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Commit 9c1cd1b6 authored by Andy Grover's avatar Andy Grover Committed by Nicholas Bellinger
Browse files

target/user: Only support full command pass-through 



After much discussion, give up on only passing a subset of SCSI commands
to userspace and pass them all. Based on what pscsi is doing, make sure
to set SCF_SCSI_DATA_CDB for I/O ops, and define attributes identical to
pscsi.

Make hw_block_size configurable via dev param.

Remove mention of command filtering from tcmu-design.txt.

Signed-off-by: default avatarAndy Grover <agrover@redhat.com>
Reviewed-by: default avatarIlias Tsitsimpis <iliastsi@arrikto.com>
Signed-off-by: default avatarNicholas Bellinger <nab@linux-iscsi.org>
parent cf87edc6

Documentation/target/tcmu-design.txt

+1 −20
Original line number Diff line number Diff line
@@ -15,8 +15,7 @@ Contents: 
  a) Discovering and configuring TCMU uio devices

  b) Waiting for events on the device(s)

  c) Managing the command ring

3) Command filtering

4) A final note

3) A final note





TCM Userspace Design
@@ -364,24 +363,6 @@ int handle_device_events(int fd, void *map) 
}





Command filtering

-----------------



Initial TCMU support is for a filtered commandset.  Only IO-related

commands are presented to userspace, and the rest are handled by LIO's

in-kernel command emulation. The commands presented are all versions

of:



READ

WRITE

WRITE_VERIFY

XDWRITEREAD

WRITE_SAME

COMPARE_AND_WRITE

SYNCHRONIZE_CACHE

UNMAP





A final note

------------

drivers/target/target_core_user.c

+74 −50
Original line number Diff line number Diff line
@@ -938,12 +938,13 @@ static void tcmu_free_device(struct se_device *dev) 
}



enum {

	Opt_dev_config, Opt_dev_size, Opt_err,

	Opt_dev_config, Opt_dev_size, Opt_hw_block_size, Opt_err,

};



static match_table_t tokens = {

	{Opt_dev_config, "dev_config=%s"},

	{Opt_dev_size, "dev_size=%u"},

	{Opt_hw_block_size, "hw_block_size=%u"},

	{Opt_err, NULL}

};
@@ -954,6 +955,7 @@ static ssize_t tcmu_set_configfs_dev_params(struct se_device *dev, 
	char *orig, *ptr, *opts, *arg_p;

	substring_t args[MAX_OPT_ARGS];

	int ret = 0, token;

	unsigned long tmp_ul;



	opts = kstrdup(page, GFP_KERNEL);

	if (!opts)
@@ -986,6 +988,24 @@ static ssize_t tcmu_set_configfs_dev_params(struct se_device *dev, 
			if (ret < 0)

				pr_err("kstrtoul() failed for dev_size=\n");

			break;

		case Opt_hw_block_size:

			arg_p = match_strdup(&args[0]);

			if (!arg_p) {

				ret = -ENOMEM;

				break;

			}

			ret = kstrtoul(arg_p, 0, &tmp_ul);

			kfree(arg_p);

			if (ret < 0) {

				pr_err("kstrtoul() failed for hw_block_size=\n");

				break;

			}

			if (!tmp_ul) {

				pr_err("hw_block_size must be nonzero\n");

				break;

			}

			dev->dev_attrib.hw_block_size = tmp_ul;

			break;

		default:

			break;

		}
@@ -1016,12 +1036,9 @@ static sector_t tcmu_get_blocks(struct se_device *dev) 
}



static sense_reason_t

tcmu_execute_rw(struct se_cmd *se_cmd, struct scatterlist *sgl, u32 sgl_nents,

		enum dma_data_direction data_direction)

tcmu_pass_op(struct se_cmd *se_cmd)

{

	int ret;



	ret = tcmu_queue_cmd(se_cmd);

	int ret = tcmu_queue_cmd(se_cmd);



	if (ret != 0)

		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;
@@ -1030,62 +1047,69 @@ tcmu_execute_rw(struct se_cmd *se_cmd, struct scatterlist *sgl, u32 sgl_nents, 
}



static sense_reason_t

tcmu_pass_op(struct se_cmd *se_cmd)

tcmu_parse_cdb(struct se_cmd *cmd)

{

	int ret = tcmu_queue_cmd(se_cmd);

	unsigned char *cdb = cmd->t_task_cdb;



	if (ret != 0)

		return TCM_LOGICAL_UNIT_COMMUNICATION_FAILURE;

	else

	/*

	 * For REPORT LUNS we always need to emulate the response, for everything

	 * else, pass it up.

	 */

	if (cdb[0] == REPORT_LUNS) {

		cmd->execute_cmd = spc_emulate_report_luns;

		return TCM_NO_SENSE;

	}



static struct sbc_ops tcmu_sbc_ops = {

	.execute_rw = tcmu_execute_rw,

	.execute_sync_cache	= tcmu_pass_op,

	.execute_write_same	= tcmu_pass_op,

	.execute_write_same_unmap = tcmu_pass_op,

	.execute_unmap		= tcmu_pass_op,

};

	/* Set DATA_CDB flag for ops that should have it */

	switch (cdb[0]) {

	case READ_6:

	case READ_10:

	case READ_12:

	case READ_16:

	case WRITE_6:

	case WRITE_10:

	case WRITE_12:

	case WRITE_16:

	case WRITE_VERIFY:

	case WRITE_VERIFY_12:

	case 0x8e: /* WRITE_VERIFY_16 */

	case COMPARE_AND_WRITE:

	case XDWRITEREAD_10:

		cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;

		break;

	case VARIABLE_LENGTH_CMD:

		switch (get_unaligned_be16(&cdb[8])) {

		case READ_32:

		case WRITE_32:

		case 0x0c: /* WRITE_VERIFY_32 */

		case XDWRITEREAD_32:

			cmd->se_cmd_flags |= SCF_SCSI_DATA_CDB;

			break;

		}

	}



static sense_reason_t

tcmu_parse_cdb(struct se_cmd *cmd)

{

	return sbc_parse_cdb(cmd, &tcmu_sbc_ops);

	cmd->execute_cmd = tcmu_pass_op;



	return TCM_NO_SENSE;

}



DEF_TB_DEFAULT_ATTRIBS(tcmu);

DEF_TB_DEV_ATTRIB_RO(tcmu, hw_pi_prot_type);

TB_DEV_ATTR_RO(tcmu, hw_pi_prot_type);



DEF_TB_DEV_ATTRIB_RO(tcmu, hw_block_size);

TB_DEV_ATTR_RO(tcmu, hw_block_size);



DEF_TB_DEV_ATTRIB_RO(tcmu, hw_max_sectors);

TB_DEV_ATTR_RO(tcmu, hw_max_sectors);



DEF_TB_DEV_ATTRIB_RO(tcmu, hw_queue_depth);

TB_DEV_ATTR_RO(tcmu, hw_queue_depth);



static struct configfs_attribute *tcmu_backend_dev_attrs[] = {

	&tcmu_dev_attrib_emulate_model_alias.attr,

	&tcmu_dev_attrib_emulate_dpo.attr,

	&tcmu_dev_attrib_emulate_fua_write.attr,

	&tcmu_dev_attrib_emulate_fua_read.attr,

	&tcmu_dev_attrib_emulate_write_cache.attr,

	&tcmu_dev_attrib_emulate_ua_intlck_ctrl.attr,

	&tcmu_dev_attrib_emulate_tas.attr,

	&tcmu_dev_attrib_emulate_tpu.attr,

	&tcmu_dev_attrib_emulate_tpws.attr,

	&tcmu_dev_attrib_emulate_caw.attr,

	&tcmu_dev_attrib_emulate_3pc.attr,

	&tcmu_dev_attrib_pi_prot_type.attr,

	&tcmu_dev_attrib_hw_pi_prot_type.attr,

	&tcmu_dev_attrib_pi_prot_format.attr,

	&tcmu_dev_attrib_enforce_pr_isids.attr,

	&tcmu_dev_attrib_is_nonrot.attr,

	&tcmu_dev_attrib_emulate_rest_reord.attr,

	&tcmu_dev_attrib_force_pr_aptpl.attr,

	&tcmu_dev_attrib_hw_block_size.attr,

	&tcmu_dev_attrib_block_size.attr,

	&tcmu_dev_attrib_hw_max_sectors.attr,

	&tcmu_dev_attrib_optimal_sectors.attr,

	&tcmu_dev_attrib_hw_queue_depth.attr,

	&tcmu_dev_attrib_queue_depth.attr,

	&tcmu_dev_attrib_max_unmap_lba_count.attr,

	&tcmu_dev_attrib_max_unmap_block_desc_count.attr,

	&tcmu_dev_attrib_unmap_granularity.attr,

	&tcmu_dev_attrib_unmap_granularity_alignment.attr,

	&tcmu_dev_attrib_max_write_same_len.attr,

	NULL,

};
@@ -1094,7 +1118,7 @@ static struct se_subsystem_api tcmu_template = { 
	.inquiry_prod		= "USER",

	.inquiry_rev		= TCMU_VERSION,

	.owner			= THIS_MODULE,

	.transport_type		= TRANSPORT_PLUGIN_VHBA_PDEV,

	.transport_type		= TRANSPORT_PLUGIN_PHBA_PDEV,

	.attach_hba		= tcmu_attach_hba,

	.detach_hba		= tcmu_detach_hba,

	.alloc_device		= tcmu_alloc_device,