[SCSI] target: Add LIO target core v4.0.0-rc6

LIO target is a full featured in-kernel target framework with the
following feature set:

High-performance, non-blocking, multithreaded architecture with SIMD
support.

Advanced SCSI feature set:

    * Persistent Reservations (PRs)
    * Asymmetric Logical Unit Assignment (ALUA)
    * Protocol and intra-nexus multiplexing, load-balancing and failover (MC/S)
    * Full Error Recovery (ERL=0,1,2)
    * Active/active task migration and session continuation (ERL=2)
    * Thin LUN provisioning (UNMAP and WRITE_SAMExx)

Multiprotocol target plugins

Storage media independence:

    * Virtualization of all storage media; transparent mapping of IO to LUNs
    * No hard limits on number of LUNs per Target; maximum LUN size ~750 TB
    * Backstores: SATA, SAS, SCSI, BluRay, DVD, FLASH, USB, ramdisk, etc.

Standards compliance:

    * Full compliance with IETF (RFC 3720)
    * Full implementation of SPC-4 PRs and ALUA

Significant code cleanups done by Christoph Hellwig.

[jejb: fix up for new block bdev exclusive interface. Minor fixes from
 Randy Dunlap and Dan Carpenter.]
Signed-off-by: Nicholas A. Bellinger <nab@linux-iscsi.org>
Signed-off-by: James Bottomley <James.Bottomley@suse.de>

1 files changed, 1131 insertions, 0 deletions

diff --git a/drivers/target/target_core_cdb.c b/drivers/target/target_core_cdb.c
new file mode 100644
index 0000000..366080b
--- /dev/null
+++ b/drivers/target/target_core_cdb.c
@@ -0,0 +1,1131 @@
+/*
+ * CDB emulation for non-READ/WRITE commands.
+ *
+ * Copyright (c) 2002, 2003, 2004, 2005 PyX Technologies, Inc.
+ * Copyright (c) 2005, 2006, 2007 SBE, Inc.
+ * Copyright (c) 2007-2010 Rising Tide Systems
+ * Copyright (c) 2008-2010 Linux-iSCSI.org
+ *
+ * Nicholas A. Bellinger <nab@kernel.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.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA.
+ */
+
+#include <asm/unaligned.h>
+#include <scsi/scsi.h>
+
+#include <target/target_core_base.h>
+#include <target/target_core_transport.h>
+#include <target/target_core_fabric_ops.h>
+#include "target_core_ua.h"
+
+static void
+target_fill_alua_data(struct se_port *port, unsigned char *buf)
+{
+	struct t10_alua_tg_pt_gp *tg_pt_gp;
+	struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem;
+
+	/*
+	 * Set SCCS for MAINTENANCE_IN + REPORT_TARGET_PORT_GROUPS.
+	 */
+	buf[5]	= 0x80;
+
+	/*
+	 * Set TPGS field for explict and/or implict ALUA access type
+	 * and opteration.
+	 *
+	 * See spc4r17 section 6.4.2 Table 135
+	 */
+	if (!port)
+		return;
+	tg_pt_gp_mem = port->sep_alua_tg_pt_gp_mem;
+	if (!tg_pt_gp_mem)
+		return;
+
+	spin_lock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);
+	tg_pt_gp = tg_pt_gp_mem->tg_pt_gp;
+	if (tg_pt_gp)
+		buf[5] |= tg_pt_gp->tg_pt_gp_alua_access_type;
+	spin_unlock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);
+}
+
+static int
+target_emulate_inquiry_std(struct se_cmd *cmd)
+{
+	struct se_lun *lun = SE_LUN(cmd);
+	struct se_device *dev = SE_DEV(cmd);
+	unsigned char *buf = cmd->t_task->t_task_buf;
+
+	/*
+	 * Make sure we at least have 6 bytes of INQUIRY response
+	 * payload going back for EVPD=0
+	 */
+	if (cmd->data_length < 6) {
+		printk(KERN_ERR "SCSI Inquiry payload length: %u"
+			" too small for EVPD=0\n", cmd->data_length);
+		return -1;
+	}
+
+	buf[0] = dev->transport->get_device_type(dev);
+	if (buf[0] == TYPE_TAPE)
+		buf[1] = 0x80;
+	buf[2] = dev->transport->get_device_rev(dev);
+
+	/*
+	 * Enable SCCS and TPGS fields for Emulated ALUA
+	 */
+	if (T10_ALUA(dev->se_sub_dev)->alua_type == SPC3_ALUA_EMULATED)
+		target_fill_alua_data(lun->lun_sep, buf);
+
+	if (cmd->data_length < 8) {
+		buf[4] = 1; /* Set additional length to 1 */
+		return 0;
+	}
+
+	buf[7] = 0x32; /* Sync=1 and CmdQue=1 */
+
+	/*
+	 * Do not include vendor, product, reversion info in INQUIRY
+	 * response payload for cdbs with a small allocation length.
+	 */
+	if (cmd->data_length < 36) {
+		buf[4] = 3; /* Set additional length to 3 */
+		return 0;
+	}
+
+	snprintf((unsigned char *)&buf[8], 8, "LIO-ORG");
+	snprintf((unsigned char *)&buf[16], 16, "%s",
+		 &DEV_T10_WWN(dev)->model[0]);
+	snprintf((unsigned char *)&buf[32], 4, "%s",
+		 &DEV_T10_WWN(dev)->revision[0]);
+	buf[4] = 31; /* Set additional length to 31 */
+	return 0;
+}
+
+/* supported vital product data pages */
+static int
+target_emulate_evpd_00(struct se_cmd *cmd, unsigned char *buf)
+{
+	buf[1] = 0x00;
+	if (cmd->data_length < 8)
+		return 0;
+
+	buf[4] = 0x0;
+	/*
+	 * Only report the INQUIRY EVPD=1 pages after a valid NAA
+	 * Registered Extended LUN WWN has been set via ConfigFS
+	 * during device creation/restart.
+	 */
+	if (SE_DEV(cmd)->se_sub_dev->su_dev_flags &
+			SDF_EMULATED_VPD_UNIT_SERIAL) {
+		buf[3] = 3;
+		buf[5] = 0x80;
+		buf[6] = 0x83;
+		buf[7] = 0x86;
+	}
+
+	return 0;
+}
+
+/* unit serial number */
+static int
+target_emulate_evpd_80(struct se_cmd *cmd, unsigned char *buf)
+{
+	struct se_device *dev = SE_DEV(cmd);
+	u16 len = 0;
+
+	buf[1] = 0x80;
+	if (dev->se_sub_dev->su_dev_flags &
+			SDF_EMULATED_VPD_UNIT_SERIAL) {
+		u32 unit_serial_len;
+
+		unit_serial_len =
+			strlen(&DEV_T10_WWN(dev)->unit_serial[0]);
+		unit_serial_len++; /* For NULL Terminator */
+
+		if (((len + 4) + unit_serial_len) > cmd->data_length) {
+			len += unit_serial_len;
+			buf[2] = ((len >> 8) & 0xff);
+			buf[3] = (len & 0xff);
+			return 0;
+		}
+		len += sprintf((unsigned char *)&buf[4], "%s",
+			&DEV_T10_WWN(dev)->unit_serial[0]);
+		len++; /* Extra Byte for NULL Terminator */
+		buf[3] = len;
+	}
+	return 0;
+}
+
+/*
+ * Device identification VPD, for a complete list of
+ * DESIGNATOR TYPEs see spc4r17 Table 459.
+ */
+static int
+target_emulate_evpd_83(struct se_cmd *cmd, unsigned char *buf)
+{
+	struct se_device *dev = SE_DEV(cmd);
+	struct se_lun *lun = SE_LUN(cmd);
+	struct se_port *port = NULL;
+	struct se_portal_group *tpg = NULL;
+	struct t10_alua_lu_gp_member *lu_gp_mem;
+	struct t10_alua_tg_pt_gp *tg_pt_gp;
+	struct t10_alua_tg_pt_gp_member *tg_pt_gp_mem;
+	unsigned char binary, binary_new;
+	unsigned char *prod = &DEV_T10_WWN(dev)->model[0];
+	u32 prod_len;
+	u32 unit_serial_len, off = 0;
+	int i;
+	u16 len = 0, id_len;
+
+	buf[1] = 0x83;
+	off = 4;
+
+	/*
+	 * NAA IEEE Registered Extended Assigned designator format, see
+	 * spc4r17 section 7.7.3.6.5
+	 *
+	 * We depend upon a target_core_mod/ConfigFS provided
+	 * /sys/kernel/config/target/core/$HBA/$DEV/wwn/vpd_unit_serial
+	 * value in order to return the NAA id.
+	 */
+	if (!(dev->se_sub_dev->su_dev_flags & SDF_EMULATED_VPD_UNIT_SERIAL))
+		goto check_t10_vend_desc;
+
+	if (off + 20 > cmd->data_length)
+		goto check_t10_vend_desc;
+
+	/* CODE SET == Binary */
+	buf[off++] = 0x1;
+
+	/* Set ASSOICATION == addressed logical unit: 0)b */
+	buf[off] = 0x00;
+
+	/* Identifier/Designator type == NAA identifier */
+	buf[off++] = 0x3;
+	off++;
+
+	/* Identifier/Designator length */
+	buf[off++] = 0x10;
+
+	/*
+	 * Start NAA IEEE Registered Extended Identifier/Designator
+	 */
+	buf[off++] = (0x6 << 4);
+
+	/*
+	 * Use OpenFabrics IEEE Company ID: 00 14 05
+	 */
+	buf[off++] = 0x01;
+	buf[off++] = 0x40;
+	buf[off] = (0x5 << 4);
+
+	/*
+	 * Return ConfigFS Unit Serial Number information for
+	 * VENDOR_SPECIFIC_IDENTIFIER and
+	 * VENDOR_SPECIFIC_IDENTIFIER_EXTENTION
+	 */
+	binary = transport_asciihex_to_binaryhex(
+				&DEV_T10_WWN(dev)->unit_serial[0]);
+	buf[off++] |= (binary & 0xf0) >> 4;
+	for (i = 0; i < 24; i += 2) {
+		binary_new = transport_asciihex_to_binaryhex(
+			&DEV_T10_WWN(dev)->unit_serial[i+2]);
+		buf[off] = (binary & 0x0f) << 4;
+		buf[off++] |= (binary_new & 0xf0) >> 4;
+		binary = binary_new;
+	}
+	len = 20;
+	off = (len + 4);
+
+check_t10_vend_desc:
+	/*
+	 * T10 Vendor Identifier Page, see spc4r17 section 7.7.3.4
+	 */
+	id_len = 8; /* For Vendor field */
+	prod_len = 4; /* For VPD Header */
+	prod_len += 8; /* For Vendor field */
+	prod_len += strlen(prod);
+	prod_len++; /* For : */
+
+	if (dev->se_sub_dev->su_dev_flags &
+			SDF_EMULATED_VPD_UNIT_SERIAL) {
+		unit_serial_len =
+			strlen(&DEV_T10_WWN(dev)->unit_serial[0]);
+		unit_serial_len++; /* For NULL Terminator */
+
+		if ((len + (id_len + 4) +
+		    (prod_len + unit_serial_len)) >
+				cmd->data_length) {
+			len += (prod_len + unit_serial_len);
+			goto check_port;
+		}
+		id_len += sprintf((unsigned char *)&buf[off+12],
+				"%s:%s", prod,
+				&DEV_T10_WWN(dev)->unit_serial[0]);
+	}
+	buf[off] = 0x2; /* ASCII */
+	buf[off+1] = 0x1; /* T10 Vendor ID */
+	buf[off+2] = 0x0;
+	memcpy((unsigned char *)&buf[off+4], "LIO-ORG", 8);
+	/* Extra Byte for NULL Terminator */
+	id_len++;
+	/* Identifier Length */
+	buf[off+3] = id_len;
+	/* Header size for Designation descriptor */
+	len += (id_len + 4);
+	off += (id_len + 4);
+	/*
+	 * struct se_port is only set for INQUIRY VPD=1 through $FABRIC_MOD
+	 */
+check_port:
+	port = lun->lun_sep;
+	if (port) {
+		struct t10_alua_lu_gp *lu_gp;
+		u32 padding, scsi_name_len;
+		u16 lu_gp_id = 0;
+		u16 tg_pt_gp_id = 0;
+		u16 tpgt;
+
+		tpg = port->sep_tpg;
+		/*
+		 * Relative target port identifer, see spc4r17
+		 * section 7.7.3.7
+		 *
+		 * Get the PROTOCOL IDENTIFIER as defined by spc4r17
+		 * section 7.5.1 Table 362
+		 */
+		if (((len + 4) + 8) > cmd->data_length) {
+			len += 8;
+			goto check_tpgi;
+		}
+		buf[off] =
+			(TPG_TFO(tpg)->get_fabric_proto_ident(tpg) << 4);
+		buf[off++] |= 0x1; /* CODE SET == Binary */
+		buf[off] = 0x80; /* Set PIV=1 */
+		/* Set ASSOICATION == target port: 01b */
+		buf[off] |= 0x10;
+		/* DESIGNATOR TYPE == Relative target port identifer */
+		buf[off++] |= 0x4;
+		off++; /* Skip over Reserved */
+		buf[off++] = 4; /* DESIGNATOR LENGTH */
+		/* Skip over Obsolete field in RTPI payload
+		 * in Table 472 */
+		off += 2;
+		buf[off++] = ((port->sep_rtpi >> 8) & 0xff);
+		buf[off++] = (port->sep_rtpi & 0xff);
+		len += 8; /* Header size + Designation descriptor */
+		/*
+		 * Target port group identifier, see spc4r17
+		 * section 7.7.3.8
+		 *
+		 * Get the PROTOCOL IDENTIFIER as defined by spc4r17
+		 * section 7.5.1 Table 362
+		 */
+check_tpgi:
+		if (T10_ALUA(dev->se_sub_dev)->alua_type !=
+				SPC3_ALUA_EMULATED)
+			goto check_scsi_name;
+
+		if (((len + 4) + 8) > cmd->data_length) {
+			len += 8;
+			goto check_lu_gp;
+		}
+		tg_pt_gp_mem = port->sep_alua_tg_pt_gp_mem;
+		if (!tg_pt_gp_mem)
+			goto check_lu_gp;
+
+		spin_lock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);
+		tg_pt_gp = tg_pt_gp_mem->tg_pt_gp;
+		if (!(tg_pt_gp)) {
+			spin_unlock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);
+			goto check_lu_gp;
+		}
+		tg_pt_gp_id = tg_pt_gp->tg_pt_gp_id;
+		spin_unlock(&tg_pt_gp_mem->tg_pt_gp_mem_lock);
+
+		buf[off] =
+			(TPG_TFO(tpg)->get_fabric_proto_ident(tpg) << 4);
+		buf[off++] |= 0x1; /* CODE SET == Binary */
+		buf[off] = 0x80; /* Set PIV=1 */
+		/* Set ASSOICATION == target port: 01b */
+		buf[off] |= 0x10;
+		/* DESIGNATOR TYPE == Target port group identifier */
+		buf[off++] |= 0x5;
+		off++; /* Skip over Reserved */
+		buf[off++] = 4; /* DESIGNATOR LENGTH */
+		off += 2; /* Skip over Reserved Field */
+		buf[off++] = ((tg_pt_gp_id >> 8) & 0xff);
+		buf[off++] = (tg_pt_gp_id & 0xff);
+		len += 8; /* Header size + Designation descriptor */
+		/*
+		 * Logical Unit Group identifier, see spc4r17
+		 * section 7.7.3.8
+		 */
+check_lu_gp:
+		if (((len + 4) + 8) > cmd->data_length) {
+			len += 8;
+			goto check_scsi_name;
+		}
+		lu_gp_mem = dev->dev_alua_lu_gp_mem;
+		if (!(lu_gp_mem))
+			goto check_scsi_name;
+
+		spin_lock(&lu_gp_mem->lu_gp_mem_lock);
+		lu_gp = lu_gp_mem->lu_gp;
+		if (!(lu_gp)) {
+			spin_unlock(&lu_gp_mem->lu_gp_mem_lock);
+			goto check_scsi_name;
+		}
+		lu_gp_id = lu_gp->lu_gp_id;
+		spin_unlock(&lu_gp_mem->lu_gp_mem_lock);
+
+		buf[off++] |= 0x1; /* CODE SET == Binary */
+		/* DESIGNATOR TYPE == Logical Unit Group identifier */
+		buf[off++] |= 0x6;
+		off++; /* Skip over Reserved */
+		buf[off++] = 4; /* DESIGNATOR LENGTH */
+		off += 2; /* Skip over Reserved Field */
+		buf[off++] = ((lu_gp_id >> 8) & 0xff);
+		buf[off++] = (lu_gp_id & 0xff);
+		len += 8; /* Header size + Designation descriptor */
+		/*
+		 * SCSI name string designator, see spc4r17
+		 * section 7.7.3.11
+		 *
+		 * Get the PROTOCOL IDENTIFIER as defined by spc4r17
+		 * section 7.5.1 Table 362
+		 */
+check_scsi_name:
+		scsi_name_len = strlen(TPG_TFO(tpg)->tpg_get_wwn(tpg));
+		/* UTF-8 ",t,0x<16-bit TPGT>" + NULL Terminator */
+		scsi_name_len += 10;
+		/* Check for 4-byte padding */
+		padding = ((-scsi_name_len) & 3);
+		if (padding != 0)
+			scsi_name_len += padding;
+		/* Header size + Designation descriptor */
+		scsi_name_len += 4;
+
+		if (((len + 4) + scsi_name_len) > cmd->data_length) {
+			len += scsi_name_len;
+			goto set_len;
+		}
+		buf[off] =
+			(TPG_TFO(tpg)->get_fabric_proto_ident(tpg) << 4);
+		buf[off++] |= 0x3; /* CODE SET == UTF-8 */
+		buf[off] = 0x80; /* Set PIV=1 */
+		/* Set ASSOICATION == target port: 01b */
+		buf[off] |= 0x10;
+		/* DESIGNATOR TYPE == SCSI name string */
+		buf[off++] |= 0x8;
+		off += 2; /* Skip over Reserved and length */
+		/*
+		 * SCSI name string identifer containing, $FABRIC_MOD
+		 * dependent information.  For LIO-Target and iSCSI
+		 * Target Port, this means "<iSCSI name>,t,0x<TPGT> in
+		 * UTF-8 encoding.
+		 */
+		tpgt = TPG_TFO(tpg)->tpg_get_tag(tpg);
+		scsi_name_len = sprintf(&buf[off], "%s,t,0x%04x",
+					TPG_TFO(tpg)->tpg_get_wwn(tpg), tpgt);
+		scsi_name_len += 1 /* Include  NULL terminator */;
+		/*
+		 * The null-terminated, null-padded (see 4.4.2) SCSI
+		 * NAME STRING field contains a UTF-8 format string.
+		 * The number of bytes in the SCSI NAME STRING field
+		 * (i.e., the value in the DESIGNATOR LENGTH field)
+		 * shall be no larger than 256 and shall be a multiple
+		 * of four.
+		 */
+		if (padding)
+			scsi_name_len += padding;
+
+		buf[off-1] = scsi_name_len;
+		off += scsi_name_len;
+		/* Header size + Designation descriptor */
+		len += (scsi_name_len + 4);
+	}
+set_len:
+	buf[2] = ((len >> 8) & 0xff);
+	buf[3] = (len & 0xff); /* Page Length for VPD 0x83 */
+	return 0;
+}
+
+/* Extended INQUIRY Data VPD Page */
+static int
+target_emulate_evpd_86(struct se_cmd *cmd, unsigned char *buf)
+{
+	if (cmd->data_length < 60)
+		return 0;
+
+	buf[1] = 0x86;
+	buf[2] = 0x3c;
+	/* Set HEADSUP, ORDSUP, SIMPSUP */
+	buf[5] = 0x07;
+
+	/* If WriteCache emulation is enabled, set V_SUP */
+	if (DEV_ATTRIB(SE_DEV(cmd))->emulate_write_cache > 0)
+		buf[6] = 0x01;
+	return 0;
+}
+
+/* Block Limits VPD page */
+static int
+target_emulate_evpd_b0(struct se_cmd *cmd, unsigned char *buf)
+{
+	struct se_device *dev = SE_DEV(cmd);
+	int have_tp = 0;
+
+	/*
+	 * Following sbc3r22 section 6.5.3 Block Limits VPD page, when
+	 * emulate_tpu=1 or emulate_tpws=1 we will be expect a
+	 * different page length for Thin Provisioning.
+	 */
+	if (DEV_ATTRIB(dev)->emulate_tpu || DEV_ATTRIB(dev)->emulate_tpws)
+		have_tp = 1;
+
+	if (cmd->data_length < (0x10 + 4)) {
+		printk(KERN_INFO "Received data_length: %u"
+			" too small for EVPD 0xb0\n",
+			cmd->data_length);
+		return -1;
+	}
+
+	if (have_tp && cmd->data_length < (0x3c + 4)) {
+		printk(KERN_INFO "Received data_length: %u"
+			" too small for TPE=1 EVPD 0xb0\n",
+			cmd->data_length);
+		have_tp = 0;
+	}
+
+	buf[0] = dev->transport->get_device_type(dev);
+	buf[1] = 0xb0;
+	buf[3] = have_tp ? 0x3c : 0x10;
+
+	/*
+	 * Set OPTIMAL TRANSFER LENGTH GRANULARITY
+	 */
+	put_unaligned_be16(1, &buf[6]);
+
+	/*
+	 * Set MAXIMUM TRANSFER LENGTH
+	 */
+	put_unaligned_be32(DEV_ATTRIB(dev)->max_sectors, &buf[8]);
+
+	/*
+	 * Set OPTIMAL TRANSFER LENGTH
+	 */
+	put_unaligned_be32(DEV_ATTRIB(dev)->optimal_sectors, &buf[12]);
+
+	/*
+	 * Exit now if we don't support TP or the initiator sent a too
+	 * short buffer.
+	 */
+	if (!have_tp || cmd->data_length < (0x3c + 4))
+		return 0;
+
+	/*
+	 * Set MAXIMUM UNMAP LBA COUNT
+	 */
+	put_unaligned_be32(DEV_ATTRIB(dev)->max_unmap_lba_count, &buf[20]);
+
+	/*
+	 * Set MAXIMUM UNMAP BLOCK DESCRIPTOR COUNT
+	 */
+	put_unaligned_be32(DEV_ATTRIB(dev)->max_unmap_block_desc_count,
+			   &buf[24]);
+
+	/*
+	 * Set OPTIMAL UNMAP GRANULARITY
+	 */
+	put_unaligned_be32(DEV_ATTRIB(dev)->unmap_granularity, &buf[28]);
+
+	/*
+	 * UNMAP GRANULARITY ALIGNMENT
+	 */
+	put_unaligned_be32(DEV_ATTRIB(dev)->unmap_granularity_alignment,
+			   &buf[32]);
+	if (DEV_ATTRIB(dev)->unmap_granularity_alignment != 0)
+		buf[32] |= 0x80; /* Set the UGAVALID bit */
+
+	return 0;
+}
+
+/* Thin Provisioning VPD */
+static int
+target_emulate_evpd_b2(struct se_cmd *cmd, unsigned char *buf)
+{
+	struct se_device *dev = SE_DEV(cmd);
+
+	/*
+	 * From sbc3r22 section 6.5.4 Thin Provisioning VPD page:
+	 *
+	 * The PAGE LENGTH field is defined in SPC-4. If the DP bit is set to
+	 * zero, then the page length shall be set to 0004h.  If the DP bit
+	 * is set to one, then the page length shall be set to the value
+	 * defined in table 162.
+	 */
+	buf[0] = dev->transport->get_device_type(dev);
+	buf[1] = 0xb2;
+
+	/*
+	 * Set Hardcoded length mentioned above for DP=0
+	 */
+	put_unaligned_be16(0x0004, &buf[2]);
+
+	/*
+	 * The THRESHOLD EXPONENT field indicates the threshold set size in
+	 * LBAs as a power of 2 (i.e., the threshold set size is equal to
+	 * 2(threshold exponent)).
+	 *
+	 * Note that this is currently set to 0x00 as mkp says it will be
+	 * changing again.  We can enable this once it has settled in T10
+	 * and is actually used by Linux/SCSI ML code.
+	 */
+	buf[4] = 0x00;
+
+	/*
+	 * A TPU bit set to one indicates that the device server supports
+	 * the UNMAP command (see 5.25). A TPU bit set to zero indicates
+	 * that the device server does not support the UNMAP command.
+	 */
+	if (DEV_ATTRIB(dev)->emulate_tpu != 0)
+		buf[5] = 0x80;
+
+	/*
+	 * A TPWS bit set to one indicates that the device server supports
+	 * the use of the WRITE SAME (16) command (see 5.42) to unmap LBAs.
+	 * A TPWS bit set to zero indicates that the device server does not
+	 * support the use of the WRITE SAME (16) command to unmap LBAs.
+	 */
+	if (DEV_ATTRIB(dev)->emulate_tpws != 0)
+		buf[5] |= 0x40;
+
+	return 0;
+}
+
+static int
+target_emulate_inquiry(struct se_cmd *cmd)
+{
+	struct se_device *dev = SE_DEV(cmd);
+	unsigned char *buf = cmd->t_task->t_task_buf;
+	unsigned char *cdb = cmd->t_task->t_task_cdb;
+
+	if (!(cdb[1] & 0x1))
+		return target_emulate_inquiry_std(cmd);
+
+	/*
+	 * Make sure we at least have 4 bytes of INQUIRY response
+	 * payload for 0x00 going back for EVPD=1.  Note that 0x80
+	 * and 0x83 will check for enough payload data length and
+	 * jump to set_len: label when there is not enough inquiry EVPD
+	 * payload length left for the next outgoing EVPD metadata
+	 */
+	if (cmd->data_length < 4) {
+		printk(KERN_ERR "SCSI Inquiry payload length: %u"
+			" too small for EVPD=1\n", cmd->data_length);
+		return -1;
+	}
+	buf[0] = dev->transport->get_device_type(dev);
+
+	switch (cdb[2]) {
+	case 0x00:
+		return target_emulate_evpd_00(cmd, buf);
+	case 0x80:
+		return target_emulate_evpd_80(cmd, buf);
+	case 0x83:
+		return target_emulate_evpd_83(cmd, buf);
+	case 0x86:
+		return target_emulate_evpd_86(cmd, buf);
+	case 0xb0:
+		return target_emulate_evpd_b0(cmd, buf);
+	case 0xb2:
+		return target_emulate_evpd_b2(cmd, buf);
+	default:
+		printk(KERN_ERR "Unknown VPD Code: 0x%02x\n", cdb[2]);
+		return -1;
+	}
+
+	return 0;
+}
+
+static int
+target_emulate_readcapacity(struct se_cmd *cmd)
+{
+	struct se_device *dev = SE_DEV(cmd);
+	unsigned char *buf = cmd->t_task->t_task_buf;
+	u32 blocks = dev->transport->get_blocks(dev);
+
+	buf[0] = (blocks >> 24) & 0xff;
+	buf[1] = (blocks >> 16) & 0xff;
+	buf[2] = (blocks >> 8) & 0xff;
+	buf[3] = blocks & 0xff;
+	buf[4] = (DEV_ATTRIB(dev)->block_size >> 24) & 0xff;
+	buf[5] = (DEV_ATTRIB(dev)->block_size >> 16) & 0xff;
+	buf[6] = (DEV_ATTRIB(dev)->block_size >> 8) & 0xff;
+	buf[7] = DEV_ATTRIB(dev)->block_size & 0xff;
+	/*
+	 * Set max 32-bit blocks to signal SERVICE ACTION READ_CAPACITY_16
+	*/
+	if (DEV_ATTRIB(dev)->emulate_tpu || DEV_ATTRIB(dev)->emulate_tpws)
+		put_unaligned_be32(0xFFFFFFFF, &buf[0]);
+
+	return 0;
+}
+
+static int
+target_emulate_readcapacity_16(struct se_cmd *cmd)
+{
+	struct se_device *dev = SE_DEV(cmd);
+	unsigned char *buf = cmd->t_task->t_task_buf;
+	unsigned long long blocks = dev->transport->get_blocks(dev);
+
+	buf[0] = (blocks >> 56) & 0xff;
+	buf[1] = (blocks >> 48) & 0xff;
+	buf[2] = (blocks >> 40) & 0xff;
+	buf[3] = (blocks >> 32) & 0xff;
+	buf[4] = (blocks >> 24) & 0xff;
+	buf[5] = (blocks >> 16) & 0xff;
+	buf[6] = (blocks >> 8) & 0xff;
+	buf[7] = blocks & 0xff;
+	buf[8] = (DEV_ATTRIB(dev)->block_size >> 24) & 0xff;
+	buf[9] = (DEV_ATTRIB(dev)->block_size >> 16) & 0xff;
+	buf[10] = (DEV_ATTRIB(dev)->block_size >> 8) & 0xff;
+	buf[11] = DEV_ATTRIB(dev)->block_size & 0xff;
+	/*
+	 * Set Thin Provisioning Enable bit following sbc3r22 in section
+	 * READ CAPACITY (16) byte 14 if emulate_tpu or emulate_tpws is enabled.
+	 */
+	if (DEV_ATTRIB(dev)->emulate_tpu || DEV_ATTRIB(dev)->emulate_tpws)
+		buf[14] = 0x80;
+
+	return 0;
+}
+
+static int
+target_modesense_rwrecovery(unsigned char *p)
+{
+	p[0] = 0x01;
+	p[1] = 0x0a;
+
+	return 12;
+}
+
+static int
+target_modesense_control(struct se_device *dev, unsigned char *p)
+{
+	p[0] = 0x0a;
+	p[1] = 0x0a;
+	p[2] = 2;
+	/*
+	 * From spc4r17, section 7.4.6 Control mode Page
+	 *
+	 * Unit Attention interlocks control (UN_INTLCK_CTRL) to code 00b
+	 *
+	 * 00b: The logical unit shall clear any unit attention condition
+	 * reported in the same I_T_L_Q nexus transaction as a CHECK CONDITION
+	 * status and shall not establish a unit attention condition when a com-
+	 * mand is completed with BUSY, TASK SET FULL, or RESERVATION CONFLICT
+	 * status.
+	 *
+	 * 10b: The logical unit shall not clear any unit attention condition
+	 * reported in the same I_T_L_Q nexus transaction as a CHECK CONDITION
+	 * status and shall not establish a unit attention condition when
+	 * a command is completed with BUSY, TASK SET FULL, or RESERVATION
+	 * CONFLICT status.
+	 *
+	 * 11b a The logical unit shall not clear any unit attention condition
+	 * reported in the same I_T_L_Q nexus transaction as a CHECK CONDITION
+	 * status and shall establish a unit attention condition for the
+	 * initiator port associated with the I_T nexus on which the BUSY,
+	 * TASK SET FULL, or RESERVATION CONFLICT status is being returned.
+	 * Depending on the status, the additional sense code shall be set to
+	 * PREVIOUS BUSY STATUS, PREVIOUS TASK SET FULL STATUS, or PREVIOUS
+	 * RESERVATION CONFLICT STATUS. Until it is cleared by a REQUEST SENSE
+	 * command, a unit attention condition shall be established only once
+	 * for a BUSY, TASK SET FULL, or RESERVATION CONFLICT status regardless
+	 * to the number of commands completed with one of those status codes.
+	 */
+	p[4] = (DEV_ATTRIB(dev)->emulate_ua_intlck_ctrl == 2) ? 0x30 :
+	       (DEV_ATTRIB(dev)->emulate_ua_intlck_ctrl == 1) ? 0x20 : 0x00;
+	/*
+	 * From spc4r17, section 7.4.6 Control mode Page
+	 *
+	 * Task Aborted Status (TAS) bit set to zero.
+	 *
+	 * A task aborted status (TAS) bit set to zero specifies that aborted
+	 * tasks shall be terminated by the device server without any response
+	 * to the application client. A TAS bit set to one specifies that tasks
+	 * aborted by the actions of an I_T nexus other than the I_T nexus on
+	 * which the command was received shall be completed with TASK ABORTED
+	 * status (see SAM-4).
+	 */
+	p[5] = (DEV_ATTRIB(dev)->emulate_tas) ? 0x40 : 0x00;
+	p[8] = 0xff;
+	p[9] = 0xff;
+	p[11] = 30;
+
+	return 12;
+}
+
+static int
+target_modesense_caching(struct se_device *dev, unsigned char *p)
+{
+	p[0] = 0x08;
+	p[1] = 0x12;
+	if (DEV_ATTRIB(dev)->emulate_write_cache > 0)
+		p[2] = 0x04; /* Write Cache Enable */
+	p[12] = 0x20; /* Disabled Read Ahead */
+
+	return 20;
+}
+
+static void
+target_modesense_write_protect(unsigned char *buf, int type)
+{
+	/*
+	 * I believe that the WP bit (bit 7) in the mode header is the same for
+	 * all device types..
+	 */
+	switch (type) {
+	case TYPE_DISK:
+	case TYPE_TAPE:
+	default:
+		buf[0] |= 0x80; /* WP bit */
+		break;
+	}
+}
+
+static void
+target_modesense_dpofua(unsigned char *buf, int type)
+{
+	switch (type) {
+	case TYPE_DISK:
+		buf[0] |= 0x10; /* DPOFUA bit */
+		break;
+	default:
+		break;
+	}
+}
+
+static int
+target_emulate_modesense(struct se_cmd *cmd, int ten)
+{
+	struct se_device *dev = SE_DEV(cmd);
+	char *cdb = cmd->t_task->t_task_cdb;
+	unsigned char *rbuf = cmd->t_task->t_task_buf;
+	int type = dev->transport->get_device_type(dev);
+	int offset = (ten) ? 8 : 4;
+	int length = 0;
+	unsigned char buf[SE_MODE_PAGE_BUF];
+
+	memset(buf, 0, SE_MODE_PAGE_BUF);
+
+	switch (cdb[2] & 0x3f) {
+	case 0x01:
+		length = target_modesense_rwrecovery(&buf[offset]);
+		break;
+	case 0x08:
+		length = target_modesense_caching(dev, &buf[offset]);
+		break;
+	case 0x0a:
+		length = target_modesense_control(dev, &buf[offset]);
+		break;
+	case 0x3f:
+		length = target_modesense_rwrecovery(&buf[offset]);
+		length += target_modesense_caching(dev, &buf[offset+length]);
+		length += target_modesense_control(dev, &buf[offset+length]);
+		break;
+	default:
+		printk(KERN_ERR "Got Unknown Mode Page: 0x%02x\n",
+				cdb[2] & 0x3f);
+		return PYX_TRANSPORT_UNKNOWN_MODE_PAGE;
+	}
+	offset += length;
+
+	if (ten) {
+		offset -= 2;
+		buf[0] = (offset >> 8) & 0xff;
+		buf[1] = offset & 0xff;
+
+		if ((SE_LUN(cmd)->lun_access & TRANSPORT_LUNFLAGS_READ_ONLY) ||
+		    (cmd->se_deve &&
+		    (cmd->se_deve->lun_flags & TRANSPORT_LUNFLAGS_READ_ONLY)))
+			target_modesense_write_protect(&buf[3], type);
+
+		if ((DEV_ATTRIB(dev)->emulate_write_cache > 0) &&
+		    (DEV_ATTRIB(dev)->emulate_fua_write > 0))
+			target_modesense_dpofua(&buf[3], type);
+
+		if ((offset + 2) > cmd->data_length)
+			offset = cmd->data_length;
+
+	} else {
+		offset -= 1;
+		buf[0] = offset & 0xff;
+
+		if ((SE_LUN(cmd)->lun_access & TRANSPORT_LUNFLAGS_READ_ONLY) ||
+		    (cmd->se_deve &&
+		    (cmd->se_deve->lun_flags & TRANSPORT_LUNFLAGS_READ_ONLY)))
+			target_modesense_write_protect(&buf[2], type);
+
+		if ((DEV_ATTRIB(dev)->emulate_write_cache > 0) &&
+		    (DEV_ATTRIB(dev)->emulate_fua_write > 0))
+			target_modesense_dpofua(&buf[2], type);
+
+		if ((offset + 1) > cmd->data_length)
+			offset = cmd->data_length;
+	}
+	memcpy(rbuf, buf, offset);
+
+	return 0;
+}
+
+static int
+target_emulate_request_sense(struct se_cmd *cmd)
+{
+	unsigned char *cdb = cmd->t_task->t_task_cdb;
+	unsigned char *buf = cmd->t_task->t_task_buf;
+	u8 ua_asc = 0, ua_ascq = 0;
+
+	if (cdb[1] & 0x01) {
+		printk(KERN_ERR "REQUEST_SENSE description emulation not"
+			" supported\n");
+		return PYX_TRANSPORT_INVALID_CDB_FIELD;
+	}
+	if (!(core_scsi3_ua_clear_for_request_sense(cmd, &ua_asc, &ua_ascq))) {
+		/*
+		 * CURRENT ERROR, UNIT ATTENTION
+		 */
+		buf[0] = 0x70;
+		buf[SPC_SENSE_KEY_OFFSET] = UNIT_ATTENTION;
+		/*
+		 * Make sure request data length is enough for additional
+		 * sense data.
+		 */
+		if (cmd->data_length <= 18) {
+			buf[7] = 0x00;
+			return 0;
+		}
+		/*
+		 * The Additional Sense Code (ASC) from the UNIT ATTENTION
+		 */
+		buf[SPC_ASC_KEY_OFFSET] = ua_asc;
+		buf[SPC_ASCQ_KEY_OFFSET] = ua_ascq;
+		buf[7] = 0x0A;
+	} else {
+		/*
+		 * CURRENT ERROR, NO SENSE
+		 */
+		buf[0] = 0x70;
+		buf[SPC_SENSE_KEY_OFFSET] = NO_SENSE;
+		/*
+		 * Make sure request data length is enough for additional
+		 * sense data.
+		 */
+		if (cmd->data_length <= 18) {
+			buf[7] = 0x00;
+			return 0;
+		}
+		/*
+		 * NO ADDITIONAL SENSE INFORMATION
+		 */
+		buf[SPC_ASC_KEY_OFFSET] = 0x00;
+		buf[7] = 0x0A;
+	}
+
+	return 0;
+}
+
+/*
+ * Used for TCM/IBLOCK and TCM/FILEIO for block/blk-lib.c level discard support.
+ * Note this is not used for TCM/pSCSI passthrough
+ */
+static int
+target_emulate_unmap(struct se_task *task)
+{
+	struct se_cmd *cmd = TASK_CMD(task);
+	struct se_device *dev = SE_DEV(cmd);
+	unsigned char *buf = cmd->t_task->t_task_buf, *ptr = NULL;
+	unsigned char *cdb = &cmd->t_task->t_task_cdb[0];
+	sector_t lba;
+	unsigned int size = cmd->data_length, range;
+	int ret, offset;
+	unsigned short dl, bd_dl;
+
+	/* First UNMAP block descriptor starts at 8 byte offset */
+	offset = 8;
+	size -= 8;
+	dl = get_unaligned_be16(&cdb[0]);
+	bd_dl = get_unaligned_be16(&cdb[2]);
+	ptr = &buf[offset];
+	printk(KERN_INFO "UNMAP: Sub: %s Using dl: %hu bd_dl: %hu size: %hu"
+		" ptr: %p\n", dev->transport->name, dl, bd_dl, size, ptr);
+
+	while (size) {
+		lba = get_unaligned_be64(&ptr[0]);
+		range = get_unaligned_be32(&ptr[8]);
+		printk(KERN_INFO "UNMAP: Using lba: %llu and range: %u\n",
+				 (unsigned long long)lba, range);
+
+		ret = dev->transport->do_discard(dev, lba, range);
+		if (ret < 0) {
+			printk(KERN_ERR "blkdev_issue_discard() failed: %d\n",
+					ret);
+			return -1;
+		}
+
+		ptr += 16;
+		size -= 16;
+	}
+
+	task->task_scsi_status = GOOD;
+	transport_complete_task(task, 1);
+	return 0;
+}
+
+/*
+ * Used for TCM/IBLOCK and TCM/FILEIO for block/blk-lib.c level discard support.
+ * Note this is not used for TCM/pSCSI passthrough
+ */
+static int
+target_emulate_write_same(struct se_task *task)
+{
+	struct se_cmd *cmd = TASK_CMD(task);
+	struct se_device *dev = SE_DEV(cmd);
+	sector_t lba = cmd->t_task->t_task_lba;
+	unsigned int range;
+	int ret;
+
+	range = (cmd->data_length / DEV_ATTRIB(dev)->block_size);
+
+	printk(KERN_INFO "WRITE_SAME UNMAP: LBA: %llu Range: %u\n",
+			 (unsigned long long)lba, range);
+
+	ret = dev->transport->do_discard(dev, lba, range);
+	if (ret < 0) {
+		printk(KERN_INFO "blkdev_issue_discard() failed for WRITE_SAME\n");
+		return -1;
+	}
+
+	task->task_scsi_status = GOOD;
+	transport_complete_task(task, 1);
+	return 0;
+}
+
+int
+transport_emulate_control_cdb(struct se_task *task)
+{
+	struct se_cmd *cmd = TASK_CMD(task);
+	struct se_device *dev = SE_DEV(cmd);
+	unsigned short service_action;
+	int ret = 0;
+
+	switch (cmd->t_task->t_task_cdb[0]) {
+	case INQUIRY:
+		ret = target_emulate_inquiry(cmd);
+		break;
+	case READ_CAPACITY:
+		ret = target_emulate_readcapacity(cmd);
+		break;
+	case MODE_SENSE:
+		ret = target_emulate_modesense(cmd, 0);
+		break;
+	case MODE_SENSE_10:
+		ret = target_emulate_modesense(cmd, 1);
+		break;
+	case SERVICE_ACTION_IN:
+		switch (cmd->t_task->t_task_cdb[1] & 0x1f) {
+		case SAI_READ_CAPACITY_16:
+			ret = target_emulate_readcapacity_16(cmd);
+			break;
+		default:
+			printk(KERN_ERR "Unsupported SA: 0x%02x\n",
+				cmd->t_task->t_task_cdb[1] & 0x1f);
+			return PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
+		}
+		break;
+	case REQUEST_SENSE:
+		ret = target_emulate_request_sense(cmd);
+		break;
+	case UNMAP:
+		if (!dev->transport->do_discard) {
+			printk(KERN_ERR "UNMAP emulation not supported for: %s\n",
+					dev->transport->name);
+			return PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
+		}
+		ret = target_emulate_unmap(task);
+		break;
+	case WRITE_SAME_16:
+		if (!dev->transport->do_discard) {
+			printk(KERN_ERR "WRITE_SAME_16 emulation not supported"
+					" for: %s\n", dev->transport->name);
+			return PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
+		}
+		ret = target_emulate_write_same(task);
+		break;
+	case VARIABLE_LENGTH_CMD:
+		service_action =
+			get_unaligned_be16(&cmd->t_task->t_task_cdb[8]);
+		switch (service_action) {
+		case WRITE_SAME_32:
+			if (!dev->transport->do_discard) {
+				printk(KERN_ERR "WRITE_SAME_32 SA emulation not"
+					" supported for: %s\n",
+					dev->transport->name);
+				return PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
+			}
+			ret = target_emulate_write_same(task);
+			break;
+		default:
+			printk(KERN_ERR "Unsupported VARIABLE_LENGTH_CMD SA:"
+					" 0x%02x\n", service_action);
+			break;
+		}
+		break;
+	case SYNCHRONIZE_CACHE:
+	case 0x91: /* SYNCHRONIZE_CACHE_16: */
+		if (!dev->transport->do_sync_cache) {
+			printk(KERN_ERR
+				"SYNCHRONIZE_CACHE emulation not supported"
+				" for: %s\n", dev->transport->name);
+			return PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
+		}
+		dev->transport->do_sync_cache(task);
+		break;
+	case ALLOW_MEDIUM_REMOVAL:
+	case ERASE:
+	case REZERO_UNIT:
+	case SEEK_10:
+	case SPACE:
+	case START_STOP:
+	case TEST_UNIT_READY:
+	case VERIFY:
+	case WRITE_FILEMARKS:
+		break;
+	default:
+		printk(KERN_ERR "Unsupported SCSI Opcode: 0x%02x for %s\n",
+			cmd->t_task->t_task_cdb[0], dev->transport->name);
+		return PYX_TRANSPORT_UNKNOWN_SAM_OPCODE;
+	}
+
+	if (ret < 0)
+		return ret;
+	task->task_scsi_status = GOOD;
+	transport_complete_task(task, 1);
+
+	return PYX_TRANSPORT_SENT_TO_TRANSPORT;
+}