[PATCH 3/4] scsi: target: Allow userspace to set the completion type

[Mike Christie <michael.christie@oracle.com>]

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>
---
 drivers/target/target_core_configfs.c        | 22 ++++++++++++++++++
 drivers/target/target_core_fabric_configfs.c | 24 ++++++++++++++++++++
 2 files changed, 46 insertions(+)

diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
index f7868b41c5e6..1c1c83c6752c 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 13159928e365..cab48c372e8f 100644
--- a/drivers/target/target_core_fabric_configfs.c
+++ b/drivers/target/target_core_fabric_configfs.c
@@ -1065,6 +1065,28 @@ 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,
-- 
2.43.0