[PATCH] knfsd: add a callback for when last rpc thread finishes

nfsd has some cleanup that it wants to do when the last thread exits, and
there will shortly be some more.  So collect this all into one place and
define a callback for an rpc service to call when the service is about to be
destroyed.

[akpm@osdl.org: cleanups, build fix]
Signed-off-by: Neil Brown <neilb@suse.de>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>

fs/lockd/svc.c

@@ -236,7 +236,7 @@ lockd_up(void)
 			"lockd_up: no pid, %d users??\n", nlmsvc_users);
 
 	error = -ENOMEM;
-	serv = svc_create(&nlmsvc_program, LOCKD_BUFSIZE);
+	serv = svc_create(&nlmsvc_program, LOCKD_BUFSIZE, NULL);
 	if (!serv) {
 		printk(KERN_WARNING "lockd_up: create service failed\n");
 		goto out;

fs/nfs/callback.c

@@ -116,7 +116,7 @@ int nfs_callback_up(void)
 		goto out;
 	init_completion(&nfs_callback_info.started);
 	init_completion(&nfs_callback_info.stopped);
-	serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE);
+	serv = svc_create(&nfs4_callback_program, NFS4_CALLBACK_BUFSIZE, NULL);
 	ret = -ENOMEM;
 	if (!serv)
 		goto out_err;

fs/nfsd/nfssvc.c

@@ -130,11 +130,25 @@ int nfsd_nrthreads(void)
 		return nfsd_serv->sv_nrthreads;
 }
 
+static int killsig;	/* signal that was used to kill last nfsd */
+static void nfsd_last_thread(struct svc_serv *serv)
+{
+	/* When last nfsd thread exits we need to do some clean-up */
+	nfsd_serv = NULL;
+	nfsd_racache_shutdown();
+	nfs4_state_shutdown();
+
+	printk(KERN_WARNING "nfsd: last server has exited\n");
+	if (killsig != SIG_NOCLEAN) {
+		printk(KERN_WARNING "nfsd: unexporting all filesystems\n");
+		nfsd_export_flush();
+	}
+}
 int
 nfsd_svc(unsigned short port, int nrservs)
 {
 	int	error;
-	int	none_left, found_one, i;
+	int	found_one, i;
 	struct list_head *victim;
 
 	lock_kernel();
@@ -197,7 +211,8 @@ nfsd_svc(unsigned short port, int nrservs)
 
 		atomic_set(&nfsd_busy, 0);
 		error = -ENOMEM;
-		nfsd_serv = svc_create(&nfsd_program, NFSD_BUFSIZE);
+		nfsd_serv = svc_create(&nfsd_program, NFSD_BUFSIZE,
+				       nfsd_last_thread);
 		if (nfsd_serv == NULL)
 			goto out;
 		error = svc_makesock(nfsd_serv, IPPROTO_UDP, port);
@@ -231,13 +246,7 @@ nfsd_svc(unsigned short port, int nrservs)
 		nrservs++;
 	}
  failure:
-	none_left = (nfsd_serv->sv_nrthreads == 1);
 	svc_destroy(nfsd_serv);		/* Release server */
-	if (none_left) {
-		nfsd_serv = NULL;
-		nfsd_racache_shutdown();
-		nfs4_state_shutdown();
-	}
  out:
 	unlock_kernel();
 	return error;
@@ -353,7 +362,7 @@ nfsd(struct svc_rqst *rqstp)
 			if (sigismember(&current->pending.signal, signo) &&
 			    !sigismember(&current->blocked, signo))
 				break;
-		err = signo;
+		killsig = signo;
 	}
 	/* Clear signals before calling lockd_down() and svc_exit_thread() */
 	flush_signals(current);
@@ -362,19 +371,6 @@ nfsd(struct svc_rqst *rqstp)
 
 	/* Release lockd */
 	lockd_down();
-
-	/* Check if this is last thread */
-	if (serv->sv_nrthreads==1) {
-
-		printk(KERN_WARNING "nfsd: last server has exited\n");
-		if (err != SIG_NOCLEAN) {
-			printk(KERN_WARNING "nfsd: unexporting all filesystems\n");
-			nfsd_export_flush();
-		}
-		nfsd_serv = NULL;
-	        nfsd_racache_shutdown();	/* release read-ahead cache */
-		nfs4_state_shutdown();
-	}
 	list_del(&me.list);
 	nfsdstats.th_cnt --;
 

include/linux/sunrpc/svc.h

@@ -42,6 +42,11 @@ struct svc_serv {
 	int			sv_tmpcnt;	/* count of temporary sockets */
 
 	char *			sv_name;	/* service name */
+
+	void			(*sv_shutdown)(struct svc_serv *serv);
+						/* Callback to use when last thread
+						 * exits.
+						 */
 };
 
 /*
@@ -328,7 +333,8 @@ typedef void		(*svc_thread_fn)(struct svc_rqst *);
 /*
  * Function prototypes.
  */
-struct svc_serv *  svc_create(struct svc_program *, unsigned int);
+struct svc_serv *  svc_create(struct svc_program *, unsigned int,
+			      void (*shutdown)(struct svc_serv*));
 int		   svc_create_thread(svc_thread_fn, struct svc_serv *);
 void		   svc_exit_thread(struct svc_rqst *);
 void		   svc_destroy(struct svc_serv *);

net/sunrpc/svc.c

@@ -26,7 +26,8 @@
  * Create an RPC service
  */
 struct svc_serv *
-svc_create(struct svc_program *prog, unsigned int bufsize)
+svc_create(struct svc_program *prog, unsigned int bufsize,
+	   void (*shutdown)(struct svc_serv *serv))
 {
 	struct svc_serv	*serv;
 	int vers;
@@ -39,6 +40,7 @@ svc_create(struct svc_program *prog, unsigned int bufsize)
 	serv->sv_nrthreads = 1;
 	serv->sv_stats     = prog->pg_stats;
 	serv->sv_bufsz	   = bufsize? bufsize : 4096;
+	serv->sv_shutdown  = shutdown;
 	xdrsize = 0;
 	while (prog) {
 		prog->pg_lovers = prog->pg_nvers-1;
@@ -91,6 +93,9 @@ svc_destroy(struct svc_serv *serv)
 				  sk_list);
 		svc_delete_socket(svsk);
 	}
+	if (serv->sv_shutdown)
+		serv->sv_shutdown(serv);
+
 	while (!list_empty(&serv->sv_permsocks)) {
 		svsk = list_entry(serv->sv_permsocks.next,
 				  struct svc_sock,