RPCSEC_GSS: Share rpc_pipes when an rpc_clnt owns multiple rpcsec auth caches

Ensure that if an rpc_clnt owns more than one RPCSEC_GSS-based authentication
mechanism, then those caches will share the same 'gssd' upcall pipe.

Signed-off-by: Trond Myklebust <Trond.Myklebust@netapp.com>

diff --git a/net/sunrpc/auth_gss/auth_gss.c b/net/sunrpc/auth_gss/auth_gss.c
index d214aec..5ec15bb 100644 (file)
--- a/net/sunrpc/auth_gss/auth_gss.c
+++ b/net/sunrpc/auth_gss/auth_gss.c
@@ -76,6 +76,7 @@ struct gss_pipe {
        struct rpc_pipe *pipe;
        struct rpc_clnt *clnt;
        const char *name;
+       struct kref kref;
 };
 
 struct gss_auth {
@@ -832,7 +833,6 @@ static struct gss_pipe *gss_pipe_alloc(struct rpc_clnt *clnt,
                const char *name,
                const struct rpc_pipe_ops *upcall_ops)
 {
-       struct net *net = rpc_net_ns(clnt);
        struct gss_pipe *p;
        int err = -ENOMEM;
 
@@ -846,19 +846,71 @@ static struct gss_pipe *gss_pipe_alloc(struct rpc_clnt *clnt,
        }
        p->name = name;
        p->clnt = clnt;
+       kref_init(&p->kref);
        rpc_init_pipe_dir_object(&p->pdo,
                        &gss_pipe_dir_object_ops,
                        p);
-       err = rpc_add_pipe_dir_object(net, &clnt->cl_pipedir_objects, &p->pdo);
-       if (!err)
-               return p;
-       rpc_destroy_pipe_data(p->pipe);
+       return p;
 err_free_gss_pipe:
        kfree(p);
 err:
        return ERR_PTR(err);
 }
 
+struct gss_alloc_pdo {
+       struct rpc_clnt *clnt;
+       const char *name;
+       const struct rpc_pipe_ops *upcall_ops;
+};
+
+static int gss_pipe_match_pdo(struct rpc_pipe_dir_object *pdo, void *data)
+{
+       struct gss_pipe *gss_pipe;
+       struct gss_alloc_pdo *args = data;
+
+       if (pdo->pdo_ops != &gss_pipe_dir_object_ops)
+               return 0;
+       gss_pipe = container_of(pdo, struct gss_pipe, pdo);
+       if (strcmp(gss_pipe->name, args->name) != 0)
+               return 0;
+       if (!kref_get_unless_zero(&gss_pipe->kref))
+               return 0;
+       return 1;
+}
+
+static struct rpc_pipe_dir_object *gss_pipe_alloc_pdo(void *data)
+{
+       struct gss_pipe *gss_pipe;
+       struct gss_alloc_pdo *args = data;
+
+       gss_pipe = gss_pipe_alloc(args->clnt, args->name, args->upcall_ops);
+       if (!IS_ERR(gss_pipe))
+               return &gss_pipe->pdo;
+       return NULL;
+}
+
+static struct gss_pipe *gss_pipe_get(struct rpc_clnt *clnt,
+               const char *name,
+               const struct rpc_pipe_ops *upcall_ops)
+{
+       struct net *net = rpc_net_ns(clnt);
+       struct rpc_pipe_dir_object *pdo;
+       struct gss_alloc_pdo args = {
+               .clnt = clnt,
+               .name = name,
+               .upcall_ops = upcall_ops,
+       };
+
+       pdo = rpc_find_or_alloc_pipe_dir_object(net,
+                       &clnt->cl_pipedir_objects,
+                       gss_pipe_match_pdo,
+                       gss_pipe_alloc_pdo,
+                       &args);
+       if (pdo != NULL)
+               return container_of(pdo, struct gss_pipe, pdo);
+       return ERR_PTR(-ENOMEM);
+}
+
 static void __gss_pipe_free(struct gss_pipe *p)
 {
        struct rpc_clnt *clnt = p->clnt;
@@ -871,10 +923,17 @@ static void __gss_pipe_free(struct gss_pipe *p)
        kfree(p);
 }
 
+static void __gss_pipe_release(struct kref *kref)
+{
+       struct gss_pipe *p = container_of(kref, struct gss_pipe, kref);
+
+       __gss_pipe_free(p);
+}
+
 static void gss_pipe_free(struct gss_pipe *p)
 {
        if (p != NULL)
-               __gss_pipe_free(p);
+               kref_put(&p->kref, __gss_pipe_release);
 }
 
 /*
@@ -930,14 +989,14 @@ gss_create(struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
         * that we supported only the old pipe.  So we instead create
         * the new pipe first.
         */
-       gss_pipe = gss_pipe_alloc(clnt, "gssd", &gss_upcall_ops_v1);
+       gss_pipe = gss_pipe_get(clnt, "gssd", &gss_upcall_ops_v1);
        if (IS_ERR(gss_pipe)) {
                err = PTR_ERR(gss_pipe);
                goto err_destroy_credcache;
        }
        gss_auth->gss_pipe[1] = gss_pipe;
 
-       gss_pipe = gss_pipe_alloc(clnt, gss_auth->mech->gm_name,
+       gss_pipe = gss_pipe_get(clnt, gss_auth->mech->gm_name,
                        &gss_upcall_ops_v0);
        if (IS_ERR(gss_pipe)) {
                err = PTR_ERR(gss_pipe);
@@ -947,7 +1006,7 @@ gss_create(struct rpc_auth_create_args *args, struct rpc_clnt *clnt)
 
        return auth;
 err_destroy_pipe_1:
-       __gss_pipe_free(gss_auth->gss_pipe[1]);
+       gss_pipe_free(gss_auth->gss_pipe[1]);
 err_destroy_credcache:
        rpcauth_destroy_credcache(auth);
 err_put_mech: