scsi_transport_iscsi.c

linux 内核源代码

/*
 * iSCSI transport class definitions
 *
 * Copyright (C) IBM Corporation, 2004
 * Copyright (C) Mike Christie, 2004 - 2005
 * Copyright (C) Dmitry Yusupov, 2004 - 2005
 * Copyright (C) Alex Aizman, 2004 - 2005
 *
 * 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.
 */
#include <linux/module.h>
#include <linux/mutex.h>
#include <net/tcp.h>
#include <scsi/scsi.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_transport.h>
#include <scsi/scsi_transport_iscsi.h>
#include <scsi/iscsi_if.h>

#define ISCSI_SESSION_ATTRS 15
#define ISCSI_CONN_ATTRS 11
#define ISCSI_HOST_ATTRS 4
#define ISCSI_TRANSPORT_VERSION "2.0-724"

struct iscsi_internal {
	int daemon_pid;
	struct scsi_transport_template t;
	struct iscsi_transport *iscsi_transport;
	struct list_head list;
	struct class_device cdev;

	struct class_device_attribute *host_attrs[ISCSI_HOST_ATTRS + 1];
	struct transport_container conn_cont;
	struct class_device_attribute *conn_attrs[ISCSI_CONN_ATTRS + 1];
	struct transport_container session_cont;
	struct class_device_attribute *session_attrs[ISCSI_SESSION_ATTRS + 1];
};

static atomic_t iscsi_session_nr; /* sysfs session id for next new session */

/*
 * list of registered transports and lock that must
 * be held while accessing list. The iscsi_transport_lock must
 * be acquired after the rx_queue_mutex.
 */
static LIST_HEAD(iscsi_transports);
static DEFINE_SPINLOCK(iscsi_transport_lock);

#define to_iscsi_internal(tmpl) \
	container_of(tmpl, struct iscsi_internal, t)

#define cdev_to_iscsi_internal(_cdev) \
	container_of(_cdev, struct iscsi_internal, cdev)

static void iscsi_transport_release(struct class_device *cdev)
{
	struct iscsi_internal *priv = cdev_to_iscsi_internal(cdev);
	kfree(priv);
}

/*
 * iscsi_transport_class represents the iscsi_transports that are
 * registered.
 */
static struct class iscsi_transport_class = {
	.name = "iscsi_transport",
	.release = iscsi_transport_release,
};

static ssize_t
show_transport_handle(struct class_device *cdev, char *buf)
{
	struct iscsi_internal *priv = cdev_to_iscsi_internal(cdev);
	return sprintf(buf, "%llu\n", (unsigned long long)iscsi_handle(priv->iscsi_transport));
}
static CLASS_DEVICE_ATTR(handle, S_IRUGO, show_transport_handle, NULL);

#define show_transport_attr(name, format)				\
static ssize_t								\
show_transport_##name(struct class_device *cdev, char *buf)		\
{									\
	struct iscsi_internal *priv = cdev_to_iscsi_internal(cdev);	\
	return sprintf(buf, format"\n", priv->iscsi_transport->name);	\
}									\
static CLASS_DEVICE_ATTR(name, S_IRUGO, show_transport_##name, NULL);

show_transport_attr(caps, "0x%x");
show_transport_attr(max_lun, "%d");
show_transport_attr(max_conn, "%d");
show_transport_attr(max_cmd_len, "%d");

static struct attribute *iscsi_transport_attrs[] = {
	&class_device_attr_handle.attr,
	&class_device_attr_caps.attr,
	&class_device_attr_max_lun.attr,
	&class_device_attr_max_conn.attr,
	&class_device_attr_max_cmd_len.attr,
	NULL,
};

static struct attribute_group iscsi_transport_group = {
	.attrs = iscsi_transport_attrs,
};

static int iscsi_setup_host(struct transport_container *tc, struct device *dev,
			    struct class_device *cdev)
{
	struct Scsi_Host *shost = dev_to_shost(dev);
	struct iscsi_host *ihost = shost->shost_data;

	memset(ihost, 0, sizeof(*ihost));
	INIT_LIST_HEAD(&ihost->sessions);
	mutex_init(&ihost->mutex);
	return 0;
}

static DECLARE_TRANSPORT_CLASS(iscsi_host_class,
			       "iscsi_host",
			       iscsi_setup_host,
			       NULL,
			       NULL);

static DECLARE_TRANSPORT_CLASS(iscsi_session_class,
			       "iscsi_session",
			       NULL,
			       NULL,
			       NULL);

static DECLARE_TRANSPORT_CLASS(iscsi_connection_class,
			       "iscsi_connection",
			       NULL,
			       NULL,
			       NULL);

static struct sock *nls;
static DEFINE_MUTEX(rx_queue_mutex);

static LIST_HEAD(sesslist);
static DEFINE_SPINLOCK(sesslock);
static LIST_HEAD(connlist);
static DEFINE_SPINLOCK(connlock);

static uint32_t iscsi_conn_get_sid(struct iscsi_cls_conn *conn)
{
	struct iscsi_cls_session *sess = iscsi_dev_to_session(conn->dev.parent);
	return sess->sid;
}

/*
 * Returns the matching session to a given sid
 */
static struct iscsi_cls_session *iscsi_session_lookup(uint32_t sid)
{
	unsigned long flags;
	struct iscsi_cls_session *sess;

	spin_lock_irqsave(&sesslock, flags);
	list_for_each_entry(sess, &sesslist, sess_list) {
		if (sess->sid == sid) {
			spin_unlock_irqrestore(&sesslock, flags);
			return sess;
		}
	}
	spin_unlock_irqrestore(&sesslock, flags);
	return NULL;
}

/*
 * Returns the matching connection to a given sid / cid tuple
 */
static struct iscsi_cls_conn *iscsi_conn_lookup(uint32_t sid, uint32_t cid)
{
	unsigned long flags;
	struct iscsi_cls_conn *conn;

	spin_lock_irqsave(&connlock, flags);
	list_for_each_entry(conn, &connlist, conn_list) {
		if ((conn->cid == cid) && (iscsi_conn_get_sid(conn) == sid)) {
			spin_unlock_irqrestore(&connlock, flags);
			return conn;
		}
	}
	spin_unlock_irqrestore(&connlock, flags);
	return NULL;
}

/*
 * The following functions can be used by LLDs that allocate
 * their own scsi_hosts or by software iscsi LLDs
 */
static void iscsi_session_release(struct device *dev)
{
	struct iscsi_cls_session *session = iscsi_dev_to_session(dev);
	struct Scsi_Host *shost;

	shost = iscsi_session_to_shost(session);
	scsi_host_put(shost);
	kfree(session);
}

static int iscsi_is_session_dev(const struct device *dev)
{
	return dev->release == iscsi_session_release;
}

static int iscsi_user_scan(struct Scsi_Host *shost, uint channel,
			   uint id, uint lun)
{
	struct iscsi_host *ihost = shost->shost_data;
	struct iscsi_cls_session *session;

	mutex_lock(&ihost->mutex);
	list_for_each_entry(session, &ihost->sessions, host_list) {
		if ((channel == SCAN_WILD_CARD || channel == 0) &&
		    (id == SCAN_WILD_CARD || id == session->target_id))
			scsi_scan_target(&session->dev, 0,
					 session->target_id, lun, 1);
	}
	mutex_unlock(&ihost->mutex);

	return 0;
}

static void session_recovery_timedout(struct work_struct *work)
{
	struct iscsi_cls_session *session =
		container_of(work, struct iscsi_cls_session,
			     recovery_work.work);

	dev_printk(KERN_INFO, &session->dev, "iscsi: session recovery timed "
		  "out after %d secs\n", session->recovery_tmo);

	if (session->transport->session_recovery_timedout)
		session->transport->session_recovery_timedout(session);

	scsi_target_unblock(&session->dev);
}

void iscsi_unblock_session(struct iscsi_cls_session *session)
{
	if (!cancel_delayed_work(&session->recovery_work))
		flush_scheduled_work();
	scsi_target_unblock(&session->dev);
}
EXPORT_SYMBOL_GPL(iscsi_unblock_session);

void iscsi_block_session(struct iscsi_cls_session *session)
{
	scsi_target_block(&session->dev);
	schedule_delayed_work(&session->recovery_work,
			     session->recovery_tmo * HZ);
}
EXPORT_SYMBOL_GPL(iscsi_block_session);

struct iscsi_cls_session *
iscsi_alloc_session(struct Scsi_Host *shost,
		    struct iscsi_transport *transport)
{
	struct iscsi_cls_session *session;

	session = kzalloc(sizeof(*session) + transport->sessiondata_size,
			  GFP_KERNEL);
	if (!session)
		return NULL;

	session->transport = transport;
	session->recovery_tmo = 120;
	INIT_DELAYED_WORK(&session->recovery_work, session_recovery_timedout);
	INIT_LIST_HEAD(&session->host_list);
	INIT_LIST_HEAD(&session->sess_list);

	/* this is released in the dev's release function */
	scsi_host_get(shost);
	session->dev.parent = &shost->shost_gendev;
	session->dev.release = iscsi_session_release;
	device_initialize(&session->dev);
	if (transport->sessiondata_size)
		session->dd_data = &session[1];
	return session;
}
EXPORT_SYMBOL_GPL(iscsi_alloc_session);

int iscsi_add_session(struct iscsi_cls_session *session, unsigned int target_id)
{
	struct Scsi_Host *shost = iscsi_session_to_shost(session);
	struct iscsi_host *ihost;
	int err;

	ihost = shost->shost_data;
	session->sid = atomic_add_return(1, &iscsi_session_nr);
	session->target_id = target_id;

	snprintf(session->dev.bus_id, BUS_ID_SIZE, "session%u",
		 session->sid);
	err = device_add(&session->dev);
	if (err) {
		dev_printk(KERN_ERR, &session->dev, "iscsi: could not "
			   "register session's dev\n");
		goto release_host;
	}
	transport_register_device(&session->dev);

	mutex_lock(&ihost->mutex);
	list_add(&session->host_list, &ihost->sessions);
	mutex_unlock(&ihost->mutex);
	return 0;

release_host:
	scsi_host_put(shost);
	return err;
}
EXPORT_SYMBOL_GPL(iscsi_add_session);

/**
 * iscsi_create_session - create iscsi class session
 * @shost: scsi host
 * @transport: iscsi transport
 *
 * This can be called from a LLD or iscsi_transport.
 **/
struct iscsi_cls_session *
iscsi_create_session(struct Scsi_Host *shost,
		     struct iscsi_transport *transport,
		     unsigned int target_id)
{
	struct iscsi_cls_session *session;

	session = iscsi_alloc_session(shost, transport);
	if (!session)
		return NULL;

	if (iscsi_add_session(session, target_id)) {
		iscsi_free_session(session);
		return NULL;
	}
	return session;
}
EXPORT_SYMBOL_GPL(iscsi_create_session);

void iscsi_remove_session(struct iscsi_cls_session *session)
{
	struct Scsi_Host *shost = iscsi_session_to_shost(session);
	struct iscsi_host *ihost = shost->shost_data;

	if (!cancel_delayed_work(&session->recovery_work))
		flush_scheduled_work();

	mutex_lock(&ihost->mutex);
	list_del(&session->host_list);
	mutex_unlock(&ihost->mutex);

	scsi_remove_target(&session->dev);

	transport_unregister_device(&session->dev);
	device_del(&session->dev);
}
EXPORT_SYMBOL_GPL(iscsi_remove_session);

void iscsi_free_session(struct iscsi_cls_session *session)
{
	put_device(&session->dev);
}

EXPORT_SYMBOL_GPL(iscsi_free_session);

/**
 * iscsi_destroy_session - destroy iscsi session
 * @session: iscsi_session
 *
 * Can be called by a LLD or iscsi_transport. There must not be
 * any running connections.
 **/
int iscsi_destroy_session(struct iscsi_cls_session *session)
{
	iscsi_remove_session(session);
	iscsi_free_session(session);
	return 0;
}
EXPORT_SYMBOL_GPL(iscsi_destroy_session);

static void iscsi_conn_release(struct device *dev)
{
	struct iscsi_cls_conn *conn = iscsi_dev_to_conn(dev);
	struct device *parent = conn->dev.parent;

	kfree(conn);
	put_device(parent);
}

static int iscsi_is_conn_dev(const struct device *dev)
{
	return dev->release == iscsi_conn_release;
}

/**
 * iscsi_create_conn - create iscsi class connection
 * @session: iscsi cls session
 * @cid: connection id
 *
 * This can be called from a LLD or iscsi_transport. The connection
 * is child of the session so cid must be unique for all connections
 * on the session.
 *
 * Since we do not support MCS, cid will normally be zero. In some cases
 * for software iscsi we could be trying to preallocate a connection struct
 * in which case there could be two connection structs and cid would be
 * non-zero.
 **/
struct iscsi_cls_conn *
iscsi_create_conn(struct iscsi_cls_session *session, uint32_t cid)
{
	struct iscsi_transport *transport = session->transport;
	struct iscsi_cls_conn *conn;
	int err;

	conn = kzalloc(sizeof(*conn) + transport->conndata_size, GFP_KERNEL);
	if (!conn)
		return NULL;

	if (transport->conndata_size)
		conn->dd_data = &conn[1];

	INIT_LIST_HEAD(&conn->conn_list);
	conn->transport = transport;
	conn->cid = cid;

	/* this is released in the dev's release function */
	if (!get_device(&session->dev))
		goto free_conn;

	snprintf(conn->dev.bus_id, BUS_ID_SIZE, "connection%d:%u",
		 session->sid, cid);
	conn->dev.parent = &session->dev;
	conn->dev.release = iscsi_conn_release;
	err = device_register(&conn->dev);
	if (err) {
		dev_printk(KERN_ERR, &conn->dev, "iscsi: could not register "
			   "connection's dev\n");
		goto release_parent_ref;
	}
	transport_register_device(&conn->dev);
	return conn;

release_parent_ref:
	put_device(&session->dev);
free_conn:
	kfree(conn);
	return NULL;
}

EXPORT_SYMBOL_GPL(iscsi_create_conn);

/**
 * iscsi_destroy_conn - destroy iscsi class connection
 * @session: iscsi cls session
 *
 * This can be called from a LLD or iscsi_transport.
 **/
int iscsi_destroy_conn(struct iscsi_cls_conn *conn)
{
	transport_unregister_device(&conn->dev);
	device_unregister(&conn->dev);
	return 0;
}

EXPORT_SYMBOL_GPL(iscsi_destroy_conn);

/*
 * iscsi interface functions
 */
static struct iscsi_internal *
iscsi_if_transport_lookup(struct iscsi_transport *tt)
{
	struct iscsi_internal *priv;
	unsigned long flags;

	spin_lock_irqsave(&iscsi_transport_lock, flags);
	list_for_each_entry(priv, &iscsi_transports, list) {
		if (tt == priv->iscsi_transport) {
			spin_unlock_irqrestore(&iscsi_transport_lock, flags);
			return priv;
		}
	}
	spin_unlock_irqrestore(&iscsi_transport_lock, flags);
	return NULL;
}

static int
iscsi_broadcast_skb(struct sk_buff *skb, gfp_t gfp)
{
	int rc;

	rc = netlink_broadcast(nls, skb, 0, 1, gfp);
	if (rc < 0) {
		printk(KERN_ERR "iscsi: can not broadcast skb (%d)\n", rc);
		return rc;
	}

	return 0;
}

static int
iscsi_unicast_skb(struct sk_buff *skb, int pid)
{
	int rc;