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: Andy Grover <agrover@redhat.com>
Reviewed-by: Ilias Tsitsimpis <iliastsi@arrikto.com>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

Documentation/target/tcmu-design.txt

@@ -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

@@ -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,