Quelle  target_core_xcopy.c   Sprache: C

// SPDX-License-Identifier: GPL-2.0-or-later
/*******************************************************************************
 * Filename: target_core_xcopy.c
 *
 * This file contains support for SPC-4 Extended-Copy offload with generic
 * TCM backends.
 *
 * Copyright (c) 2011-2013 Datera, Inc. All rights reserved.
 *
 * Author:
 * Nicholas A. Bellinger <nab@daterainc.com>
 *
 ******************************************************************************/

#include <linux/slab.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/rculist.h>
#include <linux/configfs.h>
#include <linux/ratelimit.h>
#include <scsi/scsi_proto.h>
#include <linux/unaligned.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_pr.h"
#include "target_core_ua.h"
#include "target_core_xcopy.h"

static struct workqueue_struct *xcopy_wq = NULL;

static sense_reason_t target_parse_xcopy_cmd(struct xcopy_op *xop);

/**
 * target_xcopy_locate_se_dev_e4_iter - compare XCOPY NAA device identifiers
 *
 * @se_dev: device being considered for match
 * @dev_wwn: XCOPY requested NAA dev_wwn
 * @return: 1 on match, 0 on no-match
 */
static int target_xcopy_locate_se_dev_e4_iter(struct se_device *se_dev,
           const unsigned char *dev_wwn)
{
 unsigned char tmp_dev_wwn[XCOPY_NAA_IEEE_REGEX_LEN];
 int rc;

 if (!se_dev->dev_attrib.emulate_3pc) {
  pr_debug("XCOPY: emulate_3pc disabled on se_dev %p\n", se_dev);
  return 0;
 }

 memset(&tmp_dev_wwn[0], 0, XCOPY_NAA_IEEE_REGEX_LEN);
 spc_gen_naa_6h_vendor_specific(se_dev, &tmp_dev_wwn[0]);

 rc = memcmp(&tmp_dev_wwn[0], dev_wwn, XCOPY_NAA_IEEE_REGEX_LEN);
 if (rc != 0) {
  pr_debug("XCOPY: skip non-matching: %*ph\n",
    XCOPY_NAA_IEEE_REGEX_LEN, tmp_dev_wwn);
  return 0;
 }
 pr_debug("XCOPY 0xe4: located se_dev: %p\n", se_dev);

 return 1;
}

static int target_xcopy_locate_se_dev_e4(struct se_session *sess,
     const unsigned char *dev_wwn,
     struct se_device **_found_dev,
     struct percpu_ref **_found_lun_ref)
{
 struct se_dev_entry *deve;
 struct se_node_acl *nacl;
 struct se_lun *this_lun = NULL;
 struct se_device *found_dev = NULL;

 /* cmd with NULL sess indicates no associated $FABRIC_MOD */
 if (!sess)
  goto err_out;

 pr_debug("XCOPY 0xe4: searching for: %*ph\n",
   XCOPY_NAA_IEEE_REGEX_LEN, dev_wwn);

 nacl = sess->se_node_acl;
 rcu_read_lock();
 hlist_for_each_entry_rcu(deve, &nacl->lun_entry_hlist, link) {
  struct se_device *this_dev;
  int rc;

  this_lun = deve->se_lun;
  this_dev = rcu_dereference_raw(this_lun->lun_se_dev);

  rc = target_xcopy_locate_se_dev_e4_iter(this_dev, dev_wwn);
  if (rc) {
   if (percpu_ref_tryget_live(&this_lun->lun_ref))
    found_dev = this_dev;
   break;
  }
 }
 rcu_read_unlock();
 if (found_dev == NULL)
  goto err_out;

 pr_debug("lun_ref held for se_dev: %p se_dev->se_dev_group: %p\n",
   found_dev, &found_dev->dev_group);
 *_found_dev = found_dev;
 *_found_lun_ref = &this_lun->lun_ref;
 return 0;
err_out:
 pr_debug_ratelimited("Unable to locate 0xe4 descriptor for EXTENDED_COPY\n");
 return -EINVAL;
}

static int target_xcopy_parse_tiddesc_e4(struct se_cmd *se_cmd, struct xcopy_op *xop,
    unsigned char *p, unsigned short cscd_index)
{
 unsigned char *desc = p;
 unsigned short ript;
 u8 desig_len;
 /*
 * Extract RELATIVE INITIATOR PORT IDENTIFIER
 */
 ript = get_unaligned_be16(&desc[2]);
 pr_debug("XCOPY 0xe4: RELATIVE INITIATOR PORT IDENTIFIER: %hu\n", ript);
 /*
 * Check for supported code set, association, and designator type
 */
 if ((desc[4] & 0x0f) != 0x1) {
  pr_err("XCOPY 0xe4: code set of non binary type not supported\n");
  return -EINVAL;
 }
 if ((desc[5] & 0x30) != 0x00) {
  pr_err("XCOPY 0xe4: association other than LUN not supported\n");
  return -EINVAL;
 }
 if ((desc[5] & 0x0f) != 0x3) {
  pr_err("XCOPY 0xe4: designator type unsupported: 0x%02x\n",
    (desc[5] & 0x0f));
  return -EINVAL;
 }
 /*
 * Check for matching 16 byte length for NAA IEEE Registered Extended
 * Assigned designator
 */
 desig_len = desc[7];
 if (desig_len != XCOPY_NAA_IEEE_REGEX_LEN) {
  pr_err("XCOPY 0xe4: invalid desig_len: %d\n", (int)desig_len);
  return -EINVAL;
 }
 pr_debug("XCOPY 0xe4: desig_len: %d\n", (int)desig_len);
 /*
 * Check for NAA IEEE Registered Extended Assigned header..
 */
 if ((desc[8] & 0xf0) != 0x60) {
  pr_err("XCOPY 0xe4: Unsupported DESIGNATOR TYPE: 0x%02x\n",
     (desc[8] & 0xf0));
  return -EINVAL;
 }

 if (cscd_index != xop->stdi && cscd_index != xop->dtdi) {
  pr_debug("XCOPY 0xe4: ignoring CSCD entry %d - neither src nor "
    "dest\n", cscd_index);
  return 0;
 }

 if (cscd_index == xop->stdi) {
  memcpy(&xop->src_tid_wwn[0], &desc[8], XCOPY_NAA_IEEE_REGEX_LEN);
  /*
 * Determine if the source designator matches the local device
 */
  if (!memcmp(&xop->local_dev_wwn[0], &xop->src_tid_wwn[0],
    XCOPY_NAA_IEEE_REGEX_LEN)) {
   xop->op_origin = XCOL_SOURCE_RECV_OP;
   xop->src_dev = se_cmd->se_dev;
   pr_debug("XCOPY 0xe4: Set xop->src_dev %p from source"
     " received xop\n", xop->src_dev);
  }
 }

 if (cscd_index == xop->dtdi) {
  memcpy(&xop->dst_tid_wwn[0], &desc[8], XCOPY_NAA_IEEE_REGEX_LEN);
  /*
 * Determine if the destination designator matches the local
 * device. If @cscd_index corresponds to both source (stdi) and
 * destination (dtdi), or dtdi comes after stdi, then
 * XCOL_DEST_RECV_OP wins.
 */
  if (!memcmp(&xop->local_dev_wwn[0], &xop->dst_tid_wwn[0],
    XCOPY_NAA_IEEE_REGEX_LEN)) {
   xop->op_origin = XCOL_DEST_RECV_OP;
   xop->dst_dev = se_cmd->se_dev;
   pr_debug("XCOPY 0xe4: Set xop->dst_dev: %p from destination"
    " received xop\n", xop->dst_dev);
  }
 }

 return 0;
}

static int target_xcopy_parse_target_descriptors(struct se_cmd *se_cmd,
    struct xcopy_op *xop, unsigned char *p,
    unsigned short tdll, sense_reason_t *sense_ret)
{
 struct se_device *local_dev = se_cmd->se_dev;
 unsigned char *desc = p;
 int offset = tdll % XCOPY_TARGET_DESC_LEN, rc;
 unsigned short cscd_index = 0;
 unsigned short start = 0;

 *sense_ret = TCM_INVALID_PARAMETER_LIST;

 if (offset != 0) {
  pr_err("XCOPY target descriptor list length is not"
   " multiple of %d\n", XCOPY_TARGET_DESC_LEN);
  *sense_ret = TCM_UNSUPPORTED_TARGET_DESC_TYPE_CODE;
  return -EINVAL;
 }
 if (tdll > RCR_OP_MAX_TARGET_DESC_COUNT * XCOPY_TARGET_DESC_LEN) {
  pr_err("XCOPY target descriptor supports a maximum"
   " two src/dest descriptors, tdll: %hu too large..\n", tdll);
  /* spc4r37 6.4.3.4 CSCD DESCRIPTOR LIST LENGTH field */
  *sense_ret = TCM_TOO_MANY_TARGET_DESCS;
  return -EINVAL;
 }
 /*
 * Generate an IEEE Registered Extended designator based upon the
 * se_device the XCOPY was received upon..
 */
 memset(&xop->local_dev_wwn[0], 0, XCOPY_NAA_IEEE_REGEX_LEN);
 spc_gen_naa_6h_vendor_specific(local_dev, &xop->local_dev_wwn[0]);

 while (start < tdll) {
  /*
 * Check target descriptor identification with 0xE4 type, and
 * compare the current index with the CSCD descriptor IDs in
 * the segment descriptor. Use VPD 0x83 WWPN matching ..
 */
  switch (desc[0]) {
  case 0xe4:
   rc = target_xcopy_parse_tiddesc_e4(se_cmd, xop,
       &desc[0], cscd_index);
   if (rc != 0)
    goto out;
   start += XCOPY_TARGET_DESC_LEN;
   desc += XCOPY_TARGET_DESC_LEN;
   cscd_index++;
   break;
  default:
   pr_err("XCOPY unsupported descriptor type code:"
     " 0x%02x\n", desc[0]);
   *sense_ret = TCM_UNSUPPORTED_TARGET_DESC_TYPE_CODE;
   goto out;
  }
 }

 switch (xop->op_origin) {
 case XCOL_SOURCE_RECV_OP:
  rc = target_xcopy_locate_se_dev_e4(se_cmd->se_sess,
      xop->dst_tid_wwn,
      &xop->dst_dev,
      &xop->remote_lun_ref);
  break;
 case XCOL_DEST_RECV_OP:
  rc = target_xcopy_locate_se_dev_e4(se_cmd->se_sess,
      xop->src_tid_wwn,
      &xop->src_dev,
      &xop->remote_lun_ref);
  break;
 default:
  pr_err("XCOPY CSCD descriptor IDs not found in CSCD list - "
   "stdi: %hu dtdi: %hu\n", xop->stdi, xop->dtdi);
  rc = -EINVAL;
  break;
 }
 /*
 * If a matching IEEE NAA 0x83 descriptor for the requested device
 * is not located on this node, return COPY_ABORTED with ASQ/ASQC
 * 0x0d/0x02 - COPY_TARGET_DEVICE_NOT_REACHABLE to request the
 * initiator to fall back to normal copy method.
 */
 if (rc < 0) {
  *sense_ret = TCM_COPY_TARGET_DEVICE_NOT_REACHABLE;
  goto out;
 }

 pr_debug("XCOPY TGT desc: Source dev: %p NAA IEEE WWN: 0x%16phN\n",
   xop->src_dev, &xop->src_tid_wwn[0]);
 pr_debug("XCOPY TGT desc: Dest dev: %p NAA IEEE WWN: 0x%16phN\n",
   xop->dst_dev, &xop->dst_tid_wwn[0]);

 return cscd_index;

out:
 return -EINVAL;
}

static int target_xcopy_parse_segdesc_02(struct xcopy_op *xop, unsigned char *p)
{
 unsigned char *desc = p;
 int dc = (desc[1] & 0x02);
 unsigned short desc_len;

 desc_len = get_unaligned_be16(&desc[2]);
 if (desc_len != 0x18) {
  pr_err("XCOPY segment desc 0x02: Illegal desc_len:"
    " %hu\n", desc_len);
  return -EINVAL;
 }

 xop->stdi = get_unaligned_be16(&desc[4]);
 xop->dtdi = get_unaligned_be16(&desc[6]);

 if (xop->stdi > XCOPY_CSCD_DESC_ID_LIST_OFF_MAX ||
     xop->dtdi > XCOPY_CSCD_DESC_ID_LIST_OFF_MAX) {
  pr_err("XCOPY segment desc 0x02: unsupported CSCD ID > 0x%x; stdi: %hu dtdi: %hu\n",
   XCOPY_CSCD_DESC_ID_LIST_OFF_MAX, xop->stdi, xop->dtdi);
  return -EINVAL;
 }

 pr_debug("XCOPY seg desc 0x02: desc_len: %hu stdi: %hu dtdi: %hu, DC: %d\n",
  desc_len, xop->stdi, xop->dtdi, dc);

 xop->nolb = get_unaligned_be16(&desc[10]);
 xop->src_lba = get_unaligned_be64(&desc[12]);
 xop->dst_lba = get_unaligned_be64(&desc[20]);
 pr_debug("XCOPY seg desc 0x02: nolb: %hu src_lba: %llu dst_lba: %llu\n",
  xop->nolb, (unsigned long long)xop->src_lba,
  (unsigned long long)xop->dst_lba);

 return 0;
}

static int target_xcopy_parse_segment_descriptors(struct xcopy_op *xop,
    unsigned char *p, unsigned int sdll,
    sense_reason_t *sense_ret)
{
 unsigned char *desc = p;
 unsigned int start = 0;
 int offset = sdll % XCOPY_SEGMENT_DESC_LEN, rc, ret = 0;

 *sense_ret = TCM_INVALID_PARAMETER_LIST;

 if (offset != 0) {
  pr_err("XCOPY segment descriptor list length is not"
   " multiple of %d\n", XCOPY_SEGMENT_DESC_LEN);
  *sense_ret = TCM_UNSUPPORTED_SEGMENT_DESC_TYPE_CODE;
  return -EINVAL;
 }
 if (sdll > RCR_OP_MAX_SG_DESC_COUNT * XCOPY_SEGMENT_DESC_LEN) {
  pr_err("XCOPY supports %u segment descriptor(s), sdll: %u too"
   " large..\n", RCR_OP_MAX_SG_DESC_COUNT, sdll);
  /* spc4r37 6.4.3.5 SEGMENT DESCRIPTOR LIST LENGTH field */
  *sense_ret = TCM_TOO_MANY_SEGMENT_DESCS;
  return -EINVAL;
 }

 while (start < sdll) {
  /*
 * Check segment descriptor type code for block -> block
 */
  switch (desc[0]) {
  case 0x02:
   rc = target_xcopy_parse_segdesc_02(xop, desc);
   if (rc < 0)
    goto out;

   ret++;
   start += XCOPY_SEGMENT_DESC_LEN;
   desc += XCOPY_SEGMENT_DESC_LEN;
   break;
  default:
   pr_err("XCOPY unsupported segment descriptor"
    "type: 0x%02x\n", desc[0]);
   *sense_ret = TCM_UNSUPPORTED_SEGMENT_DESC_TYPE_CODE;
   goto out;
  }
 }

 return ret;

out:
 return -EINVAL;
}

/*
 * Start xcopy_pt ops
 */

struct xcopy_pt_cmd {
 struct se_cmd se_cmd;
 struct completion xpt_passthrough_sem;
 unsigned char sense_buffer[TRANSPORT_SENSE_BUFFER];
};

struct se_portal_group xcopy_pt_tpg;
static struct se_session xcopy_pt_sess;
static struct se_node_acl xcopy_pt_nacl;

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

static void xcopy_pt_undepend_remotedev(struct xcopy_op *xop)
{
 if (xop->op_origin == XCOL_SOURCE_RECV_OP)
  pr_debug("putting dst lun_ref for %p\n", xop->dst_dev);
 else
  pr_debug("putting src lun_ref for %p\n", xop->src_dev);

 percpu_ref_put(xop->remote_lun_ref);
}

static void xcopy_pt_release_cmd(struct se_cmd *se_cmd)
{
 struct xcopy_pt_cmd *xpt_cmd = container_of(se_cmd,
    struct xcopy_pt_cmd, se_cmd);

 /* xpt_cmd is on the stack, nothing to free here */
 pr_debug("xpt_cmd done: %p\n", xpt_cmd);
}

static int xcopy_pt_check_stop_free(struct se_cmd *se_cmd)
{
 struct xcopy_pt_cmd *xpt_cmd = container_of(se_cmd,
    struct xcopy_pt_cmd, se_cmd);

 complete(&xpt_cmd->xpt_passthrough_sem);
 return 0;
}

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

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

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

static const struct target_core_fabric_ops xcopy_pt_tfo = {
 .fabric_name  = "xcopy-pt",
 .get_cmd_state  = xcopy_pt_get_cmd_state,
 .release_cmd  = xcopy_pt_release_cmd,
 .check_stop_free = xcopy_pt_check_stop_free,
 .write_pending  = xcopy_pt_write_pending,
 .queue_data_in  = xcopy_pt_queue_data_in,
 .queue_status  = xcopy_pt_queue_status,
};

/*
 * End xcopy_pt_ops
 */

int target_xcopy_setup_pt(void)
{
 xcopy_wq = alloc_workqueue("xcopy_wq", WQ_MEM_RECLAIM, 0);
 if (!xcopy_wq) {
  pr_err("Unable to allocate xcopy_wq\n");
  return -ENOMEM;
 }

 memset(&xcopy_pt_tpg, 0, sizeof(struct se_portal_group));
 INIT_LIST_HEAD(&xcopy_pt_tpg.acl_node_list);
 INIT_LIST_HEAD(&xcopy_pt_tpg.tpg_sess_list);

 xcopy_pt_tpg.se_tpg_tfo = &xcopy_pt_tfo;

 memset(&xcopy_pt_nacl, 0, sizeof(struct se_node_acl));
 INIT_LIST_HEAD(&xcopy_pt_nacl.acl_list);
 INIT_LIST_HEAD(&xcopy_pt_nacl.acl_sess_list);
 memset(&xcopy_pt_sess, 0, sizeof(struct se_session));
 transport_init_session(&xcopy_pt_sess);

 xcopy_pt_nacl.se_tpg = &xcopy_pt_tpg;
 xcopy_pt_nacl.nacl_sess = &xcopy_pt_sess;

 xcopy_pt_sess.se_tpg = &xcopy_pt_tpg;
 xcopy_pt_sess.se_node_acl = &xcopy_pt_nacl;

 return 0;
}

void target_xcopy_release_pt(void)
{
 if (xcopy_wq)
  destroy_workqueue(xcopy_wq);
}

/*
 * target_xcopy_setup_pt_cmd - set up a pass-through command
 * @xpt_cmd:  Data structure to initialize.
 * @xop:  Describes the XCOPY operation received from an initiator.
 * @se_dev:  Backend device to associate with @xpt_cmd if
 *  @remote_port == true.
 * @cdb:  SCSI CDB to be copied into @xpt_cmd.
 * @remote_port: If false, use the LUN through which the XCOPY command has
 *  been received. If true, use @se_dev->xcopy_lun.
 *
 * Set up a SCSI command (READ or WRITE) that will be used to execute an
 * XCOPY command.
 */
static int target_xcopy_setup_pt_cmd(
 struct xcopy_pt_cmd *xpt_cmd,
 struct xcopy_op *xop,
 struct se_device *se_dev,
 unsigned char *cdb,
 bool remote_port)
{
 struct se_cmd *cmd = &xpt_cmd->se_cmd;

 /*
 * Setup LUN+port to honor reservations based upon xop->op_origin for
 * X-COPY PUSH or X-COPY PULL based upon where the CDB was received.
 */
 if (remote_port) {
  cmd->se_lun = &se_dev->xcopy_lun;
  cmd->se_dev = se_dev;
 } else {
  cmd->se_lun = xop->xop_se_cmd->se_lun;
  cmd->se_dev = xop->xop_se_cmd->se_dev;
 }
 cmd->se_cmd_flags |= SCF_SE_LUN_CMD;

 if (target_cmd_init_cdb(cmd, cdb, GFP_KERNEL))
  return -EINVAL;

 cmd->tag = 0;
 if (target_cmd_parse_cdb(cmd))
  return -EINVAL;

 if (transport_generic_map_mem_to_cmd(cmd, xop->xop_data_sg,
     xop->xop_data_nents, NULL, 0))
  return -EINVAL;

 pr_debug("Setup PASSTHROUGH_NOALLOC t_data_sg: %p t_data_nents:"
   " %u\n", cmd->t_data_sg, cmd->t_data_nents);

 return 0;
}

static int target_xcopy_issue_pt_cmd(struct xcopy_pt_cmd *xpt_cmd)
{
 struct se_cmd *se_cmd = &xpt_cmd->se_cmd;
 sense_reason_t sense_rc;

 sense_rc = transport_generic_new_cmd(se_cmd);
 if (sense_rc)
  return -EINVAL;

 if (se_cmd->data_direction == DMA_TO_DEVICE)
  target_execute_cmd(se_cmd);

 wait_for_completion_interruptible(&xpt_cmd->xpt_passthrough_sem);

 pr_debug("target_xcopy_issue_pt_cmd(): SCSI status: 0x%02x\n",
   se_cmd->scsi_status);

 return (se_cmd->scsi_status) ? -EINVAL : 0;
}

static int target_xcopy_read_source(
 struct se_cmd *ec_cmd,
 struct xcopy_op *xop,
 struct se_device *src_dev,
 sector_t src_lba,
 u32 src_bytes)
{
 struct xcopy_pt_cmd xpt_cmd;
 struct se_cmd *se_cmd = &xpt_cmd.se_cmd;
 u32 transfer_length_block = src_bytes / src_dev->dev_attrib.block_size;
 int rc;
 unsigned char cdb[16];
 bool remote_port = (xop->op_origin == XCOL_DEST_RECV_OP);

 memset(&xpt_cmd, 0, sizeof(xpt_cmd));
 init_completion(&xpt_cmd.xpt_passthrough_sem);

 memset(&cdb[0], 0, 16);
 cdb[0] = READ_16;
 put_unaligned_be64(src_lba, &cdb[2]);
 put_unaligned_be32(transfer_length_block, &cdb[10]);
 pr_debug("XCOPY: Built READ_16: LBA: %llu Blocks: %u Length: %u\n",
  (unsigned long long)src_lba, transfer_length_block, src_bytes);

 __target_init_cmd(se_cmd, &xcopy_pt_tfo, &xcopy_pt_sess, src_bytes,
     DMA_FROM_DEVICE, 0, &xpt_cmd.sense_buffer[0], 0,
     NULL);
 rc = target_xcopy_setup_pt_cmd(&xpt_cmd, xop, src_dev, &cdb[0],
    remote_port);
 if (rc < 0) {
  ec_cmd->scsi_status = se_cmd->scsi_status;
  goto out;
 }

 pr_debug("XCOPY-READ: Saved xop->xop_data_sg: %p, num: %u for READ"
  " memory\n", xop->xop_data_sg, xop->xop_data_nents);

 rc = target_xcopy_issue_pt_cmd(&xpt_cmd);
 if (rc < 0)
  ec_cmd->scsi_status = se_cmd->scsi_status;
out:
 transport_generic_free_cmd(se_cmd, 0);
 return rc;
}

static int target_xcopy_write_destination(
 struct se_cmd *ec_cmd,
 struct xcopy_op *xop,
 struct se_device *dst_dev,
 sector_t dst_lba,
 u32 dst_bytes)
{
 struct xcopy_pt_cmd xpt_cmd;
 struct se_cmd *se_cmd = &xpt_cmd.se_cmd;
 u32 transfer_length_block = dst_bytes / dst_dev->dev_attrib.block_size;
 int rc;
 unsigned char cdb[16];
 bool remote_port = (xop->op_origin == XCOL_SOURCE_RECV_OP);

 memset(&xpt_cmd, 0, sizeof(xpt_cmd));
 init_completion(&xpt_cmd.xpt_passthrough_sem);

 memset(&cdb[0], 0, 16);
 cdb[0] = WRITE_16;
 put_unaligned_be64(dst_lba, &cdb[2]);
 put_unaligned_be32(transfer_length_block, &cdb[10]);
 pr_debug("XCOPY: Built WRITE_16: LBA: %llu Blocks: %u Length: %u\n",
  (unsigned long long)dst_lba, transfer_length_block, dst_bytes);

 __target_init_cmd(se_cmd, &xcopy_pt_tfo, &xcopy_pt_sess, dst_bytes,
     DMA_TO_DEVICE, 0, &xpt_cmd.sense_buffer[0], 0,
     NULL);
 rc = target_xcopy_setup_pt_cmd(&xpt_cmd, xop, dst_dev, &cdb[0],
    remote_port);
 if (rc < 0) {
  ec_cmd->scsi_status = se_cmd->scsi_status;
  goto out;
 }

 rc = target_xcopy_issue_pt_cmd(&xpt_cmd);
 if (rc < 0)
  ec_cmd->scsi_status = se_cmd->scsi_status;
out:
 transport_generic_free_cmd(se_cmd, 0);
 return rc;
}

static void target_xcopy_do_work(struct work_struct *work)
{
 struct xcopy_op *xop = container_of(work, struct xcopy_op, xop_work);
 struct se_cmd *ec_cmd = xop->xop_se_cmd;
 struct se_device *src_dev, *dst_dev;
 sector_t src_lba, dst_lba, end_lba;
 unsigned long long max_bytes, max_bytes_src, max_bytes_dst, max_blocks;
 int rc = 0;
 unsigned short nolb;
 unsigned int copied_bytes = 0;
 sense_reason_t sense_rc;

 sense_rc = target_parse_xcopy_cmd(xop);
 if (sense_rc != TCM_NO_SENSE)
  goto err_free;

 if (WARN_ON_ONCE(!xop->src_dev) || WARN_ON_ONCE(!xop->dst_dev)) {
  sense_rc = TCM_INVALID_PARAMETER_LIST;
  goto err_free;
 }

 src_dev = xop->src_dev;
 dst_dev = xop->dst_dev;
 src_lba = xop->src_lba;
 dst_lba = xop->dst_lba;
 nolb = xop->nolb;
 end_lba = src_lba + nolb;
 /*
 * Break up XCOPY I/O into hw_max_sectors * hw_block_size sized
 * I/O based on the smallest max_bytes between src_dev + dst_dev
 */
 max_bytes_src = (unsigned long long) src_dev->dev_attrib.hw_max_sectors *
   src_dev->dev_attrib.hw_block_size;
 max_bytes_dst = (unsigned long long) dst_dev->dev_attrib.hw_max_sectors *
   dst_dev->dev_attrib.hw_block_size;

 max_bytes = min_t(u64, max_bytes_src, max_bytes_dst);
 max_bytes = min_t(u64, max_bytes, XCOPY_MAX_BYTES);

 /*
 * Using shift instead of the division because otherwise GCC
 * generates __udivdi3 that is missing on i386
 */
 max_blocks = max_bytes >> ilog2(src_dev->dev_attrib.block_size);

 pr_debug("%s: nolb: %u, max_blocks: %llu end_lba: %llu\n", __func__,
   nolb, max_blocks, (unsigned long long)end_lba);
 pr_debug("%s: Starting src_lba: %llu, dst_lba: %llu\n", __func__,
   (unsigned long long)src_lba, (unsigned long long)dst_lba);

 while (nolb) {
  u32 cur_bytes = min_t(u64, max_bytes, nolb * src_dev->dev_attrib.block_size);
  unsigned short cur_nolb = cur_bytes / src_dev->dev_attrib.block_size;

  if (cur_bytes != xop->xop_data_bytes) {
   /*
 * (Re)allocate a buffer large enough to hold the XCOPY
 * I/O size, which can be reused each read / write loop.
 */
   target_free_sgl(xop->xop_data_sg, xop->xop_data_nents);
   rc = target_alloc_sgl(&xop->xop_data_sg,
           &xop->xop_data_nents,
           cur_bytes,
           false, false);
   if (rc < 0)
    goto out;
   xop->xop_data_bytes = cur_bytes;
  }

  pr_debug("%s: Calling read src_dev: %p src_lba: %llu, cur_nolb: %hu\n",
    __func__, src_dev, (unsigned long long)src_lba, cur_nolb);

  rc = target_xcopy_read_source(ec_cmd, xop, src_dev, src_lba, cur_bytes);
  if (rc < 0)
   goto out;

  src_lba += cur_bytes / src_dev->dev_attrib.block_size;
  pr_debug("%s: Incremented READ src_lba to %llu\n", __func__,
    (unsigned long long)src_lba);

  pr_debug("%s: Calling write dst_dev: %p dst_lba: %llu, cur_nolb: %u\n",
    __func__, dst_dev, (unsigned long long)dst_lba, cur_nolb);

  rc = target_xcopy_write_destination(ec_cmd, xop, dst_dev,
      dst_lba, cur_bytes);
  if (rc < 0)
   goto out;

  dst_lba += cur_bytes / dst_dev->dev_attrib.block_size;
  pr_debug("%s: Incremented WRITE dst_lba to %llu\n", __func__,
    (unsigned long long)dst_lba);

  copied_bytes += cur_bytes;
  nolb -= cur_bytes / src_dev->dev_attrib.block_size;
 }

 xcopy_pt_undepend_remotedev(xop);
 target_free_sgl(xop->xop_data_sg, xop->xop_data_nents);
 kfree(xop);

 pr_debug("%s: Final src_lba: %llu, dst_lba: %llu\n", __func__,
  (unsigned long long)src_lba, (unsigned long long)dst_lba);
 pr_debug("%s: Blocks copied: %u, Bytes Copied: %u\n", __func__,
  copied_bytes / dst_dev->dev_attrib.block_size, copied_bytes);

 pr_debug("%s: Setting X-COPY GOOD status -> sending response\n", __func__);
 target_complete_cmd(ec_cmd, SAM_STAT_GOOD);
 return;

out:
 /*
 * The XCOPY command was aborted after some data was transferred.
 * Terminate command with CHECK CONDITION status, with the sense key
 * set to COPY ABORTED.
 */
 sense_rc = TCM_COPY_TARGET_DEVICE_NOT_REACHABLE;
 xcopy_pt_undepend_remotedev(xop);
 target_free_sgl(xop->xop_data_sg, xop->xop_data_nents);

err_free:
 kfree(xop);
 pr_warn_ratelimited("%s: rc: %d, sense: %u, XCOPY operation failed\n",
      __func__, rc, sense_rc);
 target_complete_cmd_with_sense(ec_cmd, SAM_STAT_CHECK_CONDITION, sense_rc);
}

/*
 * Returns TCM_NO_SENSE upon success or a sense code != TCM_NO_SENSE if parsing
 * fails.
 */
static sense_reason_t target_parse_xcopy_cmd(struct xcopy_op *xop)
{
 struct se_cmd *se_cmd = xop->xop_se_cmd;
 unsigned char *p = NULL, *seg_desc;
 unsigned int list_id, list_id_usage, sdll, inline_dl;
 sense_reason_t ret = TCM_INVALID_PARAMETER_LIST;
 int rc;
 unsigned short tdll;

 p = transport_kmap_data_sg(se_cmd);
 if (!p) {
  pr_err("transport_kmap_data_sg() failed in target_do_xcopy\n");
  return TCM_OUT_OF_RESOURCES;
 }

 list_id = p[0];
 list_id_usage = (p[1] & 0x18) >> 3;

 /*
 * Determine TARGET DESCRIPTOR LIST LENGTH + SEGMENT DESCRIPTOR LIST LENGTH
 */
 tdll = get_unaligned_be16(&p[2]);
 sdll = get_unaligned_be32(&p[8]);
 if (tdll + sdll > RCR_OP_MAX_DESC_LIST_LEN) {
  pr_err("XCOPY descriptor list length %u exceeds maximum %u\n",
         tdll + sdll, RCR_OP_MAX_DESC_LIST_LEN);
  ret = TCM_PARAMETER_LIST_LENGTH_ERROR;
  goto out;
 }

 inline_dl = get_unaligned_be32(&p[12]);
 if (inline_dl != 0) {
  pr_err("XCOPY with non zero inline data length\n");
  goto out;
 }

 if (se_cmd->data_length < (XCOPY_HDR_LEN + tdll + sdll + inline_dl)) {
  pr_err("XCOPY parameter truncation: data length %u too small "
   "for tdll: %hu sdll: %u inline_dl: %u\n",
   se_cmd->data_length, tdll, sdll, inline_dl);
  ret = TCM_PARAMETER_LIST_LENGTH_ERROR;
  goto out;
 }

 pr_debug("Processing XCOPY with list_id: 0x%02x list_id_usage: 0x%02x"
  " tdll: %hu sdll: %u inline_dl: %u\n", list_id, list_id_usage,
  tdll, sdll, inline_dl);

 /*
 * skip over the target descriptors until segment descriptors
 * have been passed - CSCD ids are needed to determine src and dest.
 */
 seg_desc = &p[16] + tdll;

 rc = target_xcopy_parse_segment_descriptors(xop, seg_desc, sdll, &ret);
 if (rc <= 0)
  goto out;

 pr_debug("XCOPY: Processed %d segment descriptors, length: %u\n", rc,
    rc * XCOPY_SEGMENT_DESC_LEN);

 rc = target_xcopy_parse_target_descriptors(se_cmd, xop, &p[16], tdll, &ret);
 if (rc <= 0)
  goto out;

 if (xop->src_dev->dev_attrib.block_size !=
     xop->dst_dev->dev_attrib.block_size) {
  pr_err("XCOPY: Non matching src_dev block_size: %u + dst_dev"
         " block_size: %u currently unsupported\n",
   xop->src_dev->dev_attrib.block_size,
   xop->dst_dev->dev_attrib.block_size);
  xcopy_pt_undepend_remotedev(xop);
  ret = TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
  goto out;
 }

 pr_debug("XCOPY: Processed %d target descriptors, length: %u\n", rc,
    rc * XCOPY_TARGET_DESC_LEN);
 transport_kunmap_data_sg(se_cmd);
 return TCM_NO_SENSE;

out:
 if (p)
  transport_kunmap_data_sg(se_cmd);
 return ret;
}

sense_reason_t target_do_xcopy(struct se_cmd *se_cmd)
{
 struct se_device *dev = se_cmd->se_dev;
 struct xcopy_op *xop;
 unsigned int sa;

 if (!dev->dev_attrib.emulate_3pc) {
  pr_err("EXTENDED_COPY operation explicitly disabled\n");
  return TCM_UNSUPPORTED_SCSI_OPCODE;
 }

 sa = se_cmd->t_task_cdb[1] & 0x1f;
 if (sa != 0x00) {
  pr_err("EXTENDED_COPY(LID4) not supported\n");
  return TCM_UNSUPPORTED_SCSI_OPCODE;
 }

 if (se_cmd->data_length == 0) {
  target_complete_cmd(se_cmd, SAM_STAT_GOOD);
  return TCM_NO_SENSE;
 }
 if (se_cmd->data_length < XCOPY_HDR_LEN) {
  pr_err("XCOPY parameter truncation: length %u < hdr_len %u\n",
    se_cmd->data_length, XCOPY_HDR_LEN);
  return TCM_PARAMETER_LIST_LENGTH_ERROR;
 }

 xop = kzalloc(sizeof(struct xcopy_op), GFP_KERNEL);
 if (!xop)
  goto err;
 xop->xop_se_cmd = se_cmd;
 INIT_WORK(&xop->xop_work, target_xcopy_do_work);
 if (WARN_ON_ONCE(!queue_work(xcopy_wq, &xop->xop_work)))
  goto free;
 return TCM_NO_SENSE;

free:
 kfree(xop);

err:
 return TCM_OUT_OF_RESOURCES;
}

static sense_reason_t target_rcr_operating_parameters(struct se_cmd *se_cmd)
{
 unsigned char *p;

 p = transport_kmap_data_sg(se_cmd);
 if (!p) {
  pr_err("transport_kmap_data_sg failed in"
         " target_rcr_operating_parameters\n");
  return TCM_OUT_OF_RESOURCES;
 }

 if (se_cmd->data_length < 54) {
  pr_err("Receive Copy Results Op Parameters length"
         " too small: %u\n", se_cmd->data_length);
  transport_kunmap_data_sg(se_cmd);
  return TCM_INVALID_CDB_FIELD;
 }
 /*
 * Set SNLID=1 (Supports no List ID)
 */
 p[4] = 0x1;
 /*
 * MAXIMUM TARGET DESCRIPTOR COUNT
 */
 put_unaligned_be16(RCR_OP_MAX_TARGET_DESC_COUNT, &p[8]);
 /*
 * MAXIMUM SEGMENT DESCRIPTOR COUNT
 */
 put_unaligned_be16(RCR_OP_MAX_SG_DESC_COUNT, &p[10]);
 /*
 * MAXIMUM DESCRIPTOR LIST LENGTH
 */
 put_unaligned_be32(RCR_OP_MAX_DESC_LIST_LEN, &p[12]);
 /*
 * MAXIMUM SEGMENT LENGTH
 */
 put_unaligned_be32(RCR_OP_MAX_SEGMENT_LEN, &p[16]);
 /*
 * MAXIMUM INLINE DATA LENGTH for SA 0x04 (NOT SUPPORTED)
 */
 put_unaligned_be32(0x0, &p[20]);
 /*
 * HELD DATA LIMIT
 */
 put_unaligned_be32(0x0, &p[24]);
 /*
 * MAXIMUM STREAM DEVICE TRANSFER SIZE
 */
 put_unaligned_be32(0x0, &p[28]);
 /*
 * TOTAL CONCURRENT COPIES
 */
 put_unaligned_be16(RCR_OP_TOTAL_CONCURR_COPIES, &p[34]);
 /*
 * MAXIMUM CONCURRENT COPIES
 */
 p[36] = RCR_OP_MAX_CONCURR_COPIES;
 /*
 * DATA SEGMENT GRANULARITY (log 2)
 */
 p[37] = RCR_OP_DATA_SEG_GRAN_LOG2;
 /*
 * INLINE DATA GRANULARITY log 2)
 */
 p[38] = RCR_OP_INLINE_DATA_GRAN_LOG2;
 /*
 * HELD DATA GRANULARITY
 */
 p[39] = RCR_OP_HELD_DATA_GRAN_LOG2;
 /*
 * IMPLEMENTED DESCRIPTOR LIST LENGTH
 */
 p[43] = 0x2;
 /*
 * List of implemented descriptor type codes (ordered)
 */
 p[44] = 0x02; /* Copy Block to Block device */
 p[45] = 0xe4; /* Identification descriptor target descriptor */

 /*
 * AVAILABLE DATA (n-3)
 */
 put_unaligned_be32(42, &p[0]);

 transport_kunmap_data_sg(se_cmd);
 target_complete_cmd(se_cmd, SAM_STAT_GOOD);

 return TCM_NO_SENSE;
}

sense_reason_t target_do_receive_copy_results(struct se_cmd *se_cmd)
{
 unsigned char *cdb = &se_cmd->t_task_cdb[0];
 int sa = (cdb[1] & 0x1f), list_id = cdb[2];
 struct se_device *dev = se_cmd->se_dev;
 sense_reason_t rc = TCM_NO_SENSE;

 if (!dev->dev_attrib.emulate_3pc) {
  pr_debug("Third-party copy operations explicitly disabled\n");
  return TCM_UNSUPPORTED_SCSI_OPCODE;
 }

 pr_debug("Entering target_do_receive_copy_results: SA: 0x%02x, List ID:"
  " 0x%02x, AL: %u\n", sa, list_id, se_cmd->data_length);

 if (list_id != 0) {
  pr_err("Receive Copy Results with non zero list identifier"
         " not supported\n");
  return TCM_INVALID_CDB_FIELD;
 }

 switch (sa) {
 case RCR_SA_OPERATING_PARAMETERS:
  rc = target_rcr_operating_parameters(se_cmd);
  break;
 case RCR_SA_COPY_STATUS:
 case RCR_SA_RECEIVE_DATA:
 case RCR_SA_FAILED_SEGMENT_DETAILS:
 default:
  pr_err("Unsupported SA for receive copy results: 0x%02x\n", sa);
  return TCM_INVALID_CDB_FIELD;
 }

 return rc;
}