NFSD: Remove svc_serv_ops::svo_module

struct svc_serv_ops is about to be removed.

Neil Brown says:
> I suspect svo_module can go as well - I don't think the thread is
> ever the thing that primarily keeps a module active.

A random sample of kthread_create() callers shows sunrpc is the only
one that manages module reference count in this way.
Suggested-by: Neil Brown <neilb@suse.de>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

fs/lockd/svc.c

@@ -184,8 +184,7 @@ lockd(void *vrqstp)
 	dprintk("lockd_down: service stopped\n");
 
 	svc_exit_thread(rqstp);
-
-	module_put_and_kthread_exit(0);
+	return 0;
 }
 
 static int create_lockd_listener(struct svc_serv *serv, const char *name,
@@ -352,7 +351,6 @@ static struct notifier_block lockd_inet6addr_notifier = {
 
 static const struct svc_serv_ops lockd_sv_ops = {
 	.svo_function		= lockd,
-	.svo_module		= THIS_MODULE,
 };
 
 static int lockd_get(void)

fs/nfs/callback.c

@@ -17,7 +17,6 @@
 #include <linux/errno.h>
 #include <linux/mutex.h>
 #include <linux/freezer.h>
-#include <linux/kthread.h>
 #include <linux/sunrpc/svcauth_gss.h>
 #include <linux/sunrpc/bc_xprt.h>
 
@@ -92,8 +91,8 @@ nfs4_callback_svc(void *vrqstp)
 			continue;
 		svc_process(rqstp);
 	}
+
 	svc_exit_thread(rqstp);
-	module_put_and_kthread_exit(0);
 	return 0;
 }
 
@@ -136,8 +135,8 @@ nfs41_callback_svc(void *vrqstp)
 			finish_wait(&serv->sv_cb_waitq, &wq);
 		}
 	}
+
 	svc_exit_thread(rqstp);
-	module_put_and_kthread_exit(0);
 	return 0;
 }
 
@@ -234,12 +233,10 @@ static int nfs_callback_up_net(int minorversion, struct svc_serv *serv,
 
 static const struct svc_serv_ops nfs40_cb_sv_ops = {
 	.svo_function		= nfs4_callback_svc,
-	.svo_module		= THIS_MODULE,
 };
 #if defined(CONFIG_NFS_V4_1)
 static const struct svc_serv_ops nfs41_cb_sv_ops = {
 	.svo_function		= nfs41_callback_svc,
-	.svo_module		= THIS_MODULE,
 };
 
 static const struct svc_serv_ops *nfs4_cb_sv_ops[] = {

fs/nfs/nfs4state.c

@@ -2697,6 +2697,5 @@ static int nfs4_run_state_manager(void *ptr)
 	allow_signal(SIGKILL);
 	nfs4_state_manager(clp);
 	nfs_put_client(clp);
-	module_put_and_kthread_exit(0);
 	return 0;
 }

fs/nfsd/nfssvc.c

@@ -614,7 +614,6 @@ static int nfsd_get_default_max_blksize(void)
 
 static const struct svc_serv_ops nfsd_thread_sv_ops = {
 	.svo_function		= nfsd,
-	.svo_module		= THIS_MODULE,
 };
 
 void nfsd_shutdown_threads(struct net *net)
@@ -1018,8 +1017,6 @@ nfsd(void *vrqstp)
 		msleep(20);
 	}
 
-	/* Release module */
-	module_put_and_kthread_exit(0);
 	return 0;
 }
 

include/linux/sunrpc/svc.h

@@ -57,11 +57,6 @@ struct svc_serv;
 struct svc_serv_ops {
 	/* function for service threads to run */
 	int		(*svo_function)(void *);
-
-	/* optional module to count when adding threads.
-	 * Thread function must call module_put_and_kthread_exit() to exit.
-	 */
-	struct module	*svo_module;
 };
 
 /*

kernel/module.c

@@ -335,7 +335,7 @@ static inline void add_taint_module(struct module *mod, unsigned flag,
 
 /*
  * A thread that wants to hold a reference to a module only while it
- * is running can call this to safely exit.  nfsd and lockd use this.
+ * is running can call this to safely exit.
  */
 void __noreturn __module_put_and_kthread_exit(struct module *mod, long code)
 {

net/sunrpc/svc.c

@@ -736,11 +736,9 @@ svc_start_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
 		if (IS_ERR(rqstp))
 			return PTR_ERR(rqstp);
 
-		__module_get(serv->sv_ops->svo_module);
 		task = kthread_create_on_node(serv->sv_ops->svo_function, rqstp,
 					      node, "%s", serv->sv_name);
 		if (IS_ERR(task)) {
-			module_put(serv->sv_ops->svo_module);
 			svc_exit_thread(rqstp);
 			return PTR_ERR(task);
 		}