iscsi_iser.c

linux 内核源代码

/*
 * iSCSI Initiator over iSER Data-Path
 *
 * Copyright (C) 2004 Dmitry Yusupov
 * Copyright (C) 2004 Alex Aizman
 * Copyright (C) 2005 Mike Christie
 * Copyright (c) 2005, 2006 Voltaire, Inc. All rights reserved.
 * maintained by [e-mail]
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *	- Redistributions of source code must retain the above
 *	  copyright notice, this list of conditions and the following
 *	  disclaimer.
 *
 *	- Redistributions in binary form must reproduce the above
 *	  copyright notice, this list of conditions and the following
 *	  disclaimer in the documentation and/or other materials
 *	  provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 * Credits:
 *	Christoph Hellwig
 *	FUJITA Tomonori
 *	Arne Redlich
 *	Zhenyu Wang
 * Modified by:
 *      Erez Zilber
 *
 *
 * $Id: iscsi_iser.c 6965 2006-05-07 11:36:20Z ogerlitz $
 */

#include <linux/types.h>
#include <linux/list.h>
#include <linux/hardirq.h>
#include <linux/kfifo.h>
#include <linux/blkdev.h>
#include <linux/init.h>
#include <linux/ioctl.h>
#include <linux/cdev.h>
#include <linux/in.h>
#include <linux/net.h>
#include <linux/scatterlist.h>
#include <linux/delay.h>

#include <net/sock.h>

#include <asm/uaccess.h>

#include <scsi/scsi_cmnd.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_eh.h>
#include <scsi/scsi_tcq.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi.h>
#include <scsi/scsi_transport_iscsi.h>

#include "iscsi_iser.h"

static unsigned int iscsi_max_lun = 512;
module_param_named(max_lun, iscsi_max_lun, uint, S_IRUGO);

int iser_debug_level = 0;

MODULE_DESCRIPTION("iSER (iSCSI Extensions for RDMA) Datamover "
		   "v" DRV_VER " (" DRV_DATE ")");
MODULE_LICENSE("Dual BSD/GPL");
MODULE_AUTHOR("Alex Nezhinsky, Dan Bar Dov, Or Gerlitz");

module_param_named(debug_level, iser_debug_level, int, 0644);
MODULE_PARM_DESC(debug_level, "Enable debug tracing if > 0 (default:disabled)");

struct iser_global ig;

void
iscsi_iser_recv(struct iscsi_conn *conn,
		struct iscsi_hdr *hdr, char *rx_data, int rx_data_len)
{
	int rc = 0;
	uint32_t ret_itt;
	int datalen;
	int ahslen;

	/* verify PDU length */
	datalen = ntoh24(hdr->dlength);
	if (datalen != rx_data_len) {
		printk(KERN_ERR "iscsi_iser: datalen %d (hdr) != %d (IB) \n",
		       datalen, rx_data_len);
		rc = ISCSI_ERR_DATALEN;
		goto error;
	}

	/* read AHS */
	ahslen = hdr->hlength * 4;

	/* verify itt (itt encoding: age+cid+itt) */
	rc = iscsi_verify_itt(conn, hdr, &ret_itt);

	if (!rc)
		rc = iscsi_complete_pdu(conn, hdr, rx_data, rx_data_len);

	if (rc && rc != ISCSI_ERR_NO_SCSI_CMD)
		goto error;

	return;
error:
	iscsi_conn_failure(conn, rc);
}


/**
 * iscsi_iser_cmd_init - Initialize iSCSI SCSI_READ or SCSI_WRITE commands
 *
 **/
static void
iscsi_iser_cmd_init(struct iscsi_cmd_task *ctask)
{
	struct iscsi_iser_conn     *iser_conn  = ctask->conn->dd_data;
	struct iscsi_iser_cmd_task *iser_ctask = ctask->dd_data;

	iser_ctask->command_sent = 0;
	iser_ctask->iser_conn    = iser_conn;
	iser_ctask_rdma_init(iser_ctask);
}

/**
 * iscsi_mtask_xmit - xmit management(immediate) task
 * @conn: iscsi connection
 * @mtask: task management task
 *
 * Notes:
 *	The function can return -EAGAIN in which case caller must
 *	call it again later, or recover. '0' return code means successful
 *	xmit.
 *
 **/
static int
iscsi_iser_mtask_xmit(struct iscsi_conn *conn,
		      struct iscsi_mgmt_task *mtask)
{
	int error = 0;

	debug_scsi("mtask deq [cid %d itt 0x%x]\n", conn->id, mtask->itt);

	error = iser_send_control(conn, mtask);

	/* since iser xmits control with zero copy, mtasks can not be recycled
	 * right after sending them.
	 * The recycling scheme is based on whether a response is expected
	 * - if yes, the mtask is recycled at iscsi_complete_pdu
	 * - if no,  the mtask is recycled at iser_snd_completion
	 */
	if (error && error != -ENOBUFS)
		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);

	return error;
}

static int
iscsi_iser_ctask_xmit_unsol_data(struct iscsi_conn *conn,
				 struct iscsi_cmd_task *ctask)
{
	struct iscsi_data  hdr;
	int error = 0;

	/* Send data-out PDUs while there's still unsolicited data to send */
	while (ctask->unsol_count > 0) {
		iscsi_prep_unsolicit_data_pdu(ctask, &hdr);
		debug_scsi("Sending data-out: itt 0x%x, data count %d\n",
			   hdr.itt, ctask->data_count);

		/* the buffer description has been passed with the command */
		/* Send the command */
		error = iser_send_data_out(conn, ctask, &hdr);
		if (error) {
			ctask->unsol_datasn--;
			goto iscsi_iser_ctask_xmit_unsol_data_exit;
		}
		ctask->unsol_count -= ctask->data_count;
		debug_scsi("Need to send %d more as data-out PDUs\n",
			   ctask->unsol_count);
	}

iscsi_iser_ctask_xmit_unsol_data_exit:
	return error;
}

static int
iscsi_iser_ctask_xmit(struct iscsi_conn *conn,
		      struct iscsi_cmd_task *ctask)
{
	struct iscsi_iser_cmd_task *iser_ctask = ctask->dd_data;
	int error = 0;

	if (ctask->sc->sc_data_direction == DMA_TO_DEVICE) {
		BUG_ON(scsi_bufflen(ctask->sc) == 0);

		debug_scsi("cmd [itt %x total %d imm %d unsol_data %d\n",
			   ctask->itt, scsi_bufflen(ctask->sc),
			   ctask->imm_count, ctask->unsol_count);
	}

	debug_scsi("ctask deq [cid %d itt 0x%x]\n",
		   conn->id, ctask->itt);

	/*
	 * serialize with TMF AbortTask
	 */
	if (ctask->mtask)
		return error;

	/* Send the cmd PDU */
	if (!iser_ctask->command_sent) {
		error = iser_send_command(conn, ctask);
		if (error)
			goto iscsi_iser_ctask_xmit_exit;
		iser_ctask->command_sent = 1;
	}

	/* Send unsolicited data-out PDU(s) if necessary */
	if (ctask->unsol_count)
		error = iscsi_iser_ctask_xmit_unsol_data(conn, ctask);

 iscsi_iser_ctask_xmit_exit:
	if (error && error != -ENOBUFS)
		iscsi_conn_failure(conn, ISCSI_ERR_CONN_FAILED);
	return error;
}

static void
iscsi_iser_cleanup_ctask(struct iscsi_conn *conn, struct iscsi_cmd_task *ctask)
{
	struct iscsi_iser_cmd_task *iser_ctask = ctask->dd_data;

	if (iser_ctask->status == ISER_TASK_STATUS_STARTED) {
		iser_ctask->status = ISER_TASK_STATUS_COMPLETED;
		iser_ctask_rdma_finalize(iser_ctask);
	}
}

static struct iser_conn *
iscsi_iser_ib_conn_lookup(__u64 ep_handle)
{
	struct iser_conn *ib_conn;
	struct iser_conn *uib_conn = (struct iser_conn *)(unsigned long)ep_handle;

	mutex_lock(&ig.connlist_mutex);
	list_for_each_entry(ib_conn, &ig.connlist, conn_list) {
		if (ib_conn == uib_conn) {
			mutex_unlock(&ig.connlist_mutex);
			return ib_conn;
		}
	}
	mutex_unlock(&ig.connlist_mutex);
	iser_err("no conn exists for eph %llx\n",(unsigned long long)ep_handle);
	return NULL;
}

static struct iscsi_cls_conn *
iscsi_iser_conn_create(struct iscsi_cls_session *cls_session, uint32_t conn_idx)
{
	struct iscsi_conn *conn;
	struct iscsi_cls_conn *cls_conn;
	struct iscsi_iser_conn *iser_conn;

	cls_conn = iscsi_conn_setup(cls_session, conn_idx);
	if (!cls_conn)
		return NULL;
	conn = cls_conn->dd_data;

	/*
	 * due to issues with the login code re iser sematics
	 * this not set in iscsi_conn_setup - FIXME
	 */
	conn->max_recv_dlength = 128;

	iser_conn = kzalloc(sizeof(*iser_conn), GFP_KERNEL);
	if (!iser_conn)
		goto conn_alloc_fail;

	/* currently this is the only field which need to be initiated */
	rwlock_init(&iser_conn->lock);

	conn->dd_data = iser_conn;
	iser_conn->iscsi_conn = conn;

	return cls_conn;

conn_alloc_fail:
	iscsi_conn_teardown(cls_conn);
	return NULL;
}

static void
iscsi_iser_conn_destroy(struct iscsi_cls_conn *cls_conn)
{
	struct iscsi_conn *conn = cls_conn->dd_data;
	struct iscsi_iser_conn *iser_conn = conn->dd_data;

	iscsi_conn_teardown(cls_conn);
	if (iser_conn->ib_conn)
		iser_conn->ib_conn->iser_conn = NULL;
	kfree(iser_conn);
}

static int
iscsi_iser_conn_bind(struct iscsi_cls_session *cls_session,
		     struct iscsi_cls_conn *cls_conn, uint64_t transport_eph,
		     int is_leading)
{
	struct iscsi_conn *conn = cls_conn->dd_data;
	struct iscsi_iser_conn *iser_conn;
	struct iser_conn *ib_conn;
	int error;

	error = iscsi_conn_bind(cls_session, cls_conn, is_leading);
	if (error)
		return error;

	/* the transport ep handle comes from user space so it must be