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, 4 insertions, 10 deletions

diff --git a/drivers/target/target_core_pscsi.c b/drivers/target/target_core_pscsi.c
index 21db991b4465..2e3a0b004f9a 100644
--- a/drivers/target/target_core_pscsi.c
+++ b/drivers/target/target_core_pscsi.c
@@ -57,8 +57,6 @@ static inline struct pscsi_dev_virt *PSCSI_DEV(struct se_device *dev)
 	return container_of(dev, struct pscsi_dev_virt, dev);
 }
 
-static struct se_subsystem_api pscsi_template;
-
 static sense_reason_t pscsi_execute_cmd(struct se_cmd *cmd);
 static void pscsi_req_done(struct request *, int);
 
@@ -1141,7 +1139,7 @@ static struct configfs_attribute *pscsi_backend_dev_attrs[] = {
 	NULL,
 };
 
-static struct se_subsystem_api pscsi_template = {
+static const struct target_backend_ops pscsi_ops = {
 	.name			= "pscsi",
 	.owner			= THIS_MODULE,
 	.transport_flags	= TRANSPORT_FLAG_PASSTHROUGH,
@@ -1157,21 +1155,17 @@ static struct se_subsystem_api pscsi_template = {
 	.show_configfs_dev_params = pscsi_show_configfs_dev_params,
 	.get_device_type	= pscsi_get_device_type,
 	.get_blocks		= pscsi_get_blocks,
+	.tb_dev_attrib_attrs	= pscsi_backend_dev_attrs,
 };
 
 static int __init pscsi_module_init(void)
 {
-	struct target_backend_cits *tbc = &pscsi_template.tb_cits;
-
-	target_core_setup_sub_cits(&pscsi_template);
-	tbc->tb_dev_attrib_cit.ct_attrs = pscsi_backend_dev_attrs;
-
-	return transport_subsystem_register(&pscsi_template);
+	return transport_backend_register(&pscsi_ops);
 }
 
 static void __exit pscsi_module_exit(void)
 {
-	transport_subsystem_release(&pscsi_template);
+	target_backend_unregister(&pscsi_ops);
 }
 
 MODULE_DESCRIPTION("TCM PSCSI subsystem plugin");