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linux/drivers/target/target_core_sbc.c
Bernhard Kohl 1a1ff38c4c target: reintroduce some obsolete SCSI-2 commands 
With kernel 3.6 some obsolete SCSI-2 commands including SEEK_10 have
have been removed by commit 1fd032ee10
"target: move code for CDB emulation".

There are still clients out there which use these old SCSI-2 commands.
This mainly happens when running VMs with legacy guest systems,
connected via SCSI command pass-through to iSCSI targets. Make them
happy and return status GOOD.

Many real SCSI disks or external iSCSI storage devices still support
these old commands. So let's make LIO backward compatible as well.

This patch adds support for the previously removed SEEK_10 and
additionally the SEEK_6 and REZERO_UNIT commands.

Signed-off-by: Bernhard Kohl <bernhard.kohl@nsn.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: stable@vger.kernel.org
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>
2012-10-26 16:49:40 -07:00

606 lines
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/*
* 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 int sbc_emulate_readcapacity(struct se_cmd *cmd)
{
struct se_device *dev = cmd->se_dev;
unsigned long long blocks_long = dev->transport->get_blocks(dev);
unsigned char *rbuf;
unsigned char buf[8];
u32 blocks;
if (blocks_long >= 0x00000000ffffffff)
blocks = 0xffffffff;
else
blocks = (u32)blocks_long;
buf[0] = (blocks >> 24) & 0xff;
buf[1] = (blocks >> 16) & 0xff;
buf[2] = (blocks >> 8) & 0xff;
buf[3] = blocks & 0xff;
buf[4] = (dev->se_sub_dev->se_dev_attrib.block_size >> 24) & 0xff;
buf[5] = (dev->se_sub_dev->se_dev_attrib.block_size >> 16) & 0xff;
buf[6] = (dev->se_sub_dev->se_dev_attrib.block_size >> 8) & 0xff;
buf[7] = dev->se_sub_dev->se_dev_attrib.block_size & 0xff;
rbuf = transport_kmap_data_sg(cmd);
if (rbuf) {
memcpy(rbuf, buf, min_t(u32, sizeof(buf), cmd->data_length));
transport_kunmap_data_sg(cmd);
}
target_complete_cmd(cmd, GOOD);
return 0;
}
static int sbc_emulate_readcapacity_16(struct se_cmd *cmd)
{
struct se_device *dev = cmd->se_dev;
unsigned char *rbuf;
unsigned char buf[32];
unsigned long long blocks = dev->transport->get_blocks(dev);
memset(buf, 0, sizeof(buf));
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->se_sub_dev->se_dev_attrib.block_size >> 24) & 0xff;
buf[9] = (dev->se_sub_dev->se_dev_attrib.block_size >> 16) & 0xff;
buf[10] = (dev->se_sub_dev->se_dev_attrib.block_size >> 8) & 0xff;
buf[11] = dev->se_sub_dev->se_dev_attrib.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->se_sub_dev->se_dev_attrib.emulate_tpu || dev->se_sub_dev->se_dev_attrib.emulate_tpws)
buf[14] = 0x80;
rbuf = transport_kmap_data_sg(cmd);
if (rbuf) {
memcpy(rbuf, buf, min_t(u32, sizeof(buf), cmd->data_length));
transport_kunmap_data_sg(cmd);
}
target_complete_cmd(cmd, GOOD);
return 0;
}
int spc_get_write_same_sectors(struct se_cmd *cmd)
{
u32 num_blocks;
if (cmd->t_task_cdb[0] == WRITE_SAME)
num_blocks = get_unaligned_be16(&cmd->t_task_cdb[7]);
else if (cmd->t_task_cdb[0] == WRITE_SAME_16)
num_blocks = get_unaligned_be32(&cmd->t_task_cdb[10]);
else /* WRITE_SAME_32 via VARIABLE_LENGTH_CMD */
num_blocks = get_unaligned_be32(&cmd->t_task_cdb[28]);
/*
* Use the explicit range when non zero is supplied, otherwise calculate
* the remaining range based on ->get_blocks() - starting LBA.
*/
if (num_blocks)
return num_blocks;
return cmd->se_dev->transport->get_blocks(cmd->se_dev) -
cmd->t_task_lba + 1;
}
EXPORT_SYMBOL(spc_get_write_same_sectors);
static int sbc_emulate_verify(struct se_cmd *cmd)
{
target_complete_cmd(cmd, GOOD);
return 0;
}
static int sbc_emulate_noop(struct se_cmd *cmd)
{
target_complete_cmd(cmd, GOOD);
return 0;
}
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, struct spc_ops *ops)
{
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;
unsigned int size;
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;
cmd->execute_cmd = ops->execute_rw;
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;
cmd->execute_cmd = ops->execute_rw;
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;
cmd->execute_cmd = ops->execute_rw;
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;
cmd->execute_cmd = ops->execute_rw;
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;
cmd->execute_cmd = ops->execute_rw;
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;
cmd->execute_cmd = ops->execute_rw;
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;
cmd->execute_cmd = ops->execute_rw;
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;
cmd->execute_cmd = ops->execute_rw;
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->execute_cmd = ops->execute_rw;
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->execute_cmd = ops->execute_rw;
cmd->transport_complete_callback = &xdreadwrite_callback;
if (cdb[1] & 0x8)
cmd->se_cmd_flags |= SCF_FUA;
break;
case WRITE_SAME_32:
if (!ops->execute_write_same)
goto out_unsupported_cdb;
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 = ops->execute_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 = sbc_emulate_readcapacity;
break;
case SERVICE_ACTION_IN:
switch (cmd->t_task_cdb[1] & 0x1f) {
case SAI_READ_CAPACITY_16:
cmd->execute_cmd = sbc_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:
if (!ops->execute_sync_cache)
goto out_unsupported_cdb;
/*
* 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 = ops->execute_sync_cache;
break;
case UNMAP:
if (!ops->execute_unmap)
goto out_unsupported_cdb;
size = get_unaligned_be16(&cdb[7]);
cmd->execute_cmd = ops->execute_unmap;
break;
case WRITE_SAME_16:
if (!ops->execute_write_same)
goto out_unsupported_cdb;
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 = ops->execute_write_same;
break;
case WRITE_SAME:
if (!ops->execute_write_same)
goto out_unsupported_cdb;
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 = ops->execute_write_same;
break;
case VERIFY:
size = 0;
cmd->execute_cmd = sbc_emulate_verify;
break;
case REZERO_UNIT:
case SEEK_6:
case SEEK_10:
/*
* There are still clients out there which use these old SCSI-2
* commands. This mainly happens when running VMs with legacy
* guest systems, connected via SCSI command pass-through to
* iSCSI targets. Make them happy and return status GOOD.
*/
size = 0;
cmd->execute_cmd = sbc_emulate_noop;
break;
default:
ret = spc_parse_cdb(cmd, &size);
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) {
unsigned long long end_lba;
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;
}
end_lba = dev->transport->get_blocks(dev) + 1;
if (cmd->t_task_lba + sectors > end_lba) {
pr_err("cmd exceeds last lba %llu "
"(lba %llu, sectors %u)\n",
end_lba, cmd->t_task_lba, sectors);
goto out_invalid_cdb_field;
}
size = sbc_get_size(cmd, sectors);
}
ret = target_cmd_size_check(cmd, size);
if (ret < 0)
return ret;
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);
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