lockd: Use xdrgen XDR functions for the NLMv3 SM_NOTIFY procedure

Continue the xdrgen migration by converting NLMv3 SM_NOTIFY,
a private callback from statd to notify lockd when a remote
host has rebooted.  The procedure now uses
nlm_svc_decode_nlm_notifyargs and nlm_svc_encode_void,
generated from the NLM version 3 protocol specification.

A new struct nlm_notifyargs_wrapper bridges between the
xdrgen-generated nlm_notifyargs and the lockd_reboot
structure expected by nlm_host_rebooted().  The wrapper
contains both the xdrgen-decoded arguments and a reboot
field for the existing API.

Setting pc_argzero to zero is safe because the generated
decoder fills argp->xdrgen before the procedure runs, so
the zeroing memset performed by the dispatch layer is no
longer needed.

Setting pc_xdrressize to XDR_void reflects that SM_NOTIFY
returns no data; the previous value of St over-reserved a
status word in the reply buffer.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>

diff --git a/fs/lockd/svcproc.c b/fs/lockd/svcproc.c
index a2ac747e96ce978924bd270767cc9a0f78675b64..e0328dc89debba21a4c6d1c474f148ba0b56cb84 100644 (file)
--- a/fs/lockd/svcproc.c
+++ b/fs/lockd/svcproc.c
@@ -80,6 +80,13 @@ struct nlm_unlockargs_wrapper {
 
 static_assert(offsetof(struct nlm_unlockargs_wrapper, xdrgen) == 0);
 
+struct nlm_notifyargs_wrapper {
+       struct nlm_notifyargs           xdrgen;
+       struct lockd_reboot             reboot;
+};
+
+static_assert(offsetof(struct nlm_notifyargs_wrapper, xdrgen) == 0);
+
 static __be32
 nlm_netobj_to_cookie(struct lockd_cookie *cookie, netobj *object)
 {
@@ -1022,6 +1029,44 @@ static __be32 nlmsvc_proc_granted_res(struct svc_rqst *rqstp)
        return rpc_success;
 }
 
+/**
+ * nlmsvc_proc_sm_notify - SM_NOTIFY: Peer has rebooted
+ * @rqstp: RPC transaction context
+ *
+ * Returns:
+ *   %rpc_success:             RPC executed successfully.
+ *   %rpc_system_err:          RPC execution failed.
+ *
+ * The SM_NOTIFY procedure is a private callback from Linux statd and is
+ * not part of the official NLM protocol.
+ *
+ * RPC synopsis:
+ *   void NLM_SM_NOTIFY(nlm_notifyargs) = 16;
+ */
+static __be32 nlmsvc_proc_sm_notify(struct svc_rqst *rqstp)
+{
+       struct nlm_notifyargs_wrapper *argp = rqstp->rq_argp;
+       struct lockd_reboot *reboot = &argp->reboot;
+
+       if (!nlm_privileged_requester(rqstp)) {
+               char buf[RPC_MAX_ADDRBUFLEN];
+
+               pr_warn("lockd: rejected NSM callback from %s\n",
+                       svc_print_addr(rqstp, buf, sizeof(buf)));
+               return rpc_system_err;
+       }
+
+       reboot->len = argp->xdrgen.notify.name.len;
+       reboot->mon = (char *)argp->xdrgen.notify.name.data;
+       reboot->state = argp->xdrgen.notify.state;
+       memcpy(&reboot->priv.data, argp->xdrgen.private,
+              sizeof(reboot->priv.data));
+
+       nlm_host_rebooted(SVC_NET(rqstp), reboot);
+
+       return rpc_success;
+}
+
 /*
  * SHARE: create a DOS share or alter existing share.
  */
@@ -1129,27 +1174,6 @@ nlmsvc_proc_free_all(struct svc_rqst *rqstp)
        return rpc_success;
 }
 
-/*
- * SM_NOTIFY: private callback from statd (not part of official NLM proto)
- */
-static __be32
-nlmsvc_proc_sm_notify(struct svc_rqst *rqstp)
-{
-       struct lockd_reboot *argp = rqstp->rq_argp;
-
-       dprintk("lockd: SM_NOTIFY     called\n");
-
-       if (!nlm_privileged_requester(rqstp)) {
-               char buf[RPC_MAX_ADDRBUFLEN];
-               printk(KERN_WARNING "lockd: rejected NSM callback from %s\n",
-                               svc_print_addr(rqstp, buf, sizeof(buf)));
-               return rpc_system_err;
-       }
-
-       nlm_host_rebooted(SVC_NET(rqstp), argp);
-       return rpc_success;
-}
-
 static __be32
 nlmsvc_proc_unused(struct svc_rqst *rqstp)
 {
@@ -1328,15 +1352,15 @@ static const struct svc_procedure nlmsvc_procedures[24] = {
                .pc_xdrressize  = XDR_void,
                .pc_name        = "GRANTED_RES",
        },
-       [NLMPROC_NSM_NOTIFY] = {
-               .pc_func = nlmsvc_proc_sm_notify,
-               .pc_decode = nlmsvc_decode_reboot,
-               .pc_encode = nlmsvc_encode_void,
-               .pc_argsize = sizeof(struct lockd_reboot),
-               .pc_argzero = sizeof(struct lockd_reboot),
-               .pc_ressize = sizeof(struct nlm_void),
-               .pc_xdrressize = St,
-               .pc_name = "SM_NOTIFY",
+       [NLM_SM_NOTIFY] = {
+               .pc_func        = nlmsvc_proc_sm_notify,
+               .pc_decode      = nlm_svc_decode_nlm_notifyargs,
+               .pc_encode      = nlm_svc_encode_void,
+               .pc_argsize     = sizeof(struct nlm_notifyargs_wrapper),
+               .pc_argzero     = 0,
+               .pc_ressize     = 0,
+               .pc_xdrressize  = XDR_void,
+               .pc_name        = "SM_NOTIFY",
        },
        [17] = {
                .pc_func = nlmsvc_proc_unused,
@@ -1418,10 +1442,10 @@ union nlmsvc_xdrstore {
        struct nlm_lockargs_wrapper     lockargs;
        struct nlm_cancargs_wrapper     cancargs;
        struct nlm_unlockargs_wrapper   unlockargs;
+       struct nlm_notifyargs_wrapper   notifyargs;
        struct nlm_testres_wrapper      testres;
        struct nlm_res_wrapper          res;
        struct lockd_args               args;
-       struct lockd_reboot             reboot;
 };
 
 /*