5 files changed, 97 insertions, 38 deletions

diff --git a/fs/lockd/svc.c b/fs/lockd/svc.c
index 346ed161756d..75415b21efda 100644
--- a/fs/lockd/svc.c
+++ b/fs/lockd/svc.c
@@ -807,5 +807,6 @@ static struct svc_program	nlmsvc_program = {
         .pg_name                = "lockd",              /* service name */
         .pg_class               = "nfsd",               /* share authentication with nfsd */
         .pg_stats               = &nlmsvc_stats,        /* stats table */
-        .pg_authenticate = &lockd_authenticate  /* export authentication */
+        .pg_authenticate        = &lockd_authenticate,  /* export authentication */
+        .pg_init_request        = svc_generic_init_request,
 };
diff --git a/fs/nfs/callback.c b/fs/nfs/callback.c
index 0b602a39dd71..a9510374bad7 100644
--- a/fs/nfs/callback.c
+++ b/fs/nfs/callback.c
@@ -457,4 +457,5 @@ static struct svc_program nfs4_callback_program = {
         .pg_class = "nfs",                              /* authentication class */
         .pg_stats = &nfs4_callback_stats,
         .pg_authenticate = nfs_callback_authenticate,
+        .pg_init_request = svc_generic_init_request,
 };
diff --git a/fs/nfsd/nfssvc.c b/fs/nfsd/nfssvc.c
index 89cb484f1cfb..e26762e84798 100644
--- a/fs/nfsd/nfssvc.c
+++ b/fs/nfsd/nfssvc.c
@@ -86,6 +86,7 @@ static struct svc_program	nfsd_acl_program = {
         .pg_class               = "nfsd",
         .pg_stats               = &nfsd_acl_svcstats,
         .pg_authenticate        = &svc_set_client,
+        .pg_init_request        = svc_generic_init_request,
 };
 
 static struct svc_stat  nfsd_acl_svcstats = {
@@ -118,6 +119,7 @@ struct svc_program		nfsd_program = {
         .pg_class               = "nfsd",               /* authentication class */
         .pg_stats               = &nfsd_svcstats,       /* version table */
         .pg_authenticate        = &svc_set_client,      /* export authentication */
+        .pg_init_request        = svc_generic_init_request,
 
 };
 
diff --git a/include/linux/sunrpc/svc.h b/include/linux/sunrpc/svc.h
index 7ff12c9dbeaf..f43d5765acff 100644
--- a/include/linux/sunrpc/svc.h
+++ b/include/linux/sunrpc/svc.h
@@ -383,6 +383,16 @@ struct svc_deferred_req {
         __be32                  args[0];
 };
 
+struct svc_process_info {
+        union {
+                int  (*dispatch)(struct svc_rqst *, __be32 *);
+                struct {
+                        unsigned int lovers;
+                        unsigned int hivers;
+                } mismatch;
+        };
+};
+
 /*
  * List of RPC programs on the same transport endpoint
  */
@@ -397,6 +407,9 @@ struct svc_program {
         char *                  pg_class;       /* class name: services sharing authentication */
         struct svc_stat *       pg_stats;       /* rpc statistics */
         int                     (*pg_authenticate)(struct svc_rqst *);
+        __be32                  (*pg_init_request)(struct svc_rqst *,
+                                                   const struct svc_program *,
+                                                   struct svc_process_info *);
 };
 
 /*
@@ -506,6 +519,9 @@ char		  *svc_fill_symlink_pathname(struct svc_rqst *rqstp,
                                              struct kvec *first, void *p,
                                              size_t total);
 __be32             svc_return_autherr(struct svc_rqst *rqstp, __be32 auth_err);
+__be32             svc_generic_init_request(struct svc_rqst *rqstp,
+                                            const struct svc_program *progp,
+                                            struct svc_process_info *procinfo);
 
 #define RPC_MAX_ADDRBUFLEN      (63U)
 
diff --git a/net/sunrpc/svc.c b/net/sunrpc/svc.c
index 3d5dd6b86652..69f3b9e015ce 100644
--- a/net/sunrpc/svc.c
+++ b/net/sunrpc/svc.c
@@ -1160,6 +1160,59 @@ svc_get_autherr(struct svc_rqst *rqstp, __be32 *statp)
         return rpc_auth_ok;
 }
 
+__be32
+svc_generic_init_request(struct svc_rqst *rqstp,
+                const struct svc_program *progp,
+                struct svc_process_info *ret)
+{
+        const struct svc_version *versp = NULL; /* compiler food */
+        const struct svc_procedure *procp = NULL;
+
+        if (rqstp->rq_vers >= progp->pg_nvers )
+                goto err_bad_vers;
+          versp = progp->pg_vers[rqstp->rq_vers];
+          if (!versp)
+                goto err_bad_vers;
+
+        /*
+         * Some protocol versions (namely NFSv4) require some form of
+         * congestion control.  (See RFC 7530 section 3.1 paragraph 2)
+         * In other words, UDP is not allowed. We mark those when setting
+         * up the svc_xprt, and verify that here.
+         *
+         * The spec is not very clear about what error should be returned
+         * when someone tries to access a server that is listening on UDP
+         * for lower versions. RPC_PROG_MISMATCH seems to be the closest
+         * fit.
+         */
+        if (versp->vs_need_cong_ctrl && rqstp->rq_xprt &&
+            !test_bit(XPT_CONG_CTRL, &rqstp->rq_xprt->xpt_flags))
+                goto err_bad_vers;
+
+        if (rqstp->rq_proc >= versp->vs_nproc)
+                goto err_bad_proc;
+        rqstp->rq_procinfo = procp = &versp->vs_proc[rqstp->rq_proc];
+        if (!procp)
+                goto err_bad_proc;
+
+        /* Initialize storage for argp and resp */
+        memset(rqstp->rq_argp, 0, procp->pc_argsize);
+        memset(rqstp->rq_resp, 0, procp->pc_ressize);
+
+        /* Bump per-procedure stats counter */
+        versp->vs_count[rqstp->rq_proc]++;
+
+        ret->dispatch = versp->vs_dispatch;
+        return rpc_success;
+err_bad_vers:
+        ret->mismatch.lovers = progp->pg_lovers;
+        ret->mismatch.hivers = progp->pg_hivers;
+        return rpc_prog_mismatch;
+err_bad_proc:
+        return rpc_proc_unavail;
+}
+EXPORT_SYMBOL_GPL(svc_generic_init_request);
+
 /*
  * Common routine for processing the RPC request.
  */
@@ -1167,11 +1220,11 @@ static int
 svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
 {
         struct svc_program      *progp;
-        const struct svc_version *versp = NULL; /* compiler food */
         const struct svc_procedure *procp = NULL;
         struct svc_serv         *serv = rqstp->rq_server;
+        struct svc_process_info process;
         __be32                  *statp;
-        u32                     prog, vers, proc;
+        u32                     prog, vers;
         __be32                  auth_stat, rpc_stat;
         int                     auth_res;
         __be32                  *reply_statp;
@@ -1203,8 +1256,8 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
         svc_putnl(resv, 0);             /* ACCEPT */
 
         rqstp->rq_prog = prog = svc_getnl(argv);        /* program number */
-        rqstp->rq_vers = vers = svc_getnl(argv);        /* version number */
-        rqstp->rq_proc = proc = svc_getnl(argv);        /* procedure number */
+        rqstp->rq_vers = svc_getnl(argv);       /* version number */
+        rqstp->rq_proc = svc_getnl(argv);       /* procedure number */
 
         for (progp = serv->sv_program; progp; progp = progp->pg_next)
                 if (prog == progp->pg_prog)
@@ -1242,29 +1295,22 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
         if (progp == NULL)
                 goto err_bad_prog;
 
-        if (vers >= progp->pg_nvers ||
-          !(versp = progp->pg_vers[vers]))
-                goto err_bad_vers;
-
-        /*
-         * Some protocol versions (namely NFSv4) require some form of
-         * congestion control.  (See RFC 7530 section 3.1 paragraph 2)
-         * In other words, UDP is not allowed. We mark those when setting
-         * up the svc_xprt, and verify that here.
-         *
-         * The spec is not very clear about what error should be returned
-         * when someone tries to access a server that is listening on UDP
-         * for lower versions. RPC_PROG_MISMATCH seems to be the closest
-         * fit.
-         */
-        if (versp->vs_need_cong_ctrl && rqstp->rq_xprt &&
-            !test_bit(XPT_CONG_CTRL, &rqstp->rq_xprt->xpt_flags))
+        rpc_stat = progp->pg_init_request(rqstp, progp, &process);
+        switch (rpc_stat) {
+        case rpc_success:
+                break;
+        case rpc_prog_unavail:
+                goto err_bad_prog;
+        case rpc_prog_mismatch:
                 goto err_bad_vers;
+        case rpc_proc_unavail:
+                goto err_bad_proc;
+        }
 
-        procp = versp->vs_proc + proc;
-        if (proc >= versp->vs_nproc || !procp->pc_func)
+        procp = rqstp->rq_procinfo;
+        /* Should this check go into the dispatcher? */
+        if (!procp || !procp->pc_func)
                 goto err_bad_proc;
-        rqstp->rq_procinfo = procp;
 
         /* Syntactic check complete */
         serv->sv_stats->rpccnt++;
@@ -1274,13 +1320,6 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
         statp = resv->iov_base +resv->iov_len;
         svc_putnl(resv, RPC_SUCCESS);
 
-        /* Bump per-procedure stats counter */
-        versp->vs_count[proc]++;
-
-        /* Initialize storage for argp and resp */
-        memset(rqstp->rq_argp, 0, procp->pc_argsize);
-        memset(rqstp->rq_resp, 0, procp->pc_ressize);
-
         /* un-reserve some of the out-queue now that we have a
          * better idea of reply size
          */
@@ -1288,7 +1327,7 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
                 svc_reserve_auth(rqstp, procp->pc_xdrressize<<2);
 
         /* Call the function that processes the request. */
-        if (!versp->vs_dispatch) {
+        if (!process.dispatch) {
                 /*
                  * Decode arguments
                  * XXX: why do we ignore the return value?
@@ -1317,7 +1356,7 @@ svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
                 }
         } else {
                 dprintk("svc: calling dispatcher\n");
-                if (!versp->vs_dispatch(rqstp, statp)) {
+                if (!process.dispatch(rqstp, statp)) {
                         /* Release reply info */
                         if (procp->pc_release)
                                 procp->pc_release(rqstp);
@@ -1386,16 +1425,16 @@ err_bad_prog:
 
 err_bad_vers:
         svc_printk(rqstp, "unknown version (%d for prog %d, %s)\n",
-                       vers, prog, progp->pg_name);
+                       rqstp->rq_vers, rqstp->rq_prog, progp->pg_name);
 
         serv->sv_stats->rpcbadfmt++;
         svc_putnl(resv, RPC_PROG_MISMATCH);
-        svc_putnl(resv, progp->pg_lovers);
-        svc_putnl(resv, progp->pg_hivers);
+        svc_putnl(resv, process.mismatch.lovers);
+        svc_putnl(resv, process.mismatch.hivers);
         goto sendit;
 
 err_bad_proc:
-        svc_printk(rqstp, "unknown procedure (%d)\n", proc);
+        svc_printk(rqstp, "unknown procedure (%d)\n", rqstp->rq_proc);
 
         serv->sv_stats->rpcbadfmt++;
         svc_putnl(resv, RPC_PROC_UNAVAIL);