Documentation: Add the RPC language description of NLM version 3

In order to generate source code to encode and decode NLMv3 protocol
elements, include a copy of the RPC language description of NLMv3
for xdrgen to process. The language description is derived from the
Open Group's XNFS specification:

  https://pubs.opengroup.org/onlinepubs/9629799/chap10.htm#tagcjh_11_03

The C code committed here was generated from the new nlm3.x file
using tools/net/sunrpc/xdrgen/xdrgen.

The goals of replacing hand-written XDR functions with ones that
are tool-generated are to improve memory safety and make XDR
encoding and decoding less brittle to maintain. Parts of the
NFSv4 protocol are still being extended actively. Tool-generated
XDR code reduces the time it takes to get a working implementation
of new protocol elements.

The xdrgen utility derives both the type definitions and the
encode/decode functions directly from protocol specifications,
using names and symbols familiar to anyone who knows those specs.
Unlike hand-written code that can inadvertently diverge from the
specification, xdrgen guarantees that the generated code matches
the specification exactly.

We would eventually like xdrgen to generate Rust code as well,
making the conversion of the kernel's NFS stacks to use Rust just
a little easier for us.

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

1 files changed, 210 insertions, 0 deletions

diff --git a/include/linux/sunrpc/xdrgen/nlm3.h b/include/linux/sunrpc/xdrgen/nlm3.h
new file mode 100644
index 000000000000..897e7d91807c
--- /dev/null
+++ b/include/linux/sunrpc/xdrgen/nlm3.h
@@ -0,0 +1,210 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+/* Generated by xdrgen. Manual edits will be lost. */
+/* XDR specification file: ../../Documentation/sunrpc/xdr/nlm3.x */
+/* XDR specification modification time: Thu Apr 23 10:56:34 2026 */
+
+#ifndef _LINUX_XDRGEN_NLM3_DEF_H
+#define _LINUX_XDRGEN_NLM3_DEF_H
+
+#include <linux/types.h>
+#include <linux/sunrpc/xdrgen/_defs.h>
+
+enum { LM_MAXSTRLEN = 1024 };
+
+enum { LM_MAXNAMELEN = 1025 };
+
+enum { MAXNETOBJ_SZ = 1024 };
+
+typedef opaque netobj;
+
+enum nlm_stats {
+	LCK_GRANTED = 0,
+	LCK_DENIED = 1,
+	LCK_DENIED_NOLOCKS = 2,
+	LCK_BLOCKED = 3,
+	LCK_DENIED_GRACE_PERIOD = 4,
+};
+
+typedef __be32 nlm_stats;
+
+struct nlm_stat {
+	nlm_stats stat;
+};
+
+struct nlm_res {
+	netobj cookie;
+	struct nlm_stat stat;
+};
+
+struct nlm_holder {
+	bool exclusive;
+	s32 uppid;
+	netobj oh;
+	u32 l_offset;
+	u32 l_len;
+};
+
+struct nlm_testrply {
+	nlm_stats stat;
+	union {
+		struct nlm_holder holder;
+	} u;
+};
+
+struct nlm_testres {
+	netobj cookie;
+	struct nlm_testrply test_stat;
+};
+
+struct nlm_lock {
+	string caller_name;
+	netobj fh;
+	netobj oh;
+	s32 uppid;
+	u32 l_offset;
+	u32 l_len;
+};
+
+struct nlm_lockargs {
+	netobj cookie;
+	bool block;
+	bool exclusive;
+	struct nlm_lock alock;
+	bool reclaim;
+	s32 state;
+};
+
+struct nlm_cancargs {
+	netobj cookie;
+	bool block;
+	bool exclusive;
+	struct nlm_lock alock;
+};
+
+struct nlm_testargs {
+	netobj cookie;
+	bool exclusive;
+	struct nlm_lock alock;
+};
+
+struct nlm_unlockargs {
+	netobj cookie;
+	struct nlm_lock alock;
+};
+
+enum fsh_mode {
+	fsm_DN = 0,
+	fsm_DR = 1,
+	fsm_DW = 2,
+	fsm_DRW = 3,
+};
+
+typedef enum fsh_mode fsh_mode;
+
+enum fsh_access {
+	fsa_NONE = 0,
+	fsa_R = 1,
+	fsa_W = 2,
+	fsa_RW = 3,
+};
+
+typedef enum fsh_access fsh_access;
+
+struct nlm_share {
+	string caller_name;
+	netobj fh;
+	netobj oh;
+	fsh_mode mode;
+	fsh_access access;
+};
+
+struct nlm_shareargs {
+	netobj cookie;
+	struct nlm_share share;
+	bool reclaim;
+};
+
+struct nlm_shareres {
+	netobj cookie;
+	nlm_stats stat;
+	s32 sequence;
+};
+
+struct nlm_notify {
+	string name;
+	s32 state;
+};
+
+enum { SM_PRIV_SIZE = 16 };
+
+struct nlm_notifyargs {
+	struct nlm_notify notify;
+	u8 private[SM_PRIV_SIZE];
+};
+
+enum {
+	NLM_NULL = 0,
+	NLM_TEST = 1,
+	NLM_LOCK = 2,
+	NLM_CANCEL = 3,
+	NLM_UNLOCK = 4,
+	NLM_GRANTED = 5,
+	NLM_TEST_MSG = 6,
+	NLM_LOCK_MSG = 7,
+	NLM_CANCEL_MSG = 8,
+	NLM_UNLOCK_MSG = 9,
+	NLM_GRANTED_MSG = 10,
+	NLM_TEST_RES = 11,
+	NLM_LOCK_RES = 12,
+	NLM_CANCEL_RES = 13,
+	NLM_UNLOCK_RES = 14,
+	NLM_GRANTED_RES = 15,
+	NLM_SM_NOTIFY = 16,
+	NLM_SHARE = 20,
+	NLM_UNSHARE = 21,
+	NLM_NM_LOCK = 22,
+	NLM_FREE_ALL = 23,
+};
+
+#ifndef NLM_PROG
+#define NLM_PROG (100021)
+#endif
+
+#define NLM3_netobj_sz                  (XDR_unsigned_int + XDR_QUADLEN(MAXNETOBJ_SZ))
+#define NLM3_nlm_stats_sz               (XDR_int)
+#define NLM3_nlm_stat_sz                \
+	(NLM3_nlm_stats_sz)
+#define NLM3_nlm_res_sz                 \
+	(NLM3_netobj_sz + NLM3_nlm_stat_sz)
+#define NLM3_nlm_holder_sz              \
+	(XDR_bool + XDR_int + NLM3_netobj_sz + XDR_unsigned_int + XDR_unsigned_int)
+#define NLM3_nlm_testrply_sz            \
+	(NLM3_nlm_stats_sz + NLM3_nlm_holder_sz)
+#define NLM3_nlm_testres_sz             \
+	(NLM3_netobj_sz + NLM3_nlm_testrply_sz)
+#define NLM3_nlm_lock_sz                \
+	(XDR_unsigned_int + XDR_QUADLEN(LM_MAXSTRLEN) + NLM3_netobj_sz + NLM3_netobj_sz + XDR_int + XDR_unsigned_int + XDR_unsigned_int)
+#define NLM3_nlm_lockargs_sz            \
+	(NLM3_netobj_sz + XDR_bool + XDR_bool + NLM3_nlm_lock_sz + XDR_bool + XDR_int)
+#define NLM3_nlm_cancargs_sz            \
+	(NLM3_netobj_sz + XDR_bool + XDR_bool + NLM3_nlm_lock_sz)
+#define NLM3_nlm_testargs_sz            \
+	(NLM3_netobj_sz + XDR_bool + NLM3_nlm_lock_sz)
+#define NLM3_nlm_unlockargs_sz          \
+	(NLM3_netobj_sz + NLM3_nlm_lock_sz)
+#define NLM3_fsh_mode_sz                (XDR_int)
+#define NLM3_fsh_access_sz              (XDR_int)
+#define NLM3_nlm_share_sz               \
+	(XDR_unsigned_int + XDR_QUADLEN(LM_MAXSTRLEN) + NLM3_netobj_sz + NLM3_netobj_sz + NLM3_fsh_mode_sz + NLM3_fsh_access_sz)
+#define NLM3_nlm_shareargs_sz           \
+	(NLM3_netobj_sz + NLM3_nlm_share_sz + XDR_bool)
+#define NLM3_nlm_shareres_sz            \
+	(NLM3_netobj_sz + NLM3_nlm_stats_sz + XDR_int)
+#define NLM3_nlm_notify_sz              \
+	(XDR_unsigned_int + XDR_QUADLEN(LM_MAXNAMELEN) + XDR_long)
+#define NLM3_nlm_notifyargs_sz          \
+	(NLM3_nlm_notify_sz + XDR_QUADLEN(SM_PRIV_SIZE))
+#define NLM3_MAX_ARGS_SZ                \
+	(NLM3_nlm_lockargs_sz)
+
+#endif /* _LINUX_XDRGEN_NLM3_DEF_H */