LXR linux/drivers/target/iscsi/iscsi_target

   1/*******************************************************************************
   2 * This file contains the iSCSI Virtual Device and Disk Transport
   3 * agnostic related functions.
   4 *
   5 \u00a9 Copyright 2007-2011 RisingTide Systems LLC.
   6 *
   7 * Licensed to the Linux Foundation under the General Public License (GPL) version 2.
   8 *
   9 * Author: Nicholas A. Bellinger <nab@linux-iscsi.org>
  10 *
  11 * This program is free software; you can redistribute it and/or modify
  12 * it under the terms of the GNU General Public License as published by
  13 * the Free Software Foundation; either version 2 of the License, or
  14 * (at your option) any later version.
  15 *
  16 * This program is distributed in the hope that it will be useful,
  17 * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19 * GNU General Public License for more details.
  20 ******************************************************************************/
  21
  22#include <scsi/scsi_device.h>
  23#include <target/target_core_base.h>
  24#include <target/target_core_fabric.h>
  25
  26#include "iscsi_target_core.h"
  27#include "iscsi_target_device.h"
  28#include "iscsi_target_tpg.h"
  29#include "iscsi_target_util.h"
  30
  31void iscsit_determine_maxcmdsn(struct iscsi_session *sess)
  32{
  33        struct se_node_acl *se_nacl;
  34
  35        /*
  36         * This is a discovery session, the single queue slot was already
  37         * assigned in iscsi_login_zero_tsih().  Since only Logout and
  38         * Text Opcodes are allowed during discovery we do not have to worry
  39         * about the HBA's queue depth here.
  40         */
  41        if (sess->sess_ops->SessionType)
  42                return;
  43
  44        se_nacl = sess->se_sess->se_node_acl;
  45
  46        /*
  47         * This is a normal session, set the Session's CmdSN window to the
  48         * struct se_node_acl->queue_depth.  The value in struct se_node_acl->queue_depth
  49         * has already been validated as a legal value in
  50         * core_set_queue_depth_for_node().
  51         */
  52        sess->cmdsn_window = se_nacl->queue_depth;
  53        sess->max_cmd_sn = (sess->max_cmd_sn + se_nacl->queue_depth) - 1;
  54}
  55
  56void iscsit_increment_maxcmdsn(struct iscsi_cmd *cmd, struct iscsi_session *sess)
  57{
  58        if (cmd->immediate_cmd || cmd->maxcmdsn_inc)
  59                return;
  60
  61        cmd->maxcmdsn_inc = 1;
  62
  63        if (!mutex_trylock(&sess->cmdsn_mutex)) {
  64                sess->max_cmd_sn += 1;
  65                pr_debug("Updated MaxCmdSN to 0x%08x\n", sess->max_cmd_sn);
  66                return;
  67        }
  68        sess->max_cmd_sn += 1;
  69        pr_debug("Updated MaxCmdSN to 0x%08x\n", sess->max_cmd_sn);
  70        mutex_unlock(&sess->cmdsn_mutex);
  71}
  72EXPORT_SYMBOL(iscsit_increment_maxcmdsn);
  73