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, 12 deletions

diff --git a/drivers/target/target_core_file.c b/drivers/target/target_core_file.c
index e865885352da..7c5b1ef57d34 100644
--- a/drivers/target/target_core_file.c
+++ b/drivers/target/target_core_file.c
@@ -46,10 +46,6 @@ static inline struct fd_dev *FD_DEV(struct se_device *dev)
 	return container_of(dev, struct fd_dev, dev);
 }
 
-/*	fd_attach_hba(): (Part of se_subsystem_api_t template)
- *
- *
- */
 static int fd_attach_hba(struct se_hba *hba, u32 host_id)
 {
 	struct fd_host *fd_host;
@@ -881,7 +877,7 @@ static struct configfs_attribute *fileio_backend_dev_attrs[] = {
 	NULL,
 };
 
-static struct se_subsystem_api fileio_template = {
+static const struct target_backend_ops fileio_ops = {
 	.name			= "fileio",
 	.inquiry_prod		= "FILEIO",
 	.inquiry_rev		= FD_VERSION,
@@ -899,21 +895,17 @@ static struct se_subsystem_api fileio_template = {
 	.init_prot		= fd_init_prot,
 	.format_prot		= fd_format_prot,
 	.free_prot		= fd_free_prot,
+	.tb_dev_attrib_attrs	= fileio_backend_dev_attrs,
 };
 
 static int __init fileio_module_init(void)
 {
-	struct target_backend_cits *tbc = &fileio_template.tb_cits;
-
-	target_core_setup_sub_cits(&fileio_template);
-	tbc->tb_dev_attrib_cit.ct_attrs = fileio_backend_dev_attrs;
-
-	return transport_subsystem_register(&fileio_template);
+	return transport_backend_register(&fileio_ops);
 }
 
 static void __exit fileio_module_exit(void)
 {
-	transport_subsystem_release(&fileio_template);
+	target_backend_unregister(&fileio_ops);
 }
 
 MODULE_DESCRIPTION("TCM FILEIO subsystem plugin");