target: add a parse_cdb method to the backend drivers

Instead of trying to handle all SCSI command sets in one function
(transport_generic_cmd_sequencer) call out to the backend driver to perform
this functionality.  For pSCSI a copy of the existing code is used, but for
all virtual backends we can use a new parse_sbc_cdb helper is used to
provide a simple SBC emulation.

For now this setups means a fair amount of duplication between pSCSI and the
SBC library, but patches later in this series will sort out that problem.

(nab: Fix up build failure in target_core_pscsi.c)

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

drivers/target/Makefile

@@ -10,6 +10,7 @@ target_core_mod-y		:= target_core_configfs.o \
 				   target_core_tpg.o \
 				   target_core_transport.o \
 				   target_core_cdb.o \
+				   target_core_sbc.o \
 				   target_core_spc.o \
 				   target_core_ua.o \
 				   target_core_rd.o \

drivers/target/target_core_file.c

@@ -561,6 +561,7 @@ static struct se_subsystem_api fileio_template = {
 	.allocate_virtdevice	= fd_allocate_virtdevice,
 	.create_virtdevice	= fd_create_virtdevice,
 	.free_device		= fd_free_device,
+	.parse_cdb		= sbc_parse_cdb,
 	.execute_cmd		= fd_execute_cmd,
 	.do_sync_cache		= fd_emulate_sync_cache,
 	.check_configfs_dev_params = fd_check_configfs_dev_params,

drivers/target/target_core_iblock.c

@@ -653,6 +653,7 @@ static struct se_subsystem_api iblock_template = {
 	.allocate_virtdevice	= iblock_allocate_virtdevice,
 	.create_virtdevice	= iblock_create_virtdevice,
 	.free_device		= iblock_free_device,
+	.parse_cdb		= sbc_parse_cdb,
 	.execute_cmd		= iblock_execute_cmd,
 	.do_discard		= iblock_do_discard,
 	.do_sync_cache		= iblock_emulate_sync_cache,

drivers/target/target_core_internal.h

@@ -96,9 +96,6 @@ int	core_tpg_post_addlun(struct se_portal_group *, struct se_lun *,
 struct se_lun *core_tpg_pre_dellun(struct se_portal_group *, u32 unpacked_lun);
 int	core_tpg_post_dellun(struct se_portal_group *, struct se_lun *);
 
-/* target_core_spc.c */
-int	spc_parse_cdb(struct se_cmd *cmd, unsigned int *size, bool passthrough);
-
 /* target_core_transport.c */
 extern struct kmem_cache *se_tmr_req_cache;
 

drivers/target/target_core_pscsi.c

@@ -35,8 +35,10 @@
 #include <linux/spinlock.h>
 #include <linux/genhd.h>
 #include <linux/cdrom.h>
-#include <linux/file.h>
+#include <linux/ratelimit.h>
 #include <linux/module.h>
+#include <asm/unaligned.h>
+
 #include <scsi/scsi.h>
 #include <scsi/scsi_device.h>
 #include <scsi/scsi_cmnd.h>
@@ -46,6 +48,7 @@
 #include <target/target_core_base.h>
 #include <target/target_core_backend.h>
 
+#include "target_core_alua.h"
 #include "target_core_pscsi.h"
 
 #define ISPRINT(a)  ((a >= ' ') && (a <= '~'))
@@ -1019,6 +1022,470 @@ fail:
 	return -ENOMEM;
 }
 
+static inline u32 pscsi_get_sectors_6(
+	unsigned char *cdb,
+	struct se_cmd *cmd,
+	int *ret)
+{
+	struct se_device *dev = cmd->se_dev;
+
+	/*
+	 * Assume TYPE_DISK for non struct se_device objects.
+	 * Use 8-bit sector value.
+	 */
+	if (!dev)
+		goto type_disk;
+
+	/*
+	 * Use 24-bit allocation length for TYPE_TAPE.
+	 */
+	if (dev->transport->get_device_type(dev) == TYPE_TAPE)
+		return (u32)(cdb[2] << 16) + (cdb[3] << 8) + cdb[4];
+
+	/*
+	 * Everything else assume TYPE_DISK Sector CDB location.
+	 * Use 8-bit sector value.  SBC-3 says:
+	 *
+	 *   A TRANSFER LENGTH field set to zero specifies that 256
+	 *   logical blocks shall be written.  Any other value
+	 *   specifies the number of logical blocks that shall be
+	 *   written.
+	 */
+type_disk:
+	return cdb[4] ? : 256;
+}
+
+static inline u32 pscsi_get_sectors_10(
+	unsigned char *cdb,
+	struct se_cmd *cmd,
+	int *ret)
+{
+	struct se_device *dev = cmd->se_dev;
+
+	/*
+	 * Assume TYPE_DISK for non struct se_device objects.
+	 * Use 16-bit sector value.
+	 */
+	if (!dev)
+		goto type_disk;
+
+	/*
+	 * XXX_10 is not defined in SSC, throw an exception
+	 */
+	if (dev->transport->get_device_type(dev) == TYPE_TAPE) {
+		*ret = -EINVAL;
+		return 0;
+	}
+
+	/*
+	 * Everything else assume TYPE_DISK Sector CDB location.
+	 * Use 16-bit sector value.
+	 */
+type_disk:
+	return (u32)(cdb[7] << 8) + cdb[8];
+}
+
+static inline u32 pscsi_get_sectors_12(
+	unsigned char *cdb,
+	struct se_cmd *cmd,
+	int *ret)
+{
+	struct se_device *dev = cmd->se_dev;
+
+	/*
+	 * Assume TYPE_DISK for non struct se_device objects.
+	 * Use 32-bit sector value.
+	 */
+	if (!dev)
+		goto type_disk;
+
+	/*
+	 * XXX_12 is not defined in SSC, throw an exception
+	 */
+	if (dev->transport->get_device_type(dev) == TYPE_TAPE) {
+		*ret = -EINVAL;
+		return 0;
+	}
+
+	/*
+	 * Everything else assume TYPE_DISK Sector CDB location.
+	 * Use 32-bit sector value.
+	 */
+type_disk:
+	return (u32)(cdb[6] << 24) + (cdb[7] << 16) + (cdb[8] << 8) + cdb[9];
+}
+
+static inline u32 pscsi_get_sectors_16(
+	unsigned char *cdb,
+	struct se_cmd *cmd,
+	int *ret)
+{
+	struct se_device *dev = cmd->se_dev;
+
+	/*
+	 * Assume TYPE_DISK for non struct se_device objects.
+	 * Use 32-bit sector value.
+	 */
+	if (!dev)
+		goto type_disk;
+
+	/*
+	 * Use 24-bit allocation length for TYPE_TAPE.
+	 */
+	if (dev->transport->get_device_type(dev) == TYPE_TAPE)
+		return (u32)(cdb[12] << 16) + (cdb[13] << 8) + cdb[14];
+
+type_disk:
+	return (u32)(cdb[10] << 24) + (cdb[11] << 16) +
+		    (cdb[12] << 8) + cdb[13];
+}
+
+/*
+ * Used for VARIABLE_LENGTH_CDB WRITE_32 and READ_32 variants
+ */
+static inline u32 pscsi_get_sectors_32(
+	unsigned char *cdb,
+	struct se_cmd *cmd,
+	int *ret)
+{
+	/*
+	 * Assume TYPE_DISK for non struct se_device objects.
+	 * Use 32-bit sector value.
+	 */
+	return (u32)(cdb[28] << 24) + (cdb[29] << 16) +
+		    (cdb[30] << 8) + cdb[31];
+
+}
+
+static inline u32 pscsi_get_lba_21(unsigned char *cdb)
+{
+	return ((cdb[1] & 0x1f) << 16) | (cdb[2] << 8) | cdb[3];
+}
+
+static inline u32 pscsi_get_lba_32(unsigned char *cdb)
+{
+	return (cdb[2] << 24) | (cdb[3] << 16) | (cdb[4] << 8) | cdb[5];
+}
+
+static inline unsigned long long pscsi_get_lba_64(unsigned char *cdb)
+{
+	unsigned int __v1, __v2;
+
+	__v1 = (cdb[2] << 24) | (cdb[3] << 16) | (cdb[4] << 8) | cdb[5];
+	__v2 = (cdb[6] << 24) | (cdb[7] << 16) | (cdb[8] << 8) | cdb[9];
+
+	return ((unsigned long long)__v2) | (unsigned long long)__v1 << 32;
+}
+
+/*
+ * For VARIABLE_LENGTH_CDB w/ 32 byte extended CDBs
+ */
+static inline unsigned long long pscsi_get_lba_64_ext(unsigned char *cdb)
+{
+	unsigned int __v1, __v2;
+
+	__v1 = (cdb[12] << 24) | (cdb[13] << 16) | (cdb[14] << 8) | cdb[15];
+	__v2 = (cdb[16] << 24) | (cdb[17] << 16) | (cdb[18] << 8) | cdb[19];
+
+	return ((unsigned long long)__v2) | (unsigned long long)__v1 << 32;
+}
+
+
+static inline u32 pscsi_get_size(
+	u32 sectors,
+	unsigned char *cdb,
+	struct se_cmd *cmd)
+{
+	struct se_device *dev = cmd->se_dev;
+
+	if (dev->transport->get_device_type(dev) == TYPE_TAPE) {
+		if (cdb[1] & 1) { /* sectors */
+			return dev->se_sub_dev->se_dev_attrib.block_size * sectors;
+		} else /* bytes */
+			return sectors;
+	}
+
+	pr_debug("Returning block_size: %u, sectors: %u == %u for"
+		" %s object\n", dev->se_sub_dev->se_dev_attrib.block_size,
+		sectors, dev->se_sub_dev->se_dev_attrib.block_size * sectors,
+		dev->transport->name);
+
+	return dev->se_sub_dev->se_dev_attrib.block_size * sectors;
+}
+
+static int pscsi_parse_cdb(struct se_cmd *cmd, unsigned int *size)
+{
+	struct se_device *dev = cmd->se_dev;
+	struct se_subsystem_dev *su_dev = dev->se_sub_dev;
+	unsigned char *cdb = cmd->t_task_cdb;
+	int sector_ret = 0;
+	u32 sectors = 0;
+	u16 service_action;
+	int ret;
+
+	if (cmd->se_cmd_flags & SCF_BIDI)
+		goto out_unsupported_cdb;
+
+	switch (cdb[0]) {
+	case READ_6:
+		sectors = pscsi_get_sectors_6(cdb, cmd, &sector_ret);
+		if (sector_ret)
+			goto out_unsupported_cdb;
+		*size = pscsi_get_size(sectors, cdb, cmd);
+		cmd->t_task_lba = pscsi_get_lba_21(cdb);
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		break;
+	case READ_10:
+		sectors = pscsi_get_sectors_10(cdb, cmd, &sector_ret);
+		if (sector_ret)
+			goto out_unsupported_cdb;
+		*size = pscsi_get_size(sectors, cdb, cmd);
+		cmd->t_task_lba = pscsi_get_lba_32(cdb);
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		break;
+	case READ_12:
+		sectors = pscsi_get_sectors_12(cdb, cmd, &sector_ret);
+		if (sector_ret)
+			goto out_unsupported_cdb;
+		*size = pscsi_get_size(sectors, cdb, cmd);
+		cmd->t_task_lba = pscsi_get_lba_32(cdb);
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		break;
+	case READ_16:
+		sectors = pscsi_get_sectors_16(cdb, cmd, &sector_ret);
+		if (sector_ret)
+			goto out_unsupported_cdb;
+		*size = pscsi_get_size(sectors, cdb, cmd);
+		cmd->t_task_lba = pscsi_get_lba_64(cdb);
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		break;
+	case WRITE_6:
+		sectors = pscsi_get_sectors_6(cdb, cmd, &sector_ret);
+		if (sector_ret)
+			goto out_unsupported_cdb;
+		*size = pscsi_get_size(sectors, cdb, cmd);
+		cmd->t_task_lba = pscsi_get_lba_21(cdb);
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		break;
+	case WRITE_10:
+	case WRITE_VERIFY:
+		sectors = pscsi_get_sectors_10(cdb, cmd, &sector_ret);
+		if (sector_ret)
+			goto out_unsupported_cdb;
+		*size = pscsi_get_size(sectors, cdb, cmd);
+		cmd->t_task_lba = pscsi_get_lba_32(cdb);
+		if (cdb[1] & 0x8)
+			cmd->se_cmd_flags |= SCF_FUA;
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		break;
+	case WRITE_12:
+		sectors = pscsi_get_sectors_12(cdb, cmd, &sector_ret);
+		if (sector_ret)
+			goto out_unsupported_cdb;
+		*size = pscsi_get_size(sectors, cdb, cmd);
+		cmd->t_task_lba = pscsi_get_lba_32(cdb);
+		if (cdb[1] & 0x8)
+			cmd->se_cmd_flags |= SCF_FUA;
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		break;
+	case WRITE_16:
+		sectors = pscsi_get_sectors_16(cdb, cmd, &sector_ret);
+		if (sector_ret)
+			goto out_unsupported_cdb;
+		*size = pscsi_get_size(sectors, cdb, cmd);
+		cmd->t_task_lba = pscsi_get_lba_64(cdb);
+		if (cdb[1] & 0x8)
+			cmd->se_cmd_flags |= SCF_FUA;
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		break;
+	case VARIABLE_LENGTH_CMD:
+		service_action = get_unaligned_be16(&cdb[8]);
+		switch (service_action) {
+		case WRITE_SAME_32:
+			sectors = pscsi_get_sectors_32(cdb, cmd, &sector_ret);
+			if (sector_ret)
+				goto out_unsupported_cdb;
+
+			if (!sectors) {
+				pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not"
+				       " supported\n");
+				goto out_invalid_cdb_field;
+			}
+
+			*size = pscsi_get_size(1, cdb, cmd);
+			cmd->t_task_lba = get_unaligned_be64(&cdb[12]);
+			break;
+		default:
+			pr_err("VARIABLE_LENGTH_CMD service action"
+				" 0x%04x not supported\n", service_action);
+			goto out_unsupported_cdb;
+		}
+		break;
+	case GPCMD_READ_BUFFER_CAPACITY:
+	case GPCMD_SEND_OPC:
+		*size = (cdb[7] << 8) + cdb[8];
+		break;
+	case READ_BLOCK_LIMITS:
+		*size = READ_BLOCK_LEN;
+		break;
+	case GPCMD_GET_CONFIGURATION:
+	case GPCMD_READ_FORMAT_CAPACITIES:
+	case GPCMD_READ_DISC_INFO:
+	case GPCMD_READ_TRACK_RZONE_INFO:
+		*size = (cdb[7] << 8) + cdb[8];
+		break;
+	case GPCMD_MECHANISM_STATUS:
+	case GPCMD_READ_DVD_STRUCTURE:
+		*size = (cdb[8] << 8) + cdb[9];
+		break;
+	case READ_POSITION:
+		*size = READ_POSITION_LEN;
+		break;
+	case READ_BUFFER:
+		*size = (cdb[6] << 16) + (cdb[7] << 8) + cdb[8];
+		break;
+	case READ_CAPACITY:
+		*size = READ_CAP_LEN;
+		break;
+	case READ_MEDIA_SERIAL_NUMBER:
+	case SERVICE_ACTION_IN:
+	case ACCESS_CONTROL_IN:
+	case ACCESS_CONTROL_OUT:
+		*size = (cdb[10] << 24) | (cdb[11] << 16) |
+		       (cdb[12] << 8) | cdb[13];
+		break;
+	case READ_TOC:
+		*size = cdb[8];
+		break;
+	case READ_ELEMENT_STATUS:
+		*size = 65536 * cdb[7] + 256 * cdb[8] + cdb[9];
+		break;
+	case SYNCHRONIZE_CACHE:
+	case SYNCHRONIZE_CACHE_16:
+		/*
+		 * Extract LBA and range to be flushed for emulated SYNCHRONIZE_CACHE
+		 */
+		if (cdb[0] == SYNCHRONIZE_CACHE) {
+			sectors = pscsi_get_sectors_10(cdb, cmd, &sector_ret);
+			cmd->t_task_lba = pscsi_get_lba_32(cdb);
+		} else {
+			sectors = pscsi_get_sectors_16(cdb, cmd, &sector_ret);
+			cmd->t_task_lba = pscsi_get_lba_64(cdb);
+		}
+		if (sector_ret)
+			goto out_unsupported_cdb;
+
+		*size = pscsi_get_size(sectors, cdb, cmd);
+		break;
+	case UNMAP:
+		*size = get_unaligned_be16(&cdb[7]);
+		break;
+	case WRITE_SAME_16:
+		sectors = pscsi_get_sectors_16(cdb, cmd, &sector_ret);
+		if (sector_ret)
+			goto out_unsupported_cdb;
+
+		if (!sectors) {
+			pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");
+			goto out_invalid_cdb_field;
+		}
+
+		*size = pscsi_get_size(1, cdb, cmd);
+		cmd->t_task_lba = get_unaligned_be64(&cdb[2]);
+		break;
+	case WRITE_SAME:
+		sectors = pscsi_get_sectors_10(cdb, cmd, &sector_ret);
+		if (sector_ret)
+			goto out_unsupported_cdb;
+
+		if (!sectors) {
+			pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");
+			goto out_invalid_cdb_field;
+		}
+
+		*size = pscsi_get_size(1, cdb, cmd);
+		cmd->t_task_lba = get_unaligned_be32(&cdb[2]);
+		break;
+	case ALLOW_MEDIUM_REMOVAL:
+	case ERASE:
+	case REZERO_UNIT:
+	case SEEK_10:
+	case SPACE:
+	case START_STOP:
+	case VERIFY:
+	case WRITE_FILEMARKS:
+	case GPCMD_CLOSE_TRACK:
+	case INITIALIZE_ELEMENT_STATUS:
+	case GPCMD_LOAD_UNLOAD:
+	case GPCMD_SET_SPEED:
+	case MOVE_MEDIUM:
+		*size = 0;
+		break;
+	case GET_EVENT_STATUS_NOTIFICATION:
+		*size = (cdb[7] << 8) | cdb[8];
+		break;
+	case ATA_16:
+		switch (cdb[2] & 0x3) {		/* T_LENGTH */
+		case 0x0:
+			sectors = 0;
+			break;
+		case 0x1:
+			sectors = (((cdb[1] & 0x1) ? cdb[3] : 0) << 8) | cdb[4];
+			break;
+		case 0x2:
+			sectors = (((cdb[1] & 0x1) ? cdb[5] : 0) << 8) | cdb[6];
+			break;
+		case 0x3:
+			pr_err("T_LENGTH=0x3 not supported for ATA_16\n");
+			goto out_invalid_cdb_field;
+		}
+
+		/* BYTE_BLOCK */
+		if (cdb[2] & 0x4) {
+			/* BLOCK T_TYPE: 512 or sector */
+			*size = sectors * ((cdb[2] & 0x10) ?
+				dev->se_sub_dev->se_dev_attrib.block_size : 512);
+		} else {
+			/* BYTE */
+			*size = sectors;
+		}
+		break;
+	default:
+		ret = spc_parse_cdb(cmd, size, true);
+		if (ret)
+			return ret;
+	}
+
+	if (cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {
+		if (sectors > su_dev->se_dev_attrib.fabric_max_sectors) {
+			printk_ratelimited(KERN_ERR "SCSI OP %02xh with too"
+				" big sectors %u exceeds fabric_max_sectors:"
+				" %u\n", cdb[0], sectors,
+				su_dev->se_dev_attrib.fabric_max_sectors);
+			goto out_invalid_cdb_field;
+		}
+		if (sectors > su_dev->se_dev_attrib.hw_max_sectors) {
+			printk_ratelimited(KERN_ERR "SCSI OP %02xh with too"
+				" big sectors %u exceeds backend hw_max_sectors:"
+				" %u\n", cdb[0], sectors,
+				su_dev->se_dev_attrib.hw_max_sectors);
+			goto out_invalid_cdb_field;
+		}
+	}
+
+	return 0;
+
+out_unsupported_cdb:
+	cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
+	cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
+	return -EINVAL;
+out_invalid_cdb_field:
+	cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
+	cmd->scsi_sense_reason = TCM_INVALID_CDB_FIELD;
+	return -EINVAL;
+}
+
+
 static int pscsi_execute_cmd(struct se_cmd *cmd, struct scatterlist *sgl,
 		u32 sgl_nents, enum dma_data_direction data_direction)
 {
@@ -1188,6 +1655,7 @@ static struct se_subsystem_api pscsi_template = {
 	.create_virtdevice	= pscsi_create_virtdevice,
 	.free_device		= pscsi_free_device,
 	.transport_complete	= pscsi_transport_complete,
+	.parse_cdb		= pscsi_parse_cdb,
 	.execute_cmd		= pscsi_execute_cmd,
 	.check_configfs_dev_params = pscsi_check_configfs_dev_params,
 	.set_configfs_dev_params = pscsi_set_configfs_dev_params,

drivers/target/target_core_rd.c

@@ -468,6 +468,7 @@ static struct se_subsystem_api rd_mcp_template = {
 	.allocate_virtdevice	= rd_allocate_virtdevice,
 	.create_virtdevice	= rd_create_virtdevice,
 	.free_device		= rd_free_device,
+	.parse_cdb		= sbc_parse_cdb,
 	.execute_cmd		= rd_execute_cmd,
 	.check_configfs_dev_params = rd_check_configfs_dev_params,
 	.set_configfs_dev_params = rd_set_configfs_dev_params,

drivers/target/target_core_sbc.c

@@ -0,0 +1,450 @@
+/*
+ * SCSI Block Commands (SBC) parsing and emulation.
+ *
+ * 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 <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/ratelimit.h>
+#include <asm/unaligned.h>
+#include <scsi/scsi.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_ua.h"
+
+
+static inline u32 sbc_get_size(struct se_cmd *cmd, u32 sectors)
+{
+	return cmd->se_dev->se_sub_dev->se_dev_attrib.block_size * sectors;
+}
+
+static int sbc_check_valid_sectors(struct se_cmd *cmd)
+{
+	struct se_device *dev = cmd->se_dev;
+	unsigned long long end_lba;
+	u32 sectors;
+
+	sectors = cmd->data_length / dev->se_sub_dev->se_dev_attrib.block_size;
+	end_lba = dev->transport->get_blocks(dev) + 1;
+
+	if (cmd->t_task_lba + sectors > end_lba) {
+		pr_err("target: lba %llu, sectors %u exceeds end lba %llu\n",
+			cmd->t_task_lba, sectors, end_lba);
+		return -EINVAL;
+	}
+
+	return 0;
+}
+
+static inline u32 transport_get_sectors_6(unsigned char *cdb)
+{
+	/*
+	 * Use 8-bit sector value.  SBC-3 says:
+	 *
+	 *   A TRANSFER LENGTH field set to zero specifies that 256
+	 *   logical blocks shall be written.  Any other value
+	 *   specifies the number of logical blocks that shall be
+	 *   written.
+	 */
+	return cdb[4] ? : 256;
+}
+
+static inline u32 transport_get_sectors_10(unsigned char *cdb)
+{
+	return (u32)(cdb[7] << 8) + cdb[8];
+}
+
+static inline u32 transport_get_sectors_12(unsigned char *cdb)
+{
+	return (u32)(cdb[6] << 24) + (cdb[7] << 16) + (cdb[8] << 8) + cdb[9];
+}
+
+static inline u32 transport_get_sectors_16(unsigned char *cdb)
+{
+	return (u32)(cdb[10] << 24) + (cdb[11] << 16) +
+		    (cdb[12] << 8) + cdb[13];
+}
+
+/*
+ * Used for VARIABLE_LENGTH_CDB WRITE_32 and READ_32 variants
+ */
+static inline u32 transport_get_sectors_32(unsigned char *cdb)
+{
+	return (u32)(cdb[28] << 24) + (cdb[29] << 16) +
+		    (cdb[30] << 8) + cdb[31];
+
+}
+
+static inline u32 transport_lba_21(unsigned char *cdb)
+{
+	return ((cdb[1] & 0x1f) << 16) | (cdb[2] << 8) | cdb[3];
+}
+
+static inline u32 transport_lba_32(unsigned char *cdb)
+{
+	return (cdb[2] << 24) | (cdb[3] << 16) | (cdb[4] << 8) | cdb[5];
+}
+
+static inline unsigned long long transport_lba_64(unsigned char *cdb)
+{
+	unsigned int __v1, __v2;
+
+	__v1 = (cdb[2] << 24) | (cdb[3] << 16) | (cdb[4] << 8) | cdb[5];
+	__v2 = (cdb[6] << 24) | (cdb[7] << 16) | (cdb[8] << 8) | cdb[9];
+
+	return ((unsigned long long)__v2) | (unsigned long long)__v1 << 32;
+}
+
+/*
+ * For VARIABLE_LENGTH_CDB w/ 32 byte extended CDBs
+ */
+static inline unsigned long long transport_lba_64_ext(unsigned char *cdb)
+{
+	unsigned int __v1, __v2;
+
+	__v1 = (cdb[12] << 24) | (cdb[13] << 16) | (cdb[14] << 8) | cdb[15];
+	__v2 = (cdb[16] << 24) | (cdb[17] << 16) | (cdb[18] << 8) | cdb[19];
+
+	return ((unsigned long long)__v2) | (unsigned long long)__v1 << 32;
+}
+
+static int sbc_write_same_supported(struct se_device *dev,
+		unsigned char *flags)
+{
+	if ((flags[0] & 0x04) || (flags[0] & 0x02)) {
+		pr_err("WRITE_SAME PBDATA and LBDATA"
+			" bits not supported for Block Discard"
+			" Emulation\n");
+		return -ENOSYS;
+	}
+
+	/*
+	 * Currently for the emulated case we only accept
+	 * tpws with the UNMAP=1 bit set.
+	 */
+	if (!(flags[0] & 0x08)) {
+		pr_err("WRITE_SAME w/o UNMAP bit not"
+			" supported for Block Discard Emulation\n");
+		return -ENOSYS;
+	}
+
+	return 0;
+}
+
+static void xdreadwrite_callback(struct se_cmd *cmd)
+{
+	unsigned char *buf, *addr;
+	struct scatterlist *sg;
+	unsigned int offset;
+	int i;
+	int count;
+	/*
+	 * From sbc3r22.pdf section 5.48 XDWRITEREAD (10) command
+	 *
+	 * 1) read the specified logical block(s);
+	 * 2) transfer logical blocks from the data-out buffer;
+	 * 3) XOR the logical blocks transferred from the data-out buffer with
+	 *    the logical blocks read, storing the resulting XOR data in a buffer;
+	 * 4) if the DISABLE WRITE bit is set to zero, then write the logical
+	 *    blocks transferred from the data-out buffer; and
+	 * 5) transfer the resulting XOR data to the data-in buffer.
+	 */
+	buf = kmalloc(cmd->data_length, GFP_KERNEL);
+	if (!buf) {
+		pr_err("Unable to allocate xor_callback buf\n");
+		return;
+	}
+	/*
+	 * Copy the scatterlist WRITE buffer located at cmd->t_data_sg
+	 * into the locally allocated *buf
+	 */
+	sg_copy_to_buffer(cmd->t_data_sg,
+			  cmd->t_data_nents,
+			  buf,
+			  cmd->data_length);
+
+	/*
+	 * Now perform the XOR against the BIDI read memory located at
+	 * cmd->t_mem_bidi_list
+	 */
+
+	offset = 0;
+	for_each_sg(cmd->t_bidi_data_sg, sg, cmd->t_bidi_data_nents, count) {
+		addr = kmap_atomic(sg_page(sg));
+		if (!addr)
+			goto out;
+
+		for (i = 0; i < sg->length; i++)
+			*(addr + sg->offset + i) ^= *(buf + offset + i);
+
+		offset += sg->length;
+		kunmap_atomic(addr);
+	}
+
+out:
+	kfree(buf);
+}
+
+int sbc_parse_cdb(struct se_cmd *cmd, unsigned int *size)
+{
+	struct se_subsystem_dev *su_dev = cmd->se_dev->se_sub_dev;
+	struct se_device *dev = cmd->se_dev;
+	unsigned char *cdb = cmd->t_task_cdb;
+	u32 sectors = 0;
+	int ret;
+
+	switch (cdb[0]) {
+	case READ_6:
+		sectors = transport_get_sectors_6(cdb);
+		cmd->t_task_lba = transport_lba_21(cdb);
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		break;
+	case READ_10:
+		sectors = transport_get_sectors_10(cdb);
+		cmd->t_task_lba = transport_lba_32(cdb);
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		break;
+	case READ_12:
+		sectors = transport_get_sectors_12(cdb);
+		cmd->t_task_lba = transport_lba_32(cdb);
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		break;
+	case READ_16:
+		sectors = transport_get_sectors_16(cdb);
+		cmd->t_task_lba = transport_lba_64(cdb);
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		break;
+	case WRITE_6:
+		sectors = transport_get_sectors_6(cdb);
+		cmd->t_task_lba = transport_lba_21(cdb);
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		break;
+	case WRITE_10:
+	case WRITE_VERIFY:
+		sectors = transport_get_sectors_10(cdb);
+		cmd->t_task_lba = transport_lba_32(cdb);
+		if (cdb[1] & 0x8)
+			cmd->se_cmd_flags |= SCF_FUA;
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		break;
+	case WRITE_12:
+		sectors = transport_get_sectors_12(cdb);
+		cmd->t_task_lba = transport_lba_32(cdb);
+		if (cdb[1] & 0x8)
+			cmd->se_cmd_flags |= SCF_FUA;
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		break;
+	case WRITE_16:
+		sectors = transport_get_sectors_16(cdb);
+		cmd->t_task_lba = transport_lba_64(cdb);
+		if (cdb[1] & 0x8)
+			cmd->se_cmd_flags |= SCF_FUA;
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+		break;
+	case XDWRITEREAD_10:
+		if ((cmd->data_direction != DMA_TO_DEVICE) ||
+		    !(cmd->se_cmd_flags & SCF_BIDI))
+			goto out_invalid_cdb_field;
+		sectors = transport_get_sectors_10(cdb);
+
+		cmd->t_task_lba = transport_lba_32(cdb);
+		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+
+		/*
+		 * Setup BIDI XOR callback to be run after I/O completion.
+		 */
+		cmd->transport_complete_callback = &xdreadwrite_callback;
+		if (cdb[1] & 0x8)
+			cmd->se_cmd_flags |= SCF_FUA;
+		break;
+	case VARIABLE_LENGTH_CMD:
+	{
+		u16 service_action = get_unaligned_be16(&cdb[8]);
+		switch (service_action) {
+		case XDWRITEREAD_32:
+			sectors = transport_get_sectors_32(cdb);
+
+			/*
+			 * Use WRITE_32 and READ_32 opcodes for the emulated
+			 * XDWRITE_READ_32 logic.
+			 */
+			cmd->t_task_lba = transport_lba_64_ext(cdb);
+			cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
+
+			/*
+			 * Setup BIDI XOR callback to be run during after I/O
+			 * completion.
+			 */
+			cmd->transport_complete_callback = &xdreadwrite_callback;
+			if (cdb[1] & 0x8)
+				cmd->se_cmd_flags |= SCF_FUA;
+			break;
+		case WRITE_SAME_32:
+			sectors = transport_get_sectors_32(cdb);
+			if (!sectors) {
+				pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not"
+				       " supported\n");
+				goto out_invalid_cdb_field;
+			}
+
+			*size = sbc_get_size(cmd, 1);
+			cmd->t_task_lba = get_unaligned_be64(&cdb[12]);
+
+			if (sbc_write_same_supported(dev, &cdb[10]) < 0)
+				goto out_unsupported_cdb;
+			cmd->execute_cmd = target_emulate_write_same;
+			break;
+		default:
+			pr_err("VARIABLE_LENGTH_CMD service action"
+				" 0x%04x not supported\n", service_action);
+			goto out_unsupported_cdb;
+		}
+		break;
+	}
+	case READ_CAPACITY:
+		*size = READ_CAP_LEN;
+		cmd->execute_cmd = target_emulate_readcapacity;
+		break;
+	case SERVICE_ACTION_IN:
+		switch (cmd->t_task_cdb[1] & 0x1f) {
+		case SAI_READ_CAPACITY_16:
+			cmd->execute_cmd = target_emulate_readcapacity_16;
+			break;
+		default:
+			pr_err("Unsupported SA: 0x%02x\n",
+				cmd->t_task_cdb[1] & 0x1f);
+			goto out_invalid_cdb_field;
+		}
+		*size = (cdb[10] << 24) | (cdb[11] << 16) |
+		       (cdb[12] << 8) | cdb[13];
+		break;
+	case SYNCHRONIZE_CACHE:
+	case SYNCHRONIZE_CACHE_16:
+		/*
+		 * Extract LBA and range to be flushed for emulated SYNCHRONIZE_CACHE
+		 */
+		if (cdb[0] == SYNCHRONIZE_CACHE) {
+			sectors = transport_get_sectors_10(cdb);
+			cmd->t_task_lba = transport_lba_32(cdb);
+		} else {
+			sectors = transport_get_sectors_16(cdb);
+			cmd->t_task_lba = transport_lba_64(cdb);
+		}
+
+		*size = sbc_get_size(cmd, sectors);
+
+		/*
+		 * Check to ensure that LBA + Range does not exceed past end of
+		 * device for IBLOCK and FILEIO ->do_sync_cache() backend calls
+		 */
+		if (cmd->t_task_lba || sectors) {
+			if (sbc_check_valid_sectors(cmd) < 0)
+				goto out_invalid_cdb_field;
+		}
+		cmd->execute_cmd = target_emulate_synchronize_cache;
+		break;
+	case UNMAP:
+		*size = get_unaligned_be16(&cdb[7]);
+		cmd->execute_cmd = target_emulate_unmap;
+		break;
+	case WRITE_SAME_16:
+		sectors = transport_get_sectors_16(cdb);
+		if (!sectors) {
+			pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");
+			goto out_invalid_cdb_field;
+		}
+
+		*size = sbc_get_size(cmd, 1);
+		cmd->t_task_lba = get_unaligned_be64(&cdb[2]);
+
+		if (sbc_write_same_supported(dev, &cdb[1]) < 0)
+			goto out_unsupported_cdb;
+		cmd->execute_cmd = target_emulate_write_same;
+		break;
+	case WRITE_SAME:
+		sectors = transport_get_sectors_10(cdb);
+		if (!sectors) {
+			pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");
+			goto out_invalid_cdb_field;
+		}
+
+		*size = sbc_get_size(cmd, 1);
+		cmd->t_task_lba = get_unaligned_be32(&cdb[2]);
+
+		/*
+		 * Follow sbcr26 with WRITE_SAME (10) and check for the existence
+		 * of byte 1 bit 3 UNMAP instead of original reserved field
+		 */
+		if (sbc_write_same_supported(dev, &cdb[1]) < 0)
+			goto out_unsupported_cdb;
+		cmd->execute_cmd = target_emulate_write_same;
+		break;
+	case VERIFY:
+		*size = 0;
+		cmd->execute_cmd = target_emulate_noop;
+		break;
+	default:
+		ret = spc_parse_cdb(cmd, size, false);
+		if (ret)
+			return ret;
+	}
+
+	/* reject any command that we don't have a handler for */
+	if (!(cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) && !cmd->execute_cmd)
+		goto out_unsupported_cdb;
+
+	if (cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {
+		if (sectors > su_dev->se_dev_attrib.fabric_max_sectors) {
+			printk_ratelimited(KERN_ERR "SCSI OP %02xh with too"
+				" big sectors %u exceeds fabric_max_sectors:"
+				" %u\n", cdb[0], sectors,
+				su_dev->se_dev_attrib.fabric_max_sectors);
+			goto out_invalid_cdb_field;
+		}
+		if (sectors > su_dev->se_dev_attrib.hw_max_sectors) {
+			printk_ratelimited(KERN_ERR "SCSI OP %02xh with too"
+				" big sectors %u exceeds backend hw_max_sectors:"
+				" %u\n", cdb[0], sectors,
+				su_dev->se_dev_attrib.hw_max_sectors);
+			goto out_invalid_cdb_field;
+		}
+
+		*size = sbc_get_size(cmd, sectors);
+	}
+
+	return 0;
+
+out_unsupported_cdb:
+	cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
+	cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
+	return -EINVAL;
+out_invalid_cdb_field:
+	cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
+	cmd->scsi_sense_reason = TCM_INVALID_CDB_FIELD;
+	return -EINVAL;
+}
+EXPORT_SYMBOL(sbc_parse_cdb);

drivers/target/target_core_spc.c

@@ -152,6 +152,7 @@ int spc_parse_cdb(struct se_cmd *cmd, unsigned int *size, bool passthrough)
 			cmd->sam_task_attr = MSG_HEAD_TAG;
 		break;
 	case TEST_UNIT_READY:
+		*size = 0;
 		if (!passthrough)
 			cmd->execute_cmd = target_emulate_noop;
 		break;

drivers/target/target_core_transport.c

@@ -1343,8 +1343,6 @@ static inline void transport_generic_prepare_cdb(
 	}
 }
 
-static int transport_generic_cmd_sequencer(struct se_cmd *, unsigned char *);
-
 static int target_cmd_size_check(struct se_cmd *cmd, unsigned int size)
 {
 	struct se_device *dev = cmd->se_dev;
@@ -1471,6 +1469,7 @@ int target_setup_cmd_from_cdb(
 	u32 pr_reg_type = 0;
 	u8 alua_ascq = 0;
 	unsigned long flags;
+	unsigned int size;
 	int ret;
 
 	transport_generic_prepare_cdb(cdb);
@@ -1562,13 +1561,11 @@ int target_setup_cmd_from_cdb(
 		 */
 	}
 
-	/*
-	 * Setup the received CDB based on SCSI defined opcodes and
-	 * perform unit attention, persistent reservations and ALUA
-	 * checks for virtual device backends.  The cmd->t_task_cdb
-	 * pointer is expected to be setup before we reach this point.
-	 */
-	ret = transport_generic_cmd_sequencer(cmd, cdb);
+	ret = cmd->se_dev->transport->parse_cdb(cmd, &size);
+	if (ret < 0)
+		return ret;
+
+	ret = target_cmd_size_check(cmd, size);
 	if (ret < 0)
 		return ret;
 
@@ -1694,10 +1691,7 @@ void target_submit_cmd(struct se_cmd *se_cmd, struct se_session *se_sess,
 		target_put_sess_cmd(se_sess, se_cmd);
 		return;
 	}
-	/*
-	 * Sanitize CDBs via transport_generic_cmd_sequencer() and
-	 * allocate the necessary tasks to complete the received CDB+data
-	 */
+
 	rc = target_setup_cmd_from_cdb(se_cmd, cdb);
 	if (rc != 0) {
 		transport_generic_request_failure(se_cmd);
@@ -1966,39 +1960,6 @@ queue_full:
 }
 EXPORT_SYMBOL(transport_generic_request_failure);
 
-static inline u32 transport_lba_21(unsigned char *cdb)
-{
-	return ((cdb[1] & 0x1f) << 16) | (cdb[2] << 8) | cdb[3];
-}
-
-static inline u32 transport_lba_32(unsigned char *cdb)
-{
-	return (cdb[2] << 24) | (cdb[3] << 16) | (cdb[4] << 8) | cdb[5];
-}
-
-static inline unsigned long long transport_lba_64(unsigned char *cdb)
-{
-	unsigned int __v1, __v2;
-
-	__v1 = (cdb[2] << 24) | (cdb[3] << 16) | (cdb[4] << 8) | cdb[5];
-	__v2 = (cdb[6] << 24) | (cdb[7] << 16) | (cdb[8] << 8) | cdb[9];
-
-	return ((unsigned long long)__v2) | (unsigned long long)__v1 << 32;
-}
-
-/*
- * For VARIABLE_LENGTH_CDB w/ 32 byte extended CDBs
- */
-static inline unsigned long long transport_lba_64_ext(unsigned char *cdb)
-{
-	unsigned int __v1, __v2;
-
-	__v1 = (cdb[12] << 24) | (cdb[13] << 16) | (cdb[14] << 8) | cdb[15];
-	__v2 = (cdb[16] << 24) | (cdb[17] << 16) | (cdb[18] << 8) | cdb[19];
-
-	return ((unsigned long long)__v2) | (unsigned long long)__v1 << 32;
-}
-
 /*
  * Called from Fabric Module context from transport_execute_tasks()
  *
@@ -2147,217 +2108,6 @@ check_depth:
 	return 0;
 }
 
-static inline u32 transport_get_sectors_6(
-	unsigned char *cdb,
-	struct se_cmd *cmd,
-	int *ret)
-{
-	struct se_device *dev = cmd->se_dev;
-
-	/*
-	 * Assume TYPE_DISK for non struct se_device objects.
-	 * Use 8-bit sector value.
-	 */
-	if (!dev)
-		goto type_disk;
-
-	/*
-	 * Use 24-bit allocation length for TYPE_TAPE.
-	 */
-	if (dev->transport->get_device_type(dev) == TYPE_TAPE)
-		return (u32)(cdb[2] << 16) + (cdb[3] << 8) + cdb[4];
-
-	/*
-	 * Everything else assume TYPE_DISK Sector CDB location.
-	 * Use 8-bit sector value.  SBC-3 says:
-	 *
-	 *   A TRANSFER LENGTH field set to zero specifies that 256
-	 *   logical blocks shall be written.  Any other value
-	 *   specifies the number of logical blocks that shall be
-	 *   written.
-	 */
-type_disk:
-	return cdb[4] ? : 256;
-}
-
-static inline u32 transport_get_sectors_10(
-	unsigned char *cdb,
-	struct se_cmd *cmd,
-	int *ret)
-{
-	struct se_device *dev = cmd->se_dev;
-
-	/*
-	 * Assume TYPE_DISK for non struct se_device objects.
-	 * Use 16-bit sector value.
-	 */
-	if (!dev)
-		goto type_disk;
-
-	/*
-	 * XXX_10 is not defined in SSC, throw an exception
-	 */
-	if (dev->transport->get_device_type(dev) == TYPE_TAPE) {
-		*ret = -EINVAL;
-		return 0;
-	}
-
-	/*
-	 * Everything else assume TYPE_DISK Sector CDB location.
-	 * Use 16-bit sector value.
-	 */
-type_disk:
-	return (u32)(cdb[7] << 8) + cdb[8];
-}
-
-static inline u32 transport_get_sectors_12(
-	unsigned char *cdb,
-	struct se_cmd *cmd,
-	int *ret)
-{
-	struct se_device *dev = cmd->se_dev;
-
-	/*
-	 * Assume TYPE_DISK for non struct se_device objects.
-	 * Use 32-bit sector value.
-	 */
-	if (!dev)
-		goto type_disk;
-
-	/*
-	 * XXX_12 is not defined in SSC, throw an exception
-	 */
-	if (dev->transport->get_device_type(dev) == TYPE_TAPE) {
-		*ret = -EINVAL;
-		return 0;
-	}
-
-	/*
-	 * Everything else assume TYPE_DISK Sector CDB location.
-	 * Use 32-bit sector value.
-	 */
-type_disk:
-	return (u32)(cdb[6] << 24) + (cdb[7] << 16) + (cdb[8] << 8) + cdb[9];
-}
-
-static inline u32 transport_get_sectors_16(
-	unsigned char *cdb,
-	struct se_cmd *cmd,
-	int *ret)
-{
-	struct se_device *dev = cmd->se_dev;
-
-	/*
-	 * Assume TYPE_DISK for non struct se_device objects.
-	 * Use 32-bit sector value.
-	 */
-	if (!dev)
-		goto type_disk;
-
-	/*
-	 * Use 24-bit allocation length for TYPE_TAPE.
-	 */
-	if (dev->transport->get_device_type(dev) == TYPE_TAPE)
-		return (u32)(cdb[12] << 16) + (cdb[13] << 8) + cdb[14];
-
-type_disk:
-	return (u32)(cdb[10] << 24) + (cdb[11] << 16) +
-		    (cdb[12] << 8) + cdb[13];
-}
-
-/*
- * Used for VARIABLE_LENGTH_CDB WRITE_32 and READ_32 variants
- */
-static inline u32 transport_get_sectors_32(
-	unsigned char *cdb,
-	struct se_cmd *cmd,
-	int *ret)
-{
-	/*
-	 * Assume TYPE_DISK for non struct se_device objects.
-	 * Use 32-bit sector value.
-	 */
-	return (u32)(cdb[28] << 24) + (cdb[29] << 16) +
-		    (cdb[30] << 8) + cdb[31];
-
-}
-
-static inline u32 transport_get_size(
-	u32 sectors,
-	unsigned char *cdb,
-	struct se_cmd *cmd)
-{
-	struct se_device *dev = cmd->se_dev;
-
-	if (dev->transport->get_device_type(dev) == TYPE_TAPE) {
-		if (cdb[1] & 1) { /* sectors */
-			return dev->se_sub_dev->se_dev_attrib.block_size * sectors;
-		} else /* bytes */
-			return sectors;
-	}
-
-	pr_debug("Returning block_size: %u, sectors: %u == %u for"
-		" %s object\n", dev->se_sub_dev->se_dev_attrib.block_size,
-		sectors, dev->se_sub_dev->se_dev_attrib.block_size * sectors,
-		dev->transport->name);
-
-	return dev->se_sub_dev->se_dev_attrib.block_size * sectors;
-}
-
-static void transport_xor_callback(struct se_cmd *cmd)
-{
-	unsigned char *buf, *addr;
-	struct scatterlist *sg;
-	unsigned int offset;
-	int i;
-	int count;
-	/*
-	 * From sbc3r22.pdf section 5.48 XDWRITEREAD (10) command
-	 *
-	 * 1) read the specified logical block(s);
-	 * 2) transfer logical blocks from the data-out buffer;
-	 * 3) XOR the logical blocks transferred from the data-out buffer with
-	 *    the logical blocks read, storing the resulting XOR data in a buffer;
-	 * 4) if the DISABLE WRITE bit is set to zero, then write the logical
-	 *    blocks transferred from the data-out buffer; and
-	 * 5) transfer the resulting XOR data to the data-in buffer.
-	 */
-	buf = kmalloc(cmd->data_length, GFP_KERNEL);
-	if (!buf) {
-		pr_err("Unable to allocate xor_callback buf\n");
-		return;
-	}
-	/*
-	 * Copy the scatterlist WRITE buffer located at cmd->t_data_sg
-	 * into the locally allocated *buf
-	 */
-	sg_copy_to_buffer(cmd->t_data_sg,
-			  cmd->t_data_nents,
-			  buf,
-			  cmd->data_length);
-
-	/*
-	 * Now perform the XOR against the BIDI read memory located at
-	 * cmd->t_mem_bidi_list
-	 */
-
-	offset = 0;
-	for_each_sg(cmd->t_bidi_data_sg, sg, cmd->t_bidi_data_nents, count) {
-		addr = kmap_atomic(sg_page(sg));
-		if (!addr)
-			goto out;
-
-		for (i = 0; i < sg->length; i++)
-			*(addr + sg->offset + i) ^= *(buf + offset + i);
-
-		offset += sg->length;
-		kunmap_atomic(addr);
-	}
-
-out:
-	kfree(buf);
-}
-
 /*
  * Used to obtain Sense Data from underlying Linux/SCSI struct scsi_cmnd
  */
@@ -2439,478 +2189,6 @@ static int transport_cmd_get_valid_sectors(struct se_cmd *cmd)
 	return 0;
 }
 
-static int target_check_write_same_discard(unsigned char *flags, struct se_device *dev)
-{
-	/*
-	 * Determine if the received WRITE_SAME is used to for direct
-	 * passthrough into Linux/SCSI with struct request via TCM/pSCSI
-	 * or we are signaling the use of internal WRITE_SAME + UNMAP=1
-	 * emulation for -> Linux/BLOCK disbard with TCM/IBLOCK code.
-	 */
-	int passthrough = (dev->transport->transport_type ==
-				TRANSPORT_PLUGIN_PHBA_PDEV);
-
-	if (!passthrough) {
-		if ((flags[0] & 0x04) || (flags[0] & 0x02)) {
-			pr_err("WRITE_SAME PBDATA and LBDATA"
-				" bits not supported for Block Discard"
-				" Emulation\n");
-			return -ENOSYS;
-		}
-		/*
-		 * Currently for the emulated case we only accept
-		 * tpws with the UNMAP=1 bit set.
-		 */
-		if (!(flags[0] & 0x08)) {
-			pr_err("WRITE_SAME w/o UNMAP bit not"
-				" supported for Block Discard Emulation\n");
-			return -ENOSYS;
-		}
-	}
-
-	return 0;
-}
-
-static int transport_generic_cmd_sequencer(
-	struct se_cmd *cmd,
-	unsigned char *cdb)
-{
-	struct se_device *dev = cmd->se_dev;
-	struct se_subsystem_dev *su_dev = dev->se_sub_dev;
-	int sector_ret = 0, passthrough;
-	u32 sectors = 0, size = 0;
-	u16 service_action;
-	int ret;
-
-	/*
-	 * If we operate in passthrough mode we skip most CDB emulation and
-	 * instead hand the commands down to the physical SCSI device.
-	 */
-	passthrough =
-		(dev->transport->transport_type == TRANSPORT_PLUGIN_PHBA_PDEV);
-
-	switch (cdb[0]) {
-	case READ_6:
-		sectors = transport_get_sectors_6(cdb, cmd, &sector_ret);
-		if (sector_ret)
-			goto out_unsupported_cdb;
-		size = transport_get_size(sectors, cdb, cmd);
-		cmd->t_task_lba = transport_lba_21(cdb);
-		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
-		break;
-	case READ_10:
-		sectors = transport_get_sectors_10(cdb, cmd, &sector_ret);
-		if (sector_ret)
-			goto out_unsupported_cdb;
-		size = transport_get_size(sectors, cdb, cmd);
-		cmd->t_task_lba = transport_lba_32(cdb);
-		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
-		break;
-	case READ_12:
-		sectors = transport_get_sectors_12(cdb, cmd, &sector_ret);
-		if (sector_ret)
-			goto out_unsupported_cdb;
-		size = transport_get_size(sectors, cdb, cmd);
-		cmd->t_task_lba = transport_lba_32(cdb);
-		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
-		break;
-	case READ_16:
-		sectors = transport_get_sectors_16(cdb, cmd, &sector_ret);
-		if (sector_ret)
-			goto out_unsupported_cdb;
-		size = transport_get_size(sectors, cdb, cmd);
-		cmd->t_task_lba = transport_lba_64(cdb);
-		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
-		break;
-	case WRITE_6:
-		sectors = transport_get_sectors_6(cdb, cmd, &sector_ret);
-		if (sector_ret)
-			goto out_unsupported_cdb;
-		size = transport_get_size(sectors, cdb, cmd);
-		cmd->t_task_lba = transport_lba_21(cdb);
-		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
-		break;
-	case WRITE_10:
-	case WRITE_VERIFY:
-		sectors = transport_get_sectors_10(cdb, cmd, &sector_ret);
-		if (sector_ret)
-			goto out_unsupported_cdb;
-		size = transport_get_size(sectors, cdb, cmd);
-		cmd->t_task_lba = transport_lba_32(cdb);
-		if (cdb[1] & 0x8)
-			cmd->se_cmd_flags |= SCF_FUA;
-		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
-		break;
-	case WRITE_12:
-		sectors = transport_get_sectors_12(cdb, cmd, &sector_ret);
-		if (sector_ret)
-			goto out_unsupported_cdb;
-		size = transport_get_size(sectors, cdb, cmd);
-		cmd->t_task_lba = transport_lba_32(cdb);
-		if (cdb[1] & 0x8)
-			cmd->se_cmd_flags |= SCF_FUA;
-		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
-		break;
-	case WRITE_16:
-		sectors = transport_get_sectors_16(cdb, cmd, &sector_ret);
-		if (sector_ret)
-			goto out_unsupported_cdb;
-		size = transport_get_size(sectors, cdb, cmd);
-		cmd->t_task_lba = transport_lba_64(cdb);
-		if (cdb[1] & 0x8)
-			cmd->se_cmd_flags |= SCF_FUA;
-		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
-		break;
-	case XDWRITEREAD_10:
-		if ((cmd->data_direction != DMA_TO_DEVICE) ||
-		    !(cmd->se_cmd_flags & SCF_BIDI))
-			goto out_invalid_cdb_field;
-		sectors = transport_get_sectors_10(cdb, cmd, &sector_ret);
-		if (sector_ret)
-			goto out_unsupported_cdb;
-		size = transport_get_size(sectors, cdb, cmd);
-		cmd->t_task_lba = transport_lba_32(cdb);
-		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
-
-		/*
-		 * Do now allow BIDI commands for passthrough mode.
-		 */
-		if (passthrough)
-			goto out_unsupported_cdb;
-
-		/*
-		 * Setup BIDI XOR callback to be run after I/O completion.
-		 */
-		cmd->transport_complete_callback = &transport_xor_callback;
-		if (cdb[1] & 0x8)
-			cmd->se_cmd_flags |= SCF_FUA;
-		break;
-	case VARIABLE_LENGTH_CMD:
-		service_action = get_unaligned_be16(&cdb[8]);
-		switch (service_action) {
-		case XDWRITEREAD_32:
-			sectors = transport_get_sectors_32(cdb, cmd, &sector_ret);
-			if (sector_ret)
-				goto out_unsupported_cdb;
-			size = transport_get_size(sectors, cdb, cmd);
-			/*
-			 * Use WRITE_32 and READ_32 opcodes for the emulated
-			 * XDWRITE_READ_32 logic.
-			 */
-			cmd->t_task_lba = transport_lba_64_ext(cdb);
-			cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;
-
-			/*
-			 * Do now allow BIDI commands for passthrough mode.
-			 */
-			if (passthrough)
-				goto out_unsupported_cdb;
-
-			/*
-			 * Setup BIDI XOR callback to be run during after I/O
-			 * completion.
-			 */
-			cmd->transport_complete_callback = &transport_xor_callback;
-			if (cdb[1] & 0x8)
-				cmd->se_cmd_flags |= SCF_FUA;
-			break;
-		case WRITE_SAME_32:
-			sectors = transport_get_sectors_32(cdb, cmd, &sector_ret);
-			if (sector_ret)
-				goto out_unsupported_cdb;
-
-			if (sectors)
-				size = transport_get_size(1, cdb, cmd);
-			else {
-				pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not"
-				       " supported\n");
-				goto out_invalid_cdb_field;
-			}
-
-			cmd->t_task_lba = get_unaligned_be64(&cdb[12]);
-
-			if (target_check_write_same_discard(&cdb[10], dev) < 0)
-				goto out_unsupported_cdb;
-			if (!passthrough)
-				cmd->execute_cmd = target_emulate_write_same;
-			break;
-		default:
-			pr_err("VARIABLE_LENGTH_CMD service action"
-				" 0x%04x not supported\n", service_action);
-			goto out_unsupported_cdb;
-		}
-		break;
-	case MAINTENANCE_IN:
-		if (dev->transport->get_device_type(dev) != TYPE_ROM) {
-			/* MAINTENANCE_IN from SCC-2 */
-			/*
-			 * Check for emulated MI_REPORT_TARGET_PGS.
-			 */
-			if ((cdb[1] & 0x1f) == MI_REPORT_TARGET_PGS &&
-			    su_dev->t10_alua.alua_type == SPC3_ALUA_EMULATED) {
-				cmd->execute_cmd =
-					target_emulate_report_target_port_groups;
-			}
-			size = (cdb[6] << 24) | (cdb[7] << 16) |
-			       (cdb[8] << 8) | cdb[9];
-		} else {
-			/* GPCMD_SEND_KEY from multi media commands */
-			size = (cdb[8] << 8) + cdb[9];
-		}
-		break;
-	case GPCMD_READ_BUFFER_CAPACITY:
-	case GPCMD_SEND_OPC:
-		size = (cdb[7] << 8) + cdb[8];
-		break;
-	case READ_BLOCK_LIMITS:
-		size = READ_BLOCK_LEN;
-		break;
-	case GPCMD_GET_CONFIGURATION:
-	case GPCMD_READ_FORMAT_CAPACITIES:
-	case GPCMD_READ_DISC_INFO:
-	case GPCMD_READ_TRACK_RZONE_INFO:
-		size = (cdb[7] << 8) + cdb[8];
-		break;
-	case GPCMD_MECHANISM_STATUS:
-	case GPCMD_READ_DVD_STRUCTURE:
-		size = (cdb[8] << 8) + cdb[9];
-		break;
-	case READ_POSITION:
-		size = READ_POSITION_LEN;
-		break;
-	case MAINTENANCE_OUT:
-		if (dev->transport->get_device_type(dev) != TYPE_ROM) {
-			/* MAINTENANCE_OUT from SCC-2
-			 *
-			 * Check for emulated MO_SET_TARGET_PGS.
-			 */
-			if (cdb[1] == MO_SET_TARGET_PGS &&
-			    su_dev->t10_alua.alua_type == SPC3_ALUA_EMULATED) {
-				cmd->execute_cmd =
-					target_emulate_set_target_port_groups;
-			}
-
-			size = (cdb[6] << 24) | (cdb[7] << 16) |
-			       (cdb[8] << 8) | cdb[9];
-		} else  {
-			/* GPCMD_REPORT_KEY from multi media commands */
-			size = (cdb[8] << 8) + cdb[9];
-		}
-		break;
-	case READ_BUFFER:
-		size = (cdb[6] << 16) + (cdb[7] << 8) + cdb[8];
-		break;
-	case READ_CAPACITY:
-		size = READ_CAP_LEN;
-		if (!passthrough)
-			cmd->execute_cmd = target_emulate_readcapacity;
-		break;
-	case READ_MEDIA_SERIAL_NUMBER:
-	case SERVICE_ACTION_IN:
-		switch (cmd->t_task_cdb[1] & 0x1f) {
-		case SAI_READ_CAPACITY_16:
-			if (!passthrough)
-				cmd->execute_cmd =
-					target_emulate_readcapacity_16;
-			break;
-		default:
-			if (passthrough)
-				break;
-
-			pr_err("Unsupported SA: 0x%02x\n",
-				cmd->t_task_cdb[1] & 0x1f);
-			goto out_invalid_cdb_field;
-		}
-		/*FALLTHROUGH*/
-	case ACCESS_CONTROL_IN:
-	case ACCESS_CONTROL_OUT:
-		size = (cdb[10] << 24) | (cdb[11] << 16) |
-		       (cdb[12] << 8) | cdb[13];
-		break;
-/* #warning FIXME: Figure out correct GPCMD_READ_CD blocksize. */
-#if 0
-	case GPCMD_READ_CD:
-		sectors = (cdb[6] << 16) + (cdb[7] << 8) + cdb[8];
-		size = (2336 * sectors);
-		break;
-#endif
-	case READ_TOC:
-		size = cdb[8];
-		break;
-	case READ_ELEMENT_STATUS:
-		size = 65536 * cdb[7] + 256 * cdb[8] + cdb[9];
-		break;
-	case SYNCHRONIZE_CACHE:
-	case SYNCHRONIZE_CACHE_16:
-		/*
-		 * Extract LBA and range to be flushed for emulated SYNCHRONIZE_CACHE
-		 */
-		if (cdb[0] == SYNCHRONIZE_CACHE) {
-			sectors = transport_get_sectors_10(cdb, cmd, &sector_ret);
-			cmd->t_task_lba = transport_lba_32(cdb);
-		} else {
-			sectors = transport_get_sectors_16(cdb, cmd, &sector_ret);
-			cmd->t_task_lba = transport_lba_64(cdb);
-		}
-		if (sector_ret)
-			goto out_unsupported_cdb;
-
-		size = transport_get_size(sectors, cdb, cmd);
-
-		if (passthrough)
-			break;
-
-		/*
-		 * Check to ensure that LBA + Range does not exceed past end of
-		 * device for IBLOCK and FILEIO ->do_sync_cache() backend calls
-		 */
-		if ((cmd->t_task_lba != 0) || (sectors != 0)) {
-			if (transport_cmd_get_valid_sectors(cmd) < 0)
-				goto out_invalid_cdb_field;
-		}
-		cmd->execute_cmd = target_emulate_synchronize_cache;
-		break;
-	case UNMAP:
-		size = get_unaligned_be16(&cdb[7]);
-		if (!passthrough)
-			cmd->execute_cmd = target_emulate_unmap;
-		break;
-	case WRITE_SAME_16:
-		sectors = transport_get_sectors_16(cdb, cmd, &sector_ret);
-		if (sector_ret)
-			goto out_unsupported_cdb;
-
-		if (sectors)
-			size = transport_get_size(1, cdb, cmd);
-		else {
-			pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");
-			goto out_invalid_cdb_field;
-		}
-
-		cmd->t_task_lba = get_unaligned_be64(&cdb[2]);
-
-		if (target_check_write_same_discard(&cdb[1], dev) < 0)
-			goto out_unsupported_cdb;
-		if (!passthrough)
-			cmd->execute_cmd = target_emulate_write_same;
-		break;
-	case WRITE_SAME:
-		sectors = transport_get_sectors_10(cdb, cmd, &sector_ret);
-		if (sector_ret)
-			goto out_unsupported_cdb;
-
-		if (sectors)
-			size = transport_get_size(1, cdb, cmd);
-		else {
-			pr_err("WSNZ=1, WRITE_SAME w/sectors=0 not supported\n");
-			goto out_invalid_cdb_field;
-		}
-
-		cmd->t_task_lba = get_unaligned_be32(&cdb[2]);
-		/*
-		 * Follow sbcr26 with WRITE_SAME (10) and check for the existence
-		 * of byte 1 bit 3 UNMAP instead of original reserved field
-		 */
-		if (target_check_write_same_discard(&cdb[1], dev) < 0)
-			goto out_unsupported_cdb;
-		if (!passthrough)
-			cmd->execute_cmd = target_emulate_write_same;
-		break;
-	case ALLOW_MEDIUM_REMOVAL:
-	case ERASE:
-	case REZERO_UNIT:
-	case SEEK_10:
-	case SPACE:
-	case START_STOP:
-	case VERIFY:
-	case WRITE_FILEMARKS:
-		if (!passthrough)
-			cmd->execute_cmd = target_emulate_noop;
-		break;
-	case GPCMD_CLOSE_TRACK:
-	case INITIALIZE_ELEMENT_STATUS:
-	case GPCMD_LOAD_UNLOAD:
-	case GPCMD_SET_SPEED:
-	case MOVE_MEDIUM:
-		break;
-	case GET_EVENT_STATUS_NOTIFICATION:
-		size = (cdb[7] << 8) | cdb[8];
-		break;
-	case ATA_16:
-		/* Only support ATA passthrough to pSCSI backends.. */
-		if (!passthrough)
-			goto out_unsupported_cdb;
-
-		/* T_LENGTH */
-		switch (cdb[2] & 0x3) {
-		case 0x0:
-			sectors = 0;
-			break;
-		case 0x1:
-			sectors = (((cdb[1] & 0x1) ? cdb[3] : 0) << 8) | cdb[4];
-			break;
-		case 0x2:
-			sectors = (((cdb[1] & 0x1) ? cdb[5] : 0) << 8) | cdb[6];
-			break;
-		case 0x3:
-			pr_err("T_LENGTH=0x3 not supported for ATA_16\n");
-			goto out_invalid_cdb_field;
-		}
-
-		/* BYTE_BLOCK */
-		if (cdb[2] & 0x4) {
-			/* BLOCK T_TYPE: 512 or sector */
-			size = sectors * ((cdb[2] & 0x10) ?
-				dev->se_sub_dev->se_dev_attrib.block_size : 512);
-		} else {
-			/* BYTE */
-			size = sectors;
-		}
-		break;
-	default:
-		ret = spc_parse_cdb(cmd, &size, passthrough);
-		if (ret)
-			return ret;
-	}
-
-	ret = target_cmd_size_check(cmd, size);
-	if (ret)
-		return ret;
-
-	if (cmd->se_cmd_flags & SCF_SCSI_DATA_CDB) {
-		if (sectors > su_dev->se_dev_attrib.fabric_max_sectors) {
-			printk_ratelimited(KERN_ERR "SCSI OP %02xh with too"
-				" big sectors %u exceeds fabric_max_sectors:"
-				" %u\n", cdb[0], sectors,
-				su_dev->se_dev_attrib.fabric_max_sectors);
-			goto out_invalid_cdb_field;
-		}
-		if (sectors > su_dev->se_dev_attrib.hw_max_sectors) {
-			printk_ratelimited(KERN_ERR "SCSI OP %02xh with too"
-				" big sectors %u exceeds backend hw_max_sectors:"
-				" %u\n", cdb[0], sectors,
-				su_dev->se_dev_attrib.hw_max_sectors);
-			goto out_invalid_cdb_field;
-		}
-	}
-
-	/* reject any command that we don't have a handler for */
-	if (!(passthrough || cmd->execute_cmd ||
-	     (cmd->se_cmd_flags & SCF_SCSI_DATA_CDB)))
-		goto out_unsupported_cdb;
-
-	return 0;
-
-out_unsupported_cdb:
-	cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
-	cmd->scsi_sense_reason = TCM_UNSUPPORTED_SCSI_OPCODE;
-	return -EINVAL;
-out_invalid_cdb_field:
-	cmd->se_cmd_flags |= SCF_SCSI_CDB_EXCEPTION;
-	cmd->scsi_sense_reason = TCM_INVALID_CDB_FIELD;
-	return -EINVAL;
-}
-
 /*
  * Called from I/O completion to determine which dormant/delayed
  * and ordered cmds need to have their tasks added to the execution queue.

include/target/target_core_backend.h

@@ -24,6 +24,8 @@ struct se_subsystem_api {
 				struct se_subsystem_dev *, void *);
 	void (*free_device)(void *);
 	int (*transport_complete)(struct se_cmd *cmd, struct scatterlist *);
+
+	int (*parse_cdb)(struct se_cmd *cmd, unsigned int *size);
 	int (*execute_cmd)(struct se_cmd *, struct scatterlist *, u32,
 			enum dma_data_direction);
 	int (*do_discard)(struct se_device *, sector_t, u32);
@@ -49,6 +51,9 @@ struct se_device *transport_add_device_to_core_hba(struct se_hba *,
 
 void	target_complete_cmd(struct se_cmd *, u8);
 
+int	sbc_parse_cdb(struct se_cmd *cmd, unsigned int *size);
+int	spc_parse_cdb(struct se_cmd *cmd, unsigned int *size, bool passthrough);
+
 void	transport_set_vpd_proto_id(struct t10_vpd *, unsigned char *);
 int	transport_set_vpd_assoc(struct t10_vpd *, unsigned char *);
 int	transport_set_vpd_ident_type(struct t10_vpd *, unsigned char *);