svcrpc: fix xpt_list traversal locking on shutdown

Server threads are not running at this point, but svc_age_temp_xprts
still may be, so we need this locking.

Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 15 insertions, 9 deletions

diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
index bac973a31367..e1810b947dea 100644
--- a/net/sunrpc/svc_xprt.c
+++ b/net/sunrpc/svc_xprt.c
@@ -917,16 +917,18 @@ void svc_close_xprt(struct svc_xprt *xprt)
 }
 EXPORT_SYMBOL_GPL(svc_close_xprt);
 
-static void svc_close_list(struct list_head *xprt_list, struct net *net)
+static void svc_close_list(struct svc_serv *serv, struct list_head *xprt_list, struct net *net)
 {
         struct svc_xprt *xprt;
 
+        spin_lock(&serv->sv_lock);
         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);
         }
+        spin_unlock(&serv->sv_lock);
 }
 
 static void svc_clear_pools(struct svc_serv *serv, struct net *net)
@@ -949,24 +951,28 @@ static void svc_clear_pools(struct svc_serv *serv, struct net *net)
         }
 }
 
-static void svc_clear_list(struct list_head *xprt_list, struct net *net)
+static void svc_clear_list(struct svc_serv *serv, struct list_head *xprt_list, struct net *net)
 {
         struct svc_xprt *xprt;
         struct svc_xprt *tmp;
+        LIST_HEAD(victims);
 
+        spin_lock(&serv->sv_lock);
         list_for_each_entry_safe(xprt, tmp, xprt_list, xpt_list) {
                 if (xprt->xpt_net != net)
                         continue;
-                svc_delete_xprt(xprt);
+                list_move(&xprt->xpt_list, &victims);
         }
-        list_for_each_entry(xprt, xprt_list, xpt_list)
-                BUG_ON(xprt->xpt_net == net);
+        spin_unlock(&serv->sv_lock);
+
+        list_for_each_entry_safe(xprt, tmp, &victims, xpt_list)
+                svc_delete_xprt(xprt);
 }
 
 void svc_close_net(struct svc_serv *serv, struct net *net)
 {
-        svc_close_list(&serv->sv_tempsocks, net);
-        svc_close_list(&serv->sv_permsocks, net);
+        svc_close_list(serv, &serv->sv_tempsocks, net);
+        svc_close_list(serv, &serv->sv_permsocks, net);
 
         svc_clear_pools(serv, net);
         /*
@@ -974,8 +980,8 @@ void svc_close_net(struct svc_serv *serv, struct net *net)
          * svc_xprt_enqueue will not add new entries without taking the
          * sp_lock and checking XPT_BUSY.
          */
-        svc_clear_list(&serv->sv_tempsocks, net);
-        svc_clear_list(&serv->sv_permsocks, net);
+        svc_clear_list(serv, &serv->sv_tempsocks, net);
+        svc_clear_list(serv, &serv->sv_permsocks, net);
 }
 
 /*