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26 results

target_core_xcopy.c

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  • target_core_xcopy.c 27.86 KiB
    /*******************************************************************************
     * 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>
     *
     * 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/slab.h>
    #include <linux/spinlock.h>
    #include <linux/list.h>
    #include <linux/configfs.h>
    #include <scsi/scsi_proto.h>
    #include <asm/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 int target_xcopy_gen_naa_ieee(struct se_device *dev, unsigned char *buf)
    {
    	int off = 0;
    
    	buf[off++] = (0x6 << 4);
    	buf[off++] = 0x01;
    	buf[off++] = 0x40;
    	buf[off] = (0x5 << 4);
    
    	spc_parse_naa_6h_vendor_specific(dev, &buf[off]);
    	return 0;
    }
    
    static int target_xcopy_locate_se_dev_e4(struct se_cmd *se_cmd, struct xcopy_op *xop,
    					bool src)
    {
    	struct se_device *se_dev;
    	unsigned char tmp_dev_wwn[XCOPY_NAA_IEEE_REGEX_LEN], *dev_wwn;
    	int rc;
    
    	if (src)
    		dev_wwn = &xop->dst_tid_wwn[0];
    	else
    		dev_wwn = &xop->src_tid_wwn[0];
    
    	mutex_lock(&g_device_mutex);
    	list_for_each_entry(se_dev, &g_device_list, g_dev_node) {
    
    		if (!se_dev->dev_attrib.emulate_3pc)
    			continue;
    
    		memset(&tmp_dev_wwn[0], 0, XCOPY_NAA_IEEE_REGEX_LEN);
    		target_xcopy_gen_naa_ieee(se_dev, &tmp_dev_wwn[0]);
    
    		rc = memcmp(&tmp_dev_wwn[0], dev_wwn, XCOPY_NAA_IEEE_REGEX_LEN);
    		if (rc != 0)
    			continue;
    
    		if (src) {
    			xop->dst_dev = se_dev;
    			pr_debug("XCOPY 0xe4: Setting xop->dst_dev: %p from located"
    				" se_dev\n", xop->dst_dev);
    		} else {
    			xop->src_dev = se_dev;
    			pr_debug("XCOPY 0xe4: Setting xop->src_dev: %p from located"
    				" se_dev\n", xop->src_dev);
    		}
    
    		rc = target_depend_item(&se_dev->dev_group.cg_item);
    		if (rc != 0) {
    			pr_err("configfs_depend_item attempt failed:"
    				" %d for se_dev: %p\n", rc, se_dev);
    			mutex_unlock(&g_device_mutex);
    			return rc;
    		}
    
    		pr_debug("Called configfs_depend_item for se_dev: %p"
    			" se_dev->se_dev_group: %p\n", se_dev,
    			&se_dev->dev_group);
    
    		mutex_unlock(&g_device_mutex);
    		return 0;
    	}
    	mutex_unlock(&g_device_mutex);
    
    	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, bool src)
    {
    	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 != 16) {
    		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 (src) {
    		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);
    		}
    	} else {
    		memcpy(&xop->dst_tid_wwn[0], &desc[8], XCOPY_NAA_IEEE_REGEX_LEN);
    		/*
    		 * Determine if the destination designator matches the local device
    		 */
    		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, ret = 0;
    	unsigned short start = 0;
    	bool src = true;
    
    	*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);
    		return -EINVAL;
    	}
    	if (tdll > 64) {
    		pr_err("XCOPY target descriptor supports a maximum"
    			" two src/dest descriptors, tdll: %hu too large..\n", tdll);
    		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);
    	target_xcopy_gen_naa_ieee(local_dev, &xop->local_dev_wwn[0]);
    
    	while (start < tdll) {
    		/*
    		 * Check target descriptor identification with 0xE4 type with
    		 * use VPD 0x83 WWPN matching ..
    		 */
    		switch (desc[0]) {
    		case 0xe4:
    			rc = target_xcopy_parse_tiddesc_e4(se_cmd, xop,
    							&desc[0], src);
    			if (rc != 0)
    				goto out;
    			/*
    			 * Assume target descriptors are in source -> destination order..
    			 */
    			if (src)
    				src = false;
    			else
    				src = true;
    			start += XCOPY_TARGET_DESC_LEN;
    			desc += XCOPY_TARGET_DESC_LEN;
    			ret++;
    			break;
    		default:
    			pr_err("XCOPY unsupported descriptor type code:"
    					" 0x%02x\n", desc[0]);
    			goto out;
    		}
    	}
    
    	if (xop->op_origin == XCOL_SOURCE_RECV_OP)
    		rc = target_xcopy_locate_se_dev_e4(se_cmd, xop, true);
    	else
    		rc = target_xcopy_locate_se_dev_e4(se_cmd, xop, false);
    	/*
    	 * 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 ret;
    
    out:
    	return -EINVAL;
    }
    
    static int target_xcopy_parse_segdesc_02(struct se_cmd *se_cmd, 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]);
    	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);
    
    	if (dc != 0) {
    		xop->dbl = (desc[29] & 0xff) << 16;
    		xop->dbl |= (desc[30] & 0xff) << 8;
    		xop->dbl |= desc[31] & 0xff;
    
    		pr_debug("XCOPY seg desc 0x02: DC=1 w/ dbl: %u\n", xop->dbl);
    	}
    	return 0;
    }
    
    static int target_xcopy_parse_segment_descriptors(struct se_cmd *se_cmd,
    				struct xcopy_op *xop, unsigned char *p,
    				unsigned int sdll)
    {
    	unsigned char *desc = p;
    	unsigned int start = 0;
    	int offset = sdll % XCOPY_SEGMENT_DESC_LEN, rc, ret = 0;
    
    	if (offset != 0) {
    		pr_err("XCOPY segment descriptor list length is not"
    			" multiple of %d\n", XCOPY_SEGMENT_DESC_LEN);
    		return -EINVAL;
    	}
    
    	while (start < sdll) {
    		/*
    		 * Check segment descriptor type code for block -> block
    		 */
    		switch (desc[0]) {
    		case 0x02:
    			rc = target_xcopy_parse_segdesc_02(se_cmd, 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]);
    			goto out;
    		}
    	}
    
    	return ret;
    
    out:
    	return -EINVAL;
    }
    
    /*
     * Start xcopy_pt ops
     */
    
    struct xcopy_pt_cmd {
    	bool remote_port;
    	struct se_cmd se_cmd;
    	struct xcopy_op *xcopy_op;
    	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 char *xcopy_pt_get_fabric_name(void)
    {
            return "xcopy-pt";
    }
    
    static int xcopy_pt_get_cmd_state(struct se_cmd *se_cmd)
    {
            return 0;
    }
    
    static void xcopy_pt_undepend_remotedev(struct xcopy_op *xop)
    {
    	struct se_device *remote_dev;
    
    	if (xop->op_origin == XCOL_SOURCE_RECV_OP)
    		remote_dev = xop->dst_dev;
    	else
    		remote_dev = xop->src_dev;
    
    	pr_debug("Calling configfs_undepend_item for"
    		  " remote_dev: %p remote_dev->dev_group: %p\n",
    		  remote_dev, &remote_dev->dev_group.cg_item);
    
    	target_undepend_item(&remote_dev->dev_group.cg_item);
    }
    
    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);
    
    	kfree(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_write_pending_status(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 = {
    	.get_fabric_name	= xcopy_pt_get_fabric_name,
    	.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,
    	.write_pending_status	= xcopy_pt_write_pending_status,
    	.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.se_tpg_node);
    	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));
    	INIT_LIST_HEAD(&xcopy_pt_sess.sess_list);
    	INIT_LIST_HEAD(&xcopy_pt_sess.sess_acl_list);
    	INIT_LIST_HEAD(&xcopy_pt_sess.sess_cmd_list);
    	spin_lock_init(&xcopy_pt_sess.sess_cmd_lock);
    
    	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);
    }
    
    static void target_xcopy_setup_pt_port(
    	struct xcopy_pt_cmd *xpt_cmd,
    	struct xcopy_op *xop,
    	bool remote_port)
    {
    	struct se_cmd *ec_cmd = xop->xop_se_cmd;
    	struct se_cmd *pt_cmd = &xpt_cmd->se_cmd;
    
    	if (xop->op_origin == XCOL_SOURCE_RECV_OP) {
    		/*
    		 * Honor destination port reservations for X-COPY PUSH emulation
    		 * when CDB is received on local source port, and READs blocks to
    		 * WRITE on remote destination port.
    		 */
    		if (remote_port) {
    			xpt_cmd->remote_port = remote_port;
    		} else {
    			pt_cmd->se_lun = ec_cmd->se_lun;
    			pt_cmd->se_dev = ec_cmd->se_dev;
    
    			pr_debug("Honoring local SRC port from ec_cmd->se_dev:"
    				" %p\n", pt_cmd->se_dev);
    			pt_cmd->se_lun = ec_cmd->se_lun;
    			pr_debug("Honoring local SRC port from ec_cmd->se_lun: %p\n",
    				pt_cmd->se_lun);
    		}
    	} else {
    		/*
    		 * Honor source port reservation for X-COPY PULL emulation
    		 * when CDB is received on local desintation port, and READs
    		 * blocks from the remote source port to WRITE on local
    		 * destination port.
    		 */
    		if (remote_port) {
    			xpt_cmd->remote_port = remote_port;
    		} else {
    			pt_cmd->se_lun = ec_cmd->se_lun;
    			pt_cmd->se_dev = ec_cmd->se_dev;
    
    			pr_debug("Honoring local DST port from ec_cmd->se_dev:"
    				" %p\n", pt_cmd->se_dev);
    			pt_cmd->se_lun = ec_cmd->se_lun;
    			pr_debug("Honoring local DST port from ec_cmd->se_lun: %p\n",
    				pt_cmd->se_lun);
    		}
    	}
    }
    
    static void target_xcopy_init_pt_lun(struct se_device *se_dev,
    		struct se_cmd *pt_cmd, bool remote_port)
    {
    	/*
    	 * Don't allocate + init an pt_cmd->se_lun if honoring local port for
    	 * reservations.  The pt_cmd->se_lun pointer will be setup from within
    	 * target_xcopy_setup_pt_port()
    	 */
    	if (remote_port) {
    		pr_debug("Setup emulated se_dev: %p from se_dev\n",
    			pt_cmd->se_dev);
    		pt_cmd->se_lun = &se_dev->xcopy_lun;
    		pt_cmd->se_dev = se_dev;
    	}
    
    	pt_cmd->se_cmd_flags |= SCF_SE_LUN_CMD;
    }
    
    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,
    	bool alloc_mem)
    {
    	struct se_cmd *cmd = &xpt_cmd->se_cmd;
    	sense_reason_t sense_rc;
    	int ret = 0, rc;
    	/*
    	 * 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.
    	 */
    	target_xcopy_init_pt_lun(se_dev, cmd, remote_port);
    
    	xpt_cmd->xcopy_op = xop;
    	target_xcopy_setup_pt_port(xpt_cmd, xop, remote_port);
    
    	cmd->tag = 0;
    	sense_rc = target_setup_cmd_from_cdb(cmd, cdb);
    	if (sense_rc) {
    		ret = -EINVAL;
    		goto out;
    	}
    
    	if (alloc_mem) {
    		rc = target_alloc_sgl(&cmd->t_data_sg, &cmd->t_data_nents,
    				      cmd->data_length, false, false);
    		if (rc < 0) {
    			ret = rc;
    			goto out;
    		}
    		/*
    		 * Set this bit so that transport_free_pages() allows the
    		 * caller to release SGLs + physical memory allocated by
    		 * transport_generic_get_mem()..
    		 */
    		cmd->se_cmd_flags |= SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
    	} else {
    		/*
    		 * Here the previously allocated SGLs for the internal READ
    		 * are mapped zero-copy to the internal WRITE.
    		 */
    		sense_rc = transport_generic_map_mem_to_cmd(cmd,
    					xop->xop_data_sg, xop->xop_data_nents,
    					NULL, 0);
    		if (sense_rc) {
    			ret = -EINVAL;
    			goto out;
    		}
    
    		pr_debug("Setup PASSTHROUGH_NOALLOC t_data_sg: %p t_data_nents:"
    			 " %u\n", cmd->t_data_sg, cmd->t_data_nents);
    	}
    
    	return 0;
    
    out:
    	return ret;
    }
    
    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_sectors)
    {
    	struct xcopy_pt_cmd *xpt_cmd;
    	struct se_cmd *se_cmd;
    	u32 length = (src_sectors * src_dev->dev_attrib.block_size);
    	int rc;
    	unsigned char cdb[16];
    	bool remote_port = (xop->op_origin == XCOL_DEST_RECV_OP);
    
    	xpt_cmd = kzalloc(sizeof(struct xcopy_pt_cmd), GFP_KERNEL);
    	if (!xpt_cmd) {
    		pr_err("Unable to allocate xcopy_pt_cmd\n");
    		return -ENOMEM;
    	}
    	init_completion(&xpt_cmd->xpt_passthrough_sem);
    	se_cmd = &xpt_cmd->se_cmd;
    
    	memset(&cdb[0], 0, 16);
    	cdb[0] = READ_16;
    	put_unaligned_be64(src_lba, &cdb[2]);
    	put_unaligned_be32(src_sectors, &cdb[10]);
    	pr_debug("XCOPY: Built READ_16: LBA: %llu Sectors: %u Length: %u\n",
    		(unsigned long long)src_lba, src_sectors, length);
    
    	transport_init_se_cmd(se_cmd, &xcopy_pt_tfo, &xcopy_pt_sess, length,
    			      DMA_FROM_DEVICE, 0, &xpt_cmd->sense_buffer[0]);
    	xop->src_pt_cmd = xpt_cmd;
    
    	rc = target_xcopy_setup_pt_cmd(xpt_cmd, xop, src_dev, &cdb[0],
    				remote_port, true);
    	if (rc < 0) {
    		ec_cmd->scsi_status = xpt_cmd->se_cmd.scsi_status;
    		transport_generic_free_cmd(se_cmd, 0);
    		return rc;
    	}
    
    	xop->xop_data_sg = se_cmd->t_data_sg;
    	xop->xop_data_nents = se_cmd->t_data_nents;
    	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 = xpt_cmd->se_cmd.scsi_status;
    		transport_generic_free_cmd(se_cmd, 0);
    		return rc;
    	}
    	/*
    	 * Clear off the allocated t_data_sg, that has been saved for
    	 * zero-copy WRITE submission reuse in struct xcopy_op..
    	 */
    	se_cmd->t_data_sg = NULL;
    	se_cmd->t_data_nents = 0;
    
    	return 0;
    }
    
    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_sectors)
    {
    	struct xcopy_pt_cmd *xpt_cmd;
    	struct se_cmd *se_cmd;
    	u32 length = (dst_sectors * dst_dev->dev_attrib.block_size);
    	int rc;
    	unsigned char cdb[16];
    	bool remote_port = (xop->op_origin == XCOL_SOURCE_RECV_OP);
    
    	xpt_cmd = kzalloc(sizeof(struct xcopy_pt_cmd), GFP_KERNEL);
    	if (!xpt_cmd) {
    		pr_err("Unable to allocate xcopy_pt_cmd\n");
    		return -ENOMEM;
    	}
    	init_completion(&xpt_cmd->xpt_passthrough_sem);
    	se_cmd = &xpt_cmd->se_cmd;
    
    	memset(&cdb[0], 0, 16);
    	cdb[0] = WRITE_16;
    	put_unaligned_be64(dst_lba, &cdb[2]);
    	put_unaligned_be32(dst_sectors, &cdb[10]);
    	pr_debug("XCOPY: Built WRITE_16: LBA: %llu Sectors: %u Length: %u\n",
    		(unsigned long long)dst_lba, dst_sectors, length);
    
    	transport_init_se_cmd(se_cmd, &xcopy_pt_tfo, &xcopy_pt_sess, length,
    			      DMA_TO_DEVICE, 0, &xpt_cmd->sense_buffer[0]);
    	xop->dst_pt_cmd = xpt_cmd;
    
    	rc = target_xcopy_setup_pt_cmd(xpt_cmd, xop, dst_dev, &cdb[0],
    				remote_port, false);
    	if (rc < 0) {
    		struct se_cmd *src_cmd = &xop->src_pt_cmd->se_cmd;
    		ec_cmd->scsi_status = xpt_cmd->se_cmd.scsi_status;
    		/*
    		 * If the failure happened before the t_mem_list hand-off in
    		 * target_xcopy_setup_pt_cmd(), Reset memory + clear flag so that
    		 * core releases this memory on error during X-COPY WRITE I/O.
    		 */
    		src_cmd->se_cmd_flags &= ~SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
    		src_cmd->t_data_sg = xop->xop_data_sg;
    		src_cmd->t_data_nents = xop->xop_data_nents;
    
    		transport_generic_free_cmd(se_cmd, 0);
    		return rc;
    	}
    
    	rc = target_xcopy_issue_pt_cmd(xpt_cmd);
    	if (rc < 0) {
    		ec_cmd->scsi_status = xpt_cmd->se_cmd.scsi_status;
    		se_cmd->se_cmd_flags &= ~SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
    		transport_generic_free_cmd(se_cmd, 0);
    		return rc;
    	}
    
    	return 0;
    }
    
    static void target_xcopy_do_work(struct work_struct *work)
    {
    	struct xcopy_op *xop = container_of(work, struct xcopy_op, xop_work);
    	struct se_device *src_dev = xop->src_dev, *dst_dev = xop->dst_dev;
    	struct se_cmd *ec_cmd = xop->xop_se_cmd;
    	sector_t src_lba = xop->src_lba, dst_lba = xop->dst_lba, end_lba;
    	unsigned int max_sectors;
    	int rc;
    	unsigned short nolb = xop->nolb, cur_nolb, max_nolb, copied_nolb = 0;
    
    	end_lba = src_lba + nolb;
    	/*
    	 * Break up XCOPY I/O into hw_max_sectors sized I/O based on the
    	 * smallest max_sectors between src_dev + dev_dev, or
    	 */
    	max_sectors = min(src_dev->dev_attrib.hw_max_sectors,
    			  dst_dev->dev_attrib.hw_max_sectors);
    	max_sectors = min_t(u32, max_sectors, XCOPY_MAX_SECTORS);
    
    	max_nolb = min_t(u16, max_sectors, ((u16)(~0U)));
    
    	pr_debug("target_xcopy_do_work: nolb: %hu, max_nolb: %hu end_lba: %llu\n",
    			nolb, max_nolb, (unsigned long long)end_lba);
    	pr_debug("target_xcopy_do_work: Starting src_lba: %llu, dst_lba: %llu\n",
    			(unsigned long long)src_lba, (unsigned long long)dst_lba);
    
    	while (src_lba < end_lba) {
    		cur_nolb = min(nolb, max_nolb);
    
    		pr_debug("target_xcopy_do_work: Calling read src_dev: %p src_lba: %llu,"
    			" cur_nolb: %hu\n", src_dev, (unsigned long long)src_lba, cur_nolb);
    
    		rc = target_xcopy_read_source(ec_cmd, xop, src_dev, src_lba, cur_nolb);
    		if (rc < 0)
    			goto out;
    
    		src_lba += cur_nolb;
    		pr_debug("target_xcopy_do_work: Incremented READ src_lba to %llu\n",
    				(unsigned long long)src_lba);
    
    		pr_debug("target_xcopy_do_work: Calling write dst_dev: %p dst_lba: %llu,"
    			" cur_nolb: %hu\n", dst_dev, (unsigned long long)dst_lba, cur_nolb);
    
    		rc = target_xcopy_write_destination(ec_cmd, xop, dst_dev,
    						dst_lba, cur_nolb);
    		if (rc < 0) {
    			transport_generic_free_cmd(&xop->src_pt_cmd->se_cmd, 0);
    			goto out;
    		}
    
    		dst_lba += cur_nolb;
    		pr_debug("target_xcopy_do_work: Incremented WRITE dst_lba to %llu\n",
    				(unsigned long long)dst_lba);
    
    		copied_nolb += cur_nolb;
    		nolb -= cur_nolb;
    
    		transport_generic_free_cmd(&xop->src_pt_cmd->se_cmd, 0);
    		xop->dst_pt_cmd->se_cmd.se_cmd_flags &= ~SCF_PASSTHROUGH_SG_TO_MEM_NOALLOC;
    
    		transport_generic_free_cmd(&xop->dst_pt_cmd->se_cmd, 0);
    	}
    
    	xcopy_pt_undepend_remotedev(xop);
    	kfree(xop);
    
    	pr_debug("target_xcopy_do_work: Final src_lba: %llu, dst_lba: %llu\n",
    		(unsigned long long)src_lba, (unsigned long long)dst_lba);
    	pr_debug("target_xcopy_do_work: Blocks copied: %hu, Bytes Copied: %u\n",
    		copied_nolb, copied_nolb * dst_dev->dev_attrib.block_size);
    
    	pr_debug("target_xcopy_do_work: Setting X-COPY GOOD status -> sending response\n");
    	target_complete_cmd(ec_cmd, SAM_STAT_GOOD);
    	return;
    
    out:
    	xcopy_pt_undepend_remotedev(xop);
    	kfree(xop);
    	/*
    	 * Don't override an error scsi status if it has already been set
    	 */
    	if (ec_cmd->scsi_status == SAM_STAT_GOOD) {
    		pr_warn_ratelimited("target_xcopy_do_work: rc: %d, Setting X-COPY"
    			" CHECK_CONDITION -> sending response\n", rc);
    		ec_cmd->scsi_status = SAM_STAT_CHECK_CONDITION;
    	}
    	target_complete_cmd(ec_cmd, SAM_STAT_CHECK_CONDITION);
    }
    
    sense_reason_t target_do_xcopy(struct se_cmd *se_cmd)
    {
    	struct se_device *dev = se_cmd->se_dev;
    	struct xcopy_op *xop = NULL;
    	unsigned char *p = NULL, *seg_desc;
    	unsigned int list_id, list_id_usage, sdll, inline_dl, sa;
    	sense_reason_t ret = TCM_INVALID_PARAMETER_LIST;
    	int rc;
    	unsigned short tdll;
    
    	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;
    	}
    
    	xop = kzalloc(sizeof(struct xcopy_op), GFP_KERNEL);
    	if (!xop) {
    		pr_err("Unable to allocate xcopy_op\n");
    		return TCM_OUT_OF_RESOURCES;
    	}
    	xop->xop_se_cmd = se_cmd;
    
    	p = transport_kmap_data_sg(se_cmd);
    	if (!p) {
    		pr_err("transport_kmap_data_sg() failed in target_do_xcopy\n");
    		kfree(xop);
    		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]);
    
    	inline_dl = get_unaligned_be32(&p[12]);
    	if (inline_dl != 0) {
    		pr_err("XCOPY with non zero inline data length\n");
    		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);
    
    	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);
    	seg_desc = &p[16];
    	seg_desc += (rc * XCOPY_TARGET_DESC_LEN);
    
    	rc = target_xcopy_parse_segment_descriptors(se_cmd, xop, seg_desc, sdll);
    	if (rc <= 0) {
    		xcopy_pt_undepend_remotedev(xop);
    		goto out;
    	}
    	transport_kunmap_data_sg(se_cmd);
    
    	pr_debug("XCOPY: Processed %d segment descriptors, length: %u\n", rc,
    				rc * XCOPY_SEGMENT_DESC_LEN);
    	INIT_WORK(&xop->xop_work, target_xcopy_do_work);
    	queue_work(xcopy_wq, &xop->xop_work);
    	return TCM_NO_SENSE;
    
    out:
    	if (p)
    		transport_kunmap_data_sg(se_cmd);
    	kfree(xop);
    	return ret;
    }
    
    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, 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];
    	sense_reason_t rc = TCM_NO_SENSE;
    
    	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;
    }