SUNRPC: Add lockless lookup of the server's auth domain

Avoid taking the global auth_domain_lock in most lookups of the auth domain
by adding an RCU protected lookup.

Signed-off-by: Trond Myklebust <trond.myklebust@hammerspace.com>
Signed-off-by: J. Bruce Fields <bfields@redhat.com>

1 files changed, 8 insertions, 2 deletions

diff --git a/net/sunrpc/svcauth_unix.c b/net/sunrpc/svcauth_unix.c
index af7f28fb8102..84cf39021a03 100644
--- a/net/sunrpc/svcauth_unix.c
+++ b/net/sunrpc/svcauth_unix.c
@@ -37,20 +37,26 @@ struct unix_domain {
 extern struct auth_ops svcauth_null;
 extern struct auth_ops svcauth_unix;
 
-static void svcauth_unix_domain_release(struct auth_domain *dom)
+static void svcauth_unix_domain_release_rcu(struct rcu_head *head)
 {
+        struct auth_domain *dom = container_of(head, struct auth_domain, rcu_head);
         struct unix_domain *ud = container_of(dom, struct unix_domain, h);
 
         kfree(dom->name);
         kfree(ud);
 }
 
+static void svcauth_unix_domain_release(struct auth_domain *dom)
+{
+        call_rcu(&dom->rcu_head, svcauth_unix_domain_release_rcu);
+}
+
 struct auth_domain *unix_domain_find(char *name)
 {
         struct auth_domain *rv;
         struct unix_domain *new = NULL;
 
-        rv = auth_domain_lookup(name, NULL);
+        rv = auth_domain_find(name);
         while(1) {
                 if (rv) {
                         if (new && rv != &new->h)