Quellcode-Bibliothek tcm_remote.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-or-later

#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/init.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/configfs.h>
#include <scsi/scsi.h>
#include <scsi/scsi_tcq.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_cmnd.h>

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

#include "tcm_remote.h"

static inline struct tcm_remote_tpg *remote_tpg(struct se_portal_group *se_tpg)
{
 return container_of(se_tpg, struct tcm_remote_tpg, remote_se_tpg);
}

static char *tcm_remote_get_endpoint_wwn(struct se_portal_group *se_tpg)
{
 /*
 * Return the passed NAA identifier for the Target Port
 */
 return &remote_tpg(se_tpg)->remote_hba->remote_wwn_address[0];
}

static u16 tcm_remote_get_tag(struct se_portal_group *se_tpg)
{
 /*
 * This Tag is used when forming SCSI Name identifier in EVPD=1 0x83
 * to represent the SCSI Target Port.
 */
 return remote_tpg(se_tpg)->remote_tpgt;
}

static int tcm_remote_dummy_cmd_fn(struct se_cmd *se_cmd)
{
 return 0;
}

static void tcm_remote_dummy_cmd_void_fn(struct se_cmd *se_cmd)
{

}

static char *tcm_remote_dump_proto_id(struct tcm_remote_hba *remote_hba)
{
 switch (remote_hba->remote_proto_id) {
 case SCSI_PROTOCOL_SAS:
  return "SAS";
 case SCSI_PROTOCOL_SRP:
  return "SRP";
 case SCSI_PROTOCOL_FCP:
  return "FCP";
 case SCSI_PROTOCOL_ISCSI:
  return "iSCSI";
 default:
  break;
 }

 return "Unknown";
}

static int tcm_remote_port_link(
 struct se_portal_group *se_tpg,
 struct se_lun *lun)
{
 pr_debug("TCM_Remote_ConfigFS: Port Link LUN %lld Successful\n",
   lun->unpacked_lun);
 return 0;
}

static void tcm_remote_port_unlink(
 struct se_portal_group *se_tpg,
 struct se_lun *lun)
{
 pr_debug("TCM_Remote_ConfigFS: Port Unlink LUN %lld Successful\n",
   lun->unpacked_lun);
}

static struct se_portal_group *tcm_remote_make_tpg(
 struct se_wwn *wwn,
 const char *name)
{
 struct tcm_remote_hba *remote_hba = container_of(wwn,
   struct tcm_remote_hba, remote_hba_wwn);
 struct tcm_remote_tpg *remote_tpg;
 unsigned long tpgt;
 int ret;

 if (strstr(name, "tpgt_") != name) {
  pr_err("Unable to locate \"tpgt_#\" directory group\n");
  return ERR_PTR(-EINVAL);
 }
 if (kstrtoul(name + 5, 10, &tpgt))
  return ERR_PTR(-EINVAL);

 if (tpgt >= TL_TPGS_PER_HBA) {
  pr_err("Passed tpgt: %lu exceeds TL_TPGS_PER_HBA: %u\n",
         tpgt, TL_TPGS_PER_HBA);
  return ERR_PTR(-EINVAL);
 }
 remote_tpg = &remote_hba->remote_hba_tpgs[tpgt];
 remote_tpg->remote_hba = remote_hba;
 remote_tpg->remote_tpgt = tpgt;
 /*
 * Register the remote_tpg as a emulated TCM Target Endpoint
 */
 ret = core_tpg_register(wwn, &remote_tpg->remote_se_tpg,
    remote_hba->remote_proto_id);
 if (ret < 0)
  return ERR_PTR(-ENOMEM);

 pr_debug("TCM_Remote_ConfigFS: Allocated Emulated %s Target Port %s,t,0x%04lx\n",
   tcm_remote_dump_proto_id(remote_hba),
   config_item_name(&wwn->wwn_group.cg_item), tpgt);
 return &remote_tpg->remote_se_tpg;
}

static void tcm_remote_drop_tpg(struct se_portal_group *se_tpg)
{
 struct se_wwn *wwn = se_tpg->se_tpg_wwn;
 struct tcm_remote_tpg *remote_tpg = container_of(se_tpg,
    struct tcm_remote_tpg, remote_se_tpg);
 struct tcm_remote_hba *remote_hba;
 unsigned short tpgt;

 remote_hba = remote_tpg->remote_hba;
 tpgt = remote_tpg->remote_tpgt;

 /*
 * Deregister the remote_tpg as a emulated TCM Target Endpoint
 */
 core_tpg_deregister(se_tpg);

 remote_tpg->remote_hba = NULL;
 remote_tpg->remote_tpgt = 0;

 pr_debug("TCM_Remote_ConfigFS: Deallocated Emulated %s Target Port %s,t,0x%04x\n",
   tcm_remote_dump_proto_id(remote_hba),
   config_item_name(&wwn->wwn_group.cg_item), tpgt);
}

static struct se_wwn *tcm_remote_make_wwn(
 struct target_fabric_configfs *tf,
 struct config_group *group,
 const char *name)
{
 struct tcm_remote_hba *remote_hba;
 char *ptr;
 int ret, off = 0;

 remote_hba = kzalloc(sizeof(*remote_hba), GFP_KERNEL);
 if (!remote_hba)
  return ERR_PTR(-ENOMEM);

 /*
 * Determine the emulated Protocol Identifier and Target Port Name
 * based on the incoming configfs directory name.
 */
 ptr = strstr(name, "naa.");
 if (ptr) {
  remote_hba->remote_proto_id = SCSI_PROTOCOL_SAS;
  goto check_len;
 }
 ptr = strstr(name, "fc.");
 if (ptr) {
  remote_hba->remote_proto_id = SCSI_PROTOCOL_FCP;
  off = 3; /* Skip over "fc." */
  goto check_len;
 }
 ptr = strstr(name, "0x");
 if (ptr) {
  remote_hba->remote_proto_id = SCSI_PROTOCOL_SRP;
  off = 2; /* Skip over "0x" */
  goto check_len;
 }
 ptr = strstr(name, "iqn.");
 if (!ptr) {
  pr_err("Unable to locate prefix for emulated Target Port: %s\n",
         name);
  ret = -EINVAL;
  goto out;
 }
 remote_hba->remote_proto_id = SCSI_PROTOCOL_ISCSI;

check_len:
 if (strlen(name) >= TL_WWN_ADDR_LEN) {
  pr_err("Emulated NAA %s Address: %s, exceeds max: %d\n",
         name, tcm_remote_dump_proto_id(remote_hba), TL_WWN_ADDR_LEN);
  ret = -EINVAL;
  goto out;
 }
 snprintf(&remote_hba->remote_wwn_address[0], TL_WWN_ADDR_LEN, "%s", &name[off]);

 pr_debug("TCM_Remote_ConfigFS: Allocated emulated Target %s Address: %s\n",
   tcm_remote_dump_proto_id(remote_hba), name);
 return &remote_hba->remote_hba_wwn;
out:
 kfree(remote_hba);
 return ERR_PTR(ret);
}

static void tcm_remote_drop_wwn(struct se_wwn *wwn)
{
 struct tcm_remote_hba *remote_hba = container_of(wwn,
    struct tcm_remote_hba, remote_hba_wwn);

 pr_debug("TCM_Remote_ConfigFS: Deallocating emulated Target %s Address: %s\n",
   tcm_remote_dump_proto_id(remote_hba),
   remote_hba->remote_wwn_address);
 kfree(remote_hba);
}

static ssize_t tcm_remote_wwn_version_show(struct config_item *item, char *page)
{
 return sprintf(page, "TCM Remote Fabric module %s\n", TCM_REMOTE_VERSION);
}

CONFIGFS_ATTR_RO(tcm_remote_wwn_, version);

static struct configfs_attribute *tcm_remote_wwn_attrs[] = {
 &tcm_remote_wwn_attr_version,
 NULL,
};

static const struct target_core_fabric_ops remote_ops = {
 .module    = THIS_MODULE,
 .fabric_name   = "remote",
 .tpg_get_wwn   = tcm_remote_get_endpoint_wwn,
 .tpg_get_tag   = tcm_remote_get_tag,
 .check_stop_free  = tcm_remote_dummy_cmd_fn,
 .release_cmd   = tcm_remote_dummy_cmd_void_fn,
 .write_pending   = tcm_remote_dummy_cmd_fn,
 .queue_data_in   = tcm_remote_dummy_cmd_fn,
 .queue_status   = tcm_remote_dummy_cmd_fn,
 .queue_tm_rsp   = tcm_remote_dummy_cmd_void_fn,
 .aborted_task   = tcm_remote_dummy_cmd_void_fn,
 .fabric_make_wwn  = tcm_remote_make_wwn,
 .fabric_drop_wwn  = tcm_remote_drop_wwn,
 .fabric_make_tpg  = tcm_remote_make_tpg,
 .fabric_drop_tpg  = tcm_remote_drop_tpg,
 .fabric_post_link  = tcm_remote_port_link,
 .fabric_pre_unlink  = tcm_remote_port_unlink,
 .tfc_wwn_attrs   = tcm_remote_wwn_attrs,
};

static int __init tcm_remote_fabric_init(void)
{
 return target_register_template(&remote_ops);
}

static void __exit tcm_remote_fabric_exit(void)
{
 target_unregister_template(&remote_ops);
}

MODULE_DESCRIPTION("TCM virtual remote target");
MODULE_AUTHOR("Dmitry Bogdanov ");
MODULE_LICENSE("GPL");
module_init(tcm_remote_fabric_init);
module_exit(tcm_remote_fabric_exit);