lockd: Use xdrgen XDR functions for the NLMv4 SM_NOTIFY procedure

Convert the SM_NOTIFY procedure to use xdrgen functions
nlm4_svc_decode_nlm4_notifyargs and nlm4_svc_encode_void.
SM_NOTIFY is a private callback from statd to notify lockd
when a remote host has rebooted.

This patch introduces struct nlm4_notifyargs_wrapper to
bridge between the xdrgen-generated nlm4_notifyargs and
the nlm_reboot structure expected by nlm_host_rebooted().
The wrapper contains both the xdrgen-decoded arguments
and a reboot field for the existing API.

The pc_argzero field is set to zero because xdrgen decoders
reliably initialize all arguments, making the early
defensive memset unnecessary.

This change also corrects the pc_xdrressize field, which
previously contained a placeholder value.

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

diff --git a/fs/lockd/svc4proc.c b/fs/lockd/svc4proc.c
index f986cdac5d004fce3ed2fb402aa9944bbbc37ced..4f8c41046ed6b0a9428b03ae1ee4a3d991138f24 100644 (file)
--- a/fs/lockd/svc4proc.c
+++ b/fs/lockd/svc4proc.c
@@ -62,6 +62,13 @@ struct nlm4_unlockargs_wrapper {
 
 static_assert(offsetof(struct nlm4_unlockargs_wrapper, xdrgen) == 0);
 
+struct nlm4_notifyargs_wrapper {
+       struct nlm4_notifyargs          xdrgen;
+       struct nlm_reboot               reboot;
+};
+
+static_assert(offsetof(struct nlm4_notifyargs_wrapper, xdrgen) == 0);
+
 struct nlm4_testres_wrapper {
        struct nlm4_testres             xdrgen;
        struct nlm_lock                 lock;
@@ -984,6 +991,44 @@ static __be32 nlm4svc_proc_granted_res(struct svc_rqst *rqstp)
        return rpc_success;
 }
 
+/**
+ * nlm4svc_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 NLMPROC4_SM_NOTIFY(nlm4_notifyargs) = 16;
+ */
+static __be32 nlm4svc_proc_sm_notify(struct svc_rqst *rqstp)
+{
+       struct nlm4_notifyargs_wrapper *argp = rqstp->rq_argp;
+       struct nlm_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.
  */
@@ -1088,27 +1133,6 @@ nlm4svc_proc_free_all(struct svc_rqst *rqstp)
        return rpc_success;
 }
 
-/*
- * SM_NOTIFY: private callback from statd (not part of official NLM proto)
- */
-static __be32
-nlm4svc_proc_sm_notify(struct svc_rqst *rqstp)
-{
-       struct nlm_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
 nlm4svc_proc_unused(struct svc_rqst *rqstp)
 {
@@ -1288,15 +1312,15 @@ static const struct svc_procedure nlm4svc_procedures[24] = {
                .pc_xdrressize  = XDR_void,
                .pc_name        = "GRANTED_RES",
        },
-       [NLMPROC_NSM_NOTIFY] = {
-               .pc_func = nlm4svc_proc_sm_notify,
-               .pc_decode = nlm4svc_decode_reboot,
-               .pc_encode = nlm4svc_encode_void,
-               .pc_argsize = sizeof(struct nlm_reboot),
-               .pc_argzero = sizeof(struct nlm_reboot),
-               .pc_ressize = sizeof(struct nlm_void),
-               .pc_xdrressize = St,
-               .pc_name = "SM_NOTIFY",
+       [NLMPROC4_SM_NOTIFY] = {
+               .pc_func        = nlm4svc_proc_sm_notify,
+               .pc_decode      = nlm4_svc_decode_nlm4_notifyargs,
+               .pc_encode      = nlm4_svc_encode_void,
+               .pc_argsize     = sizeof(struct nlm4_notifyargs_wrapper),
+               .pc_argzero     = 0,
+               .pc_ressize     = 0,
+               .pc_xdrressize  = XDR_void,
+               .pc_name        = "SM_NOTIFY",
        },
        [17] = {
                .pc_func = nlm4svc_proc_unused,
@@ -1378,10 +1402,10 @@ union nlm4svc_xdrstore {
        struct nlm4_lockargs_wrapper    lockargs;
        struct nlm4_cancargs_wrapper    cancargs;
        struct nlm4_unlockargs_wrapper  unlockargs;
+       struct nlm4_notifyargs_wrapper  notifyargs;
        struct nlm4_testres_wrapper     testres;
        struct nlm4_res_wrapper         res;
        struct nlm_args                 args;
-       struct nlm_reboot               reboot;
 };
 
 static DEFINE_PER_CPU_ALIGNED(unsigned long,