libiscsi.c

linux 内核源代码

	}
	spin_unlock_bh(&session->lock);
	mutex_unlock(&session->eh_mutex);
	scsi_queue_work(session->host, &conn->xmitwork);

	/*
	 * block eh thread until:
	 *
	 * 1) abort response
	 * 2) abort timeout
	 * 3) session is terminated or restarted or userspace has
	 * given up on recovery
	 */
	wait_event_interruptible(conn->ehwait,
				 sc->SCp.phase != session->age ||
				 session->state != ISCSI_STATE_LOGGED_IN ||
				 conn->tmabort_state != TMABORT_INITIAL);
	if (signal_pending(current))
		flush_signals(current);
	del_timer_sync(&conn->tmabort_timer);
	mutex_lock(&session->eh_mutex);
	spin_lock_bh(&session->lock);
	return 0;
}

/*
 * session lock must be held
 */
static struct iscsi_mgmt_task *
iscsi_remove_mgmt_task(struct kfifo *fifo, uint32_t itt)
{
	int i, nr_tasks = __kfifo_len(fifo) / sizeof(void*);
	struct iscsi_mgmt_task *task;

	debug_scsi("searching %d tasks\n", nr_tasks);

	for (i = 0; i < nr_tasks; i++) {
		__kfifo_get(fifo, (void*)&task, sizeof(void*));
		debug_scsi("check task %u\n", task->itt);

		if (task->itt == itt) {
			debug_scsi("matched task\n");
			return task;
		}

		__kfifo_put(fifo, (void*)&task, sizeof(void*));
	}
	return NULL;
}

static int iscsi_ctask_mtask_cleanup(struct iscsi_cmd_task *ctask)
{
	struct iscsi_conn *conn = ctask->conn;
	struct iscsi_session *session = conn->session;

	if (!ctask->mtask)
		return -EINVAL;

	if (!iscsi_remove_mgmt_task(conn->mgmtqueue, ctask->mtask->itt))
		list_del(&ctask->mtask->running);
	__kfifo_put(session->mgmtpool.queue, (void*)&ctask->mtask,
		    sizeof(void*));
	ctask->mtask = NULL;
	return 0;
}

/*
 * session lock must be held
 */
static void fail_command(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask,
			 int err)
{
	struct scsi_cmnd *sc;

	sc = ctask->sc;
	if (!sc)
		return;

	if (ctask->state == ISCSI_TASK_PENDING)
		/*
		 * cmd never made it to the xmit thread, so we should not count
		 * the cmd in the sequencing
		 */
		conn->session->queued_cmdsn--;
	else
		conn->session->tt->cleanup_cmd_task(conn, ctask);
	iscsi_ctask_mtask_cleanup(ctask);

	sc->result = err;
	scsi_set_resid(sc, scsi_bufflen(sc));
	if (conn->ctask == ctask)
		conn->ctask = NULL;
	/* release ref from queuecommand */
	__iscsi_put_ctask(ctask);
}

static void iscsi_suspend_tx(struct iscsi_conn *conn)
{
	set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
	scsi_flush_work(conn->session->host);
}

static void iscsi_start_tx(struct iscsi_conn *conn)
{
	clear_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
	scsi_queue_work(conn->session->host, &conn->xmitwork);
}

int iscsi_eh_abort(struct scsi_cmnd *sc)
{
	struct Scsi_Host *host = sc->device->host;
	struct iscsi_session *session = iscsi_hostdata(host->hostdata);
	struct iscsi_cmd_task *ctask;
	struct iscsi_conn *conn;
	int rc;

	mutex_lock(&session->eh_mutex);
	spin_lock_bh(&session->lock);
	/*
	 * if session was ISCSI_STATE_IN_RECOVERY then we may not have
	 * got the command.
	 */
	if (!sc->SCp.ptr) {
		debug_scsi("sc never reached iscsi layer or it completed.\n");
		spin_unlock_bh(&session->lock);
		mutex_unlock(&session->eh_mutex);
		return SUCCESS;
	}

	ctask = (struct iscsi_cmd_task *)sc->SCp.ptr;
	conn = ctask->conn;

	conn->eh_abort_cnt++;
	debug_scsi("aborting [sc %p itt 0x%x]\n", sc, ctask->itt);

	/*
	 * If we are not logged in or we have started a new session
	 * then let the host reset code handle this
	 */
	if (session->state != ISCSI_STATE_LOGGED_IN ||
	    sc->SCp.phase != session->age)
		goto failed;

	/* ctask completed before time out */
	if (!ctask->sc) {
		debug_scsi("sc completed while abort in progress\n");
		goto success;
	}

	/* what should we do here ? */
	if (conn->ctask == ctask) {
		printk(KERN_INFO "iscsi: sc %p itt 0x%x partially sent. "
		       "Failing abort\n", sc, ctask->itt);
		goto failed;
	}

	if (ctask->state == ISCSI_TASK_PENDING) {
		fail_command(conn, ctask, DID_ABORT << 16);
		goto success;
	}

	conn->tmabort_state = TMABORT_INITIAL;
	rc = iscsi_exec_abort_task(sc, ctask);
	if (rc || sc->SCp.phase != session->age ||
	    session->state != ISCSI_STATE_LOGGED_IN)
		goto failed;
	iscsi_ctask_mtask_cleanup(ctask);

	switch (conn->tmabort_state) {
	case TMABORT_SUCCESS:
		spin_unlock_bh(&session->lock);
		iscsi_suspend_tx(conn);
		/*
		 * clean up task if aborted. grab the recv lock as a writer
		 */
		write_lock_bh(conn->recv_lock);
		spin_lock(&session->lock);
		fail_command(conn, ctask, DID_ABORT << 16);
		spin_unlock(&session->lock);
		write_unlock_bh(conn->recv_lock);
		iscsi_start_tx(conn);
		goto success_unlocked;
	case TMABORT_NOT_FOUND:
		if (!ctask->sc) {
			/* ctask completed before tmf abort response */
			debug_scsi("sc completed while abort in progress\n");
			goto success;
		}
		/* fall through */
	default:
		/* timedout or failed */
		spin_unlock_bh(&session->lock);
		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
		goto failed_unlocked;
	}

success:
	spin_unlock_bh(&session->lock);
success_unlocked:
	debug_scsi("abort success [sc %lx itt 0x%x]\n", (long)sc, ctask->itt);
	mutex_unlock(&session->eh_mutex);
	return SUCCESS;

failed:
	spin_unlock_bh(&session->lock);
failed_unlocked:
	debug_scsi("abort failed [sc %lx itt 0x%x]\n", (long)sc, ctask->itt);
	mutex_unlock(&session->eh_mutex);
	return FAILED;
}
EXPORT_SYMBOL_GPL(iscsi_eh_abort);

int
iscsi_pool_init(struct iscsi_queue *q, int max, void ***items, int item_size)
{
	int i;

	*items = kmalloc(max * sizeof(void*), GFP_KERNEL);
	if (*items == NULL)
		return -ENOMEM;

	q->max = max;
	q->pool = kmalloc(max * sizeof(void*), GFP_KERNEL);
	if (q->pool == NULL) {
		kfree(*items);
		return -ENOMEM;
	}

	q->queue = kfifo_init((void*)q->pool, max * sizeof(void*),
			      GFP_KERNEL, NULL);
	if (q->queue == ERR_PTR(-ENOMEM)) {
		kfree(q->pool);
		kfree(*items);
		return -ENOMEM;
	}

	for (i = 0; i < max; i++) {
		q->pool[i] = kmalloc(item_size, GFP_KERNEL);
		if (q->pool[i] == NULL) {
			int j;

			for (j = 0; j < i; j++)
				kfree(q->pool[j]);

			kfifo_free(q->queue);
			kfree(q->pool);
			kfree(*items);
			return -ENOMEM;
		}
		memset(q->pool[i], 0, item_size);
		(*items)[i] = q->pool[i];
		__kfifo_put(q->queue, (void*)&q->pool[i], sizeof(void*));
	}
	return 0;
}
EXPORT_SYMBOL_GPL(iscsi_pool_init);

void iscsi_pool_free(struct iscsi_queue *q, void **items)
{
	int i;

	for (i = 0; i < q->max; i++)
		kfree(items[i]);
	kfree(q->pool);
	kfree(items);
}
EXPORT_SYMBOL_GPL(iscsi_pool_free);

/*
 * iSCSI Session's hostdata organization:
 *
 *    *------------------* <== hostdata_session(host->hostdata)
 *    | ptr to class sess|
 *    |------------------| <== iscsi_hostdata(host->hostdata)
 *    | iscsi_session    |
 *    *------------------*
 */

#define hostdata_privsize(_sz)	(sizeof(unsigned long) + _sz + \
				 _sz % sizeof(unsigned long))

#define hostdata_session(_hostdata) (iscsi_ptr(*(unsigned long *)_hostdata))

/**
 * iscsi_session_setup - create iscsi cls session and host and session
 * @scsit: scsi transport template
 * @iscsit: iscsi transport template
 * @cmds_max: scsi host can queue
 * @qdepth: scsi host cmds per lun
 * @cmd_task_size: LLD ctask private data size
 * @mgmt_task_size: LLD mtask private data size
 * @initial_cmdsn: initial CmdSN
 * @hostno: host no allocated
 *
 * This can be used by software iscsi_transports that allocate
 * a session per scsi host.
 **/
struct iscsi_cls_session *
iscsi_session_setup(struct iscsi_transport *iscsit,
		    struct scsi_transport_template *scsit,
		    uint16_t cmds_max, uint16_t qdepth,
		    int cmd_task_size, int mgmt_task_size,
		    uint32_t initial_cmdsn, uint32_t *hostno)
{
	struct Scsi_Host *shost;
	struct iscsi_session *session;
	struct iscsi_cls_session *cls_session;
	int cmd_i;

	if (qdepth > ISCSI_MAX_CMD_PER_LUN || qdepth < 1) {
		if (qdepth != 0)
			printk(KERN_ERR "iscsi: invalid queue depth of %d. "
			      "Queue depth must be between 1 and %d.\n",
			      qdepth, ISCSI_MAX_CMD_PER_LUN);
		qdepth = ISCSI_DEF_CMD_PER_LUN;
	}

	if (cmds_max < 2 || (cmds_max & (cmds_max - 1)) ||
	    cmds_max >= ISCSI_MGMT_ITT_OFFSET) {
		if (cmds_max != 0)
			printk(KERN_ERR "iscsi: invalid can_queue of %d. "
			       "can_queue must be a power of 2 and between "
			       "2 and %d - setting to %d.\n", cmds_max,
			       ISCSI_MGMT_ITT_OFFSET, ISCSI_DEF_XMIT_CMDS_MAX);
		cmds_max = ISCSI_DEF_XMIT_CMDS_MAX;
	}

	shost = scsi_host_alloc(iscsit->host_template,
				hostdata_privsize(sizeof(*session)));
	if (!shost)
		return NULL;

	/* the iscsi layer takes one task for reserve */
	shost->can_queue = cmds_max - 1;
	shost->cmd_per_lun = qdepth;
	shost->max_id = 1;
	shost->max_channel = 0;
	shost->max_lun = iscsit->max_lun;
	shost->max_cmd_len = iscsit->max_cmd_len;
	shost->transportt = scsit;
	shost->transportt->create_work_queue = 1;
	*hostno = shost->host_no;

	session = iscsi_hostdata(shost->hostdata);
	memset(session, 0, sizeof(struct iscsi_session));
	session->host = shost;
	session->state = ISCSI_STATE_FREE;
	session->mgmtpool_max = ISCSI_MGMT_CMDS_MAX;
	session->cmds_max = cmds_max;
	session->queued_cmdsn = session->cmdsn = initial_cmdsn;
	session->exp_cmdsn = initial_cmdsn + 1;
	session->max_cmdsn = initial_cmdsn + 1;
	session->max_r2t = 1;
	session->tt = iscsit;
	mutex_init(&session->eh_mutex);

	/* initialize SCSI PDU commands pool */
	if (iscsi_pool_init(&session->cmdpool, session->cmds_max,
			    (void***)&session->cmds,
			    cmd_task_size + sizeof(struct iscsi_cmd_task)))
		goto cmdpool_alloc_fail;

	/* pre-format cmds pool with ITT */
	for (cmd_i = 0; cmd_i < session->cmds_max; cmd_i++) {
		struct iscsi_cmd_task *ctask = session->cmds[cmd_i];

		if (cmd_task_size)
			ctask->dd_data = &ctask[1];
		ctask->itt = cmd_i;
		INIT_LIST_HEAD(&ctask->running);
	}

	spin_lock_init(&session->lock);

	/* initialize immediate command pool */
	if (iscsi_pool_init(&session->mgmtpool, session->mgmtpool_max,
			   (void***)&session->mgmt_cmds,
			   mgmt_task_size + sizeof(struct iscsi_mgmt_task)))
		goto mgmtpool_alloc_fail;


	/* pre-format immediate cmds pool with ITT */
	for (cmd_i = 0; cmd_i < session->mgmtpool_max; cmd_i++) {
		struct iscsi_mgmt_task *mtask = session->mgmt_cmds[cmd_i];

		if (mgmt_task_size)
			mtask->dd_data = &mtask[1];
		mtask->itt = ISCSI_MGMT_ITT_OFFSET + cmd_i;
		INIT_LIST_HEAD(&mtask->running);
	}

	if (scsi_add_host(shost, NULL))
		goto add_host_fail;

	if (!try_module_get(iscsit->owner))
		goto cls_session_fail;

	cls_session = iscsi_create_session(shost, iscsit, 0);
	if (!cls_session)
		goto module_put;
	*(unsigned long*)shost->hostdata = (unsigned long)cls_session;

	return cls_session;

module_put:
	module_put(iscsit->owner);
cls_session_fail:
	scsi_remove_host(shost);
add_host_fail:
	iscsi_pool_free(&session->mgmtpool, (void**)session->mgmt_cmds);
mgmtpool_alloc_fail:
	iscsi_pool_free(&session->cmdpool, (void**)session->cmds);
cmdpool_alloc_fail:
	scsi_host_put(shost);
	return NULL;
}
EXPORT_SYMBOL_GPL(iscsi_session_setup);

/**
 * iscsi_session_teardown - destroy session, host, and cls_session
 * shost: scsi host
 *
 * This can be used by software iscsi_transports that allocate
 * a session per scsi host.
 **/
void iscsi_session_teardown(struct iscsi_cls_session *cls_session)
{
	struct Scsi_Host *shost = iscsi_session_to_shost(cls_session);
	struct iscsi_session *session = iscsi_hostdata(shost->hostdata);
	struct module *owner = cls_session->transport->owner;

	iscsi_unblock_session(cls_session);
	scsi_remove_host(shost);

	iscsi_pool_free(&session->mgmtpool, (void**)session->mgmt_cmds);
	iscsi_pool_free(&session->cmdpool, (void**)session->cmds);

	kfree(session->password);
	kfree(session->password_in);
	kfree(session->username);
	kfree(session->username_in);
	kfree(session->targetname);
	kfree(session->netdev);
	kfree(session->hwaddress);
	kfree(session->initiatorname);

	iscsi_destroy_session(cls_session);
	scsi_host_put(shost);
	module_put(owner);
}
EXPORT_SYMBOL_GPL(iscsi_session_teardown);

/**
 * iscsi_conn_setup - create iscsi_cls_conn and iscsi_conn
 * @cls_session: iscsi_cls_session
 * @conn_idx: cid
 **/
struct iscsi_cls_conn *
iscsi_conn_setup(struct iscsi_cls_session *cls_session, uint32_t conn_idx)
{
	struct iscsi_session *session = class_to_transport_session(cls_session);
	struct iscsi_conn *conn;
	struct iscsi_cls_conn *cls_conn;
	char *data;

	cls_conn = iscsi_create_conn(cls_session, conn_idx);
	if (!cls_conn)
		return NULL;
	conn = cls_conn->dd_data;
	memset(conn, 0, sizeof(*conn));

	conn->session = session;
	conn->cls_conn = cls_conn;
	conn->c_stage = ISCSI_CONN_INITIAL_STAGE;
	conn->id = conn_idx;
	conn->exp_statsn = 0;
	conn->tmabort_state = TMABORT_INITIAL;
	INIT_LIST_HEAD(&conn->run_list);
	INIT_LIST_HEAD(&conn->mgmt_run_list);
	INIT_LIST_HEAD(&conn->xmitqueue);

	/* initialize general immediate & non-immediate PDU commands queue */
	conn->mgmtqueue = kfifo_alloc(session->mgmtpool_max * sizeof(void*),
			                GFP_KERNEL, NULL);
	if (conn->mgmtqueue == ERR_PTR(-ENOMEM))
		goto mgmtqueue_alloc_fail;

	INIT_WORK(&conn->xmitwork, iscsi_xmitworker);

	/* allocate login_mtask used for the login/text sequences */
	spin_lock_bh(&session->lock);
	if (!__kfifo_get(session->mgmtpool.queue,
                         (void*)&conn->login_mtask,
			 sizeof(void*))) {
		spin_unlock_bh(&session->lock);
		goto login_mtask_alloc_fail;
	}
	spin_unlock_bh(&session->lock);

	data = kmalloc(ISCSI_DEF_MAX_RECV_SEG_LEN, GFP_KERNEL);
	if (!data)
		goto login_mtask_data_alloc_fail;
	conn->login_mtask->data = conn->data = data;

	init_timer(&conn->tmabort_timer);
	init_waitqueue_head(&conn->ehwait);

	return cls_conn;

login_mtask_data_alloc_fail:
	__kfifo_put(session->mgmtpool.queue, (void*)&conn->login_mtask,
		    sizeof(void*));
login_mtask_alloc_fail:
	kfifo_free(conn->mgmtqueue);
mgmtqueue_alloc_fail:
	iscsi_destroy_conn(cls_conn);
	return NULL;
}
EXPORT_SYMBOL_GPL(iscsi_conn_setup);

/**
 * iscsi_conn_teardown - teardown iscsi connection
 * cls_conn: iscsi class connection
 *
 * TODO: we may need to make this into a two step process
 * like scsi-mls remove + put host
 */
void iscsi_conn_teardown(struct iscsi_cls_conn *cls_conn)
{
	struct iscsi_conn *conn = cls_conn->dd_data;
	struct iscsi_session *session = conn->session;
	unsigned long flags;

	spin_lock_bh(&session->lock);
	set_bit(ISCSI_SUSPEND_BIT, &conn->suspend_tx);
	conn->c_stage = ISCSI_CONN_CLEANUP_WAIT;