path: root/drivers/target/target_core_device.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*******************************************************************************
 * Filename:  target_core_device.c (based on iscsi_target_device.c)
 *
 * This file contains the TCM Virtual Device and Disk Transport
 * agnostic related functions.
 *
 * (c) Copyright 2003-2013 Datera, Inc.
 *
 * Nicholas A. Bellinger <nab@kernel.org>
 *
 ******************************************************************************/

#include <linux/net.h>
#include <linux/string.h>
#include <linux/delay.h>
#include <linux/timer.h>
#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/kthread.h>
#include <linux/in.h>
#include <linux/export.h>
#include <linux/t10-pi.h>
#include <asm/unaligned.h>
#include <net/sock.h>
#include <net/tcp.h>
#include <scsi/scsi_common.h>
#include <scsi/scsi_proto.h>

#include <target/target_core_base.h>
#include <target/target_core_backend.h>
#include <target/target_core_fabric.h>

#include "target_core_internal.h"
#include "target_core_alua.h"
#include "target_core_pr.h"
#include "target_core_ua.h"

static DEFINE_MUTEX(device_mutex);
static LIST_HEAD(device_list);
static DEFINE_IDR(devices_idr);

static struct se_hba *lun0_hba;
/* not static, needed by tpg.c */
struct se_device *g_lun0_dev;

sense_reason_t
transport_lookup_cmd_lun(struct se_cmd *se_cmd, u64 unpacked_lun)
{
	struct se_lun *se_lun = NULL;
	struct se_session *se_sess = se_cmd->se_sess;
	struct se_node_acl *nacl = se_sess->se_node_acl;
	struct se_dev_entry *deve;
	sense_reason_t ret = TCM_NO_SENSE;

	rcu_read_lock();
	deve = target_nacl_find_deve(nacl, unpacked_lun);
	if (deve) {
		atomic_long_inc(&deve->total_cmds);

		if (se_cmd->data_direction == DMA_TO_DEVICE)
			atomic_long_add(se_cmd->data_length,
					&deve->write_bytes);
		else if (se_cmd->data_direction == DMA_FROM_DEVICE)
			atomic_long_add(se_cmd->data_length,
					&deve->read_bytes);

		se_lun = rcu_dereference(deve->se_lun);

		if (!percpu_ref_tryget_live(&se_lun->lun_ref)) {
			se_lun = NULL;
			goto out_unlock;
		}

		se_cmd->se_lun = se_lun;
		se_cmd->pr_res_key = deve->pr_res_key;
		se_cmd->orig_fe_lun = unpacked_lun;
		se_cmd->se_cmd_flags |= SCF_SE_LUN_CMD;
		se_cmd->lun_ref_active = true;

		if ((se_cmd->data_direction == DMA_TO_DEVICE) &&
		    deve->lun_access_ro) {
			pr_err("TARGET_CORE[%s]: Detected WRITE_PROTECTED LUN"
				" Access for 0x%08llx\n",
				se_cmd->se_tfo->fabric_name,
				unpacked_lun);
			rcu_read_unlock();
			ret = TCM_WRITE_PROTECTED;
			goto ref_dev;
		}
	}
out_unlock:
	rcu_read_unlock();

	if (!se_lun) {
		/*
		 * Use the se_portal_group->tpg_virt_lun0 to allow for
		 * REPORT_LUNS, et al to be returned when no active
		 * MappedLUN=0 exists for this Initiator Port.
		 */
		if (unpacked_lun != 0) {
			pr_err("TARGET_CORE[%s]: Detected NON_EXISTENT_LUN"
				" Access for 0x%08llx\n",
				se_cmd->se_tfo->fabric_name,
				unpacked_lun);
			return TCM_NON_EXISTENT_LUN;
		}

		se_lun = se_sess->se_tpg->tpg_virt_lun0;
		se_cmd->se_lun = se_sess->se_tpg->tpg_virt_lun0;
		se_cmd->orig_fe_lun = 0;
		se_cmd->se_cmd_flags |= SCF_SE_LUN_CMD;

		percpu_ref_get(&se_lun->lun_ref);
		se_cmd->lun_ref_active = true;

		/*
		 * Force WRITE PROTECT for virtual LUN 0
		 */
		if ((se_cmd->data_direction != DMA_FROM_DEVICE) &&
		    (se_cmd->data_direction != DMA_NONE)) {
			ret = TCM_WRITE_PROTECTED;
			goto ref_dev;
		}
	}
	/*
	 * RCU reference protected by percpu se_lun->lun_ref taken above that
	 * must drop to zero (including initial reference) before this se_lun
	 * pointer can be kfree_rcu() by the final se_lun->lun_group put via
	 * target_core_fabric_configfs.c:target_fabric_port_release
	 */
ref_dev:
	se_cmd->se_dev = rcu_dereference_raw(se_lun->lun_se_dev);
	atomic_long_inc(&se_cmd->se_dev->num_cmds);

	if (se_cmd->data_direction == DMA_TO_DEVICE)
		atomic_long_add(se_cmd->data_length,
				&se_cmd->se_dev->write_bytes);
	else if (se_cmd->data_direction == DMA_FROM_DEVICE)
		atomic_long_add