target: simplify backend driver registration

Rewrite the backend driver registration based on what we did to the fabric
drivers:  introduce a read-only struct target_bakckend_ops that the driver
registers, which is then instanciate as a struct target_backend by the
core.  This allows the ops vector to be smaller and allows us to mark it
const.  At the same time the registration function can set up the
configfs attributes, avoiding the need to add additional boilerplate code
for that to the drivers.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Nicholas Bellinger <nab@linux-iscsi.org>

1 files changed, 36 insertions, 32 deletions

diff --git a/drivers/target/target_core_configfs.c b/drivers/target/target_core_configfs.c
index 4a31d4765390..57c099dd9da5 100644
--- a/drivers/target/target_core_configfs.c
+++ b/drivers/target/target_core_configfs.c
@@ -51,15 +51,26 @@
 #include "target_core_xcopy.h"
 
 #define TB_CIT_SETUP(_name, _item_ops, _group_ops, _attrs)		\
-static void target_core_setup_##_name##_cit(struct se_subsystem_api *sa) \
+static void target_core_setup_##_name##_cit(struct target_backend *tb)	\
 {									\
-	struct target_backend_cits *tbc = &sa->tb_cits;			\
-	struct config_item_type *cit = &tbc->tb_##_name##_cit;		\
+	struct config_item_type *cit = &tb->tb_##_name##_cit;		\
 									\
 	cit->ct_item_ops = _item_ops;					\
 	cit->ct_group_ops = _group_ops;					\
 	cit->ct_attrs = _attrs;						\
-	cit->ct_owner = sa->owner;					\
+	cit->ct_owner = tb->ops->owner;					\
+	pr_debug("Setup generic %s\n", __stringify(_name));		\
+}
+
+#define TB_CIT_SETUP_DRV(_name, _item_ops, _group_ops)			\
+static void target_core_setup_##_name##_cit(struct target_backend *tb)	\
+{									\
+	struct config_item_type *cit = &tb->tb_##_name##_cit;		\
+									\
+	cit->ct_item_ops = _item_ops;					\
+	cit->ct_group_ops = _group_ops;					\
+	cit->ct_attrs = tb->ops->tb_##_name##_attrs;			\
+	cit->ct_owner = tb->ops->owner;					\
 	pr_debug("Setup generic %s\n", __stringify(_name));		\
 }
 
@@ -469,7 +480,7 @@ static struct configfs_item_operations target_core_dev_attrib_ops = {
 	.store_attribute	= target_core_dev_attrib_attr_store,
 };
 
-TB_CIT_SETUP(dev_attrib, &target_core_dev_attrib_ops, NULL, NULL);
+TB_CIT_SETUP_DRV(dev_attrib, &target_core_dev_attrib_ops, NULL);
 
 /* End functions for struct config_item_type tb_dev_attrib_cit */
 
@@ -1174,13 +1185,13 @@ TB_CIT_SETUP(dev_pr, &target_core_dev_pr_ops, NULL, target_core_dev_pr_attrs);
 static ssize_t target_core_show_dev_info(void *p, char *page)
 {
 	struct se_device *dev = p;
-	struct se_subsystem_api *t = dev->transport;
 	int bl = 0;
 	ssize_t read_bytes = 0;
 
 	transport_dump_dev_state(dev, page, &bl);
 	read_bytes += bl;
-	read_bytes += t->show_configfs_dev_params(dev, page+read_bytes);
+	read_bytes += dev->transport->show_configfs_dev_params(dev,
+			page+read_bytes);
 	return read_bytes;
 }
 
@@ -1198,9 +1209,8 @@ static ssize_t target_core_store_dev_control(
 	size_t count)
 {
 	struct se_device *dev = p;
-	struct se_subsystem_api *t = dev->transport;
 
-	return t->set_configfs_dev_params(dev, page, count);
+	return dev->transport->set_configfs_dev_params(dev, page, count);
 }
 
 static struct target_core_configfs_attribute target_core_attr_dev_control = {
@@ -2477,9 +2487,9 @@ static struct config_group *target_core_make_subdev(
 	const char *name)
 {
 	struct t10_alua_tg_pt_gp *tg_pt_gp;
-	struct se_subsystem_api *t;
 	struct config_item *hba_ci = &group->cg_item;
 	struct se_hba *hba = item_to_hba(hba_ci);
+	struct target_backend *tb = hba->backend;
 	struct se_device *dev;
 	struct config_group *dev_cg = NULL, *tg_pt_gp_cg = NULL;
 	struct config_group *dev_stat_grp = NULL;
@@ -2488,10 +2498,6 @@ static struct config_group *target_core_make_subdev(
 	ret = mutex_lock_interruptible(&hba->hba_access_mutex);
 	if (ret)
 		return ERR_PTR(ret);
-	/*
-	 * Locate the struct se_subsystem_api from parent's struct se_hba.
-	 */
-	t = hba->transport;
 
 	dev = target_alloc_device(hba, name);
 	if (!dev)
@@ -2504,17 +2510,17 @@ static struct config_group *target_core_make_subdev(
 	if (!dev_cg->default_groups)
 		goto out_free_device;
 
-	config_group_init_type_name(dev_cg, name, &t->tb_cits.tb_dev_cit);
+	config_group_init_type_name(dev_cg, name, &tb->tb_dev_cit);
 	config_group_init_type_name(&dev->dev_attrib.da_group, "attrib",
-			&t->tb_cits.tb_dev_attrib_cit);
+			&tb->tb_dev_attrib_cit);
 	config_group_init_type_name(&dev->dev_pr_group, "pr",
-			&t->tb_cits.tb_dev_pr_cit);
+			&tb->tb_dev_pr_cit);
 	config_group_init_type_name(&dev->t10_wwn.t10_wwn_group, "wwn",
-			&t->tb_cits.tb_dev_wwn_cit);
+			&tb->tb_dev_wwn_cit);
 	config_group_init_type_name(&dev->t10_alua.alua_tg_pt_gps_group,
-			"alua", &t->tb_cits.tb_dev_alua_tg_pt_gps_cit);
+			"alua", &tb->tb_dev_alua_tg_pt_gps_cit);
 	config_group_init_type_name(&dev->dev_stat_grps.stat_group,
-			"statistics", &t->tb_cits.tb_dev_stat_cit);
+			"statistics", &tb->tb_dev_stat_cit);
 
 	dev_cg->default_groups[0] = &dev->dev_attrib.da_group;
 	dev_cg->default_groups[1] = &dev->dev_pr_group;
@@ -2644,7 +2650,7 @@ static ssize_t target_core_hba_show_attr_hba_info(
 	char *page)
 {
 	return sprintf(page, "HBA Index: %d plugin: %s version: %s\n",
-			hba->hba_id, hba->transport->name,
+			hba->hba_id, hba->backend->ops->name,
 			TARGET_CORE_CONFIGFS_VERSION);
 }
 
@@ -2664,11 +2670,10 @@ static ssize_t target_core_hba_show_attr_hba_mode(struct se_hba *hba,
 static ssize_t target_core_hba_store_attr_hba_mode(struct se_hba *hba,
 				const char *page, size_t count)
 {
-	struct se_subsystem_api *transport = hba->transport;
 	unsigned long mode_flag;
 	int ret;
 
-	if (transport->pmode_enable_hba == NULL)
+	if (hba->backend->ops->pmode_enable_hba == NULL)
 		return -EINVAL;
 
 	ret = kstrtoul(page, 0, &mode_flag);
@@ -2682,7 +2687,7 @@ static ssize_t target_core_hba_store_attr_hba_mode(struct se_hba *hba,
 		return -EINVAL;
 	}
 
-	ret = transport->pmode_enable_hba(hba, mode_flag);
+	ret = hba->backend->ops->pmode_enable_hba(hba, mode_flag);
 	if (ret < 0)
 		return -EINVAL;
 	if (ret > 0)
@@ -2808,16 +2813,15 @@ static struct config_item_type target_core_cit = {
 
 /* Stop functions for struct config_item_type target_core_hba_cit */
 
-void target_core_setup_sub_cits(struct se_subsystem_api *sa)
+void target_setup_backend_cits(struct target_backend *tb)
 {
-	target_core_setup_dev_cit(sa);
-	target_core_setup_dev_attrib_cit(sa);
-	target_core_setup_dev_pr_cit(sa);
-	target_core_setup_dev_wwn_cit(sa);
-	target_core_setup_dev_alua_tg_pt_gps_cit(sa);
-	target_core_setup_dev_stat_cit(sa);
+	target_core_setup_dev_cit(tb);
+	target_core_setup_dev_attrib_cit(tb);
+	target_core_setup_dev_pr_cit(tb);
+	target_core_setup_dev_wwn_cit(tb);
+	target_core_setup_dev_alua_tg_pt_gps_cit(tb);
+	target_core_setup_dev_stat_cit(tb);
 }
-EXPORT_SYMBOL(target_core_setup_sub_cits);
 
 static int __init target_core_init_configfs(void)
 {