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lockd: Relocate svc_version definitions to XDR layer

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Public RPC server interfaces become cluttered when internal
XDR implementation details leak into them. The procedure count,
maximum XDR buffer size, and per-CPU call counters serve no
purpose outside the code that encodes and decodes NLM protocol
messages. Exposing these values through global headers creates
unnecessary coupling between the RPC dispatch logic and the
XDR layer.

Relocating the svc_version structure definitions confines this
implementation information to the files where XDR encoding and
decoding occur. In svc.c, the buffer size computation now reads
vs_xdrsize from the version structures rather than relying on a
preprocessor constant. This calculation occurs at service
initialization, after the linker has resolved the version
structure definitions. The dispatch function becomes non-static
because both the version structures and the dispatcher reside in
different translation units.

The NLMSVC_XDRSIZE macro is removed from xdr.h because buffer
size is now computed from the union of XDR argument and result
structures, matching the pattern used in other RPC services.
Version 1 and 3 share the same procedure table but maintain
separate counter arrays. Version 4 remains separate due to its
distinct procedure definitions.

Reviewed-by: Jeff Layton <jlayton@kernel.org>
Signed-off-by: Chuck Lever <chuck.lever@oracle.com>
This commit is contained in:
Chuck Lever 2026-01-28 10:19:35 -05:00
parent b3f76a9b13
commit 45cd458b57
5 changed files with 74 additions and 46 deletions
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6
fs/lockd/lockd.h
View File

@ -221,9 +221,10 @@ struct nlm_block {
* Global variables
*/
extern const struct rpc_program nlm_program;
extern const struct svc_procedure nlmsvc_procedures[24];
extern const struct svc_version nlmsvc_version1;
extern const struct svc_version nlmsvc_version3;
#ifdef CONFIG_LOCKD_V4
extern const struct svc_procedure nlmsvc_procedures4[24];
extern const struct svc_version nlmsvc_version4;
#endif
extern int nlmsvc_grace_period;
extern unsigned long nlm_timeout;
@ -318,6 +319,7 @@ void nlmsvc_traverse_blocks(struct nlm_host *, struct nlm_file *,
void nlmsvc_grant_reply(struct nlm_cookie *, __be32);
void nlmsvc_release_call(struct nlm_rqst *);
void nlmsvc_locks_init_private(struct file_lock *, struct nlm_host *, pid_t);
int nlmsvc_dispatch(struct svc_rqst *rqstp);
/*
* File handling for the server personality

48
fs/lockd/svc.c
View File

@ -44,7 +44,6 @@
#include "netlink.h"
#define NLMDBG_FACILITY NLMDBG_SVC
#define LOCKD_BUFSIZE (1024 + NLMSVC_XDRSIZE)
static struct svc_program nlmsvc_program;
@ -319,6 +318,7 @@ static struct notifier_block lockd_inet6addr_notifier = {
static int lockd_get(void)
{
struct svc_serv *serv;
unsigned int bufsize;
int error;
if (nlmsvc_serv) {
@ -334,7 +334,15 @@ static int lockd_get(void)
printk(KERN_WARNING
"lockd_up: no pid, %d users??\n", nlmsvc_users);
serv = svc_create(&nlmsvc_program, LOCKD_BUFSIZE, lockd);
#ifdef CONFIG_LOCKD_V4
bufsize = 1024 + max3(nlmsvc_version1.vs_xdrsize,
nlmsvc_version3.vs_xdrsize,
nlmsvc_version4.vs_xdrsize);
#else
bufsize = 1024 + max(nlmsvc_version1.vs_xdrsize,
nlmsvc_version3.vs_xdrsize);
#endif
serv = svc_create(&nlmsvc_program, bufsize, lockd);
if (!serv) {
printk(KERN_WARNING "lockd_up: create service failed\n");
return -ENOMEM;
@ -640,7 +648,7 @@ module_exit(exit_nlm);
* %0: Processing complete; do not send a Reply
* %1: Processing complete; send Reply in rqstp->rq_res
*/
static int nlmsvc_dispatch(struct svc_rqst *rqstp)
int nlmsvc_dispatch(struct svc_rqst *rqstp)
{
const struct svc_procedure *procp = rqstp->rq_procinfo;
__be32 *statp = rqstp->rq_accept_statp;
@ -671,40 +679,6 @@ static int nlmsvc_dispatch(struct svc_rqst *rqstp)
/*
* Define NLM program and procedures
*/
static DEFINE_PER_CPU_ALIGNED(unsigned long, nlmsvc_version1_count[17]);
static const struct svc_version nlmsvc_version1 = {
.vs_vers = 1,
.vs_nproc = 17,
.vs_proc = nlmsvc_procedures,
.vs_count = nlmsvc_version1_count,
.vs_dispatch = nlmsvc_dispatch,
.vs_xdrsize = NLMSVC_XDRSIZE,
};
static DEFINE_PER_CPU_ALIGNED(unsigned long,
nlmsvc_version3_count[ARRAY_SIZE(nlmsvc_procedures)]);
static const struct svc_version nlmsvc_version3 = {
.vs_vers = 3,
.vs_nproc = ARRAY_SIZE(nlmsvc_procedures),
.vs_proc = nlmsvc_procedures,
.vs_count = nlmsvc_version3_count,
.vs_dispatch = nlmsvc_dispatch,
.vs_xdrsize = NLMSVC_XDRSIZE,
};
#ifdef CONFIG_LOCKD_V4
static DEFINE_PER_CPU_ALIGNED(unsigned long,
nlmsvc_version4_count[ARRAY_SIZE(nlmsvc_procedures4)]);
static const struct svc_version nlmsvc_version4 = {
.vs_vers = 4,
.vs_nproc = ARRAY_SIZE(nlmsvc_procedures4),
.vs_proc = nlmsvc_procedures4,
.vs_count = nlmsvc_version4_count,
.vs_dispatch = nlmsvc_dispatch,
.vs_xdrsize = NLMSVC_XDRSIZE,
};
#endif
static const struct svc_version *nlmsvc_version[] = {
[1] = &nlmsvc_version1,
[3] = &nlmsvc_version3,

23
fs/lockd/svc4proc.c
View File

@ -530,7 +530,7 @@ struct nlm_void { int dummy; };
#define St 1 /* status */
#define Rg 4 /* range (offset + length) */
const struct svc_procedure nlmsvc_procedures4[24] = {
static const struct svc_procedure nlm4svc_procedures[24] = {
[NLMPROC_NULL] = {
.pc_func = nlm4svc_proc_null,
.pc_decode = nlm4svc_decode_void,
@ -772,3 +772,24 @@ const struct svc_procedure nlmsvc_procedures4[24] = {
.pc_name = "FREE_ALL",
},
};
/*
* Storage requirements for XDR arguments and results
*/
union nlm4svc_xdrstore {
struct nlm_args args;
struct nlm_res res;
struct nlm_reboot reboot;
};
static DEFINE_PER_CPU_ALIGNED(unsigned long,
nlm4svc_call_counters[ARRAY_SIZE(nlm4svc_procedures)]);
const struct svc_version nlmsvc_version4 = {
.vs_vers = 4,
.vs_nproc = ARRAY_SIZE(nlm4svc_procedures),
.vs_proc = nlm4svc_procedures,
.vs_count = nlm4svc_call_counters,
.vs_dispatch = nlmsvc_dispatch,
.vs_xdrsize = sizeof(union nlm4svc_xdrstore),
};

38
fs/lockd/svcproc.c
View File

@ -555,7 +555,7 @@ struct nlm_void { int dummy; };
#define No (1+1024/4) /* Net Obj */
#define Rg 2 /* range - offset + size */
const struct svc_procedure nlmsvc_procedures[24] = {
static const struct svc_procedure nlmsvc_procedures[24] = {
[NLMPROC_NULL] = {
.pc_func = nlmsvc_proc_null,
.pc_decode = nlmsvc_decode_void,
@ -797,3 +797,39 @@ const struct svc_procedure nlmsvc_procedures[24] = {
.pc_name = "FREE_ALL",
},
};
/*
* Storage requirements for XDR arguments and results
*/
union nlmsvc_xdrstore {
struct nlm_args args;
struct nlm_res res;
struct nlm_reboot reboot;
};
/*
* NLMv1 defines only procedures 1 - 15. Linux lockd also implements
* procedures 0 (NULL) and 16 (SM_NOTIFY).
*/
static DEFINE_PER_CPU_ALIGNED(unsigned long, nlm1svc_call_counters[17]);
const struct svc_version nlmsvc_version1 = {
.vs_vers = 1,
.vs_nproc = 17,
.vs_proc = nlmsvc_procedures,
.vs_count = nlm1svc_call_counters,
.vs_dispatch = nlmsvc_dispatch,
.vs_xdrsize = sizeof(union nlmsvc_xdrstore),
};
static DEFINE_PER_CPU_ALIGNED(unsigned long,
nlm3svc_call_counters[ARRAY_SIZE(nlmsvc_procedures)]);
const struct svc_version nlmsvc_version3 = {
.vs_vers = 3,
.vs_nproc = ARRAY_SIZE(nlmsvc_procedures),
.vs_proc = nlmsvc_procedures,
.vs_count = nlm3svc_call_counters,
.vs_dispatch = nlmsvc_dispatch,
.vs_xdrsize = sizeof(union nlmsvc_xdrstore),
};

5
fs/lockd/xdr.h
View File

@ -88,11 +88,6 @@ struct nlm_reboot {
struct nsm_private priv;
};
/*
* Contents of statd callback when monitored host rebooted
*/
#define NLMSVC_XDRSIZE sizeof(struct nlm_args)
bool nlmsvc_decode_void(struct svc_rqst *rqstp, struct xdr_stream *xdr);
bool nlmsvc_decode_testargs(struct svc_rqst *rqstp, struct xdr_stream *xdr);
bool nlmsvc_decode_lockargs(struct svc_rqst *rqstp, struct xdr_stream *xdr);