linux/net/sunrpc/svc_xprt.c
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   1/*
   2 * linux/net/sunrpc/svc_xprt.c
   3 *
   4 * Author: Tom Tucker <tom@opengridcomputing.com>
   5 */
   6
   7#include <linux/sched.h>
   8#include <linux/errno.h>
   9#include <linux/freezer.h>
  10#include <linux/kthread.h>
  11#include <linux/slab.h>
  12#include <net/sock.h>
  13#include <linux/sunrpc/stats.h>
  14#include <linux/sunrpc/svc_xprt.h>
  15#include <linux/sunrpc/svcsock.h>
  16#include <linux/sunrpc/xprt.h>
  17#include <linux/module.h>
  18
  19#define RPCDBG_FACILITY RPCDBG_SVCXPRT
  20
  21static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt);
  22static int svc_deferred_recv(struct svc_rqst *rqstp);
  23static struct cache_deferred_req *svc_defer(struct cache_req *req);
  24static void svc_age_temp_xprts(unsigned long closure);
  25static void svc_delete_xprt(struct svc_xprt *xprt);
  26
  27/* apparently the "standard" is that clients close
  28 * idle connections after 5 minutes, servers after
  29 * 6 minutes
  30 *   http://www.connectathon.org/talks96/nfstcp.pdf
  31 */
  32static int svc_conn_age_period = 6*60;
  33
  34/* List of registered transport classes */
  35static DEFINE_SPINLOCK(svc_xprt_class_lock);
  36static LIST_HEAD(svc_xprt_class_list);
  37
  38/* SMP locking strategy:
  39 *
  40 *      svc_pool->sp_lock protects most of the fields of that pool.
  41 *      svc_serv->sv_lock protects sv_tempsocks, sv_permsocks, sv_tmpcnt.
  42 *      when both need to be taken (rare), svc_serv->sv_lock is first.
  43 *      BKL protects svc_serv->sv_nrthread.
  44 *      svc_sock->sk_lock protects the svc_sock->sk_deferred list
  45 *             and the ->sk_info_authunix cache.
  46 *
  47 *      The XPT_BUSY bit in xprt->xpt_flags prevents a transport being
  48 *      enqueued multiply. During normal transport processing this bit
  49 *      is set by svc_xprt_enqueue and cleared by svc_xprt_received.
  50 *      Providers should not manipulate this bit directly.
  51 *
  52 *      Some flags can be set to certain values at any time
  53 *      providing that certain rules are followed:
  54 *
  55 *      XPT_CONN, XPT_DATA:
  56 *              - Can be set or cleared at any time.
  57 *              - After a set, svc_xprt_enqueue must be called to enqueue
  58 *                the transport for processing.
  59 *              - After a clear, the transport must be read/accepted.
  60 *                If this succeeds, it must be set again.
  61 *      XPT_CLOSE:
  62 *              - Can set at any time. It is never cleared.
  63 *      XPT_DEAD:
  64 *              - Can only be set while XPT_BUSY is held which ensures
  65 *                that no other thread will be using the transport or will
  66 *                try to set XPT_DEAD.
  67 */
  68
  69int svc_reg_xprt_class(struct svc_xprt_class *xcl)
  70{
  71        struct svc_xprt_class *cl;
  72        int res = -EEXIST;
  73
  74        dprintk("svc: Adding svc transport class '%s'\n", xcl->xcl_name);
  75
  76        INIT_LIST_HEAD(&xcl->xcl_list);
  77        spin_lock(&svc_xprt_class_lock);
  78        /* Make sure there isn't already a class with the same name */
  79        list_for_each_entry(cl, &svc_xprt_class_list, xcl_list) {
  80                if (strcmp(xcl->xcl_name, cl->xcl_name) == 0)
  81                        goto out;
  82        }
  83        list_add_tail(&xcl->xcl_list, &svc_xprt_class_list);
  84        res = 0;
  85out:
  86        spin_unlock(&svc_xprt_class_lock);
  87        return res;
  88}
  89EXPORT_SYMBOL_GPL(svc_reg_xprt_class);
  90
  91void svc_unreg_xprt_class(struct svc_xprt_class *xcl)
  92{
  93        dprintk("svc: Removing svc transport class '%s'\n", xcl->xcl_name);
  94        spin_lock(&svc_xprt_class_lock);
  95        list_del_init(&xcl->xcl_list);
  96        spin_unlock(&svc_xprt_class_lock);
  97}
  98EXPORT_SYMBOL_GPL(svc_unreg_xprt_class);
  99
 100/*
 101 * Format the transport list for printing
 102 */
 103int svc_print_xprts(char *buf, int maxlen)
 104{
 105        struct svc_xprt_class *xcl;
 106        char tmpstr[80];
 107        int len = 0;
 108        buf[0] = '\0';
 109
 110        spin_lock(&svc_xprt_class_lock);
 111        list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
 112                int slen;
 113
 114                sprintf(tmpstr, "%s %d\n", xcl->xcl_name, xcl->xcl_max_payload);
 115                slen = strlen(tmpstr);
 116                if (len + slen > maxlen)
 117                        break;
 118                len += slen;
 119                strcat(buf, tmpstr);
 120        }
 121        spin_unlock(&svc_xprt_class_lock);
 122
 123        return len;
 124}
 125
 126static void svc_xprt_free(struct kref *kref)
 127{
 128        struct svc_xprt *xprt =
 129                container_of(kref, struct svc_xprt, xpt_ref);
 130        struct module *owner = xprt->xpt_class->xcl_owner;
 131        if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags))
 132                svcauth_unix_info_release(xprt);
 133        put_net(xprt->xpt_net);
 134        /* See comment on corresponding get in xs_setup_bc_tcp(): */
 135        if (xprt->xpt_bc_xprt)
 136                xprt_put(xprt->xpt_bc_xprt);
 137        xprt->xpt_ops->xpo_free(xprt);
 138        module_put(owner);
 139}
 140
 141void svc_xprt_put(struct svc_xprt *xprt)
 142{
 143        kref_put(&xprt->xpt_ref, svc_xprt_free);
 144}
 145EXPORT_SYMBOL_GPL(svc_xprt_put);
 146
 147/*
 148 * Called by transport drivers to initialize the transport independent
 149 * portion of the transport instance.
 150 */
 151void svc_xprt_init(struct net *net, struct svc_xprt_class *xcl,
 152                   struct svc_xprt *xprt, struct svc_serv *serv)
 153{
 154        memset(xprt, 0, sizeof(*xprt));
 155        xprt->xpt_class = xcl;
 156        xprt->xpt_ops = xcl->xcl_ops;
 157        kref_init(&xprt->xpt_ref);
 158        xprt->xpt_server = serv;
 159        INIT_LIST_HEAD(&xprt->xpt_list);
 160        INIT_LIST_HEAD(&xprt->xpt_ready);
 161        INIT_LIST_HEAD(&xprt->xpt_deferred);
 162        INIT_LIST_HEAD(&xprt->xpt_users);
 163        mutex_init(&xprt->xpt_mutex);
 164        spin_lock_init(&xprt->xpt_lock);
 165        set_bit(XPT_BUSY, &xprt->xpt_flags);
 166        rpc_init_wait_queue(&xprt->xpt_bc_pending, "xpt_bc_pending");
 167        xprt->xpt_net = get_net(net);
 168}
 169EXPORT_SYMBOL_GPL(svc_xprt_init);
 170
 171static struct svc_xprt *__svc_xpo_create(struct svc_xprt_class *xcl,
 172                                         struct svc_serv *serv,
 173                                         struct net *net,
 174                                         const int family,
 175                                         const unsigned short port,
 176                                         int flags)
 177{
 178        struct sockaddr_in sin = {
 179                .sin_family             = AF_INET,
 180                .sin_addr.s_addr        = htonl(INADDR_ANY),
 181                .sin_port               = htons(port),
 182        };
 183#if IS_ENABLED(CONFIG_IPV6)
 184        struct sockaddr_in6 sin6 = {
 185                .sin6_family            = AF_INET6,
 186                .sin6_addr              = IN6ADDR_ANY_INIT,
 187                .sin6_port              = htons(port),
 188        };
 189#endif
 190        struct sockaddr *sap;
 191        size_t len;
 192
 193        switch (family) {
 194        case PF_INET:
 195                sap = (struct sockaddr *)&sin;
 196                len = sizeof(sin);
 197                break;
 198#if IS_ENABLED(CONFIG_IPV6)
 199        case PF_INET6:
 200                sap = (struct sockaddr *)&sin6;
 201                len = sizeof(sin6);
 202                break;
 203#endif
 204        default:
 205                return ERR_PTR(-EAFNOSUPPORT);
 206        }
 207
 208        return xcl->xcl_ops->xpo_create(serv, net, sap, len, flags);
 209}
 210
 211/*
 212 * svc_xprt_received conditionally queues the transport for processing
 213 * by another thread. The caller must hold the XPT_BUSY bit and must
 214 * not thereafter touch transport data.
 215 *
 216 * Note: XPT_DATA only gets cleared when a read-attempt finds no (or
 217 * insufficient) data.
 218 */
 219static void svc_xprt_received(struct svc_xprt *xprt)
 220{
 221        BUG_ON(!test_bit(XPT_BUSY, &xprt->xpt_flags));
 222        /* As soon as we clear busy, the xprt could be closed and
 223         * 'put', so we need a reference to call svc_xprt_enqueue with:
 224         */
 225        svc_xprt_get(xprt);
 226        clear_bit(XPT_BUSY, &xprt->xpt_flags);
 227        svc_xprt_enqueue(xprt);
 228        svc_xprt_put(xprt);
 229}
 230
 231void svc_add_new_perm_xprt(struct svc_serv *serv, struct svc_xprt *new)
 232{
 233        clear_bit(XPT_TEMP, &new->xpt_flags);
 234        spin_lock_bh(&serv->sv_lock);
 235        list_add(&new->xpt_list, &serv->sv_permsocks);
 236        spin_unlock_bh(&serv->sv_lock);
 237        svc_xprt_received(new);
 238}
 239
 240int svc_create_xprt(struct svc_serv *serv, const char *xprt_name,
 241                    struct net *net, const int family,
 242                    const unsigned short port, int flags)
 243{
 244        struct svc_xprt_class *xcl;
 245
 246        dprintk("svc: creating transport %s[%d]\n", xprt_name, port);
 247        spin_lock(&svc_xprt_class_lock);
 248        list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
 249                struct svc_xprt *newxprt;
 250                unsigned short newport;
 251
 252                if (strcmp(xprt_name, xcl->xcl_name))
 253                        continue;
 254
 255                if (!try_module_get(xcl->xcl_owner))
 256                        goto err;
 257
 258                spin_unlock(&svc_xprt_class_lock);
 259                newxprt = __svc_xpo_create(xcl, serv, net, family, port, flags);
 260                if (IS_ERR(newxprt)) {
 261                        module_put(xcl->xcl_owner);
 262                        return PTR_ERR(newxprt);
 263                }
 264                svc_add_new_perm_xprt(serv, newxprt);
 265                newport = svc_xprt_local_port(newxprt);
 266                return newport;
 267        }
 268 err:
 269        spin_unlock(&svc_xprt_class_lock);
 270        dprintk("svc: transport %s not found\n", xprt_name);
 271
 272        /* This errno is exposed to user space.  Provide a reasonable
 273         * perror msg for a bad transport. */
 274        return -EPROTONOSUPPORT;
 275}
 276EXPORT_SYMBOL_GPL(svc_create_xprt);
 277
 278/*
 279 * Copy the local and remote xprt addresses to the rqstp structure
 280 */
 281void svc_xprt_copy_addrs(struct svc_rqst *rqstp, struct svc_xprt *xprt)
 282{
 283        memcpy(&rqstp->rq_addr, &xprt->xpt_remote, xprt->xpt_remotelen);
 284        rqstp->rq_addrlen = xprt->xpt_remotelen;
 285
 286        /*
 287         * Destination address in request is needed for binding the
 288         * source address in RPC replies/callbacks later.
 289         */
 290        memcpy(&rqstp->rq_daddr, &xprt->xpt_local, xprt->xpt_locallen);
 291        rqstp->rq_daddrlen = xprt->xpt_locallen;
 292}
 293EXPORT_SYMBOL_GPL(svc_xprt_copy_addrs);
 294
 295/**
 296 * svc_print_addr - Format rq_addr field for printing
 297 * @rqstp: svc_rqst struct containing address to print
 298 * @buf: target buffer for formatted address
 299 * @len: length of target buffer
 300 *
 301 */
 302char *svc_print_addr(struct svc_rqst *rqstp, char *buf, size_t len)
 303{
 304        return __svc_print_addr(svc_addr(rqstp), buf, len);
 305}
 306EXPORT_SYMBOL_GPL(svc_print_addr);
 307
 308/*
 309 * Queue up an idle server thread.  Must have pool->sp_lock held.
 310 * Note: this is really a stack rather than a queue, so that we only
 311 * use as many different threads as we need, and the rest don't pollute
 312 * the cache.
 313 */
 314static void svc_thread_enqueue(struct svc_pool *pool, struct svc_rqst *rqstp)
 315{
 316        list_add(&rqstp->rq_list, &pool->sp_threads);
 317}
 318
 319/*
 320 * Dequeue an nfsd thread.  Must have pool->sp_lock held.
 321 */
 322static void svc_thread_dequeue(struct svc_pool *pool, struct svc_rqst *rqstp)
 323{
 324        list_del(&rqstp->rq_list);
 325}
 326
 327static bool svc_xprt_has_something_to_do(struct svc_xprt *xprt)
 328{
 329        if (xprt->xpt_flags & ((1<<XPT_CONN)|(1<<XPT_CLOSE)))
 330                return true;
 331        if (xprt->xpt_flags & ((1<<XPT_DATA)|(1<<XPT_DEFERRED)))
 332                return xprt->xpt_ops->xpo_has_wspace(xprt);
 333        return false;
 334}
 335
 336/*
 337 * Queue up a transport with data pending. If there are idle nfsd
 338 * processes, wake 'em up.
 339 *
 340 */
 341void svc_xprt_enqueue(struct svc_xprt *xprt)
 342{
 343        struct svc_pool *pool;
 344        struct svc_rqst *rqstp;
 345        int cpu;
 346
 347        if (!svc_xprt_has_something_to_do(xprt))
 348                return;
 349
 350        cpu = get_cpu();
 351        pool = svc_pool_for_cpu(xprt->xpt_server, cpu);
 352        put_cpu();
 353
 354        spin_lock_bh(&pool->sp_lock);
 355
 356        if (!list_empty(&pool->sp_threads) &&
 357            !list_empty(&pool->sp_sockets))
 358                printk(KERN_ERR
 359                       "svc_xprt_enqueue: "
 360                       "threads and transports both waiting??\n");
 361
 362        pool->sp_stats.packets++;
 363
 364        /* Mark transport as busy. It will remain in this state until
 365         * the provider calls svc_xprt_received. We update XPT_BUSY
 366         * atomically because it also guards against trying to enqueue
 367         * the transport twice.
 368         */
 369        if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags)) {
 370                /* Don't enqueue transport while already enqueued */
 371                dprintk("svc: transport %p busy, not enqueued\n", xprt);
 372                goto out_unlock;
 373        }
 374
 375        if (!list_empty(&pool->sp_threads)) {
 376                rqstp = list_entry(pool->sp_threads.next,
 377                                   struct svc_rqst,
 378                                   rq_list);
 379                dprintk("svc: transport %p served by daemon %p\n",
 380                        xprt, rqstp);
 381                svc_thread_dequeue(pool, rqstp);
 382                if (rqstp->rq_xprt)
 383                        printk(KERN_ERR
 384                                "svc_xprt_enqueue: server %p, rq_xprt=%p!\n",
 385                                rqstp, rqstp->rq_xprt);
 386                rqstp->rq_xprt = xprt;
 387                svc_xprt_get(xprt);
 388                pool->sp_stats.threads_woken++;
 389                wake_up(&rqstp->rq_wait);
 390        } else {
 391                dprintk("svc: transport %p put into queue\n", xprt);
 392                list_add_tail(&xprt->xpt_ready, &pool->sp_sockets);
 393                pool->sp_stats.sockets_queued++;
 394        }
 395
 396out_unlock:
 397        spin_unlock_bh(&pool->sp_lock);
 398}
 399EXPORT_SYMBOL_GPL(svc_xprt_enqueue);
 400
 401/*
 402 * Dequeue the first transport.  Must be called with the pool->sp_lock held.
 403 */
 404static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool)
 405{
 406        struct svc_xprt *xprt;
 407
 408        if (list_empty(&pool->sp_sockets))
 409                return NULL;
 410
 411        xprt = list_entry(pool->sp_sockets.next,
 412                          struct svc_xprt, xpt_ready);
 413        list_del_init(&xprt->xpt_ready);
 414
 415        dprintk("svc: transport %p dequeued, inuse=%d\n",
 416                xprt, atomic_read(&xprt->xpt_ref.refcount));
 417
 418        return xprt;
 419}
 420
 421/**
 422 * svc_reserve - change the space reserved for the reply to a request.
 423 * @rqstp:  The request in question
 424 * @space: new max space to reserve
 425 *
 426 * Each request reserves some space on the output queue of the transport
 427 * to make sure the reply fits.  This function reduces that reserved
 428 * space to be the amount of space used already, plus @space.
 429 *
 430 */
 431void svc_reserve(struct svc_rqst *rqstp, int space)
 432{
 433        space += rqstp->rq_res.head[0].iov_len;
 434
 435        if (space < rqstp->rq_reserved) {
 436                struct svc_xprt *xprt = rqstp->rq_xprt;
 437                atomic_sub((rqstp->rq_reserved - space), &xprt->xpt_reserved);
 438                rqstp->rq_reserved = space;
 439
 440                svc_xprt_enqueue(xprt);
 441        }
 442}
 443EXPORT_SYMBOL_GPL(svc_reserve);
 444
 445static void svc_xprt_release(struct svc_rqst *rqstp)
 446{
 447        struct svc_xprt *xprt = rqstp->rq_xprt;
 448
 449        rqstp->rq_xprt->xpt_ops->xpo_release_rqst(rqstp);
 450
 451        kfree(rqstp->rq_deferred);
 452        rqstp->rq_deferred = NULL;
 453
 454        svc_free_res_pages(rqstp);
 455        rqstp->rq_res.page_len = 0;
 456        rqstp->rq_res.page_base = 0;
 457
 458        /* Reset response buffer and release
 459         * the reservation.
 460         * But first, check that enough space was reserved
 461         * for the reply, otherwise we have a bug!
 462         */
 463        if ((rqstp->rq_res.len) >  rqstp->rq_reserved)
 464                printk(KERN_ERR "RPC request reserved %d but used %d\n",
 465                       rqstp->rq_reserved,
 466                       rqstp->rq_res.len);
 467
 468        rqstp->rq_res.head[0].iov_len = 0;
 469        svc_reserve(rqstp, 0);
 470        rqstp->rq_xprt = NULL;
 471
 472        svc_xprt_put(xprt);
 473}
 474
 475/*
 476 * External function to wake up a server waiting for data
 477 * This really only makes sense for services like lockd
 478 * which have exactly one thread anyway.
 479 */
 480void svc_wake_up(struct svc_serv *serv)
 481{
 482        struct svc_rqst *rqstp;
 483        unsigned int i;
 484        struct svc_pool *pool;
 485
 486        for (i = 0; i < serv->sv_nrpools; i++) {
 487                pool = &serv->sv_pools[i];
 488
 489                spin_lock_bh(&pool->sp_lock);
 490                if (!list_empty(&pool->sp_threads)) {
 491                        rqstp = list_entry(pool->sp_threads.next,
 492                                           struct svc_rqst,
 493                                           rq_list);
 494                        dprintk("svc: daemon %p woken up.\n", rqstp);
 495                        /*
 496                        svc_thread_dequeue(pool, rqstp);
 497                        rqstp->rq_xprt = NULL;
 498                         */
 499                        wake_up(&rqstp->rq_wait);
 500                }
 501                spin_unlock_bh(&pool->sp_lock);
 502        }
 503}
 504EXPORT_SYMBOL_GPL(svc_wake_up);
 505
 506int svc_port_is_privileged(struct sockaddr *sin)
 507{
 508        switch (sin->sa_family) {
 509        case AF_INET:
 510                return ntohs(((struct sockaddr_in *)sin)->sin_port)
 511                        < PROT_SOCK;
 512        case AF_INET6:
 513                return ntohs(((struct sockaddr_in6 *)sin)->sin6_port)
 514                        < PROT_SOCK;
 515        default:
 516                return 0;
 517        }
 518}
 519
 520/*
 521 * Make sure that we don't have too many active connections. If we have,
 522 * something must be dropped. It's not clear what will happen if we allow
 523 * "too many" connections, but when dealing with network-facing software,
 524 * we have to code defensively. Here we do that by imposing hard limits.
 525 *
 526 * There's no point in trying to do random drop here for DoS
 527 * prevention. The NFS clients does 1 reconnect in 15 seconds. An
 528 * attacker can easily beat that.
 529 *
 530 * The only somewhat efficient mechanism would be if drop old
 531 * connections from the same IP first. But right now we don't even
 532 * record the client IP in svc_sock.
 533 *
 534 * single-threaded services that expect a lot of clients will probably
 535 * need to set sv_maxconn to override the default value which is based
 536 * on the number of threads
 537 */
 538static void svc_check_conn_limits(struct svc_serv *serv)
 539{
 540        unsigned int limit = serv->sv_maxconn ? serv->sv_maxconn :
 541                                (serv->sv_nrthreads+3) * 20;
 542
 543        if (serv->sv_tmpcnt > limit) {
 544                struct svc_xprt *xprt = NULL;
 545                spin_lock_bh(&serv->sv_lock);
 546                if (!list_empty(&serv->sv_tempsocks)) {
 547                        /* Try to help the admin */
 548                        net_notice_ratelimited("%s: too many open connections, consider increasing the %s\n",
 549                                               serv->sv_name, serv->sv_maxconn ?
 550                                               "max number of connections" :
 551                                               "number of threads");
 552                        /*
 553                         * Always select the oldest connection. It's not fair,
 554                         * but so is life
 555                         */
 556                        xprt = list_entry(serv->sv_tempsocks.prev,
 557                                          struct svc_xprt,
 558                                          xpt_list);
 559                        set_bit(XPT_CLOSE, &xprt->xpt_flags);
 560                        svc_xprt_get(xprt);
 561                }
 562                spin_unlock_bh(&serv->sv_lock);
 563
 564                if (xprt) {
 565                        svc_xprt_enqueue(xprt);
 566                        svc_xprt_put(xprt);
 567                }
 568        }
 569}
 570
 571int svc_alloc_arg(struct svc_rqst *rqstp)
 572{
 573        struct svc_serv *serv = rqstp->rq_server;
 574        struct xdr_buf *arg;
 575        int pages;
 576        int i;
 577
 578        /* now allocate needed pages.  If we get a failure, sleep briefly */
 579        pages = (serv->sv_max_mesg + PAGE_SIZE) / PAGE_SIZE;
 580        BUG_ON(pages >= RPCSVC_MAXPAGES);
 581        for (i = 0; i < pages ; i++)
 582                while (rqstp->rq_pages[i] == NULL) {
 583                        struct page *p = alloc_page(GFP_KERNEL);
 584                        if (!p) {
 585                                set_current_state(TASK_INTERRUPTIBLE);
 586                                if (signalled() || kthread_should_stop()) {
 587                                        set_current_state(TASK_RUNNING);
 588                                        return -EINTR;
 589                                }
 590                                schedule_timeout(msecs_to_jiffies(500));
 591                        }
 592                        rqstp->rq_pages[i] = p;
 593                }
 594        rqstp->rq_pages[i++] = NULL; /* this might be seen in nfs_read_actor */
 595
 596        /* Make arg->head point to first page and arg->pages point to rest */
 597        arg = &rqstp->rq_arg;
 598        arg->head[0].iov_base = page_address(rqstp->rq_pages[0]);
 599        arg->head[0].iov_len = PAGE_SIZE;
 600        arg->pages = rqstp->rq_pages + 1;
 601        arg->page_base = 0;
 602        /* save at least one page for response */
 603        arg->page_len = (pages-2)*PAGE_SIZE;
 604        arg->len = (pages-1)*PAGE_SIZE;
 605        arg->tail[0].iov_len = 0;
 606        return 0;
 607}
 608
 609struct svc_xprt *svc_get_next_xprt(struct svc_rqst *rqstp, long timeout)
 610{
 611        struct svc_xprt *xprt;
 612        struct svc_pool         *pool = rqstp->rq_pool;
 613        DECLARE_WAITQUEUE(wait, current);
 614        long                    time_left;
 615
 616        /* Normally we will wait up to 5 seconds for any required
 617         * cache information to be provided.
 618         */
 619        rqstp->rq_chandle.thread_wait = 5*HZ;
 620
 621        spin_lock_bh(&pool->sp_lock);
 622        xprt = svc_xprt_dequeue(pool);
 623        if (xprt) {
 624                rqstp->rq_xprt = xprt;
 625                svc_xprt_get(xprt);
 626
 627                /* As there is a shortage of threads and this request
 628                 * had to be queued, don't allow the thread to wait so
 629                 * long for cache updates.
 630                 */
 631                rqstp->rq_chandle.thread_wait = 1*HZ;
 632        } else {
 633                /* No data pending. Go to sleep */
 634                svc_thread_enqueue(pool, rqstp);
 635
 636                /*
 637                 * We have to be able to interrupt this wait
 638                 * to bring down the daemons ...
 639                 */
 640                set_current_state(TASK_INTERRUPTIBLE);
 641
 642                /*
 643                 * checking kthread_should_stop() here allows us to avoid
 644                 * locking and signalling when stopping kthreads that call
 645                 * svc_recv. If the thread has already been woken up, then
 646                 * we can exit here without sleeping. If not, then it
 647                 * it'll be woken up quickly during the schedule_timeout
 648                 */
 649                if (kthread_should_stop()) {
 650                        set_current_state(TASK_RUNNING);
 651                        spin_unlock_bh(&pool->sp_lock);
 652                        return ERR_PTR(-EINTR);
 653                }
 654
 655                add_wait_queue(&rqstp->rq_wait, &wait);
 656                spin_unlock_bh(&pool->sp_lock);
 657
 658                time_left = schedule_timeout(timeout);
 659
 660                try_to_freeze();
 661
 662                spin_lock_bh(&pool->sp_lock);
 663                remove_wait_queue(&rqstp->rq_wait, &wait);
 664                if (!time_left)
 665                        pool->sp_stats.threads_timedout++;
 666
 667                xprt = rqstp->rq_xprt;
 668                if (!xprt) {
 669                        svc_thread_dequeue(pool, rqstp);
 670                        spin_unlock_bh(&pool->sp_lock);
 671                        dprintk("svc: server %p, no data yet\n", rqstp);
 672                        if (signalled() || kthread_should_stop())
 673                                return ERR_PTR(-EINTR);
 674                        else
 675                                return ERR_PTR(-EAGAIN);
 676                }
 677        }
 678        spin_unlock_bh(&pool->sp_lock);
 679        return xprt;
 680}
 681
 682void svc_add_new_temp_xprt(struct svc_serv *serv, struct svc_xprt *newxpt)
 683{
 684        spin_lock_bh(&serv->sv_lock);
 685        set_bit(XPT_TEMP, &newxpt->xpt_flags);
 686        list_add(&newxpt->xpt_list, &serv->sv_tempsocks);
 687        serv->sv_tmpcnt++;
 688        if (serv->sv_temptimer.function == NULL) {
 689                /* setup timer to age temp transports */
 690                setup_timer(&serv->sv_temptimer, svc_age_temp_xprts,
 691                            (unsigned long)serv);
 692                mod_timer(&serv->sv_temptimer,
 693                          jiffies + svc_conn_age_period * HZ);
 694        }
 695        spin_unlock_bh(&serv->sv_lock);
 696        svc_xprt_received(newxpt);
 697}
 698
 699static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
 700{
 701        struct svc_serv *serv = rqstp->rq_server;
 702        int len = 0;
 703
 704        if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) {
 705                dprintk("svc_recv: found XPT_CLOSE\n");
 706                svc_delete_xprt(xprt);
 707                /* Leave XPT_BUSY set on the dead xprt: */
 708                return 0;
 709        }
 710        if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) {
 711                struct svc_xprt *newxpt;
 712                /*
 713                 * We know this module_get will succeed because the
 714                 * listener holds a reference too
 715                 */
 716                __module_get(xprt->xpt_class->xcl_owner);
 717                svc_check_conn_limits(xprt->xpt_server);
 718                newxpt = xprt->xpt_ops->xpo_accept(xprt);
 719                if (newxpt)
 720                        svc_add_new_temp_xprt(serv, newxpt);
 721        } else if (xprt->xpt_ops->xpo_has_wspace(xprt)) {
 722                /* XPT_DATA|XPT_DEFERRED case: */
 723                dprintk("svc: server %p, pool %u, transport %p, inuse=%d\n",
 724                        rqstp, rqstp->rq_pool->sp_id, xprt,
 725                        atomic_read(&xprt->xpt_ref.refcount));
 726                rqstp->rq_deferred = svc_deferred_dequeue(xprt);
 727                if (rqstp->rq_deferred)
 728                        len = svc_deferred_recv(rqstp);
 729                else
 730                        len = xprt->xpt_ops->xpo_recvfrom(rqstp);
 731                dprintk("svc: got len=%d\n", len);
 732                rqstp->rq_reserved = serv->sv_max_mesg;
 733                atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
 734        }
 735        /* clear XPT_BUSY: */
 736        svc_xprt_received(xprt);
 737        return len;
 738}
 739
 740/*
 741 * Receive the next request on any transport.  This code is carefully
 742 * organised not to touch any cachelines in the shared svc_serv
 743 * structure, only cachelines in the local svc_pool.
 744 */
 745int svc_recv(struct svc_rqst *rqstp, long timeout)
 746{
 747        struct svc_xprt         *xprt = NULL;
 748        struct svc_serv         *serv = rqstp->rq_server;
 749        int                     len, err;
 750
 751        dprintk("svc: server %p waiting for data (to = %ld)\n",
 752                rqstp, timeout);
 753
 754        if (rqstp->rq_xprt)
 755                printk(KERN_ERR
 756                        "svc_recv: service %p, transport not NULL!\n",
 757                         rqstp);
 758        if (waitqueue_active(&rqstp->rq_wait))
 759                printk(KERN_ERR
 760                        "svc_recv: service %p, wait queue active!\n",
 761                         rqstp);
 762
 763        err = svc_alloc_arg(rqstp);
 764        if (err)
 765                return err;
 766
 767        try_to_freeze();
 768        cond_resched();
 769        if (signalled() || kthread_should_stop())
 770                return -EINTR;
 771
 772        xprt = svc_get_next_xprt(rqstp, timeout);
 773        if (IS_ERR(xprt))
 774                return PTR_ERR(xprt);
 775
 776        len = svc_handle_xprt(rqstp, xprt);
 777
 778        /* No data, incomplete (TCP) read, or accept() */
 779        if (len <= 0)
 780                goto out;
 781
 782        clear_bit(XPT_OLD, &xprt->xpt_flags);
 783
 784        rqstp->rq_secure = svc_port_is_privileged(svc_addr(rqstp));
 785        rqstp->rq_chandle.defer = svc_defer;
 786
 787        if (serv->sv_stats)
 788                serv->sv_stats->netcnt++;
 789        return len;
 790out:
 791        rqstp->rq_res.len = 0;
 792        svc_xprt_release(rqstp);
 793        return -EAGAIN;
 794}
 795EXPORT_SYMBOL_GPL(svc_recv);
 796
 797/*
 798 * Drop request
 799 */
 800void svc_drop(struct svc_rqst *rqstp)
 801{
 802        dprintk("svc: xprt %p dropped request\n", rqstp->rq_xprt);
 803        svc_xprt_release(rqstp);
 804}
 805EXPORT_SYMBOL_GPL(svc_drop);
 806
 807/*
 808 * Return reply to client.
 809 */
 810int svc_send(struct svc_rqst *rqstp)
 811{
 812        struct svc_xprt *xprt;
 813        int             len;
 814        struct xdr_buf  *xb;
 815
 816        xprt = rqstp->rq_xprt;
 817        if (!xprt)
 818                return -EFAULT;
 819
 820        /* release the receive skb before sending the reply */
 821        rqstp->rq_xprt->xpt_ops->xpo_release_rqst(rqstp);
 822
 823        /* calculate over-all length */
 824        xb = &rqstp->rq_res;
 825        xb->len = xb->head[0].iov_len +
 826                xb->page_len +
 827                xb->tail[0].iov_len;
 828
 829        /* Grab mutex to serialize outgoing data. */
 830        mutex_lock(&xprt->xpt_mutex);
 831        if (test_bit(XPT_DEAD, &xprt->xpt_flags)
 832                        || test_bit(XPT_CLOSE, &xprt->xpt_flags))
 833                len = -ENOTCONN;
 834        else
 835                len = xprt->xpt_ops->xpo_sendto(rqstp);
 836        mutex_unlock(&xprt->xpt_mutex);
 837        rpc_wake_up(&xprt->xpt_bc_pending);
 838        svc_xprt_release(rqstp);
 839
 840        if (len == -ECONNREFUSED || len == -ENOTCONN || len == -EAGAIN)
 841                return 0;
 842        return len;
 843}
 844
 845/*
 846 * Timer function to close old temporary transports, using
 847 * a mark-and-sweep algorithm.
 848 */
 849static void svc_age_temp_xprts(unsigned long closure)
 850{
 851        struct svc_serv *serv = (struct svc_serv *)closure;
 852        struct svc_xprt *xprt;
 853        struct list_head *le, *next;
 854        LIST_HEAD(to_be_aged);
 855
 856        dprintk("svc_age_temp_xprts\n");
 857
 858        if (!spin_trylock_bh(&serv->sv_lock)) {
 859                /* busy, try again 1 sec later */
 860                dprintk("svc_age_temp_xprts: busy\n");
 861                mod_timer(&serv->sv_temptimer, jiffies + HZ);
 862                return;
 863        }
 864
 865        list_for_each_safe(le, next, &serv->sv_tempsocks) {
 866                xprt = list_entry(le, struct svc_xprt, xpt_list);
 867
 868                /* First time through, just mark it OLD. Second time
 869                 * through, close it. */
 870                if (!test_and_set_bit(XPT_OLD, &xprt->xpt_flags))
 871                        continue;
 872                if (atomic_read(&xprt->xpt_ref.refcount) > 1 ||
 873                    test_bit(XPT_BUSY, &xprt->xpt_flags))
 874                        continue;
 875                svc_xprt_get(xprt);
 876                list_move(le, &to_be_aged);
 877                set_bit(XPT_CLOSE, &xprt->xpt_flags);
 878                set_bit(XPT_DETACHED, &xprt->xpt_flags);
 879        }
 880        spin_unlock_bh(&serv->sv_lock);
 881
 882        while (!list_empty(&to_be_aged)) {
 883                le = to_be_aged.next;
 884                /* fiddling the xpt_list node is safe 'cos we're XPT_DETACHED */
 885                list_del_init(le);
 886                xprt = list_entry(le, struct svc_xprt, xpt_list);
 887
 888                dprintk("queuing xprt %p for closing\n", xprt);
 889
 890                /* a thread will dequeue and close it soon */
 891                svc_xprt_enqueue(xprt);
 892                svc_xprt_put(xprt);
 893        }
 894
 895        mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ);
 896}
 897
 898static void call_xpt_users(struct svc_xprt *xprt)
 899{
 900        struct svc_xpt_user *u;
 901
 902        spin_lock(&xprt->xpt_lock);
 903        while (!list_empty(&xprt->xpt_users)) {
 904                u = list_first_entry(&xprt->xpt_users, struct svc_xpt_user, list);
 905                list_del(&u->list);
 906                u->callback(u);
 907        }
 908        spin_unlock(&xprt->xpt_lock);
 909}
 910
 911/*
 912 * Remove a dead transport
 913 */
 914static void svc_delete_xprt(struct svc_xprt *xprt)
 915{
 916        struct svc_serv *serv = xprt->xpt_server;
 917        struct svc_deferred_req *dr;
 918
 919        /* Only do this once */
 920        if (test_and_set_bit(XPT_DEAD, &xprt->xpt_flags))
 921                BUG();
 922
 923        dprintk("svc: svc_delete_xprt(%p)\n", xprt);
 924        xprt->xpt_ops->xpo_detach(xprt);
 925
 926        spin_lock_bh(&serv->sv_lock);
 927        if (!test_and_set_bit(XPT_DETACHED, &xprt->xpt_flags))
 928                list_del_init(&xprt->xpt_list);
 929        BUG_ON(!list_empty(&xprt->xpt_ready));
 930        if (test_bit(XPT_TEMP, &xprt->xpt_flags))
 931                serv->sv_tmpcnt--;
 932        spin_unlock_bh(&serv->sv_lock);
 933
 934        while ((dr = svc_deferred_dequeue(xprt)) != NULL)
 935                kfree(dr);
 936
 937        call_xpt_users(xprt);
 938        svc_xprt_put(xprt);
 939}
 940
 941void svc_close_xprt(struct svc_xprt *xprt)
 942{
 943        set_bit(XPT_CLOSE, &xprt->xpt_flags);
 944        if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
 945                /* someone else will have to effect the close */
 946                return;
 947        /*
 948         * We expect svc_close_xprt() to work even when no threads are
 949         * running (e.g., while configuring the server before starting
 950         * any threads), so if the transport isn't busy, we delete
 951         * it ourself:
 952         */
 953        svc_delete_xprt(xprt);
 954}
 955EXPORT_SYMBOL_GPL(svc_close_xprt);
 956
 957static void svc_close_list(struct svc_serv *serv, struct list_head *xprt_list, struct net *net)
 958{
 959        struct svc_xprt *xprt;
 960
 961        spin_lock(&serv->sv_lock);
 962        list_for_each_entry(xprt, xprt_list, xpt_list) {
 963                if (xprt->xpt_net != net)
 964                        continue;
 965                set_bit(XPT_CLOSE, &xprt->xpt_flags);
 966                set_bit(XPT_BUSY, &xprt->xpt_flags);
 967        }
 968        spin_unlock(&serv->sv_lock);
 969}
 970
 971static void svc_clear_pools(struct svc_serv *serv, struct net *net)
 972{
 973        struct svc_pool *pool;
 974        struct svc_xprt *xprt;
 975        struct svc_xprt *tmp;
 976        int i;
 977
 978        for (i = 0; i < serv->sv_nrpools; i++) {
 979                pool = &serv->sv_pools[i];
 980
 981                spin_lock_bh(&pool->sp_lock);
 982                list_for_each_entry_safe(xprt, tmp, &pool->sp_sockets, xpt_ready) {
 983                        if (xprt->xpt_net != net)
 984                                continue;
 985                        list_del_init(&xprt->xpt_ready);
 986                }
 987                spin_unlock_bh(&pool->sp_lock);
 988        }
 989}
 990
 991static void svc_clear_list(struct svc_serv *serv, struct list_head *xprt_list, struct net *net)
 992{
 993        struct svc_xprt *xprt;
 994        struct svc_xprt *tmp;
 995        LIST_HEAD(victims);
 996
 997        spin_lock(&serv->sv_lock);
 998        list_for_each_entry_safe(xprt, tmp, xprt_list, xpt_list) {
 999                if (xprt->xpt_net != net)
1000                        continue;
1001                list_move(&xprt->xpt_list, &victims);
1002        }
1003        spin_unlock(&serv->sv_lock);
1004
1005        list_for_each_entry_safe(xprt, tmp, &victims, xpt_list)
1006                svc_delete_xprt(xprt);
1007}
1008
1009void svc_close_net(struct svc_serv *serv, struct net *net)
1010{
1011        svc_close_list(serv, &serv->sv_tempsocks, net);
1012        svc_close_list(serv, &serv->sv_permsocks, net);
1013
1014        svc_clear_pools(serv, net);
1015        /*
1016         * At this point the sp_sockets lists will stay empty, since
1017         * svc_xprt_enqueue will not add new entries without taking the
1018         * sp_lock and checking XPT_BUSY.
1019         */
1020        svc_clear_list(serv, &serv->sv_tempsocks, net);
1021        svc_clear_list(serv, &serv->sv_permsocks, net);
1022}
1023
1024/*
1025 * Handle defer and revisit of requests
1026 */
1027
1028static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
1029{
1030        struct svc_deferred_req *dr =
1031                container_of(dreq, struct svc_deferred_req, handle);
1032        struct svc_xprt *xprt = dr->xprt;
1033
1034        spin_lock(&xprt->xpt_lock);
1035        set_bit(XPT_DEFERRED, &xprt->xpt_flags);
1036        if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) {
1037                spin_unlock(&xprt->xpt_lock);
1038                dprintk("revisit canceled\n");
1039                svc_xprt_put(xprt);
1040                kfree(dr);
1041                return;
1042        }
1043        dprintk("revisit queued\n");
1044        dr->xprt = NULL;
1045        list_add(&dr->handle.recent, &xprt->xpt_deferred);
1046        spin_unlock(&xprt->xpt_lock);
1047        svc_xprt_enqueue(xprt);
1048        svc_xprt_put(xprt);
1049}
1050
1051/*
1052 * Save the request off for later processing. The request buffer looks
1053 * like this:
1054 *
1055 * <xprt-header><rpc-header><rpc-pagelist><rpc-tail>
1056 *
1057 * This code can only handle requests that consist of an xprt-header
1058 * and rpc-header.
1059 */
1060static struct cache_deferred_req *svc_defer(struct cache_req *req)
1061{
1062        struct svc_rqst *rqstp = container_of(req, struct svc_rqst, rq_chandle);
1063        struct svc_deferred_req *dr;
1064
1065        if (rqstp->rq_arg.page_len || !rqstp->rq_usedeferral)
1066                return NULL; /* if more than a page, give up FIXME */
1067        if (rqstp->rq_deferred) {
1068                dr = rqstp->rq_deferred;
1069                rqstp->rq_deferred = NULL;
1070        } else {
1071                size_t skip;
1072                size_t size;
1073                /* FIXME maybe discard if size too large */
1074                size = sizeof(struct svc_deferred_req) + rqstp->rq_arg.len;
1075                dr = kmalloc(size, GFP_KERNEL);
1076                if (dr == NULL)
1077                        return NULL;
1078
1079                dr->handle.owner = rqstp->rq_server;
1080                dr->prot = rqstp->rq_prot;
1081                memcpy(&dr->addr, &rqstp->rq_addr, rqstp->rq_addrlen);
1082                dr->addrlen = rqstp->rq_addrlen;
1083                dr->daddr = rqstp->rq_daddr;
1084                dr->argslen = rqstp->rq_arg.len >> 2;
1085                dr->xprt_hlen = rqstp->rq_xprt_hlen;
1086
1087                /* back up head to the start of the buffer and copy */
1088                skip = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len;
1089                memcpy(dr->args, rqstp->rq_arg.head[0].iov_base - skip,
1090                       dr->argslen << 2);
1091        }
1092        svc_xprt_get(rqstp->rq_xprt);
1093        dr->xprt = rqstp->rq_xprt;
1094        rqstp->rq_dropme = true;
1095
1096        dr->handle.revisit = svc_revisit;
1097        return &dr->handle;
1098}
1099
1100/*
1101 * recv data from a deferred request into an active one
1102 */
1103static int svc_deferred_recv(struct svc_rqst *rqstp)
1104{
1105        struct svc_deferred_req *dr = rqstp->rq_deferred;
1106
1107        /* setup iov_base past transport header */
1108        rqstp->rq_arg.head[0].iov_base = dr->args + (dr->xprt_hlen>>2);
1109        /* The iov_len does not include the transport header bytes */
1110        rqstp->rq_arg.head[0].iov_len = (dr->argslen<<2) - dr->xprt_hlen;
1111        rqstp->rq_arg.page_len = 0;
1112        /* The rq_arg.len includes the transport header bytes */
1113        rqstp->rq_arg.len     = dr->argslen<<2;
1114        rqstp->rq_prot        = dr->prot;
1115        memcpy(&rqstp->rq_addr, &dr->addr, dr->addrlen);
1116        rqstp->rq_addrlen     = dr->addrlen;
1117        /* Save off transport header len in case we get deferred again */
1118        rqstp->rq_xprt_hlen   = dr->xprt_hlen;
1119        rqstp->rq_daddr       = dr->daddr;
1120        rqstp->rq_respages    = rqstp->rq_pages;
1121        return (dr->argslen<<2) - dr->xprt_hlen;
1122}
1123
1124
1125static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt)
1126{
1127        struct svc_deferred_req *dr = NULL;
1128
1129        if (!test_bit(XPT_DEFERRED, &xprt->xpt_flags))
1130                return NULL;
1131        spin_lock(&xprt->xpt_lock);
1132        if (!list_empty(&xprt->xpt_deferred)) {
1133                dr = list_entry(xprt->xpt_deferred.next,
1134                                struct svc_deferred_req,
1135                                handle.recent);
1136                list_del_init(&dr->handle.recent);
1137        } else
1138                clear_bit(XPT_DEFERRED, &xprt->xpt_flags);
1139        spin_unlock(&xprt->xpt_lock);
1140        return dr;
1141}
1142
1143/**
1144 * svc_find_xprt - find an RPC transport instance
1145 * @serv: pointer to svc_serv to search
1146 * @xcl_name: C string containing transport's class name
1147 * @net: owner net pointer
1148 * @af: Address family of transport's local address
1149 * @port: transport's IP port number
1150 *
1151 * Return the transport instance pointer for the endpoint accepting
1152 * connections/peer traffic from the specified transport class,
1153 * address family and port.
1154 *
1155 * Specifying 0 for the address family or port is effectively a
1156 * wild-card, and will result in matching the first transport in the
1157 * service's list that has a matching class name.
1158 */
1159struct svc_xprt *svc_find_xprt(struct svc_serv *serv, const char *xcl_name,
1160                               struct net *net, const sa_family_t af,
1161                               const unsigned short port)
1162{
1163        struct svc_xprt *xprt;
1164        struct svc_xprt *found = NULL;
1165
1166        /* Sanity check the args */
1167        if (serv == NULL || xcl_name == NULL)
1168                return found;
1169
1170        spin_lock_bh(&serv->sv_lock);
1171        list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1172                if (xprt->xpt_net != net)
1173                        continue;
1174                if (strcmp(xprt->xpt_class->xcl_name, xcl_name))
1175                        continue;
1176                if (af != AF_UNSPEC && af != xprt->xpt_local.ss_family)
1177                        continue;
1178                if (port != 0 && port != svc_xprt_local_port(xprt))
1179                        continue;
1180                found = xprt;
1181                svc_xprt_get(xprt);
1182                break;
1183        }
1184        spin_unlock_bh(&serv->sv_lock);
1185        return found;
1186}
1187EXPORT_SYMBOL_GPL(svc_find_xprt);
1188
1189static int svc_one_xprt_name(const struct svc_xprt *xprt,
1190                             char *pos, int remaining)
1191{
1192        int len;
1193
1194        len = snprintf(pos, remaining, "%s %u\n",
1195                        xprt->xpt_class->xcl_name,
1196                        svc_xprt_local_port(xprt));
1197        if (len >= remaining)
1198                return -ENAMETOOLONG;
1199        return len;
1200}
1201
1202/**
1203 * svc_xprt_names - format a buffer with a list of transport names
1204 * @serv: pointer to an RPC service
1205 * @buf: pointer to a buffer to be filled in
1206 * @buflen: length of buffer to be filled in
1207 *
1208 * Fills in @buf with a string containing a list of transport names,
1209 * each name terminated with '\n'.
1210 *
1211 * Returns positive length of the filled-in string on success; otherwise
1212 * a negative errno value is returned if an error occurs.
1213 */
1214int svc_xprt_names(struct svc_serv *serv, char *buf, const int buflen)
1215{
1216        struct svc_xprt *xprt;
1217        int len, totlen;
1218        char *pos;
1219
1220        /* Sanity check args */
1221        if (!serv)
1222                return 0;
1223
1224        spin_lock_bh(&serv->sv_lock);
1225
1226        pos = buf;
1227        totlen = 0;
1228        list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1229                len = svc_one_xprt_name(xprt, pos, buflen - totlen);
1230                if (len < 0) {
1231                        *buf = '\0';
1232                        totlen = len;
1233                }
1234                if (len <= 0)
1235                        break;
1236
1237                pos += len;
1238                totlen += len;
1239        }
1240
1241        spin_unlock_bh(&serv->sv_lock);
1242        return totlen;
1243}
1244EXPORT_SYMBOL_GPL(svc_xprt_names);
1245
1246
1247/*----------------------------------------------------------------------------*/
1248
1249static void *svc_pool_stats_start(struct seq_file *m, loff_t *pos)
1250{
1251        unsigned int pidx = (unsigned int)*pos;
1252        struct svc_serv *serv = m->private;
1253
1254        dprintk("svc_pool_stats_start, *pidx=%u\n", pidx);
1255
1256        if (!pidx)
1257                return SEQ_START_TOKEN;
1258        return (pidx > serv->sv_nrpools ? NULL : &serv->sv_pools[pidx-1]);
1259}
1260
1261static void *svc_pool_stats_next(struct seq_file *m, void *p, loff_t *pos)
1262{
1263        struct svc_pool *pool = p;
1264        struct svc_serv *serv = m->private;
1265
1266        dprintk("svc_pool_stats_next, *pos=%llu\n", *pos);
1267
1268        if (p == SEQ_START_TOKEN) {
1269                pool = &serv->sv_pools[0];
1270        } else {
1271                unsigned int pidx = (pool - &serv->sv_pools[0]);
1272                if (pidx < serv->sv_nrpools-1)
1273                        pool = &serv->sv_pools[pidx+1];
1274                else
1275                        pool = NULL;
1276        }
1277        ++*pos;
1278        return pool;
1279}
1280
1281static void svc_pool_stats_stop(struct seq_file *m, void *p)
1282{
1283}
1284
1285static int svc_pool_stats_show(struct seq_file *m, void *p)
1286{
1287        struct svc_pool *pool = p;
1288
1289        if (p == SEQ_START_TOKEN) {
1290                seq_puts(m, "# pool packets-arrived sockets-enqueued threads-woken threads-timedout\n");
1291                return 0;
1292        }
1293
1294        seq_printf(m, "%u %lu %lu %lu %lu\n",
1295                pool->sp_id,
1296                pool->sp_stats.packets,
1297                pool->sp_stats.sockets_queued,
1298                pool->sp_stats.threads_woken,
1299                pool->sp_stats.threads_timedout);
1300
1301        return 0;
1302}
1303
1304static const struct seq_operations svc_pool_stats_seq_ops = {
1305        .start  = svc_pool_stats_start,
1306        .next   = svc_pool_stats_next,
1307        .stop   = svc_pool_stats_stop,
1308        .show   = svc_pool_stats_show,
1309};
1310
1311int svc_pool_stats_open(struct svc_serv *serv, struct file *file)
1312{
1313        int err;
1314
1315        err = seq_open(file, &svc_pool_stats_seq_ops);
1316        if (!err)
1317                ((struct seq_file *) file->private_data)->private = serv;
1318        return err;
1319}
1320EXPORT_SYMBOL(svc_pool_stats_open);
1321
1322/*----------------------------------------------------------------------------*/
1323
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