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, 18 deletions

diff --git a/drivers/target/target_core_rd.c b/drivers/target/target_core_rd.c
index 55315fd0f5d3..cf443a8a3cbe 100644
--- a/drivers/target/target_core_rd.c
+++ b/drivers/target/target_core_rd.c
@@ -43,10 +43,6 @@ static inline struct rd_dev *RD_DEV(struct se_device *dev)
 	return container_of(dev, struct rd_dev, dev);
 }
 
-/*	rd_attach_hba(): (Part of se_subsystem_api_t template)
- *
- *
- */
 static int rd_attach_hba(struct se_hba *hba, u32 host_id)
 {
 	struct rd_host *rd_host;
@@ -735,7 +731,7 @@ static struct configfs_attribute *rd_mcp_backend_dev_attrs[] = {
 	NULL,
 };
 
-static struct se_subsystem_api rd_mcp_template = {
+static const struct target_backend_ops rd_mcp_ops = {
 	.name			= "rd_mcp",
 	.inquiry_prod		= "RAMDISK-MCP",
 	.inquiry_rev		= RD_MCP_VERSION,
@@ -751,25 +747,15 @@ static struct se_subsystem_api rd_mcp_template = {
 	.get_blocks		= rd_get_blocks,
 	.init_prot		= rd_init_prot,
 	.free_prot		= rd_free_prot,
+	.tb_dev_attrib_attrs	= rd_mcp_backend_dev_attrs,
 };
 
 int __init rd_module_init(void)
 {
-	struct target_backend_cits *tbc = &rd_mcp_template.tb_cits;
-	int ret;
-
-	target_core_setup_sub_cits(&rd_mcp_template);
-	tbc->tb_dev_attrib_cit.ct_attrs = rd_mcp_backend_dev_attrs;
-
-	ret = transport_subsystem_register(&rd_mcp_template);
-	if (ret < 0) {
-		return ret;
-	}
-
-	return 0;
+	return transport_backend_register(&rd_mcp_ops);
 }
 
 void rd_module_exit(void)
 {
-	transport_subsystem_release(&rd_mcp_template);
+	target_backend_unregister(&rd_mcp_ops);
 }