linux/net/sunrpc/svc.c
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   1// SPDX-License-Identifier: GPL-2.0-only
   2/*
   3 * linux/net/sunrpc/svc.c
   4 *
   5 * High-level RPC service routines
   6 *
   7 * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
   8 *
   9 * Multiple threads pools and NUMAisation
  10 * Copyright (c) 2006 Silicon Graphics, Inc.
  11 * by Greg Banks <gnb@melbourne.sgi.com>
  12 */
  13
  14#include <linux/linkage.h>
  15#include <linux/sched/signal.h>
  16#include <linux/errno.h>
  17#include <linux/net.h>
  18#include <linux/in.h>
  19#include <linux/mm.h>
  20#include <linux/interrupt.h>
  21#include <linux/module.h>
  22#include <linux/kthread.h>
  23#include <linux/slab.h>
  24
  25#include <linux/sunrpc/types.h>
  26#include <linux/sunrpc/xdr.h>
  27#include <linux/sunrpc/stats.h>
  28#include <linux/sunrpc/svcsock.h>
  29#include <linux/sunrpc/clnt.h>
  30#include <linux/sunrpc/bc_xprt.h>
  31
  32#include <trace/events/sunrpc.h>
  33
  34#define RPCDBG_FACILITY RPCDBG_SVCDSP
  35
  36static void svc_unregister(const struct svc_serv *serv, struct net *net);
  37
  38#define svc_serv_is_pooled(serv)    ((serv)->sv_ops->svo_function)
  39
  40#define SVC_POOL_DEFAULT        SVC_POOL_GLOBAL
  41
  42/*
  43 * Structure for mapping cpus to pools and vice versa.
  44 * Setup once during sunrpc initialisation.
  45 */
  46struct svc_pool_map svc_pool_map = {
  47        .mode = SVC_POOL_DEFAULT
  48};
  49EXPORT_SYMBOL_GPL(svc_pool_map);
  50
  51static DEFINE_MUTEX(svc_pool_map_mutex);/* protects svc_pool_map.count only */
  52
  53static int
  54param_set_pool_mode(const char *val, const struct kernel_param *kp)
  55{
  56        int *ip = (int *)kp->arg;
  57        struct svc_pool_map *m = &svc_pool_map;
  58        int err;
  59
  60        mutex_lock(&svc_pool_map_mutex);
  61
  62        err = -EBUSY;
  63        if (m->count)
  64                goto out;
  65
  66        err = 0;
  67        if (!strncmp(val, "auto", 4))
  68                *ip = SVC_POOL_AUTO;
  69        else if (!strncmp(val, "global", 6))
  70                *ip = SVC_POOL_GLOBAL;
  71        else if (!strncmp(val, "percpu", 6))
  72                *ip = SVC_POOL_PERCPU;
  73        else if (!strncmp(val, "pernode", 7))
  74                *ip = SVC_POOL_PERNODE;
  75        else
  76                err = -EINVAL;
  77
  78out:
  79        mutex_unlock(&svc_pool_map_mutex);
  80        return err;
  81}
  82
  83static int
  84param_get_pool_mode(char *buf, const struct kernel_param *kp)
  85{
  86        int *ip = (int *)kp->arg;
  87
  88        switch (*ip)
  89        {
  90        case SVC_POOL_AUTO:
  91                return strlcpy(buf, "auto", 20);
  92        case SVC_POOL_GLOBAL:
  93                return strlcpy(buf, "global", 20);
  94        case SVC_POOL_PERCPU:
  95                return strlcpy(buf, "percpu", 20);
  96        case SVC_POOL_PERNODE:
  97                return strlcpy(buf, "pernode", 20);
  98        default:
  99                return sprintf(buf, "%d", *ip);
 100        }
 101}
 102
 103module_param_call(pool_mode, param_set_pool_mode, param_get_pool_mode,
 104                 &svc_pool_map.mode, 0644);
 105
 106/*
 107 * Detect best pool mapping mode heuristically,
 108 * according to the machine's topology.
 109 */
 110static int
 111svc_pool_map_choose_mode(void)
 112{
 113        unsigned int node;
 114
 115        if (nr_online_nodes > 1) {
 116                /*
 117                 * Actually have multiple NUMA nodes,
 118                 * so split pools on NUMA node boundaries
 119                 */
 120                return SVC_POOL_PERNODE;
 121        }
 122
 123        node = first_online_node;
 124        if (nr_cpus_node(node) > 2) {
 125                /*
 126                 * Non-trivial SMP, or CONFIG_NUMA on
 127                 * non-NUMA hardware, e.g. with a generic
 128                 * x86_64 kernel on Xeons.  In this case we
 129                 * want to divide the pools on cpu boundaries.
 130                 */
 131                return SVC_POOL_PERCPU;
 132        }
 133
 134        /* default: one global pool */
 135        return SVC_POOL_GLOBAL;
 136}
 137
 138/*
 139 * Allocate the to_pool[] and pool_to[] arrays.
 140 * Returns 0 on success or an errno.
 141 */
 142static int
 143svc_pool_map_alloc_arrays(struct svc_pool_map *m, unsigned int maxpools)
 144{
 145        m->to_pool = kcalloc(maxpools, sizeof(unsigned int), GFP_KERNEL);
 146        if (!m->to_pool)
 147                goto fail;
 148        m->pool_to = kcalloc(maxpools, sizeof(unsigned int), GFP_KERNEL);
 149        if (!m->pool_to)
 150                goto fail_free;
 151
 152        return 0;
 153
 154fail_free:
 155        kfree(m->to_pool);
 156        m->to_pool = NULL;
 157fail:
 158        return -ENOMEM;
 159}
 160
 161/*
 162 * Initialise the pool map for SVC_POOL_PERCPU mode.
 163 * Returns number of pools or <0 on error.
 164 */
 165static int
 166svc_pool_map_init_percpu(struct svc_pool_map *m)
 167{
 168        unsigned int maxpools = nr_cpu_ids;
 169        unsigned int pidx = 0;
 170        unsigned int cpu;
 171        int err;
 172
 173        err = svc_pool_map_alloc_arrays(m, maxpools);
 174        if (err)
 175                return err;
 176
 177        for_each_online_cpu(cpu) {
 178                BUG_ON(pidx >= maxpools);
 179                m->to_pool[cpu] = pidx;
 180                m->pool_to[pidx] = cpu;
 181                pidx++;
 182        }
 183        /* cpus brought online later all get mapped to pool0, sorry */
 184
 185        return pidx;
 186};
 187
 188
 189/*
 190 * Initialise the pool map for SVC_POOL_PERNODE mode.
 191 * Returns number of pools or <0 on error.
 192 */
 193static int
 194svc_pool_map_init_pernode(struct svc_pool_map *m)
 195{
 196        unsigned int maxpools = nr_node_ids;
 197        unsigned int pidx = 0;
 198        unsigned int node;
 199        int err;
 200
 201        err = svc_pool_map_alloc_arrays(m, maxpools);
 202        if (err)
 203                return err;
 204
 205        for_each_node_with_cpus(node) {
 206                /* some architectures (e.g. SN2) have cpuless nodes */
 207                BUG_ON(pidx > maxpools);
 208                m->to_pool[node] = pidx;
 209                m->pool_to[pidx] = node;
 210                pidx++;
 211        }
 212        /* nodes brought online later all get mapped to pool0, sorry */
 213
 214        return pidx;
 215}
 216
 217
 218/*
 219 * Add a reference to the global map of cpus to pools (and
 220 * vice versa).  Initialise the map if we're the first user.
 221 * Returns the number of pools.
 222 */
 223unsigned int
 224svc_pool_map_get(void)
 225{
 226        struct svc_pool_map *m = &svc_pool_map;
 227        int npools = -1;
 228
 229        mutex_lock(&svc_pool_map_mutex);
 230
 231        if (m->count++) {
 232                mutex_unlock(&svc_pool_map_mutex);
 233                return m->npools;
 234        }
 235
 236        if (m->mode == SVC_POOL_AUTO)
 237                m->mode = svc_pool_map_choose_mode();
 238
 239        switch (m->mode) {
 240        case SVC_POOL_PERCPU:
 241                npools = svc_pool_map_init_percpu(m);
 242                break;
 243        case SVC_POOL_PERNODE:
 244                npools = svc_pool_map_init_pernode(m);
 245                break;
 246        }
 247
 248        if (npools < 0) {
 249                /* default, or memory allocation failure */
 250                npools = 1;
 251                m->mode = SVC_POOL_GLOBAL;
 252        }
 253        m->npools = npools;
 254
 255        mutex_unlock(&svc_pool_map_mutex);
 256        return m->npools;
 257}
 258EXPORT_SYMBOL_GPL(svc_pool_map_get);
 259
 260/*
 261 * Drop a reference to the global map of cpus to pools.
 262 * When the last reference is dropped, the map data is
 263 * freed; this allows the sysadmin to change the pool
 264 * mode using the pool_mode module option without
 265 * rebooting or re-loading sunrpc.ko.
 266 */
 267void
 268svc_pool_map_put(void)
 269{
 270        struct svc_pool_map *m = &svc_pool_map;
 271
 272        mutex_lock(&svc_pool_map_mutex);
 273
 274        if (!--m->count) {
 275                kfree(m->to_pool);
 276                m->to_pool = NULL;
 277                kfree(m->pool_to);
 278                m->pool_to = NULL;
 279                m->npools = 0;
 280        }
 281
 282        mutex_unlock(&svc_pool_map_mutex);
 283}
 284EXPORT_SYMBOL_GPL(svc_pool_map_put);
 285
 286static int svc_pool_map_get_node(unsigned int pidx)
 287{
 288        const struct svc_pool_map *m = &svc_pool_map;
 289
 290        if (m->count) {
 291                if (m->mode == SVC_POOL_PERCPU)
 292                        return cpu_to_node(m->pool_to[pidx]);
 293                if (m->mode == SVC_POOL_PERNODE)
 294                        return m->pool_to[pidx];
 295        }
 296        return NUMA_NO_NODE;
 297}
 298/*
 299 * Set the given thread's cpus_allowed mask so that it
 300 * will only run on cpus in the given pool.
 301 */
 302static inline void
 303svc_pool_map_set_cpumask(struct task_struct *task, unsigned int pidx)
 304{
 305        struct svc_pool_map *m = &svc_pool_map;
 306        unsigned int node = m->pool_to[pidx];
 307
 308        /*
 309         * The caller checks for sv_nrpools > 1, which
 310         * implies that we've been initialized.
 311         */
 312        WARN_ON_ONCE(m->count == 0);
 313        if (m->count == 0)
 314                return;
 315
 316        switch (m->mode) {
 317        case SVC_POOL_PERCPU:
 318        {
 319                set_cpus_allowed_ptr(task, cpumask_of(node));
 320                break;
 321        }
 322        case SVC_POOL_PERNODE:
 323        {
 324                set_cpus_allowed_ptr(task, cpumask_of_node(node));
 325                break;
 326        }
 327        }
 328}
 329
 330/*
 331 * Use the mapping mode to choose a pool for a given CPU.
 332 * Used when enqueueing an incoming RPC.  Always returns
 333 * a non-NULL pool pointer.
 334 */
 335struct svc_pool *
 336svc_pool_for_cpu(struct svc_serv *serv, int cpu)
 337{
 338        struct svc_pool_map *m = &svc_pool_map;
 339        unsigned int pidx = 0;
 340
 341        /*
 342         * An uninitialised map happens in a pure client when
 343         * lockd is brought up, so silently treat it the
 344         * same as SVC_POOL_GLOBAL.
 345         */
 346        if (svc_serv_is_pooled(serv)) {
 347                switch (m->mode) {
 348                case SVC_POOL_PERCPU:
 349                        pidx = m->to_pool[cpu];
 350                        break;
 351                case SVC_POOL_PERNODE:
 352                        pidx = m->to_pool[cpu_to_node(cpu)];
 353                        break;
 354                }
 355        }
 356        return &serv->sv_pools[pidx % serv->sv_nrpools];
 357}
 358
 359int svc_rpcb_setup(struct svc_serv *serv, struct net *net)
 360{
 361        int err;
 362
 363        err = rpcb_create_local(net);
 364        if (err)
 365                return err;
 366
 367        /* Remove any stale portmap registrations */
 368        svc_unregister(serv, net);
 369        return 0;
 370}
 371EXPORT_SYMBOL_GPL(svc_rpcb_setup);
 372
 373void svc_rpcb_cleanup(struct svc_serv *serv, struct net *net)
 374{
 375        svc_unregister(serv, net);
 376        rpcb_put_local(net);
 377}
 378EXPORT_SYMBOL_GPL(svc_rpcb_cleanup);
 379
 380static int svc_uses_rpcbind(struct svc_serv *serv)
 381{
 382        struct svc_program      *progp;
 383        unsigned int            i;
 384
 385        for (progp = serv->sv_program; progp; progp = progp->pg_next) {
 386                for (i = 0; i < progp->pg_nvers; i++) {
 387                        if (progp->pg_vers[i] == NULL)
 388                                continue;
 389                        if (!progp->pg_vers[i]->vs_hidden)
 390                                return 1;
 391                }
 392        }
 393
 394        return 0;
 395}
 396
 397int svc_bind(struct svc_serv *serv, struct net *net)
 398{
 399        if (!svc_uses_rpcbind(serv))
 400                return 0;
 401        return svc_rpcb_setup(serv, net);
 402}
 403EXPORT_SYMBOL_GPL(svc_bind);
 404
 405#if defined(CONFIG_SUNRPC_BACKCHANNEL)
 406static void
 407__svc_init_bc(struct svc_serv *serv)
 408{
 409        INIT_LIST_HEAD(&serv->sv_cb_list);
 410        spin_lock_init(&serv->sv_cb_lock);
 411        init_waitqueue_head(&serv->sv_cb_waitq);
 412}
 413#else
 414static void
 415__svc_init_bc(struct svc_serv *serv)
 416{
 417}
 418#endif
 419
 420/*
 421 * Create an RPC service
 422 */
 423static struct svc_serv *
 424__svc_create(struct svc_program *prog, unsigned int bufsize, int npools,
 425             const struct svc_serv_ops *ops)
 426{
 427        struct svc_serv *serv;
 428        unsigned int vers;
 429        unsigned int xdrsize;
 430        unsigned int i;
 431
 432        if (!(serv = kzalloc(sizeof(*serv), GFP_KERNEL)))
 433                return NULL;
 434        serv->sv_name      = prog->pg_name;
 435        serv->sv_program   = prog;
 436        serv->sv_nrthreads = 1;
 437        serv->sv_stats     = prog->pg_stats;
 438        if (bufsize > RPCSVC_MAXPAYLOAD)
 439                bufsize = RPCSVC_MAXPAYLOAD;
 440        serv->sv_max_payload = bufsize? bufsize : 4096;
 441        serv->sv_max_mesg  = roundup(serv->sv_max_payload + PAGE_SIZE, PAGE_SIZE);
 442        serv->sv_ops = ops;
 443        xdrsize = 0;
 444        while (prog) {
 445                prog->pg_lovers = prog->pg_nvers-1;
 446                for (vers=0; vers<prog->pg_nvers ; vers++)
 447                        if (prog->pg_vers[vers]) {
 448                                prog->pg_hivers = vers;
 449                                if (prog->pg_lovers > vers)
 450                                        prog->pg_lovers = vers;
 451                                if (prog->pg_vers[vers]->vs_xdrsize > xdrsize)
 452                                        xdrsize = prog->pg_vers[vers]->vs_xdrsize;
 453                        }
 454                prog = prog->pg_next;
 455        }
 456        serv->sv_xdrsize   = xdrsize;
 457        INIT_LIST_HEAD(&serv->sv_tempsocks);
 458        INIT_LIST_HEAD(&serv->sv_permsocks);
 459        timer_setup(&serv->sv_temptimer, NULL, 0);
 460        spin_lock_init(&serv->sv_lock);
 461
 462        __svc_init_bc(serv);
 463
 464        serv->sv_nrpools = npools;
 465        serv->sv_pools =
 466                kcalloc(serv->sv_nrpools, sizeof(struct svc_pool),
 467                        GFP_KERNEL);
 468        if (!serv->sv_pools) {
 469                kfree(serv);
 470                return NULL;
 471        }
 472
 473        for (i = 0; i < serv->sv_nrpools; i++) {
 474                struct svc_pool *pool = &serv->sv_pools[i];
 475
 476                dprintk("svc: initialising pool %u for %s\n",
 477                                i, serv->sv_name);
 478
 479                pool->sp_id = i;
 480                INIT_LIST_HEAD(&pool->sp_sockets);
 481                INIT_LIST_HEAD(&pool->sp_all_threads);
 482                spin_lock_init(&pool->sp_lock);
 483        }
 484
 485        return serv;
 486}
 487
 488struct svc_serv *
 489svc_create(struct svc_program *prog, unsigned int bufsize,
 490           const struct svc_serv_ops *ops)
 491{
 492        return __svc_create(prog, bufsize, /*npools*/1, ops);
 493}
 494EXPORT_SYMBOL_GPL(svc_create);
 495
 496struct svc_serv *
 497svc_create_pooled(struct svc_program *prog, unsigned int bufsize,
 498                  const struct svc_serv_ops *ops)
 499{
 500        struct svc_serv *serv;
 501        unsigned int npools = svc_pool_map_get();
 502
 503        serv = __svc_create(prog, bufsize, npools, ops);
 504        if (!serv)
 505                goto out_err;
 506        return serv;
 507out_err:
 508        svc_pool_map_put();
 509        return NULL;
 510}
 511EXPORT_SYMBOL_GPL(svc_create_pooled);
 512
 513void svc_shutdown_net(struct svc_serv *serv, struct net *net)
 514{
 515        svc_close_net(serv, net);
 516
 517        if (serv->sv_ops->svo_shutdown)
 518                serv->sv_ops->svo_shutdown(serv, net);
 519}
 520EXPORT_SYMBOL_GPL(svc_shutdown_net);
 521
 522/*
 523 * Destroy an RPC service. Should be called with appropriate locking to
 524 * protect the sv_nrthreads, sv_permsocks and sv_tempsocks.
 525 */
 526void
 527svc_destroy(struct svc_serv *serv)
 528{
 529        dprintk("svc: svc_destroy(%s, %d)\n",
 530                                serv->sv_program->pg_name,
 531                                serv->sv_nrthreads);
 532
 533        if (serv->sv_nrthreads) {
 534                if (--(serv->sv_nrthreads) != 0) {
 535                        svc_sock_update_bufs(serv);
 536                        return;
 537                }
 538        } else
 539                printk("svc_destroy: no threads for serv=%p!\n", serv);
 540
 541        del_timer_sync(&serv->sv_temptimer);
 542
 543        /*
 544         * The last user is gone and thus all sockets have to be destroyed to
 545         * the point. Check this.
 546         */
 547        BUG_ON(!list_empty(&serv->sv_permsocks));
 548        BUG_ON(!list_empty(&serv->sv_tempsocks));
 549
 550        cache_clean_deferred(serv);
 551
 552        if (svc_serv_is_pooled(serv))
 553                svc_pool_map_put();
 554
 555        kfree(serv->sv_pools);
 556        kfree(serv);
 557}
 558EXPORT_SYMBOL_GPL(svc_destroy);
 559
 560/*
 561 * Allocate an RPC server's buffer space.
 562 * We allocate pages and place them in rq_argpages.
 563 */
 564static int
 565svc_init_buffer(struct svc_rqst *rqstp, unsigned int size, int node)
 566{
 567        unsigned int pages, arghi;
 568
 569        /* bc_xprt uses fore channel allocated buffers */
 570        if (svc_is_backchannel(rqstp))
 571                return 1;
 572
 573        pages = size / PAGE_SIZE + 1; /* extra page as we hold both request and reply.
 574                                       * We assume one is at most one page
 575                                       */
 576        arghi = 0;
 577        WARN_ON_ONCE(pages > RPCSVC_MAXPAGES);
 578        if (pages > RPCSVC_MAXPAGES)
 579                pages = RPCSVC_MAXPAGES;
 580        while (pages) {
 581                struct page *p = alloc_pages_node(node, GFP_KERNEL, 0);
 582                if (!p)
 583                        break;
 584                rqstp->rq_pages[arghi++] = p;
 585                pages--;
 586        }
 587        return pages == 0;
 588}
 589
 590/*
 591 * Release an RPC server buffer
 592 */
 593static void
 594svc_release_buffer(struct svc_rqst *rqstp)
 595{
 596        unsigned int i;
 597
 598        for (i = 0; i < ARRAY_SIZE(rqstp->rq_pages); i++)
 599                if (rqstp->rq_pages[i])
 600                        put_page(rqstp->rq_pages[i]);
 601}
 602
 603struct svc_rqst *
 604svc_rqst_alloc(struct svc_serv *serv, struct svc_pool *pool, int node)
 605{
 606        struct svc_rqst *rqstp;
 607
 608        rqstp = kzalloc_node(sizeof(*rqstp), GFP_KERNEL, node);
 609        if (!rqstp)
 610                return rqstp;
 611
 612        __set_bit(RQ_BUSY, &rqstp->rq_flags);
 613        spin_lock_init(&rqstp->rq_lock);
 614        rqstp->rq_server = serv;
 615        rqstp->rq_pool = pool;
 616
 617        rqstp->rq_argp = kmalloc_node(serv->sv_xdrsize, GFP_KERNEL, node);
 618        if (!rqstp->rq_argp)
 619                goto out_enomem;
 620
 621        rqstp->rq_resp = kmalloc_node(serv->sv_xdrsize, GFP_KERNEL, node);
 622        if (!rqstp->rq_resp)
 623                goto out_enomem;
 624
 625        if (!svc_init_buffer(rqstp, serv->sv_max_mesg, node))
 626                goto out_enomem;
 627
 628        return rqstp;
 629out_enomem:
 630        svc_rqst_free(rqstp);
 631        return NULL;
 632}
 633EXPORT_SYMBOL_GPL(svc_rqst_alloc);
 634
 635struct svc_rqst *
 636svc_prepare_thread(struct svc_serv *serv, struct svc_pool *pool, int node)
 637{
 638        struct svc_rqst *rqstp;
 639
 640        rqstp = svc_rqst_alloc(serv, pool, node);
 641        if (!rqstp)
 642                return ERR_PTR(-ENOMEM);
 643
 644        serv->sv_nrthreads++;
 645        spin_lock_bh(&pool->sp_lock);
 646        pool->sp_nrthreads++;
 647        list_add_rcu(&rqstp->rq_all, &pool->sp_all_threads);
 648        spin_unlock_bh(&pool->sp_lock);
 649        return rqstp;
 650}
 651EXPORT_SYMBOL_GPL(svc_prepare_thread);
 652
 653/*
 654 * Choose a pool in which to create a new thread, for svc_set_num_threads
 655 */
 656static inline struct svc_pool *
 657choose_pool(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
 658{
 659        if (pool != NULL)
 660                return pool;
 661
 662        return &serv->sv_pools[(*state)++ % serv->sv_nrpools];
 663}
 664
 665/*
 666 * Choose a thread to kill, for svc_set_num_threads
 667 */
 668static inline struct task_struct *
 669choose_victim(struct svc_serv *serv, struct svc_pool *pool, unsigned int *state)
 670{
 671        unsigned int i;
 672        struct task_struct *task = NULL;
 673
 674        if (pool != NULL) {
 675                spin_lock_bh(&pool->sp_lock);
 676        } else {
 677                /* choose a pool in round-robin fashion */
 678                for (i = 0; i < serv->sv_nrpools; i++) {
 679                        pool = &serv->sv_pools[--(*state) % serv->sv_nrpools];
 680                        spin_lock_bh(&pool->sp_lock);
 681                        if (!list_empty(&pool->sp_all_threads))
 682                                goto found_pool;
 683                        spin_unlock_bh(&pool->sp_lock);
 684                }
 685                return NULL;
 686        }
 687
 688found_pool:
 689        if (!list_empty(&pool->sp_all_threads)) {
 690                struct svc_rqst *rqstp;
 691
 692                /*
 693                 * Remove from the pool->sp_all_threads list
 694                 * so we don't try to kill it again.
 695                 */
 696                rqstp = list_entry(pool->sp_all_threads.next, struct svc_rqst, rq_all);
 697                set_bit(RQ_VICTIM, &rqstp->rq_flags);
 698                list_del_rcu(&rqstp->rq_all);
 699                task = rqstp->rq_task;
 700        }
 701        spin_unlock_bh(&pool->sp_lock);
 702
 703        return task;
 704}
 705
 706/* create new threads */
 707static int
 708svc_start_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
 709{
 710        struct svc_rqst *rqstp;
 711        struct task_struct *task;
 712        struct svc_pool *chosen_pool;
 713        unsigned int state = serv->sv_nrthreads-1;
 714        int node;
 715
 716        do {
 717                nrservs--;
 718                chosen_pool = choose_pool(serv, pool, &state);
 719
 720                node = svc_pool_map_get_node(chosen_pool->sp_id);
 721                rqstp = svc_prepare_thread(serv, chosen_pool, node);
 722                if (IS_ERR(rqstp))
 723                        return PTR_ERR(rqstp);
 724
 725                __module_get(serv->sv_ops->svo_module);
 726                task = kthread_create_on_node(serv->sv_ops->svo_function, rqstp,
 727                                              node, "%s", serv->sv_name);
 728                if (IS_ERR(task)) {
 729                        module_put(serv->sv_ops->svo_module);
 730                        svc_exit_thread(rqstp);
 731                        return PTR_ERR(task);
 732                }
 733
 734                rqstp->rq_task = task;
 735                if (serv->sv_nrpools > 1)
 736                        svc_pool_map_set_cpumask(task, chosen_pool->sp_id);
 737
 738                svc_sock_update_bufs(serv);
 739                wake_up_process(task);
 740        } while (nrservs > 0);
 741
 742        return 0;
 743}
 744
 745
 746/* destroy old threads */
 747static int
 748svc_signal_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
 749{
 750        struct task_struct *task;
 751        unsigned int state = serv->sv_nrthreads-1;
 752
 753        /* destroy old threads */
 754        do {
 755                task = choose_victim(serv, pool, &state);
 756                if (task == NULL)
 757                        break;
 758                send_sig(SIGINT, task, 1);
 759                nrservs++;
 760        } while (nrservs < 0);
 761
 762        return 0;
 763}
 764
 765/*
 766 * Create or destroy enough new threads to make the number
 767 * of threads the given number.  If `pool' is non-NULL, applies
 768 * only to threads in that pool, otherwise round-robins between
 769 * all pools.  Caller must ensure that mutual exclusion between this and
 770 * server startup or shutdown.
 771 *
 772 * Destroying threads relies on the service threads filling in
 773 * rqstp->rq_task, which only the nfs ones do.  Assumes the serv
 774 * has been created using svc_create_pooled().
 775 *
 776 * Based on code that used to be in nfsd_svc() but tweaked
 777 * to be pool-aware.
 778 */
 779int
 780svc_set_num_threads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
 781{
 782        if (pool == NULL) {
 783                /* The -1 assumes caller has done a svc_get() */
 784                nrservs -= (serv->sv_nrthreads-1);
 785        } else {
 786                spin_lock_bh(&pool->sp_lock);
 787                nrservs -= pool->sp_nrthreads;
 788                spin_unlock_bh(&pool->sp_lock);
 789        }
 790
 791        if (nrservs > 0)
 792                return svc_start_kthreads(serv, pool, nrservs);
 793        if (nrservs < 0)
 794                return svc_signal_kthreads(serv, pool, nrservs);
 795        return 0;
 796}
 797EXPORT_SYMBOL_GPL(svc_set_num_threads);
 798
 799/* destroy old threads */
 800static int
 801svc_stop_kthreads(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
 802{
 803        struct task_struct *task;
 804        unsigned int state = serv->sv_nrthreads-1;
 805
 806        /* destroy old threads */
 807        do {
 808                task = choose_victim(serv, pool, &state);
 809                if (task == NULL)
 810                        break;
 811                kthread_stop(task);
 812                nrservs++;
 813        } while (nrservs < 0);
 814        return 0;
 815}
 816
 817int
 818svc_set_num_threads_sync(struct svc_serv *serv, struct svc_pool *pool, int nrservs)
 819{
 820        if (pool == NULL) {
 821                /* The -1 assumes caller has done a svc_get() */
 822                nrservs -= (serv->sv_nrthreads-1);
 823        } else {
 824                spin_lock_bh(&pool->sp_lock);
 825                nrservs -= pool->sp_nrthreads;
 826                spin_unlock_bh(&pool->sp_lock);
 827        }
 828
 829        if (nrservs > 0)
 830                return svc_start_kthreads(serv, pool, nrservs);
 831        if (nrservs < 0)
 832                return svc_stop_kthreads(serv, pool, nrservs);
 833        return 0;
 834}
 835EXPORT_SYMBOL_GPL(svc_set_num_threads_sync);
 836
 837/*
 838 * Called from a server thread as it's exiting. Caller must hold the "service
 839 * mutex" for the service.
 840 */
 841void
 842svc_rqst_free(struct svc_rqst *rqstp)
 843{
 844        svc_release_buffer(rqstp);
 845        kfree(rqstp->rq_resp);
 846        kfree(rqstp->rq_argp);
 847        kfree(rqstp->rq_auth_data);
 848        kfree_rcu(rqstp, rq_rcu_head);
 849}
 850EXPORT_SYMBOL_GPL(svc_rqst_free);
 851
 852void
 853svc_exit_thread(struct svc_rqst *rqstp)
 854{
 855        struct svc_serv *serv = rqstp->rq_server;
 856        struct svc_pool *pool = rqstp->rq_pool;
 857
 858        spin_lock_bh(&pool->sp_lock);
 859        pool->sp_nrthreads--;
 860        if (!test_and_set_bit(RQ_VICTIM, &rqstp->rq_flags))
 861                list_del_rcu(&rqstp->rq_all);
 862        spin_unlock_bh(&pool->sp_lock);
 863
 864        svc_rqst_free(rqstp);
 865
 866        /* Release the server */
 867        if (serv)
 868                svc_destroy(serv);
 869}
 870EXPORT_SYMBOL_GPL(svc_exit_thread);
 871
 872/*
 873 * Register an "inet" protocol family netid with the local
 874 * rpcbind daemon via an rpcbind v4 SET request.
 875 *
 876 * No netconfig infrastructure is available in the kernel, so
 877 * we map IP_ protocol numbers to netids by hand.
 878 *
 879 * Returns zero on success; a negative errno value is returned
 880 * if any error occurs.
 881 */
 882static int __svc_rpcb_register4(struct net *net, const u32 program,
 883                                const u32 version,
 884                                const unsigned short protocol,
 885                                const unsigned short port)
 886{
 887        const struct sockaddr_in sin = {
 888                .sin_family             = AF_INET,
 889                .sin_addr.s_addr        = htonl(INADDR_ANY),
 890                .sin_port               = htons(port),
 891        };
 892        const char *netid;
 893        int error;
 894
 895        switch (protocol) {
 896        case IPPROTO_UDP:
 897                netid = RPCBIND_NETID_UDP;
 898                break;
 899        case IPPROTO_TCP:
 900                netid = RPCBIND_NETID_TCP;
 901                break;
 902        default:
 903                return -ENOPROTOOPT;
 904        }
 905
 906        error = rpcb_v4_register(net, program, version,
 907                                        (const struct sockaddr *)&sin, netid);
 908
 909        /*
 910         * User space didn't support rpcbind v4, so retry this
 911         * registration request with the legacy rpcbind v2 protocol.
 912         */
 913        if (error == -EPROTONOSUPPORT)
 914                error = rpcb_register(net, program, version, protocol, port);
 915
 916        return error;
 917}
 918
 919#if IS_ENABLED(CONFIG_IPV6)
 920/*
 921 * Register an "inet6" protocol family netid with the local
 922 * rpcbind daemon via an rpcbind v4 SET request.
 923 *
 924 * No netconfig infrastructure is available in the kernel, so
 925 * we map IP_ protocol numbers to netids by hand.
 926 *
 927 * Returns zero on success; a negative errno value is returned
 928 * if any error occurs.
 929 */
 930static int __svc_rpcb_register6(struct net *net, const u32 program,
 931                                const u32 version,
 932                                const unsigned short protocol,
 933                                const unsigned short port)
 934{
 935        const struct sockaddr_in6 sin6 = {
 936                .sin6_family            = AF_INET6,
 937                .sin6_addr              = IN6ADDR_ANY_INIT,
 938                .sin6_port              = htons(port),
 939        };
 940        const char *netid;
 941        int error;
 942
 943        switch (protocol) {
 944        case IPPROTO_UDP:
 945                netid = RPCBIND_NETID_UDP6;
 946                break;
 947        case IPPROTO_TCP:
 948                netid = RPCBIND_NETID_TCP6;
 949                break;
 950        default:
 951                return -ENOPROTOOPT;
 952        }
 953
 954        error = rpcb_v4_register(net, program, version,
 955                                        (const struct sockaddr *)&sin6, netid);
 956
 957        /*
 958         * User space didn't support rpcbind version 4, so we won't
 959         * use a PF_INET6 listener.
 960         */
 961        if (error == -EPROTONOSUPPORT)
 962                error = -EAFNOSUPPORT;
 963
 964        return error;
 965}
 966#endif  /* IS_ENABLED(CONFIG_IPV6) */
 967
 968/*
 969 * Register a kernel RPC service via rpcbind version 4.
 970 *
 971 * Returns zero on success; a negative errno value is returned
 972 * if any error occurs.
 973 */
 974static int __svc_register(struct net *net, const char *progname,
 975                          const u32 program, const u32 version,
 976                          const int family,
 977                          const unsigned short protocol,
 978                          const unsigned short port)
 979{
 980        int error = -EAFNOSUPPORT;
 981
 982        switch (family) {
 983        case PF_INET:
 984                error = __svc_rpcb_register4(net, program, version,
 985                                                protocol, port);
 986                break;
 987#if IS_ENABLED(CONFIG_IPV6)
 988        case PF_INET6:
 989                error = __svc_rpcb_register6(net, program, version,
 990                                                protocol, port);
 991#endif
 992        }
 993
 994        return error;
 995}
 996
 997int svc_rpcbind_set_version(struct net *net,
 998                            const struct svc_program *progp,
 999                            u32 version, int family,
1000                            unsigned short proto,
1001                            unsigned short port)
1002{
1003        dprintk("svc: svc_register(%sv%d, %s, %u, %u)\n",
1004                progp->pg_name, version,
1005                proto == IPPROTO_UDP?  "udp" : "tcp",
1006                port, family);
1007
1008        return __svc_register(net, progp->pg_name, progp->pg_prog,
1009                                version, family, proto, port);
1010
1011}
1012EXPORT_SYMBOL_GPL(svc_rpcbind_set_version);
1013
1014int svc_generic_rpcbind_set(struct net *net,
1015                            const struct svc_program *progp,
1016                            u32 version, int family,
1017                            unsigned short proto,
1018                            unsigned short port)
1019{
1020        const struct svc_version *vers = progp->pg_vers[version];
1021        int error;
1022
1023        if (vers == NULL)
1024                return 0;
1025
1026        if (vers->vs_hidden) {
1027                dprintk("svc: svc_register(%sv%d, %s, %u, %u)"
1028                        " (but not telling portmap)\n",
1029                        progp->pg_name, version,
1030                        proto == IPPROTO_UDP?  "udp" : "tcp",
1031                        port, family);
1032                return 0;
1033        }
1034
1035        /*
1036         * Don't register a UDP port if we need congestion
1037         * control.
1038         */
1039        if (vers->vs_need_cong_ctrl && proto == IPPROTO_UDP)
1040                return 0;
1041
1042        error = svc_rpcbind_set_version(net, progp, version,
1043                                        family, proto, port);
1044
1045        return (vers->vs_rpcb_optnl) ? 0 : error;
1046}
1047EXPORT_SYMBOL_GPL(svc_generic_rpcbind_set);
1048
1049/**
1050 * svc_register - register an RPC service with the local portmapper
1051 * @serv: svc_serv struct for the service to register
1052 * @net: net namespace for the service to register
1053 * @family: protocol family of service's listener socket
1054 * @proto: transport protocol number to advertise
1055 * @port: port to advertise
1056 *
1057 * Service is registered for any address in the passed-in protocol family
1058 */
1059int svc_register(const struct svc_serv *serv, struct net *net,
1060                 const int family, const unsigned short proto,
1061                 const unsigned short port)
1062{
1063        struct svc_program      *progp;
1064        unsigned int            i;
1065        int                     error = 0;
1066
1067        WARN_ON_ONCE(proto == 0 && port == 0);
1068        if (proto == 0 && port == 0)
1069                return -EINVAL;
1070
1071        for (progp = serv->sv_program; progp; progp = progp->pg_next) {
1072                for (i = 0; i < progp->pg_nvers; i++) {
1073
1074                        error = progp->pg_rpcbind_set(net, progp, i,
1075                                        family, proto, port);
1076                        if (error < 0) {
1077                                printk(KERN_WARNING "svc: failed to register "
1078                                        "%sv%u RPC service (errno %d).\n",
1079                                        progp->pg_name, i, -error);
1080                                break;
1081                        }
1082                }
1083        }
1084
1085        return error;
1086}
1087
1088/*
1089 * If user space is running rpcbind, it should take the v4 UNSET
1090 * and clear everything for this [program, version].  If user space
1091 * is running portmap, it will reject the v4 UNSET, but won't have
1092 * any "inet6" entries anyway.  So a PMAP_UNSET should be sufficient
1093 * in this case to clear all existing entries for [program, version].
1094 */
1095static void __svc_unregister(struct net *net, const u32 program, const u32 version,
1096                             const char *progname)
1097{
1098        int error;
1099
1100        error = rpcb_v4_register(net, program, version, NULL, "");
1101
1102        /*
1103         * User space didn't support rpcbind v4, so retry this
1104         * request with the legacy rpcbind v2 protocol.
1105         */
1106        if (error == -EPROTONOSUPPORT)
1107                error = rpcb_register(net, program, version, 0, 0);
1108
1109        dprintk("svc: %s(%sv%u), error %d\n",
1110                        __func__, progname, version, error);
1111}
1112
1113/*
1114 * All netids, bind addresses and ports registered for [program, version]
1115 * are removed from the local rpcbind database (if the service is not
1116 * hidden) to make way for a new instance of the service.
1117 *
1118 * The result of unregistration is reported via dprintk for those who want
1119 * verification of the result, but is otherwise not important.
1120 */
1121static void svc_unregister(const struct svc_serv *serv, struct net *net)
1122{
1123        struct svc_program *progp;
1124        unsigned long flags;
1125        unsigned int i;
1126
1127        clear_thread_flag(TIF_SIGPENDING);
1128
1129        for (progp = serv->sv_program; progp; progp = progp->pg_next) {
1130                for (i = 0; i < progp->pg_nvers; i++) {
1131                        if (progp->pg_vers[i] == NULL)
1132                                continue;
1133                        if (progp->pg_vers[i]->vs_hidden)
1134                                continue;
1135
1136                        dprintk("svc: attempting to unregister %sv%u\n",
1137                                progp->pg_name, i);
1138                        __svc_unregister(net, progp->pg_prog, i, progp->pg_name);
1139                }
1140        }
1141
1142        spin_lock_irqsave(&current->sighand->siglock, flags);
1143        recalc_sigpending();
1144        spin_unlock_irqrestore(&current->sighand->siglock, flags);
1145}
1146
1147/*
1148 * dprintk the given error with the address of the client that caused it.
1149 */
1150#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
1151static __printf(2, 3)
1152void svc_printk(struct svc_rqst *rqstp, const char *fmt, ...)
1153{
1154        struct va_format vaf;
1155        va_list args;
1156        char    buf[RPC_MAX_ADDRBUFLEN];
1157
1158        va_start(args, fmt);
1159
1160        vaf.fmt = fmt;
1161        vaf.va = &args;
1162
1163        dprintk("svc: %s: %pV", svc_print_addr(rqstp, buf, sizeof(buf)), &vaf);
1164
1165        va_end(args);
1166}
1167#else
1168static __printf(2,3) void svc_printk(struct svc_rqst *rqstp, const char *fmt, ...) {}
1169#endif
1170
1171__be32
1172svc_return_autherr(struct svc_rqst *rqstp, __be32 auth_err)
1173{
1174        set_bit(RQ_AUTHERR, &rqstp->rq_flags);
1175        return auth_err;
1176}
1177EXPORT_SYMBOL_GPL(svc_return_autherr);
1178
1179static __be32
1180svc_get_autherr(struct svc_rqst *rqstp, __be32 *statp)
1181{
1182        if (test_and_clear_bit(RQ_AUTHERR, &rqstp->rq_flags))
1183                return *statp;
1184        return rpc_auth_ok;
1185}
1186
1187static int
1188svc_generic_dispatch(struct svc_rqst *rqstp, __be32 *statp)
1189{
1190        struct kvec *argv = &rqstp->rq_arg.head[0];
1191        struct kvec *resv = &rqstp->rq_res.head[0];
1192        const struct svc_procedure *procp = rqstp->rq_procinfo;
1193
1194        /*
1195         * Decode arguments
1196         * XXX: why do we ignore the return value?
1197         */
1198        if (procp->pc_decode &&
1199            !procp->pc_decode(rqstp, argv->iov_base)) {
1200                *statp = rpc_garbage_args;
1201                return 1;
1202        }
1203
1204        *statp = procp->pc_func(rqstp);
1205
1206        if (*statp == rpc_drop_reply ||
1207            test_bit(RQ_DROPME, &rqstp->rq_flags))
1208                return 0;
1209
1210        if (test_bit(RQ_AUTHERR, &rqstp->rq_flags))
1211                return 1;
1212
1213        if (*statp != rpc_success)
1214                return 1;
1215
1216        /* Encode reply */
1217        if (procp->pc_encode &&
1218            !procp->pc_encode(rqstp, resv->iov_base + resv->iov_len)) {
1219                dprintk("svc: failed to encode reply\n");
1220                /* serv->sv_stats->rpcsystemerr++; */
1221                *statp = rpc_system_err;
1222        }
1223        return 1;
1224}
1225
1226__be32
1227svc_generic_init_request(struct svc_rqst *rqstp,
1228                const struct svc_program *progp,
1229                struct svc_process_info *ret)
1230{
1231        const struct svc_version *versp = NULL; /* compiler food */
1232        const struct svc_procedure *procp = NULL;
1233
1234        if (rqstp->rq_vers >= progp->pg_nvers )
1235                goto err_bad_vers;
1236          versp = progp->pg_vers[rqstp->rq_vers];
1237          if (!versp)
1238                goto err_bad_vers;
1239
1240        /*
1241         * Some protocol versions (namely NFSv4) require some form of
1242         * congestion control.  (See RFC 7530 section 3.1 paragraph 2)
1243         * In other words, UDP is not allowed. We mark those when setting
1244         * up the svc_xprt, and verify that here.
1245         *
1246         * The spec is not very clear about what error should be returned
1247         * when someone tries to access a server that is listening on UDP
1248         * for lower versions. RPC_PROG_MISMATCH seems to be the closest
1249         * fit.
1250         */
1251        if (versp->vs_need_cong_ctrl && rqstp->rq_xprt &&
1252            !test_bit(XPT_CONG_CTRL, &rqstp->rq_xprt->xpt_flags))
1253                goto err_bad_vers;
1254
1255        if (rqstp->rq_proc >= versp->vs_nproc)
1256                goto err_bad_proc;
1257        rqstp->rq_procinfo = procp = &versp->vs_proc[rqstp->rq_proc];
1258        if (!procp)
1259                goto err_bad_proc;
1260
1261        /* Initialize storage for argp and resp */
1262        memset(rqstp->rq_argp, 0, procp->pc_argsize);
1263        memset(rqstp->rq_resp, 0, procp->pc_ressize);
1264
1265        /* Bump per-procedure stats counter */
1266        versp->vs_count[rqstp->rq_proc]++;
1267
1268        ret->dispatch = versp->vs_dispatch;
1269        return rpc_success;
1270err_bad_vers:
1271        ret->mismatch.lovers = progp->pg_lovers;
1272        ret->mismatch.hivers = progp->pg_hivers;
1273        return rpc_prog_mismatch;
1274err_bad_proc:
1275        return rpc_proc_unavail;
1276}
1277EXPORT_SYMBOL_GPL(svc_generic_init_request);
1278
1279/*
1280 * Common routine for processing the RPC request.
1281 */
1282static int
1283svc_process_common(struct svc_rqst *rqstp, struct kvec *argv, struct kvec *resv)
1284{
1285        struct svc_program      *progp;
1286        const struct svc_procedure *procp = NULL;
1287        struct svc_serv         *serv = rqstp->rq_server;
1288        struct svc_process_info process;
1289        __be32                  *statp;
1290        u32                     prog, vers;
1291        __be32                  auth_stat, rpc_stat;
1292        int                     auth_res;
1293        __be32                  *reply_statp;
1294
1295        rpc_stat = rpc_success;
1296
1297        if (argv->iov_len < 6*4)
1298                goto err_short_len;
1299
1300        /* Will be turned off by GSS integrity and privacy services */
1301        set_bit(RQ_SPLICE_OK, &rqstp->rq_flags);
1302        /* Will be turned off only when NFSv4 Sessions are used */
1303        set_bit(RQ_USEDEFERRAL, &rqstp->rq_flags);
1304        clear_bit(RQ_DROPME, &rqstp->rq_flags);
1305
1306        svc_putu32(resv, rqstp->rq_xid);
1307
1308        vers = svc_getnl(argv);
1309
1310        /* First words of reply: */
1311        svc_putnl(resv, 1);             /* REPLY */
1312
1313        if (vers != 2)          /* RPC version number */
1314                goto err_bad_rpc;
1315
1316        /* Save position in case we later decide to reject: */
1317        reply_statp = resv->iov_base + resv->iov_len;
1318
1319        svc_putnl(resv, 0);             /* ACCEPT */
1320
1321        rqstp->rq_prog = prog = svc_getnl(argv);        /* program number */
1322        rqstp->rq_vers = svc_getnl(argv);       /* version number */
1323        rqstp->rq_proc = svc_getnl(argv);       /* procedure number */
1324
1325        for (progp = serv->sv_program; progp; progp = progp->pg_next)
1326                if (prog == progp->pg_prog)
1327                        break;
1328
1329        /*
1330         * Decode auth data, and add verifier to reply buffer.
1331         * We do this before anything else in order to get a decent
1332         * auth verifier.
1333         */
1334        auth_res = svc_authenticate(rqstp, &auth_stat);
1335        /* Also give the program a chance to reject this call: */
1336        if (auth_res == SVC_OK && progp) {
1337                auth_stat = rpc_autherr_badcred;
1338                auth_res = progp->pg_authenticate(rqstp);
1339        }
1340        switch (auth_res) {
1341        case SVC_OK:
1342                break;
1343        case SVC_GARBAGE:
1344                goto err_garbage;
1345        case SVC_SYSERR:
1346                rpc_stat = rpc_system_err;
1347                goto err_bad;
1348        case SVC_DENIED:
1349                goto err_bad_auth;
1350        case SVC_CLOSE:
1351                goto close;
1352        case SVC_DROP:
1353                goto dropit;
1354        case SVC_COMPLETE:
1355                goto sendit;
1356        }
1357
1358        if (progp == NULL)
1359                goto err_bad_prog;
1360
1361        rpc_stat = progp->pg_init_request(rqstp, progp, &process);
1362        switch (rpc_stat) {
1363        case rpc_success:
1364                break;
1365        case rpc_prog_unavail:
1366                goto err_bad_prog;
1367        case rpc_prog_mismatch:
1368                goto err_bad_vers;
1369        case rpc_proc_unavail:
1370                goto err_bad_proc;
1371        }
1372
1373        procp = rqstp->rq_procinfo;
1374        /* Should this check go into the dispatcher? */
1375        if (!procp || !procp->pc_func)
1376                goto err_bad_proc;
1377
1378        /* Syntactic check complete */
1379        serv->sv_stats->rpccnt++;
1380        trace_svc_process(rqstp, progp->pg_name);
1381
1382        /* Build the reply header. */
1383        statp = resv->iov_base +resv->iov_len;
1384        svc_putnl(resv, RPC_SUCCESS);
1385
1386        /* un-reserve some of the out-queue now that we have a
1387         * better idea of reply size
1388         */
1389        if (procp->pc_xdrressize)
1390                svc_reserve_auth(rqstp, procp->pc_xdrressize<<2);
1391
1392        /* Call the function that processes the request. */
1393        if (!process.dispatch) {
1394                if (!svc_generic_dispatch(rqstp, statp))
1395                        goto release_dropit;
1396                if (*statp == rpc_garbage_args)
1397                        goto err_garbage;
1398                auth_stat = svc_get_autherr(rqstp, statp);
1399                if (auth_stat != rpc_auth_ok)
1400                        goto err_release_bad_auth;
1401        } else {
1402                dprintk("svc: calling dispatcher\n");
1403                if (!process.dispatch(rqstp, statp))
1404                        goto release_dropit; /* Release reply info */
1405        }
1406
1407        /* Check RPC status result */
1408        if (*statp != rpc_success)
1409                resv->iov_len = ((void*)statp)  - resv->iov_base + 4;
1410
1411        /* Release reply info */
1412        if (procp->pc_release)
1413                procp->pc_release(rqstp);
1414
1415        if (procp->pc_encode == NULL)
1416                goto dropit;
1417
1418 sendit:
1419        if (svc_authorise(rqstp))
1420                goto close;
1421        return 1;               /* Caller can now send it */
1422
1423release_dropit:
1424        if (procp->pc_release)
1425                procp->pc_release(rqstp);
1426 dropit:
1427        svc_authorise(rqstp);   /* doesn't hurt to call this twice */
1428        dprintk("svc: svc_process dropit\n");
1429        return 0;
1430
1431 close:
1432        if (rqstp->rq_xprt && test_bit(XPT_TEMP, &rqstp->rq_xprt->xpt_flags))
1433                svc_close_xprt(rqstp->rq_xprt);
1434        dprintk("svc: svc_process close\n");
1435        return 0;
1436
1437err_short_len:
1438        svc_printk(rqstp, "short len %zd, dropping request\n",
1439                        argv->iov_len);
1440        goto close;
1441
1442err_bad_rpc:
1443        serv->sv_stats->rpcbadfmt++;
1444        svc_putnl(resv, 1);     /* REJECT */
1445        svc_putnl(resv, 0);     /* RPC_MISMATCH */
1446        svc_putnl(resv, 2);     /* Only RPCv2 supported */
1447        svc_putnl(resv, 2);
1448        goto sendit;
1449
1450err_release_bad_auth:
1451        if (procp->pc_release)
1452                procp->pc_release(rqstp);
1453err_bad_auth:
1454        dprintk("svc: authentication failed (%d)\n", ntohl(auth_stat));
1455        serv->sv_stats->rpcbadauth++;
1456        /* Restore write pointer to location of accept status: */
1457        xdr_ressize_check(rqstp, reply_statp);
1458        svc_putnl(resv, 1);     /* REJECT */
1459        svc_putnl(resv, 1);     /* AUTH_ERROR */
1460        svc_putnl(resv, ntohl(auth_stat));      /* status */
1461        goto sendit;
1462
1463err_bad_prog:
1464        dprintk("svc: unknown program %d\n", prog);
1465        serv->sv_stats->rpcbadfmt++;
1466        svc_putnl(resv, RPC_PROG_UNAVAIL);
1467        goto sendit;
1468
1469err_bad_vers:
1470        svc_printk(rqstp, "unknown version (%d for prog %d, %s)\n",
1471                       rqstp->rq_vers, rqstp->rq_prog, progp->pg_name);
1472
1473        serv->sv_stats->rpcbadfmt++;
1474        svc_putnl(resv, RPC_PROG_MISMATCH);
1475        svc_putnl(resv, process.mismatch.lovers);
1476        svc_putnl(resv, process.mismatch.hivers);
1477        goto sendit;
1478
1479err_bad_proc:
1480        svc_printk(rqstp, "unknown procedure (%d)\n", rqstp->rq_proc);
1481
1482        serv->sv_stats->rpcbadfmt++;
1483        svc_putnl(resv, RPC_PROC_UNAVAIL);
1484        goto sendit;
1485
1486err_garbage:
1487        svc_printk(rqstp, "failed to decode args\n");
1488
1489        rpc_stat = rpc_garbage_args;
1490err_bad:
1491        serv->sv_stats->rpcbadfmt++;
1492        svc_putnl(resv, ntohl(rpc_stat));
1493        goto sendit;
1494}
1495
1496/*
1497 * Process the RPC request.
1498 */
1499int
1500svc_process(struct svc_rqst *rqstp)
1501{
1502        struct kvec             *argv = &rqstp->rq_arg.head[0];
1503        struct kvec             *resv = &rqstp->rq_res.head[0];
1504        struct svc_serv         *serv = rqstp->rq_server;
1505        u32                     dir;
1506
1507        /*
1508         * Setup response xdr_buf.
1509         * Initially it has just one page
1510         */
1511        rqstp->rq_next_page = &rqstp->rq_respages[1];
1512        resv->iov_base = page_address(rqstp->rq_respages[0]);
1513        resv->iov_len = 0;
1514        rqstp->rq_res.pages = rqstp->rq_respages + 1;
1515        rqstp->rq_res.len = 0;
1516        rqstp->rq_res.page_base = 0;
1517        rqstp->rq_res.page_len = 0;
1518        rqstp->rq_res.buflen = PAGE_SIZE;
1519        rqstp->rq_res.tail[0].iov_base = NULL;
1520        rqstp->rq_res.tail[0].iov_len = 0;
1521
1522        dir  = svc_getnl(argv);
1523        if (dir != 0) {
1524                /* direction != CALL */
1525                svc_printk(rqstp, "bad direction %d, dropping request\n", dir);
1526                serv->sv_stats->rpcbadfmt++;
1527                goto out_drop;
1528        }
1529
1530        /* Reserve space for the record marker */
1531        if (rqstp->rq_prot == IPPROTO_TCP)
1532                svc_putnl(resv, 0);
1533
1534        /* Returns 1 for send, 0 for drop */
1535        if (likely(svc_process_common(rqstp, argv, resv)))
1536                return svc_send(rqstp);
1537
1538out_drop:
1539        svc_drop(rqstp);
1540        return 0;
1541}
1542EXPORT_SYMBOL_GPL(svc_process);
1543
1544#if defined(CONFIG_SUNRPC_BACKCHANNEL)
1545/*
1546 * Process a backchannel RPC request that arrived over an existing
1547 * outbound connection
1548 */
1549int
1550bc_svc_process(struct svc_serv *serv, struct rpc_rqst *req,
1551               struct svc_rqst *rqstp)
1552{
1553        struct kvec     *argv = &rqstp->rq_arg.head[0];
1554        struct kvec     *resv = &rqstp->rq_res.head[0];
1555        struct rpc_task *task;
1556        int proc_error;
1557        int error;
1558
1559        dprintk("svc: %s(%p)\n", __func__, req);
1560
1561        /* Build the svc_rqst used by the common processing routine */
1562        rqstp->rq_xid = req->rq_xid;
1563        rqstp->rq_prot = req->rq_xprt->prot;
1564        rqstp->rq_server = serv;
1565        rqstp->rq_bc_net = req->rq_xprt->xprt_net;
1566
1567        rqstp->rq_addrlen = sizeof(req->rq_xprt->addr);
1568        memcpy(&rqstp->rq_addr, &req->rq_xprt->addr, rqstp->rq_addrlen);
1569        memcpy(&rqstp->rq_arg, &req->rq_rcv_buf, sizeof(rqstp->rq_arg));
1570        memcpy(&rqstp->rq_res, &req->rq_snd_buf, sizeof(rqstp->rq_res));
1571
1572        /* Adjust the argument buffer length */
1573        rqstp->rq_arg.len = req->rq_private_buf.len;
1574        if (rqstp->rq_arg.len <= rqstp->rq_arg.head[0].iov_len) {
1575                rqstp->rq_arg.head[0].iov_len = rqstp->rq_arg.len;
1576                rqstp->rq_arg.page_len = 0;
1577        } else if (rqstp->rq_arg.len <= rqstp->rq_arg.head[0].iov_len +
1578                        rqstp->rq_arg.page_len)
1579                rqstp->rq_arg.page_len = rqstp->rq_arg.len -
1580                        rqstp->rq_arg.head[0].iov_len;
1581        else
1582                rqstp->rq_arg.len = rqstp->rq_arg.head[0].iov_len +
1583                        rqstp->rq_arg.page_len;
1584
1585        /* reset result send buffer "put" position */
1586        resv->iov_len = 0;
1587
1588        /*
1589         * Skip the next two words because they've already been
1590         * processed in the transport
1591         */
1592        svc_getu32(argv);       /* XID */
1593        svc_getnl(argv);        /* CALLDIR */
1594
1595        /* Parse and execute the bc call */
1596        proc_error = svc_process_common(rqstp, argv, resv);
1597
1598        atomic_inc(&req->rq_xprt->bc_free_slots);
1599        if (!proc_error) {
1600                /* Processing error: drop the request */
1601                xprt_free_bc_request(req);
1602                error = -EINVAL;
1603                goto out;
1604        }
1605        /* Finally, send the reply synchronously */
1606        memcpy(&req->rq_snd_buf, &rqstp->rq_res, sizeof(req->rq_snd_buf));
1607        task = rpc_run_bc_task(req);
1608        if (IS_ERR(task)) {
1609                error = PTR_ERR(task);
1610                goto out;
1611        }
1612
1613        WARN_ON_ONCE(atomic_read(&task->tk_count) != 1);
1614        error = task->tk_status;
1615        rpc_put_task(task);
1616
1617out:
1618        dprintk("svc: %s(), error=%d\n", __func__, error);
1619        return error;
1620}
1621EXPORT_SYMBOL_GPL(bc_svc_process);
1622#endif /* CONFIG_SUNRPC_BACKCHANNEL */
1623
1624/*
1625 * Return (transport-specific) limit on the rpc payload.
1626 */
1627u32 svc_max_payload(const struct svc_rqst *rqstp)
1628{
1629        u32 max = rqstp->rq_xprt->xpt_class->xcl_max_payload;
1630
1631        if (rqstp->rq_server->sv_max_payload < max)
1632                max = rqstp->rq_server->sv_max_payload;
1633        return max;
1634}
1635EXPORT_SYMBOL_GPL(svc_max_payload);
1636
1637/**
1638 * svc_fill_write_vector - Construct data argument for VFS write call
1639 * @rqstp: svc_rqst to operate on
1640 * @pages: list of pages containing data payload
1641 * @first: buffer containing first section of write payload
1642 * @total: total number of bytes of write payload
1643 *
1644 * Fills in rqstp::rq_vec, and returns the number of elements.
1645 */
1646unsigned int svc_fill_write_vector(struct svc_rqst *rqstp, struct page **pages,
1647                                   struct kvec *first, size_t total)
1648{
1649        struct kvec *vec = rqstp->rq_vec;
1650        unsigned int i;
1651
1652        /* Some types of transport can present the write payload
1653         * entirely in rq_arg.pages. In this case, @first is empty.
1654         */
1655        i = 0;
1656        if (first->iov_len) {
1657                vec[i].iov_base = first->iov_base;
1658                vec[i].iov_len = min_t(size_t, total, first->iov_len);
1659                total -= vec[i].iov_len;
1660                ++i;
1661        }
1662
1663        while (total) {
1664                vec[i].iov_base = page_address(*pages);
1665                vec[i].iov_len = min_t(size_t, total, PAGE_SIZE);
1666                total -= vec[i].iov_len;
1667                ++i;
1668                ++pages;
1669        }
1670
1671        WARN_ON_ONCE(i > ARRAY_SIZE(rqstp->rq_vec));
1672        return i;
1673}
1674EXPORT_SYMBOL_GPL(svc_fill_write_vector);
1675
1676/**
1677 * svc_fill_symlink_pathname - Construct pathname argument for VFS symlink call
1678 * @rqstp: svc_rqst to operate on
1679 * @first: buffer containing first section of pathname
1680 * @p: buffer containing remaining section of pathname
1681 * @total: total length of the pathname argument
1682 *
1683 * The VFS symlink API demands a NUL-terminated pathname in mapped memory.
1684 * Returns pointer to a NUL-terminated string, or an ERR_PTR. Caller must free
1685 * the returned string.
1686 */
1687char *svc_fill_symlink_pathname(struct svc_rqst *rqstp, struct kvec *first,
1688                                void *p, size_t total)
1689{
1690        size_t len, remaining;
1691        char *result, *dst;
1692
1693        result = kmalloc(total + 1, GFP_KERNEL);
1694        if (!result)
1695                return ERR_PTR(-ESERVERFAULT);
1696
1697        dst = result;
1698        remaining = total;
1699
1700        len = min_t(size_t, total, first->iov_len);
1701        if (len) {
1702                memcpy(dst, first->iov_base, len);
1703                dst += len;
1704                remaining -= len;
1705        }
1706
1707        if (remaining) {
1708                len = min_t(size_t, remaining, PAGE_SIZE);
1709                memcpy(dst, p, len);
1710                dst += len;
1711        }
1712
1713        *dst = '\0';
1714
1715        /* Sanity check: Linux doesn't allow the pathname argument to
1716         * contain a NUL byte.
1717         */
1718        if (strlen(result) != total) {
1719                kfree(result);
1720                return ERR_PTR(-EINVAL);
1721        }
1722        return result;
1723}
1724EXPORT_SYMBOL_GPL(svc_fill_symlink_pathname);
1725