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target/user: Only support full command pass-through
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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: Andy Grover <[email protected]>
Reviewed-by: Ilias Tsitsimpis <[email protected]>
Signed-off-by: Nicholas Bellinger <[email protected]>
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Andy Grover authored and Nicholas Bellinger committed May 31, 2015
1 parent cf87edc commit 9c1cd1b
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Showing 2 changed files with 75 additions and 70 deletions.
21 changes: 1 addition & 20 deletions Documentation/target/tcmu-design.txt
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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
Expand Down Expand Up @@ -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
------------

Expand Down
124 changes: 74 additions & 50 deletions drivers/target/target_core_user.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -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}
};

Expand All @@ -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)
Expand Down Expand Up @@ -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;
}
Expand Down Expand Up @@ -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;
Expand All @@ -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,
};

Expand All @@ -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,
Expand Down

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