request_buf = kvmalloc(size, GFP_KERNEL);
	if (!conn->request_buf)
	break;

	memcpy(conn->request_buf, hdr_buf, sizeof(hdr_buf));

	/*
	* We already read 4 bytes to find out PDU size, now
	* read in PDU
	*/
	size = t->ops->read(t, conn->request_buf + 4, pdu_size, 2);
	if (size < 0) {
	pr_err("sock_read failed: %d\n", size);
	break;
	}

	if (size != pdu_size) {
	pr_err("PDU error. Read: %d, Expected: %d\n",
	size, pdu_size);
	continue;
	}

	if (!ksmbd_smb_request(conn))
	break;

	if (((struct smb2_hdr *)smb2_get_msg(conn->request_buf))->ProtocolId ==
	SMB2_PROTO_NUMBER) {
	if (pdu_size < SMB2_MIN_SUPPORTED_HEADER_SIZE)
	break;
	}

	if (!default_conn_ops.process_fn) {
	pr_err("No connection request callback\n");
	break;
	}

	if (default_conn_ops.process_fn(conn)) {
	pr_err("Cannot handle request\n");
	break;
	}
	}

	out:
	ksmbd_conn_set_releasing(conn);
	/* Wait till all reference dropped to the Server object*/
	wait_event(conn->r_count_q, atomic_read(&conn->r_count) == 0);

	if (IS_ENABLED(CONFIG_UNICODE))
	utf8_unload(conn->um);
	unload_nls(conn->local_nls);
	if (default_conn_ops.terminate_fn)
	default_conn_ops.terminate_fn(conn);
	t->ops->disconnect(t);
	module_put(THIS_MODULE);
	return 0;
	}

	void ksmbd_conn_init_server_callbacks(struct ksmbd_conn_ops *ops)
	{
	default_conn_ops.process_fn = ops->process_fn;
	default_conn_ops.terminate_fn = ops->terminate_fn;
	}

	void ksmbd_conn_r_count_inc(struct ksmbd_conn *conn)
	{
	atomic_inc(&conn->r_count);
	}

	void ksmbd_conn_r_count_dec(struct ksmbd_conn *conn)
	{
	/*
	* Checking waitqueue to dropping pending requests on
	* disconnection. waitqueue_active is safe because it
	* uses atomic operation for condition.
	*/
	atomic_inc(&conn->refcnt);
	if (!atomic_dec_return(&conn->r_count) && waitqueue_active(&conn->r_count_q))
	wake_up(&conn->r_count_q);

	if (atomic_dec_and_test(&conn->refcnt))
	kfree(conn);
	}

	int ksmbd_conn_transport_init(void)
	{
	int ret;

	mutex_lock(&init_lock);
	ret = ksmbd_tcp_init();
	if (ret) {
	pr_err("Failed to init TCP subsystem: %d\n", ret);
	goto out;
	}

	ret = ksmbd_rdma_init();
	if (ret) {
	pr_err("Failed to init RDMA subsystem: %d\n", ret);
	goto out;
	}
	out:
	mutex_unlock(&init_lock);
	return ret;
	}

	static void stop_sessions(void)
	{
	struct ksmbd_conn *conn;
	struct ksmbd_transport *t;

	again:
	down_read(&conn_list_lock);
	list_for_each_entry(conn, &conn_list, conns_list) {
	t = conn->transport;
	ksmbd_conn_set_exiting(conn);
	if (t->ops->shutdown) {
	up_read(&conn_list_lock);
	t->ops->shutdown(t);
	down_read(&conn_list_lock);
	}
	}
	up_read(&conn_list_lock);

	if (!list_empty(&conn_list)) {
	schedule_timeout_interruptible(HZ / 10); /* 100ms */
	goto again;
	}
	}

	void ksmbd_conn_transport_destroy(void)
	{
	mutex_lock(&init_lock);
	ksmbd_tcp_destroy();
	ksmbd_rdma_destroy();
	stop_sessions();
	mutex_unlock(&init_lock);
	}