scsi: target: Allow userspace to set the completion type

This allows userspace to request if we complete in the backend context
or the frontend driver. It works the same as submission where you can
write 0 to 2 to complete_type:

 0 - Use the fabric driver's preference.

 1 - Complete from the backend calling context if the fabric supports
     it.

 2 - Queue the completion to LIO's completion workqueue.

Signed-off-by: Mike Christie <michael.christie@oracle.com>
Link: https://patch.msgid.link/20260222232946.7637-4-michael.christie@oracle.com
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

2 files changed, 46 insertions, 0 deletions

diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
index 17608ea39d5a..f514fa2e80dd 100644
--- a/drivers/target/target_core_configfs.c
+++ b/drivers/target/target_core_configfs.c
@@ -578,6 +578,7 @@ DEF_CONFIGFS_ATTRIB_SHOW(unmap_zeroes_data);
 DEF_CONFIGFS_ATTRIB_SHOW(max_write_same_len);
 DEF_CONFIGFS_ATTRIB_SHOW(emulate_rsoc);
 DEF_CONFIGFS_ATTRIB_SHOW(submit_type);
+DEF_CONFIGFS_ATTRIB_SHOW(complete_type);
 DEF_CONFIGFS_ATTRIB_SHOW(atomic_max_len);
 DEF_CONFIGFS_ATTRIB_SHOW(atomic_alignment);
 DEF_CONFIGFS_ATTRIB_SHOW(atomic_granularity);
@@ -1269,6 +1270,24 @@ static ssize_t submit_type_store(struct config_item *item, const char *page,
 	return count;
 }
 
+static ssize_t complete_type_store(struct config_item *item, const char *page,
+				   size_t count)
+{
+	struct se_dev_attrib *da = to_attrib(item);
+	int ret;
+	u8 val;
+
+	ret = kstrtou8(page, 0, &val);
+	if (ret < 0)
+		return ret;
+
+	if (val > TARGET_QUEUE_COMPL)
+		return -EINVAL;
+
+	da->complete_type = val;
+	return count;
+}
+
 CONFIGFS_ATTR(, emulate_model_alias);
 CONFIGFS_ATTR(, emulate_dpo);
 CONFIGFS_ATTR(, emulate_fua_write);
@@ -1305,6 +1324,7 @@ CONFIGFS_ATTR(, max_write_same_len);
 CONFIGFS_ATTR(, alua_support);
 CONFIGFS_ATTR(, pgr_support);
 CONFIGFS_ATTR(, submit_type);
+CONFIGFS_ATTR(, complete_type);
 CONFIGFS_ATTR_RO(, atomic_max_len);
 CONFIGFS_ATTR_RO(, atomic_alignment);
 CONFIGFS_ATTR_RO(, atomic_granularity);
@@ -1353,6 +1373,7 @@ struct configfs_attribute *sbc_attrib_attrs[] = {
 	&attr_pgr_support,
 	&attr_emulate_rsoc,
 	&attr_submit_type,
+	&attr_complete_type,
 	&attr_atomic_alignment,
 	&attr_atomic_max_len,
 	&attr_atomic_granularity,
@@ -1376,6 +1397,7 @@ struct configfs_attribute *passthrough_attrib_attrs[] = {
 	&attr_alua_support,
 	&attr_pgr_support,
 	&attr_submit_type,
+	&attr_complete_type,
 	NULL,
 };
 EXPORT_SYMBOL(passthrough_attrib_attrs);
diff --git a/drivers/target/target_core_fabric_configfs.c b/drivers/target/target_core_fabric_configfs.c
index 331689b30f85..166dbf4c4061 100644
--- a/drivers/target/target_core_fabric_configfs.c
+++ b/drivers/target/target_core_fabric_configfs.c
@@ -1066,6 +1066,28 @@ target_fabric_wwn_cmd_completion_affinity_store(struct config_item *item,
 CONFIGFS_ATTR(target_fabric_wwn_, cmd_completion_affinity);
 
 static ssize_t
+target_fabric_wwn_default_complete_type_show(struct config_item *item,
+					     char *page)
+{
+	struct se_wwn *wwn = container_of(to_config_group(item), struct se_wwn,
+					  param_group);
+	return sysfs_emit(page, "%u\n",
+			  wwn->wwn_tf->tf_ops->default_compl_type);
+}
+CONFIGFS_ATTR_RO(target_fabric_wwn_, default_complete_type);
+
+static ssize_t
+target_fabric_wwn_direct_complete_supported_show(struct config_item *item,
+						 char *page)
+{
+	struct se_wwn *wwn = container_of(to_config_group(item), struct se_wwn,
+					  param_group);
+	return sysfs_emit(page, "%u\n",
+			  wwn->wwn_tf->tf_ops->direct_compl_supp);
+}
+CONFIGFS_ATTR_RO(target_fabric_wwn_, direct_complete_supported);
+
+static ssize_t
 target_fabric_wwn_default_submit_type_show(struct config_item *item,
 					   char *page)
 {
@@ -1089,6 +1111,8 @@ CONFIGFS_ATTR_RO(target_fabric_wwn_, direct_submit_supported);
 
 static struct configfs_attribute *target_fabric_wwn_param_attrs[] = {
 	&target_fabric_wwn_attr_cmd_completion_affinity,
+	&target_fabric_wwn_attr_default_complete_type,
+	&target_fabric_wwn_attr_direct_complete_supported,
 	&target_fabric_wwn_attr_default_submit_type,
 	&target_fabric_wwn_attr_direct_submit_supported,
 	NULL,