SUNRPC: service destruction in network namespace context

v2: Added comment to BUG_ON's in svc_destroy() to make code looks clearer.

This patch introduces network namespace filter for service destruction
function.
Nothing special here - just do exactly the same operations, but only for
tranports in passed networks namespace context.
BTW, BUG_ON() checks for empty service transports lists were returned into
svc_destroy() function. This is because of swithing generic svc_close_all() to
networks namespace dependable svc_close_net().

Signed-off-by: Stanislav Kinsbursky <[e-mail]>
Signed-off-by: Trond Myklebust <[e-mail]>

include/linux/sunrpc/svcsock.h

···
 /*
  * Function prototypes.
  */
-void		svc_close_all(struct svc_serv *);
+void		svc_close_net(struct svc_serv *, struct net *);
 int		svc_recv(struct svc_rqst *, long);
 int		svc_send(struct svc_rqst *);
 void		svc_drop(struct svc_rqst *);

net/sunrpc/svc.c

···
 void
 svc_destroy(struct svc_serv *serv)
 {
+	struct net *net = current->nsproxy->net_ns;
+
 	dprintk("svc: svc_destroy(%s, %d)\n",
 				serv->sv_program->pg_name,
 				serv->sv_nrthreads);
···
 	 * caller is using--nfsd_mutex in the case of nfsd).  So it's
 	 * safe to traverse those lists and shut everything down:
 	 */
-	svc_close_all(serv);
+	svc_close_net(serv, net);
+
+	/*
+	 * The last user is gone and thus all sockets have to be destroyed to
+	 * the point. Check this.
+	 */
+	BUG_ON(!list_empty(&serv->sv_permsocks));
+	BUG_ON(!list_empty(&serv->sv_tempsocks));
 
 	if (serv->sv_shutdown)
-		serv->sv_shutdown(serv, current->nsproxy->net_ns);
+		serv->sv_shutdown(serv, net);
 
 	cache_clean_deferred(serv);
 

net/sunrpc/svc_xprt.c

···
 }
 EXPORT_SYMBOL_GPL(svc_close_xprt);
 
-static void svc_close_list(struct list_head *xprt_list)
+static void svc_close_list(struct list_head *xprt_list, struct net *net)
 {
 	struct svc_xprt *xprt;
 
 	list_for_each_entry(xprt, xprt_list, xpt_list) {
+		if (xprt->xpt_net != net)
+			continue;
 		set_bit(XPT_CLOSE, &xprt->xpt_flags);
 		set_bit(XPT_BUSY, &xprt->xpt_flags);
 	}
 }
 
-static void svc_clear_pools(struct svc_serv *serv)
+static void svc_clear_pools(struct svc_serv *serv, struct net *net)
 {
 	struct svc_pool *pool;
 	struct svc_xprt *xprt;
···
 
 		spin_lock_bh(&pool->sp_lock);
 		list_for_each_entry_safe(xprt, tmp, &pool->sp_sockets, xpt_ready) {
+			if (xprt->xpt_net != net)
+				continue;
 			list_del_init(&xprt->xpt_ready);
 		}
 		spin_unlock_bh(&pool->sp_lock);
 	}
 }
 
-static void svc_clear_list(struct list_head *xprt_list)
+static void svc_clear_list(struct list_head *xprt_list, struct net *net)
 {
 	struct svc_xprt *xprt;
 	struct svc_xprt *tmp;
 
 	list_for_each_entry_safe(xprt, tmp, xprt_list, xpt_list) {
+		if (xprt->xpt_net != net)
+			continue;
 		svc_delete_xprt(xprt);
 	}
-	BUG_ON(!list_empty(xprt_list));
+	list_for_each_entry(xprt, xprt_list, xpt_list)
+		BUG_ON(xprt->xpt_net == net);
 }
 
-void svc_close_all(struct svc_serv *serv)
+void svc_close_net(struct svc_serv *serv, struct net *net)
 {
-	svc_close_list(&serv->sv_tempsocks);
-	svc_close_list(&serv->sv_permsocks);
+	svc_close_list(&serv->sv_tempsocks, net);
+	svc_close_list(&serv->sv_permsocks, net);
 
-	svc_clear_pools(serv);
+	svc_clear_pools(serv, net);
 	/*
 	 * At this point the sp_sockets lists will stay empty, since
 	 * svc_enqueue will not add new entries without taking the
 	 * sp_lock and checking XPT_BUSY.
 	 */
-	svc_clear_list(&serv->sv_tempsocks);
-	svc_clear_list(&serv->sv_permsocks);
+	svc_clear_list(&serv->sv_tempsocks, net);
+	svc_clear_list(&serv->sv_permsocks, net);
 }
 
 /*