drivers/target/iscsi/iscsi_target_device.c

   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
  31 void 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
  56 void 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 }
  72 EXPORT_SYMBOL(iscsit_increment_maxcmdsn);