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authorChristoph Hellwig <hch@infradead.org>2012-05-20 11:59:14 -0400
committerNicholas Bellinger <nab@linux-iscsi.org>2012-07-16 17:25:56 -0700
commitd6e0175cf3f9737a760482d185bb73566bcc9331 (patch)
tree99ca8361ebc8c4e83f8335193963faa3f30007b5 /drivers/target/target_core_sbc.c
parent88455ec4be02c395820b1ff57656b0844ec03ac3 (diff)
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>
Diffstat (limited to 'drivers/target/target_core_sbc.c')
-rw-r--r--drivers/target/target_core_sbc.c450
1 files changed, 450 insertions, 0 deletions
diff --git a/drivers/target/target_core_sbc.c b/drivers/target/target_core_sbc.c
new file mode 100644
index 00000000000..9d1ca381487
--- /dev/null
+++ b/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);