99 lines
3.2 KiB
C
99 lines
3.2 KiB
C
/*******************************************************************************
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* This file contains the iSCSI Virtual Device and Disk Transport
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* agnostic related functions.
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*
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* (c) Copyright 2007-2013 Datera, Inc.
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*
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* Author: Nicholas A. Bellinger <nab@linux-iscsi.org>
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*
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* This program is free software; you can redistribute it and/or modify
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* it under the terms of the GNU General Public License as published by
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* the Free Software Foundation; either version 2 of the License, or
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* (at your option) any later version.
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*
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* This program is distributed in the hope that it will be useful,
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* but WITHOUT ANY WARRANTY; without even the implied warranty of
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* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
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* GNU General Public License for more details.
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******************************************************************************/
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#include <target/target_core_base.h>
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#include <target/target_core_fabric.h>
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#include <target/iscsi/iscsi_target_core.h>
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#include <target/iscsi/iscsi_transport.h>
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#include "iscsi_target_device.h"
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#include "iscsi_target_tpg.h"
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#include "iscsi_target_util.h"
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#define iscsit_needs_delayed_maxcmdsn_increment(conn) \
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(conn->conn_transport->transport_type == ISCSI_INFINIBAND)
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void iscsit_determine_maxcmdsn(struct iscsit_session *sess)
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{
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struct se_node_acl *se_nacl;
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/*
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* This is a discovery session, the single queue slot was already
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* assigned in iscsi_login_zero_tsih(). Since only Logout and
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* Text Opcodes are allowed during discovery we do not have to worry
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* about the HBA's queue depth here.
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*/
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if (sess->sess_ops->SessionType)
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return;
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se_nacl = sess->se_sess->se_node_acl;
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/*
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* This is a normal session, set the Session's CmdSN window to the
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* struct se_node_acl->queue_depth. The value in struct se_node_acl->queue_depth
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* has already been validated as a legal value in
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* core_set_queue_depth_for_node().
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*/
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sess->cmdsn_window = se_nacl->queue_depth;
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atomic_add(se_nacl->queue_depth - 1, &sess->max_cmd_sn);
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}
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void __iscsit_increment_maxcmdsn(struct iscsit_cmd *cmd, struct iscsit_session *sess)
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{
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u32 max_cmd_sn;
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if (cmd->immediate_cmd || cmd->maxcmdsn_inc)
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return;
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cmd->maxcmdsn_inc = 1;
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max_cmd_sn = atomic_inc_return(&sess->max_cmd_sn);
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pr_debug("Updated MaxCmdSN to 0x%08x\n", max_cmd_sn);
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}
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void iscsit_increment_maxcmdsn(struct iscsit_cmd *cmd, struct iscsit_session *sess)
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{
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if (!iscsit_needs_delayed_maxcmdsn_increment(cmd->conn))
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__iscsit_increment_maxcmdsn(cmd, sess);
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}
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EXPORT_SYMBOL(iscsit_increment_maxcmdsn);
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void iscsit_increment_maxcmdsn_on_release(struct iscsit_cmd *cmd, struct iscsit_session *sess)
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{
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if (iscsit_needs_delayed_maxcmdsn_increment(cmd->conn) && !cmd->no_maxcmdsn_release) {
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__iscsit_increment_maxcmdsn(cmd, sess);
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if ((u32)atomic_read(&sess->max_cmd_sn) -
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READ_ONCE(sess->last_max_cmd_sn)
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> sess->cmdsn_window / 2) {
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/*
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* Prevent nopin races if one may be needed by using
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* a lock and rechecking after grabbing the lock
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*/
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spin_lock_bh(&cmd->conn->nopin_timer_lock);
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if ((u32)atomic_read(&sess->max_cmd_sn) -
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READ_ONCE(sess->last_max_cmd_sn)
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> sess->cmdsn_window / 2)
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iscsit_add_nopin(cmd->conn, 0);
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spin_unlock_bh(&cmd->conn->nopin_timer_lock);
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}
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}
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}
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