path: root/drivers/target/iscsi/iscsi_target_util.c

/*******************************************************************************
 * This file contains the iSCSI Target specific utility functions.
 *
 * (c) Copyright 2007-2013 Datera, Inc.
 *
 * Author: Nicholas A. Bellinger <nab@linux-iscsi.org>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2 of the License, or
 * (at your option) any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 ******************************************************************************/

#include <linux/list.h>
#include <linux/percpu_ida.h>
#include <scsi/scsi_tcq.h>
#include <scsi/iscsi_proto.h>
#include <target/target_core_base.h>
#include <target/target_core_fabric.h>
#include <target/target_core_configfs.h>
#include <target/iscsi/iscsi_transport.h>

#include "iscsi_target_core.h"
#include "iscsi_target_parameters.h"
#include "iscsi_target_seq_pdu_list.h"
#include "iscsi_target_datain_values.h"
#include "iscsi_target_erl0.h"
#include "iscsi_target_erl1.h"
#include "iscsi_target_erl2.h"
#include "iscsi_target_tpg.h"
#include "iscsi_target_tq.h"
#include "iscsi_target_util.h"
#include "iscsi_target.h"

#define PRINT_BUFF(buff, len)					\
{								\
	int zzz;						\
								\
	pr_debug("%d:\n", __LINE__);				\
	for (zzz = 0; zzz < len; zzz++) {			\
		if (zzz % 16 == 0) {				\
			if (zzz)				\
				pr_debug("\n");			\
			pr_debug("%4i: ", zzz);			\
		}						\
		pr_debug("%02x ", (unsigned char) (buff)[zzz]);	\
	}							\
	if ((len + 1) % 16)					\
		pr_debug("\n");					\
}

extern struct list_head g_tiqn_list;
extern spinlock_t tiqn_lock;

/*
 *	Called with cmd->r2t_lock held.
 */
int iscsit_add_r2t_to_list(
	struct iscsi_cmd *cmd,
	u32 offset,
	u32 xfer_len,
	int recovery,
	u32 r2t_sn)
{
	struct iscsi_r2t *r2t;

	r2t = kmem_cache_zalloc(lio_r2t_cache, GFP_ATOMIC);
	if (!r2t) {
		pr_err("Unable to allocate memory for struct iscsi_r2t.\n");
		return -1;
	}
	INIT_LIST_HEAD(&r2t->r2t_list);

	r2t->recovery_r2t = recovery;
	r2t->r2t_sn = (!r2t_sn) ? cmd->r2t_sn++ : r2t_sn;
	r2t->offset = offset;
	r2t->xfer_len = xfer_len;
	list_add_tail(&r2t->r2t_list, &cmd->cmd_r2t_list);
	spin_unlock_bh(&cmd->r2t_lock);

	iscsit_add_cmd_to_immediate_queue(cmd, cmd->conn, ISTATE_SEND_R2T);

	spin_lock_bh(&cmd->r2t_lock);
	return 0;
}

struct iscsi_r2t *iscsit_get_r2t_for_eos(
	struct iscsi_cmd *cmd,
	u32 offset,
	u32 length)
{
	struct iscsi_r2t *r2t;

	spin_lock_bh(&cmd->r2t_lock);
	list_for_each_entry(r2t, &cmd->cmd_r2t_list, r2t_list) {
		if ((r2t->offset <= offset) &&
		    (r2t->offset + r2t->xfer_len) >= (offset + length)) {
			spin_unlock_bh(&cmd->r2t_lock);
			return r2t;
		}
	}
	spin_unlock_bh(&cmd->r2t_lock);

	pr_err("Unable to locate R2T for Offset: %u, Length:"
			" %u\n", offset, length);
	return NULL;
}

struct iscsi_r2t *iscsit_get_r2t_from_list(struct iscsi_cmd *cmd)
{
	struct iscsi_r2t *r2t;

	spin_lock_bh(&cmd->r2t_lock);
	list_for_each_entry(r2t, &cmd->cmd_r2t_list, r2t_list) {
		if (!r2t->sent_r2t) {
			spin_unlock_bh(&cmd->r2t_lock);
			return r2t;
		}
	}
	spin_unlock_bh(&cmd->r2t_lock);

	pr_err("Unable to locate next R2T to send for ITT:"
			" 0x%08x.\n", cmd->init_task_tag);
	return NULL;
}

/*
 *	Called with cmd->r2t_lock held.
 */
void iscsit_free_r2t(struct iscsi_r2t *r2t, struct iscsi_cmd *cmd)
{
	list_del(&r2t->r2t_list);
	kmem_cache_free(lio_r2t_cache, r2t);
}

void iscsit_free_r2ts_from_list(struct iscsi_cmd *cmd)
{
	struct iscsi_r2t *r2t, *r2t_tmp;

	spin_lock_bh(&cmd->r2t_lock);
	list_for_each_entry_safe(r2t, r2t_tmp, &cmd->cmd_r2t_list, r2t_list)
		iscsit_free_r2t(r2t, cmd);
	spin_unlock_bh(&cmd->r2t_lock);
}

/*
 * May be called from software interrupt (timer) context for allocating
 * iSCSI NopINs.
 */
struct iscsi_cmd *iscsit_allocate_cmd(struct iscsi_conn *conn, int state)
{
	struct iscsi_cmd *cmd;
	struct se_session *se_sess = conn->sess->se_sess;
	int size, tag;

	tag = percpu_ida_alloc(&se_sess->sess_tag_pool, state);
	if (tag < 0)
		return NULL;

	size = sizeof(struct iscsi_cmd) + conn->conn_transport->priv_size;
	cmd = (struct iscsi_cmd *)(se_sess->sess_cmd_map + (tag * size));
	memset(cmd, 0, size);

	cmd->se_cmd.map_tag = tag;
	cmd->conn = conn;
	INIT_LIST_HEAD(&cmd->i_conn_node);
	INIT_LIST_HEAD(&cmd->datain_list);
	INIT_LIST_HEAD(&cmd->cmd_r2t_list);
	spin_lock_init(&cmd->datain_lock);
	spin_lock_init(&cmd->dataout_timeout_lock);
	spin_lock_init(&cmd->istate_lock);
	spin_lock_init(&cmd->error_lock);
	spin_lock_init(&cmd->r2t_lock);

	return cmd;
}
EXPORT_SYMBOL(iscsit_allocate_cmd);

struct iscsi_seq *iscsit_get_seq_holder_for_datain(
	struct iscsi_cmd *cmd,
	u32 seq_send_order)
{
	u32 i;

	for (i = 0; i < cmd->seq_count; i++)
		if (cmd->seq_list[i].seq_send_order == seq_send_order)
			return &cmd->seq_list[i];

	return NULL;
}

struct iscsi_seq *iscsit_get_seq_holder_for_r2t(struct iscsi_cmd *cmd)
{
	u32 i;

	if (!cmd->seq_list) {
		pr_err("struct iscsi_cmd->seq_list is NULL!\n");
		return NULL;
	}

	for (i = 0; i < cmd->seq_count; i++) {
		if (cmd->seq_list[i].type != SEQTYPE_NORMAL)
			continue;
		if (cmd->seq_list[i].seq_send_order == cmd->seq_send_order) {
			cmd->seq_send_order++;
			return &cmd->seq_list[i];
		}
	}

	return NULL;
}

struct iscsi_r2t *iscsit_get_holder_for_r2tsn(
	struct iscsi_cmd *cmd,
	u32 r2t_sn)
{
	struct iscsi_r2t *r2t;

	spin_lock_bh(&cmd->r2t_lock);
	list_for_each_entry(r2t, &cmd->cmd_r2t_list, r2t_list) {
		if (r2t->r2t_sn == r2t_sn) {
			spin_unlock_bh(&cmd->r2t_lock);
			return r2t;
		}
	}
	spin_unlock_bh(&cmd->r2t_lock);

	return NULL;
}

static inline int iscsit_check_received_cmdsn(struct iscsi_session *sess, u32 cmdsn)
{
	int ret;

	/*
	 * This is the proper method of checking received CmdSN against
	 * ExpCmdSN and MaxCmdSN values, as well as accounting for out
	 * or order CmdSNs due to multiple connection sessions and/or
	 * CRC failures.
	 */
	if (iscsi_sna_gt(cmdsn, sess->max_cmd_sn)) {
		pr_err("Received CmdSN: 0x%08x is greater than"
		       " MaxCmdSN: 0x%08x, ignoring.\n", cmdsn,
		       sess->max_cmd_sn);
		ret = CMDSN_MAXCMDSN_OVERRUN;

	} else if (cmdsn == sess->exp_cmd_sn) {
		sess->exp_cmd_sn++;
		pr_debug("Received CmdSN matches ExpCmdSN,"
		      " incremented ExpCmdSN to: 0x%08x\n",
		      sess->exp_cmd_sn);
		ret = CMDSN_NORMAL_OPERATION;

	} else if (iscsi_sna_gt(cmdsn, sess->exp_cmd_sn)) {
		pr_debug("Received CmdSN: 0x%08x is greater"
		      " than ExpCmdSN: 0x%08x, not acknowledging.\n",
		      cmdsn, sess->exp_cmd_sn);
		ret = CMDSN_HIGHER_THAN_EXP;

	} else {
		pr_err("Received CmdSN: 0x%08x is less than"
		       " ExpCmdSN: 0x%08x, ignoring.\n", cmdsn,
		       sess->exp_cmd_sn);
		ret = CMDSN_LOWER_THAN_EXP;
	}

	return ret;
}

/*
 * Commands may be received out of order if MC/S is in use.
 * Ensure they are executed in CmdSN order.
 */
int iscsit_sequence_cmd(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
			unsigned char *buf, __be32 cmdsn)
{
	int ret, cmdsn_ret;
	bool reject = false;
	u8 reason = ISCSI_REASON_BOOKMARK_NO_RESOURCES;

	mutex_lock(&conn->sess->cmdsn_mutex);

	cmdsn_ret = iscsit_check_received_cmdsn(conn->sess, be32_to_cpu(cmdsn));
	switch (cmdsn_ret) {
	case CMDSN_NORMAL_OPERATION:
		ret = iscsit_execute_cmd(cmd, 0);
		if ((ret >