nvmet: initialize discovery subsys after debugfs is initialized

During nvme target initialization discovery subsystem is initialized
before "nvmet" debugfs directory is created. This results in discovery
subsystem debugfs directory to be created in debugfs root directory.

nvmet_init() ->
  nvmet_init_discovery() ->
    nvmet_subsys_alloc() ->
      nvmet_debugfs_subsys_setup()

In other words, the codepath above is exeucted before nvmet_debugfs is
created. We get /sys/kernel/debug/nqn.2014-08.org.nvmexpress.discovery
instead of /sys/kernel/debug/nvmet/nqn.2014-08.org.nvmexpress.discovery.
Move nvmet_init_discovery() call after nvmet_init_debugfs() to fix it.

Fixes: 649fd41 ("nvmet: add debugfs support")
Signed-off-by: Mohamed Khalfella <[email protected]>
Reviewed-by: Chaitanya Kulkarni <[email protected]>
Reviewed-by: Hannes Reinecke <[email protected]>
Reviewed-by: Daniel Wagner <[email protected]>
Signed-off-by: Christoph Hellwig <[email protected]>

Author: Mohamed Khalfella

drivers/nvme/target/core.c

@@ -1960,24 +1960,24 @@ static int __init nvmet_init(void)
 	if (!nvmet_wq)
 		goto out_free_buffered_work_queue;
 
-	error = nvmet_init_discovery();
+	error = nvmet_init_debugfs();
 	if (error)
 		goto out_free_nvmet_work_queue;
 
-	error = nvmet_init_debugfs();
+	error = nvmet_init_discovery();
 	if (error)
-		goto out_exit_discovery;
+		goto out_exit_debugfs;
 
 	error = nvmet_init_configfs();
 	if (error)
-		goto out_exit_debugfs;
+		goto out_exit_discovery;
 
 	return 0;
 
-out_exit_debugfs:
-	nvmet_exit_debugfs();
 out_exit_discovery:
 	nvmet_exit_discovery();
+out_exit_debugfs:
+	nvmet_exit_debugfs();
 out_free_nvmet_work_queue:
 	destroy_workqueue(nvmet_wq);
 out_free_buffered_work_queue: