net/sunrpc/svc

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This source file includes following definitions.
svc_reg_xprt_class
svc_unreg_xprt_class
svc_print_xprts
svc_xprt_free
svc_xprt_put
svc_xprt_init
__svc_xpo_create
svc_xprt_received
svc_add_new_perm_xprt
_svc_create_xprt
svc_create_xprt
svc_xprt_copy_addrs
svc_print_addr
svc_xprt_slots_in_range
svc_xprt_reserve_slot
svc_xprt_release_slot
svc_xprt_ready
svc_xprt_do_enqueue
svc_xprt_enqueue
svc_xprt_dequeue
svc_reserve
svc_xprt_release
svc_wake_up
svc_port_is_privileged
svc_check_conn_limits
svc_alloc_arg
rqst_should_sleep
svc_get_next_xprt
svc_add_new_temp_xprt
svc_handle_xprt
svc_recv
svc_drop
svc_send
svc_age_temp_xprts
svc_age_temp_xprts_now
call_xpt_users
svc_delete_xprt
svc_close_xprt
svc_close_list
svc_dequeue_net
svc_clean_up_xprts
svc_close_net
svc_revisit
svc_defer
svc_deferred_recv
svc_deferred_dequeue
svc_find_xprt
svc_one_xprt_name
svc_xprt_names
svc_pool_stats_start
svc_pool_stats_next
svc_pool_stats_stop
svc_pool_stats_show
svc_pool_stats_open
   1 // SPDX-License-Identifier: GPL-2.0-only
   2 /*
   3  * linux/net/sunrpc/svc_xprt.c
   4  *
   5  * Author: Tom Tucker <tom@opengridcomputing.com>
   6  */
   7 
   8 #include <linux/sched.h>
   9 #include <linux/errno.h>
  10 #include <linux/freezer.h>
  11 #include <linux/kthread.h>
  12 #include <linux/slab.h>
  13 #include <net/sock.h>
  14 #include <linux/sunrpc/addr.h>
  15 #include <linux/sunrpc/stats.h>
  16 #include <linux/sunrpc/svc_xprt.h>
  17 #include <linux/sunrpc/svcsock.h>
  18 #include <linux/sunrpc/xprt.h>
  19 #include <linux/module.h>
  20 #include <linux/netdevice.h>
  21 #include <trace/events/sunrpc.h>
  22 
  23 #define RPCDBG_FACILITY RPCDBG_SVCXPRT
  24 
  25 static unsigned int svc_rpc_per_connection_limit __read_mostly;
  26 module_param(svc_rpc_per_connection_limit, uint, 0644);
  27 
  28 
  29 static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt);
  30 static int svc_deferred_recv(struct svc_rqst *rqstp);
  31 static struct cache_deferred_req *svc_defer(struct cache_req *req);
  32 static void svc_age_temp_xprts(struct timer_list *t);
  33 static void svc_delete_xprt(struct svc_xprt *xprt);
  34 
  35 /* apparently the "standard" is that clients close
  36  * idle connections after 5 minutes, servers after
  37  * 6 minutes
  38  *   http://nfsv4bat.org/Documents/ConnectAThon/1996/nfstcp.pdf
  39  */
  40 static int svc_conn_age_period = 6*60;
  41 
  42 /* List of registered transport classes */
  43 static DEFINE_SPINLOCK(svc_xprt_class_lock);
  44 static LIST_HEAD(svc_xprt_class_list);
  45 
  46 /* SMP locking strategy:
  47  *
  48  *      svc_pool->sp_lock protects most of the fields of that pool.
  49  *      svc_serv->sv_lock protects sv_tempsocks, sv_permsocks, sv_tmpcnt.
  50  *      when both need to be taken (rare), svc_serv->sv_lock is first.
  51  *      The "service mutex" protects svc_serv->sv_nrthread.
  52  *      svc_sock->sk_lock protects the svc_sock->sk_deferred list
  53  *             and the ->sk_info_authunix cache.
  54  *
  55  *      The XPT_BUSY bit in xprt->xpt_flags prevents a transport being
  56  *      enqueued multiply. During normal transport processing this bit
  57  *      is set by svc_xprt_enqueue and cleared by svc_xprt_received.
  58  *      Providers should not manipulate this bit directly.
  59  *
  60  *      Some flags can be set to certain values at any time
  61  *      providing that certain rules are followed:
  62  *
  63  *      XPT_CONN, XPT_DATA:
  64  *              - Can be set or cleared at any time.
  65  *              - After a set, svc_xprt_enqueue must be called to enqueue
  66  *                the transport for processing.
  67  *              - After a clear, the transport must be read/accepted.
  68  *                If this succeeds, it must be set again.
  69  *      XPT_CLOSE:
  70  *              - Can set at any time. It is never cleared.
  71  *      XPT_DEAD:
  72  *              - Can only be set while XPT_BUSY is held which ensures
  73  *                that no other thread will be using the transport or will
  74  *                try to set XPT_DEAD.
  75  */
  76 int svc_reg_xprt_class(struct svc_xprt_class *xcl)
  77 {
  78         struct svc_xprt_class *cl;
  79         int res = -EEXIST;
  80 
  81         dprintk("svc: Adding svc transport class '%s'\n", xcl->xcl_name);
  82 
  83         INIT_LIST_HEAD(&xcl->xcl_list);
  84         spin_lock(&svc_xprt_class_lock);
  85         /* Make sure there isn't already a class with the same name */
  86         list_for_each_entry(cl, &svc_xprt_class_list, xcl_list) {
  87                 if (strcmp(xcl->xcl_name, cl->xcl_name) == 0)
  88                         goto out;
  89         }
  90         list_add_tail(&xcl->xcl_list, &svc_xprt_class_list);
  91         res = 0;
  92 out:
  93         spin_unlock(&svc_xprt_class_lock);
  94         return res;
  95 }
  96 EXPORT_SYMBOL_GPL(svc_reg_xprt_class);
  97 
  98 void svc_unreg_xprt_class(struct svc_xprt_class *xcl)
  99 {
 100         dprintk("svc: Removing svc transport class '%s'\n", xcl->xcl_name);
 101         spin_lock(&svc_xprt_class_lock);
 102         list_del_init(&xcl->xcl_list);
 103         spin_unlock(&svc_xprt_class_lock);
 104 }
 105 EXPORT_SYMBOL_GPL(svc_unreg_xprt_class);
 106 
 107 /*
 108  * Format the transport list for printing
 109  */
 110 int svc_print_xprts(char *buf, int maxlen)
 111 {
 112         struct svc_xprt_class *xcl;
 113         char tmpstr[80];
 114         int len = 0;
 115         buf[0] = '\0';
 116 
 117         spin_lock(&svc_xprt_class_lock);
 118         list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
 119                 int slen;
 120 
 121                 sprintf(tmpstr, "%s %d\n", xcl->xcl_name, xcl->xcl_max_payload);
 122                 slen = strlen(tmpstr);
 123                 if (len + slen > maxlen)
 124                         break;
 125                 len += slen;
 126                 strcat(buf, tmpstr);
 127         }
 128         spin_unlock(&svc_xprt_class_lock);
 129 
 130         return len;
 131 }
 132 
 133 static void svc_xprt_free(struct kref *kref)
 134 {
 135         struct svc_xprt *xprt =
 136                 container_of(kref, struct svc_xprt, xpt_ref);
 137         struct module *owner = xprt->xpt_class->xcl_owner;
 138         if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags))
 139                 svcauth_unix_info_release(xprt);
 140         put_cred(xprt->xpt_cred);
 141         put_net(xprt->xpt_net);
 142         /* See comment on corresponding get in xs_setup_bc_tcp(): */
 143         if (xprt->xpt_bc_xprt)
 144                 xprt_put(xprt->xpt_bc_xprt);
 145         if (xprt->xpt_bc_xps)
 146                 xprt_switch_put(xprt->xpt_bc_xps);
 147         xprt->xpt_ops->xpo_free(xprt);
 148         module_put(owner);
 149 }
 150 
 151 void svc_xprt_put(struct svc_xprt *xprt)
 152 {
 153         kref_put(&xprt->xpt_ref, svc_xprt_free);
 154 }
 155 EXPORT_SYMBOL_GPL(svc_xprt_put);
 156 
 157 /*
 158  * Called by transport drivers to initialize the transport independent
 159  * portion of the transport instance.
 160  */
 161 void svc_xprt_init(struct net *net, struct svc_xprt_class *xcl,
 162                    struct svc_xprt *xprt, struct svc_serv *serv)
 163 {
 164         memset(xprt, 0, sizeof(*xprt));
 165         xprt->xpt_class = xcl;
 166         xprt->xpt_ops = xcl->xcl_ops;
 167         kref_init(&xprt->xpt_ref);
 168         xprt->xpt_server = serv;
 169         INIT_LIST_HEAD(&xprt->xpt_list);
 170         INIT_LIST_HEAD(&xprt->xpt_ready);
 171         INIT_LIST_HEAD(&xprt->xpt_deferred);
 172         INIT_LIST_HEAD(&xprt->xpt_users);
 173         mutex_init(&xprt->xpt_mutex);
 174         spin_lock_init(&xprt->xpt_lock);
 175         set_bit(XPT_BUSY, &xprt->xpt_flags);
 176         xprt->xpt_net = get_net(net);
 177         strcpy(xprt->xpt_remotebuf, "uninitialized");
 178 }
 179 EXPORT_SYMBOL_GPL(svc_xprt_init);
 180 
 181 static struct svc_xprt *__svc_xpo_create(struct svc_xprt_class *xcl,
 182                                          struct svc_serv *serv,
 183                                          struct net *net,
 184                                          const int family,
 185                                          const unsigned short port,
 186                                          int flags)
 187 {
 188         struct sockaddr_in sin = {
 189                 .sin_family             = AF_INET,
 190                 .sin_addr.s_addr        = htonl(INADDR_ANY),
 191                 .sin_port               = htons(port),
 192         };
 193 #if IS_ENABLED(CONFIG_IPV6)
 194         struct sockaddr_in6 sin6 = {
 195                 .sin6_family            = AF_INET6,
 196                 .sin6_addr              = IN6ADDR_ANY_INIT,
 197                 .sin6_port              = htons(port),
 198         };
 199 #endif
 200         struct sockaddr *sap;
 201         size_t len;
 202 
 203         switch (family) {
 204         case PF_INET:
 205                 sap = (struct sockaddr *)&sin;
 206                 len = sizeof(sin);
 207                 break;
 208 #if IS_ENABLED(CONFIG_IPV6)
 209         case PF_INET6:
 210                 sap = (struct sockaddr *)&sin6;
 211                 len = sizeof(sin6);
 212                 break;
 213 #endif
 214         default:
 215                 return ERR_PTR(-EAFNOSUPPORT);
 216         }
 217 
 218         return xcl->xcl_ops->xpo_create(serv, net, sap, len, flags);
 219 }
 220 
 221 /*
 222  * svc_xprt_received conditionally queues the transport for processing
 223  * by another thread. The caller must hold the XPT_BUSY bit and must
 224  * not thereafter touch transport data.
 225  *
 226  * Note: XPT_DATA only gets cleared when a read-attempt finds no (or
 227  * insufficient) data.
 228  */
 229 static void svc_xprt_received(struct svc_xprt *xprt)
 230 {
 231         if (!test_bit(XPT_BUSY, &xprt->xpt_flags)) {
 232                 WARN_ONCE(1, "xprt=0x%p already busy!", xprt);
 233                 return;
 234         }
 235 
 236         /* As soon as we clear busy, the xprt could be closed and
 237          * 'put', so we need a reference to call svc_enqueue_xprt with:
 238          */
 239         svc_xprt_get(xprt);
 240         smp_mb__before_atomic();
 241         clear_bit(XPT_BUSY, &xprt->xpt_flags);
 242         xprt->xpt_server->sv_ops->svo_enqueue_xprt(xprt);
 243         svc_xprt_put(xprt);
 244 }
 245 
 246 void svc_add_new_perm_xprt(struct svc_serv *serv, struct svc_xprt *new)
 247 {
 248         clear_bit(XPT_TEMP, &new->xpt_flags);
 249         spin_lock_bh(&serv->sv_lock);
 250         list_add(&new->xpt_list, &serv->sv_permsocks);
 251         spin_unlock_bh(&serv->sv_lock);
 252         svc_xprt_received(new);
 253 }
 254 
 255 static int _svc_create_xprt(struct svc_serv *serv, const char *xprt_name,
 256                             struct net *net, const int family,
 257                             const unsigned short port, int flags,
 258                             const struct cred *cred)
 259 {
 260         struct svc_xprt_class *xcl;
 261 
 262         spin_lock(&svc_xprt_class_lock);
 263         list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
 264                 struct svc_xprt *newxprt;
 265                 unsigned short newport;
 266 
 267                 if (strcmp(xprt_name, xcl->xcl_name))
 268                         continue;
 269 
 270                 if (!try_module_get(xcl->xcl_owner))
 271                         goto err;
 272 
 273                 spin_unlock(&svc_xprt_class_lock);
 274                 newxprt = __svc_xpo_create(xcl, serv, net, family, port, flags);
 275                 if (IS_ERR(newxprt)) {
 276                         module_put(xcl->xcl_owner);
 277                         return PTR_ERR(newxprt);
 278                 }
 279                 newxprt->xpt_cred = get_cred(cred);
 280                 svc_add_new_perm_xprt(serv, newxprt);
 281                 newport = svc_xprt_local_port(newxprt);
 282                 return newport;
 283         }
 284  err:
 285         spin_unlock(&svc_xprt_class_lock);
 286         /* This errno is exposed to user space.  Provide a reasonable
 287          * perror msg for a bad transport. */
 288         return -EPROTONOSUPPORT;
 289 }
 290 
 291 int svc_create_xprt(struct svc_serv *serv, const char *xprt_name,
 292                     struct net *net, const int family,
 293                     const unsigned short port, int flags,
 294                     const struct cred *cred)
 295 {
 296         int err;
 297 
 298         dprintk("svc: creating transport %s[%d]\n", xprt_name, port);
 299         err = _svc_create_xprt(serv, xprt_name, net, family, port, flags, cred);
 300         if (err == -EPROTONOSUPPORT) {
 301                 request_module("svc%s", xprt_name);
 302                 err = _svc_create_xprt(serv, xprt_name, net, family, port, flags, cred);
 303         }
 304         if (err < 0)
 305                 dprintk("svc: transport %s not found, err %d\n",
 306                         xprt_name, -err);
 307         return err;
 308 }
 309 EXPORT_SYMBOL_GPL(svc_create_xprt);
 310 
 311 /*
 312  * Copy the local and remote xprt addresses to the rqstp structure
 313  */
 314 void svc_xprt_copy_addrs(struct svc_rqst *rqstp, struct svc_xprt *xprt)
 315 {
 316         memcpy(&rqstp->rq_addr, &xprt->xpt_remote, xprt->xpt_remotelen);
 317         rqstp->rq_addrlen = xprt->xpt_remotelen;
 318 
 319         /*
 320          * Destination address in request is needed for binding the
 321          * source address in RPC replies/callbacks later.
 322          */
 323         memcpy(&rqstp->rq_daddr, &xprt->xpt_local, xprt->xpt_locallen);
 324         rqstp->rq_daddrlen = xprt->xpt_locallen;
 325 }
 326 EXPORT_SYMBOL_GPL(svc_xprt_copy_addrs);
 327 
 328 /**
 329  * svc_print_addr - Format rq_addr field for printing
 330  * @rqstp: svc_rqst struct containing address to print
 331  * @buf: target buffer for formatted address
 332  * @len: length of target buffer
 333  *
 334  */
 335 char *svc_print_addr(struct svc_rqst *rqstp, char *buf, size_t len)
 336 {
 337         return __svc_print_addr(svc_addr(rqstp), buf, len);
 338 }
 339 EXPORT_SYMBOL_GPL(svc_print_addr);
 340 
 341 static bool svc_xprt_slots_in_range(struct svc_xprt *xprt)
 342 {
 343         unsigned int limit = svc_rpc_per_connection_limit;
 344         int nrqsts = atomic_read(&xprt->xpt_nr_rqsts);
 345 
 346         return limit == 0 || (nrqsts >= 0 && nrqsts < limit);
 347 }
 348 
 349 static bool svc_xprt_reserve_slot(struct svc_rqst *rqstp, struct svc_xprt *xprt)
 350 {
 351         if (!test_bit(RQ_DATA, &rqstp->rq_flags)) {
 352                 if (!svc_xprt_slots_in_range(xprt))
 353                         return false;
 354                 atomic_inc(&xprt->xpt_nr_rqsts);
 355                 set_bit(RQ_DATA, &rqstp->rq_flags);
 356         }
 357         return true;
 358 }
 359 
 360 static void svc_xprt_release_slot(struct svc_rqst *rqstp)
 361 {
 362         struct svc_xprt *xprt = rqstp->rq_xprt;
 363         if (test_and_clear_bit(RQ_DATA, &rqstp->rq_flags)) {
 364                 atomic_dec(&xprt->xpt_nr_rqsts);
 365                 smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */
 366                 svc_xprt_enqueue(xprt);
 367         }
 368 }
 369 
 370 static bool svc_xprt_ready(struct svc_xprt *xprt)
 371 {
 372         unsigned long xpt_flags;
 373 
 374         /*
 375          * If another cpu has recently updated xpt_flags,
 376          * sk_sock->flags, xpt_reserved, or xpt_nr_rqsts, we need to
 377          * know about it; otherwise it's possible that both that cpu and
 378          * this one could call svc_xprt_enqueue() without either
 379          * svc_xprt_enqueue() recognizing that the conditions below
 380          * are satisfied, and we could stall indefinitely:
 381          */
 382         smp_rmb();
 383         xpt_flags = READ_ONCE(xprt->xpt_flags);
 384 
 385         if (xpt_flags & (BIT(XPT_CONN) | BIT(XPT_CLOSE)))
 386                 return true;
 387         if (xpt_flags & (BIT(XPT_DATA) | BIT(XPT_DEFERRED))) {
 388                 if (xprt->xpt_ops->xpo_has_wspace(xprt) &&
 389                     svc_xprt_slots_in_range(xprt))
 390                         return true;
 391                 trace_svc_xprt_no_write_space(xprt);
 392                 return false;
 393         }
 394         return false;
 395 }
 396 
 397 void svc_xprt_do_enqueue(struct svc_xprt *xprt)
 398 {
 399         struct svc_pool *pool;
 400         struct svc_rqst *rqstp = NULL;
 401         int cpu;
 402 
 403         if (!svc_xprt_ready(xprt))
 404                 return;
 405 
 406         /* Mark transport as busy. It will remain in this state until
 407          * the provider calls svc_xprt_received. We update XPT_BUSY
 408          * atomically because it also guards against trying to enqueue
 409          * the transport twice.
 410          */
 411         if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
 412                 return;
 413 
 414         cpu = get_cpu();
 415         pool = svc_pool_for_cpu(xprt->xpt_server, cpu);
 416 
 417         atomic_long_inc(&pool->sp_stats.packets);
 418 
 419         spin_lock_bh(&pool->sp_lock);
 420         list_add_tail(&xprt->xpt_ready, &pool->sp_sockets);
 421         pool->sp_stats.sockets_queued++;
 422         spin_unlock_bh(&pool->sp_lock);
 423 
 424         /* find a thread for this xprt */
 425         rcu_read_lock();
 426         list_for_each_entry_rcu(rqstp, &pool->sp_all_threads, rq_all) {
 427                 if (test_and_set_bit(RQ_BUSY, &rqstp->rq_flags))
 428                         continue;
 429                 atomic_long_inc(&pool->sp_stats.threads_woken);
 430                 rqstp->rq_qtime = ktime_get();
 431                 wake_up_process(rqstp->rq_task);
 432                 goto out_unlock;
 433         }
 434         set_bit(SP_CONGESTED, &pool->sp_flags);
 435         rqstp = NULL;
 436 out_unlock:
 437         rcu_read_unlock();
 438         put_cpu();
 439         trace_svc_xprt_do_enqueue(xprt, rqstp);
 440 }
 441 EXPORT_SYMBOL_GPL(svc_xprt_do_enqueue);
 442 
 443 /*
 444  * Queue up a transport with data pending. If there are idle nfsd
 445  * processes, wake 'em up.
 446  *
 447  */
 448 void svc_xprt_enqueue(struct svc_xprt *xprt)
 449 {
 450         if (test_bit(XPT_BUSY, &xprt->xpt_flags))
 451                 return;
 452         xprt->xpt_server->sv_ops->svo_enqueue_xprt(xprt);
 453 }
 454 EXPORT_SYMBOL_GPL(svc_xprt_enqueue);
 455 
 456 /*
 457  * Dequeue the first transport, if there is one.
 458  */
 459 static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool)
 460 {
 461         struct svc_xprt *xprt = NULL;
 462 
 463         if (list_empty(&pool->sp_sockets))
 464                 goto out;
 465 
 466         spin_lock_bh(&pool->sp_lock);
 467         if (likely(!list_empty(&pool->sp_sockets))) {
 468                 xprt = list_first_entry(&pool->sp_sockets,
 469                                         struct svc_xprt, xpt_ready);
 470                 list_del_init(&xprt->xpt_ready);
 471                 svc_xprt_get(xprt);
 472         }
 473         spin_unlock_bh(&pool->sp_lock);
 474 out:
 475         return xprt;
 476 }
 477 
 478 /**
 479  * svc_reserve - change the space reserved for the reply to a request.
 480  * @rqstp:  The request in question
 481  * @space: new max space to reserve
 482  *
 483  * Each request reserves some space on the output queue of the transport
 484  * to make sure the reply fits.  This function reduces that reserved
 485  * space to be the amount of space used already, plus @space.
 486  *
 487  */
 488 void svc_reserve(struct svc_rqst *rqstp, int space)
 489 {
 490         struct svc_xprt *xprt = rqstp->rq_xprt;
 491 
 492         space += rqstp->rq_res.head[0].iov_len;
 493 
 494         if (xprt && space < rqstp->rq_reserved) {
 495                 atomic_sub((rqstp->rq_reserved - space), &xprt->xpt_reserved);
 496                 rqstp->rq_reserved = space;
 497                 smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */
 498                 svc_xprt_enqueue(xprt);
 499         }
 500 }
 501 EXPORT_SYMBOL_GPL(svc_reserve);
 502 
 503 static void svc_xprt_release(struct svc_rqst *rqstp)
 504 {
 505         struct svc_xprt *xprt = rqstp->rq_xprt;
 506 
 507         xprt->xpt_ops->xpo_release_rqst(rqstp);
 508 
 509         kfree(rqstp->rq_deferred);
 510         rqstp->rq_deferred = NULL;
 511 
 512         svc_free_res_pages(rqstp);
 513         rqstp->rq_res.page_len = 0;
 514         rqstp->rq_res.page_base = 0;
 515 
 516         /* Reset response buffer and release
 517          * the reservation.
 518          * But first, check that enough space was reserved
 519          * for the reply, otherwise we have a bug!
 520          */
 521         if ((rqstp->rq_res.len) >  rqstp->rq_reserved)
 522                 printk(KERN_ERR "RPC request reserved %d but used %d\n",
 523                        rqstp->rq_reserved,
 524                        rqstp->rq_res.len);
 525 
 526         rqstp->rq_res.head[0].iov_len = 0;
 527         svc_reserve(rqstp, 0);
 528         svc_xprt_release_slot(rqstp);
 529         rqstp->rq_xprt = NULL;
 530         svc_xprt_put(xprt);
 531 }
 532 
 533 /*
 534  * Some svc_serv's will have occasional work to do, even when a xprt is not
 535  * waiting to be serviced. This function is there to "kick" a task in one of
 536  * those services so that it can wake up and do that work. Note that we only
 537  * bother with pool 0 as we don't need to wake up more than one thread for
 538  * this purpose.
 539  */
 540 void svc_wake_up(struct svc_serv *serv)
 541 {
 542         struct svc_rqst *rqstp;
 543         struct svc_pool *pool;
 544 
 545         pool = &serv->sv_pools[0];
 546 
 547         rcu_read_lock();
 548         list_for_each_entry_rcu(rqstp, &pool->sp_all_threads, rq_all) {
 549                 /* skip any that aren't queued */
 550                 if (test_bit(RQ_BUSY, &rqstp->rq_flags))
 551                         continue;
 552                 rcu_read_unlock();
 553                 wake_up_process(rqstp->rq_task);
 554                 trace_svc_wake_up(rqstp->rq_task->pid);
 555                 return;
 556         }
 557         rcu_read_unlock();
 558 
 559         /* No free entries available */
 560         set_bit(SP_TASK_PENDING, &pool->sp_flags);
 561         smp_wmb();
 562         trace_svc_wake_up(0);
 563 }
 564 EXPORT_SYMBOL_GPL(svc_wake_up);
 565 
 566 int svc_port_is_privileged(struct sockaddr *sin)
 567 {
 568         switch (sin->sa_family) {
 569         case AF_INET:
 570                 return ntohs(((struct sockaddr_in *)sin)->sin_port)
 571                         < PROT_SOCK;
 572         case AF_INET6:
 573                 return ntohs(((struct sockaddr_in6 *)sin)->sin6_port)
 574                         < PROT_SOCK;
 575         default:
 576                 return 0;
 577         }
 578 }
 579 
 580 /*
 581  * Make sure that we don't have too many active connections. If we have,
 582  * something must be dropped. It's not clear what will happen if we allow
 583  * "too many" connections, but when dealing with network-facing software,
 584  * we have to code defensively. Here we do that by imposing hard limits.
 585  *
 586  * There's no point in trying to do random drop here for DoS
 587  * prevention. The NFS clients does 1 reconnect in 15 seconds. An
 588  * attacker can easily beat that.
 589  *
 590  * The only somewhat efficient mechanism would be if drop old
 591  * connections from the same IP first. But right now we don't even
 592  * record the client IP in svc_sock.
 593  *
 594  * single-threaded services that expect a lot of clients will probably
 595  * need to set sv_maxconn to override the default value which is based
 596  * on the number of threads
 597  */
 598 static void svc_check_conn_limits(struct svc_serv *serv)
 599 {
 600         unsigned int limit = serv->sv_maxconn ? serv->sv_maxconn :
 601                                 (serv->sv_nrthreads+3) * 20;
 602 
 603         if (serv->sv_tmpcnt > limit) {
 604                 struct svc_xprt *xprt = NULL;
 605                 spin_lock_bh(&serv->sv_lock);
 606                 if (!list_empty(&serv->sv_tempsocks)) {
 607                         /* Try to help the admin */
 608                         net_notice_ratelimited("%s: too many open connections, consider increasing the %s\n",
 609                                                serv->sv_name, serv->sv_maxconn ?
 610                                                "max number of connections" :
 611                                                "number of threads");
 612                         /*
 613                          * Always select the oldest connection. It's not fair,
 614                          * but so is life
 615                          */
 616                         xprt = list_entry(serv->sv_tempsocks.prev,
 617                                           struct svc_xprt,
 618                                           xpt_list);
 619                         set_bit(XPT_CLOSE, &xprt->xpt_flags);
 620                         svc_xprt_get(xprt);
 621                 }
 622                 spin_unlock_bh(&serv->sv_lock);
 623 
 624                 if (xprt) {
 625                         svc_xprt_enqueue(xprt);
 626                         svc_xprt_put(xprt);
 627                 }
 628         }
 629 }
 630 
 631 static int svc_alloc_arg(struct svc_rqst *rqstp)
 632 {
 633         struct svc_serv *serv = rqstp->rq_server;
 634         struct xdr_buf *arg;
 635         int pages;
 636         int i;
 637 
 638         /* now allocate needed pages.  If we get a failure, sleep briefly */
 639         pages = (serv->sv_max_mesg + 2 * PAGE_SIZE) >> PAGE_SHIFT;
 640         if (pages > RPCSVC_MAXPAGES) {
 641                 pr_warn_once("svc: warning: pages=%u > RPCSVC_MAXPAGES=%lu\n",
 642                              pages, RPCSVC_MAXPAGES);
 643                 /* use as many pages as possible */
 644                 pages = RPCSVC_MAXPAGES;
 645         }
 646         for (i = 0; i < pages ; i++)
 647                 while (rqstp->rq_pages[i] == NULL) {
 648                         struct page *p = alloc_page(GFP_KERNEL);
 649                         if (!p) {
 650                                 set_current_state(TASK_INTERRUPTIBLE);
 651                                 if (signalled() || kthread_should_stop()) {
 652                                         set_current_state(TASK_RUNNING);
 653                                         return -EINTR;
 654                                 }
 655                                 schedule_timeout(msecs_to_jiffies(500));
 656                         }
 657                         rqstp->rq_pages[i] = p;
 658                 }
 659         rqstp->rq_page_end = &rqstp->rq_pages[i];
 660         rqstp->rq_pages[i++] = NULL; /* this might be seen in nfs_read_actor */
 661 
 662         /* Make arg->head point to first page and arg->pages point to rest */
 663         arg = &rqstp->rq_arg;
 664         arg->head[0].iov_base = page_address(rqstp->rq_pages[0]);
 665         arg->head[0].iov_len = PAGE_SIZE;
 666         arg->pages = rqstp->rq_pages + 1;
 667         arg->page_base = 0;
 668         /* save at least one page for response */
 669         arg->page_len = (pages-2)*PAGE_SIZE;
 670         arg->len = (pages-1)*PAGE_SIZE;
 671         arg->tail[0].iov_len = 0;
 672         return 0;
 673 }
 674 
 675 static bool
 676 rqst_should_sleep(struct svc_rqst *rqstp)
 677 {
 678         struct svc_pool         *pool = rqstp->rq_pool;
 679 
 680         /* did someone call svc_wake_up? */
 681         if (test_and_clear_bit(SP_TASK_PENDING, &pool->sp_flags))
 682                 return false;
 683 
 684         /* was a socket queued? */
 685         if (!list_empty(&pool->sp_sockets))
 686                 return false;
 687 
 688         /* are we shutting down? */
 689         if (signalled() || kthread_should_stop())
 690                 return false;
 691 
 692         /* are we freezing? */
 693         if (freezing(current))
 694                 return false;
 695 
 696         return true;
 697 }
 698 
 699 static struct svc_xprt *svc_get_next_xprt(struct svc_rqst *rqstp, long timeout)
 700 {
 701         struct svc_pool         *pool = rqstp->rq_pool;
 702         long                    time_left = 0;
 703 
 704         /* rq_xprt should be clear on entry */
 705         WARN_ON_ONCE(rqstp->rq_xprt);
 706 
 707         rqstp->rq_xprt = svc_xprt_dequeue(pool);
 708         if (rqstp->rq_xprt)
 709                 goto out_found;
 710 
 711         /*
 712          * We have to be able to interrupt this wait
 713          * to bring down the daemons ...
 714          */
 715         set_current_state(TASK_INTERRUPTIBLE);
 716         smp_mb__before_atomic();
 717         clear_bit(SP_CONGESTED, &pool->sp_flags);
 718         clear_bit(RQ_BUSY, &rqstp->rq_flags);
 719         smp_mb__after_atomic();
 720 
 721         if (likely(rqst_should_sleep(rqstp)))
 722                 time_left = schedule_timeout(timeout);
 723         else
 724                 __set_current_state(TASK_RUNNING);
 725 
 726         try_to_freeze();
 727 
 728         set_bit(RQ_BUSY, &rqstp->rq_flags);
 729         smp_mb__after_atomic();
 730         rqstp->rq_xprt = svc_xprt_dequeue(pool);
 731         if (rqstp->rq_xprt)
 732                 goto out_found;
 733 
 734         if (!time_left)
 735                 atomic_long_inc(&pool->sp_stats.threads_timedout);
 736 
 737         if (signalled() || kthread_should_stop())
 738                 return ERR_PTR(-EINTR);
 739         return ERR_PTR(-EAGAIN);
 740 out_found:
 741         /* Normally we will wait up to 5 seconds for any required
 742          * cache information to be provided.
 743          */
 744         if (!test_bit(SP_CONGESTED, &pool->sp_flags))
 745                 rqstp->rq_chandle.thread_wait = 5*HZ;
 746         else
 747                 rqstp->rq_chandle.thread_wait = 1*HZ;
 748         trace_svc_xprt_dequeue(rqstp);
 749         return rqstp->rq_xprt;
 750 }
 751 
 752 static void svc_add_new_temp_xprt(struct svc_serv *serv, struct svc_xprt *newxpt)
 753 {
 754         spin_lock_bh(&serv->sv_lock);
 755         set_bit(XPT_TEMP, &newxpt->xpt_flags);
 756         list_add(&newxpt->xpt_list, &serv->sv_tempsocks);
 757         serv->sv_tmpcnt++;
 758         if (serv->sv_temptimer.function == NULL) {
 759                 /* setup timer to age temp transports */
 760                 serv->sv_temptimer.function = svc_age_temp_xprts;
 761                 mod_timer(&serv->sv_temptimer,
 762                           jiffies + svc_conn_age_period * HZ);
 763         }
 764         spin_unlock_bh(&serv->sv_lock);
 765         svc_xprt_received(newxpt);
 766 }
 767 
 768 static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
 769 {
 770         struct svc_serv *serv = rqstp->rq_server;
 771         int len = 0;
 772 
 773         if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) {
 774                 dprintk("svc_recv: found XPT_CLOSE\n");
 775                 if (test_and_clear_bit(XPT_KILL_TEMP, &xprt->xpt_flags))
 776                         xprt->xpt_ops->xpo_kill_temp_xprt(xprt);
 777                 svc_delete_xprt(xprt);
 778                 /* Leave XPT_BUSY set on the dead xprt: */
 779                 goto out;
 780         }
 781         if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) {
 782                 struct svc_xprt *newxpt;
 783                 /*
 784                  * We know this module_get will succeed because the
 785                  * listener holds a reference too
 786                  */
 787                 __module_get(xprt->xpt_class->xcl_owner);
 788                 svc_check_conn_limits(xprt->xpt_server);
 789                 newxpt = xprt->xpt_ops->xpo_accept(xprt);
 790                 if (newxpt) {
 791                         newxpt->xpt_cred = get_cred(xprt->xpt_cred);
 792                         svc_add_new_temp_xprt(serv, newxpt);
 793                 } else
 794                         module_put(xprt->xpt_class->xcl_owner);
 795         } else if (svc_xprt_reserve_slot(rqstp, xprt)) {
 796                 /* XPT_DATA|XPT_DEFERRED case: */
 797                 dprintk("svc: server %p, pool %u, transport %p, inuse=%d\n",
 798                         rqstp, rqstp->rq_pool->sp_id, xprt,
 799                         kref_read(&xprt->xpt_ref));
 800                 rqstp->rq_deferred = svc_deferred_dequeue(xprt);
 801                 if (rqstp->rq_deferred)
 802                         len = svc_deferred_recv(rqstp);
 803                 else
 804                         len = xprt->xpt_ops->xpo_recvfrom(rqstp);
 805                 rqstp->rq_stime = ktime_get();
 806                 rqstp->rq_reserved = serv->sv_max_mesg;
 807                 atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
 808         }
 809         /* clear XPT_BUSY: */
 810         svc_xprt_received(xprt);
 811 out:
 812         trace_svc_handle_xprt(xprt, len);
 813         return len;
 814 }
 815 
 816 /*
 817  * Receive the next request on any transport.  This code is carefully
 818  * organised not to touch any cachelines in the shared svc_serv
 819  * structure, only cachelines in the local svc_pool.
 820  */
 821 int svc_recv(struct svc_rqst *rqstp, long timeout)
 822 {
 823         struct svc_xprt         *xprt = NULL;
 824         struct svc_serv         *serv = rqstp->rq_server;
 825         int                     len, err;
 826 
 827         dprintk("svc: server %p waiting for data (to = %ld)\n",
 828                 rqstp, timeout);
 829 
 830         if (rqstp->rq_xprt)
 831                 printk(KERN_ERR
 832                         "svc_recv: service %p, transport not NULL!\n",
 833                          rqstp);
 834 
 835         err = svc_alloc_arg(rqstp);
 836         if (err)
 837                 goto out;
 838 
 839         try_to_freeze();
 840         cond_resched();
 841         err = -EINTR;
 842         if (signalled() || kthread_should_stop())
 843                 goto out;
 844 
 845         xprt = svc_get_next_xprt(rqstp, timeout);
 846         if (IS_ERR(xprt)) {
 847                 err = PTR_ERR(xprt);
 848                 goto out;
 849         }
 850 
 851         len = svc_handle_xprt(rqstp, xprt);
 852 
 853         /* No data, incomplete (TCP) read, or accept() */
 854         err = -EAGAIN;
 855         if (len <= 0)
 856                 goto out_release;
 857 
 858         clear_bit(XPT_OLD, &xprt->xpt_flags);
 859 
 860         xprt->xpt_ops->xpo_secure_port(rqstp);
 861         rqstp->rq_chandle.defer = svc_defer;
 862         rqstp->rq_xid = svc_getu32(&rqstp->rq_arg.head[0]);
 863 
 864         if (serv->sv_stats)
 865                 serv->sv_stats->netcnt++;
 866         trace_svc_recv(rqstp, len);
 867         return len;
 868 out_release:
 869         rqstp->rq_res.len = 0;
 870         svc_xprt_release(rqstp);
 871 out:
 872         return err;
 873 }
 874 EXPORT_SYMBOL_GPL(svc_recv);
 875 
 876 /*
 877  * Drop request
 878  */
 879 void svc_drop(struct svc_rqst *rqstp)
 880 {
 881         trace_svc_drop(rqstp);
 882         dprintk("svc: xprt %p dropped request\n", rqstp->rq_xprt);
 883         svc_xprt_release(rqstp);
 884 }
 885 EXPORT_SYMBOL_GPL(svc_drop);
 886 
 887 /*
 888  * Return reply to client.
 889  */
 890 int svc_send(struct svc_rqst *rqstp)
 891 {
 892         struct svc_xprt *xprt;
 893         int             len = -EFAULT;
 894         struct xdr_buf  *xb;
 895 
 896         xprt = rqstp->rq_xprt;
 897         if (!xprt)
 898                 goto out;
 899 
 900         /* calculate over-all length */
 901         xb = &rqstp->rq_res;
 902         xb->len = xb->head[0].iov_len +
 903                 xb->page_len +
 904                 xb->tail[0].iov_len;
 905 
 906         /* Grab mutex to serialize outgoing data. */
 907         mutex_lock(&xprt->xpt_mutex);
 908         trace_svc_stats_latency(rqstp);
 909         if (test_bit(XPT_DEAD, &xprt->xpt_flags)
 910                         || test_bit(XPT_CLOSE, &xprt->xpt_flags))
 911                 len = -ENOTCONN;
 912         else
 913                 len = xprt->xpt_ops->xpo_sendto(rqstp);
 914         mutex_unlock(&xprt->xpt_mutex);
 915         trace_svc_send(rqstp, len);
 916         svc_xprt_release(rqstp);
 917 
 918         if (len == -ECONNREFUSED || len == -ENOTCONN || len == -EAGAIN)
 919                 len = 0;
 920 out:
 921         return len;
 922 }
 923 
 924 /*
 925  * Timer function to close old temporary transports, using
 926  * a mark-and-sweep algorithm.
 927  */
 928 static void svc_age_temp_xprts(struct timer_list *t)
 929 {
 930         struct svc_serv *serv = from_timer(serv, t, sv_temptimer);
 931         struct svc_xprt *xprt;
 932         struct list_head *le, *next;
 933 
 934         dprintk("svc_age_temp_xprts\n");
 935 
 936         if (!spin_trylock_bh(&serv->sv_lock)) {
 937                 /* busy, try again 1 sec later */
 938                 dprintk("svc_age_temp_xprts: busy\n");
 939                 mod_timer(&serv->sv_temptimer, jiffies + HZ);
 940                 return;
 941         }
 942 
 943         list_for_each_safe(le, next, &serv->sv_tempsocks) {
 944                 xprt = list_entry(le, struct svc_xprt, xpt_list);
 945 
 946                 /* First time through, just mark it OLD. Second time
 947                  * through, close it. */
 948                 if (!test_and_set_bit(XPT_OLD, &xprt->xpt_flags))
 949                         continue;
 950                 if (kref_read(&xprt->xpt_ref) > 1 ||
 951                     test_bit(XPT_BUSY, &xprt->xpt_flags))
 952                         continue;
 953                 list_del_init(le);
 954                 set_bit(XPT_CLOSE, &xprt->xpt_flags);
 955                 dprintk("queuing xprt %p for closing\n", xprt);
 956 
 957                 /* a thread will dequeue and close it soon */
 958                 svc_xprt_enqueue(xprt);
 959         }
 960         spin_unlock_bh(&serv->sv_lock);
 961 
 962         mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ);
 963 }
 964 
 965 /* Close temporary transports whose xpt_local matches server_addr immediately
 966  * instead of waiting for them to be picked up by the timer.
 967  *
 968  * This is meant to be called from a notifier_block that runs when an ip
 969  * address is deleted.
 970  */
 971 void svc_age_temp_xprts_now(struct svc_serv *serv, struct sockaddr *server_addr)
 972 {
 973         struct svc_xprt *xprt;
 974         struct list_head *le, *next;
 975         LIST_HEAD(to_be_closed);
 976 
 977         spin_lock_bh(&serv->sv_lock);
 978         list_for_each_safe(le, next, &serv->sv_tempsocks) {
 979                 xprt = list_entry(le, struct svc_xprt, xpt_list);
 980                 if (rpc_cmp_addr(server_addr, (struct sockaddr *)
 981                                 &xprt->xpt_local)) {
 982                         dprintk("svc_age_temp_xprts_now: found %p\n", xprt);
 983                         list_move(le, &to_be_closed);
 984                 }
 985         }
 986         spin_unlock_bh(&serv->sv_lock);
 987 
 988         while (!list_empty(&to_be_closed)) {
 989                 le = to_be_closed.next;
 990                 list_del_init(le);
 991                 xprt = list_entry(le, struct svc_xprt, xpt_list);
 992                 set_bit(XPT_CLOSE, &xprt->xpt_flags);
 993                 set_bit(XPT_KILL_TEMP, &xprt->xpt_flags);
 994                 dprintk("svc_age_temp_xprts_now: queuing xprt %p for closing\n",
 995                                 xprt);
 996                 svc_xprt_enqueue(xprt);
 997         }
 998 }
 999 EXPORT_SYMBOL_GPL(svc_age_temp_xprts_now);
1000 
1001 static void call_xpt_users(struct svc_xprt *xprt)
1002 {
1003         struct svc_xpt_user *u;
1004 
1005         spin_lock(&xprt->xpt_lock);
1006         while (!list_empty(&xprt->xpt_users)) {
1007                 u = list_first_entry(&xprt->xpt_users, struct svc_xpt_user, list);
1008                 list_del_init(&u->list);
1009                 u->callback(u);
1010         }
1011         spin_unlock(&xprt->xpt_lock);
1012 }
1013 
1014 /*
1015  * Remove a dead transport
1016  */
1017 static void svc_delete_xprt(struct svc_xprt *xprt)
1018 {
1019         struct svc_serv *serv = xprt->xpt_server;
1020         struct svc_deferred_req *dr;
1021 
1022         /* Only do this once */
1023         if (test_and_set_bit(XPT_DEAD, &xprt->xpt_flags))
1024                 BUG();
1025 
1026         dprintk("svc: svc_delete_xprt(%p)\n", xprt);
1027         xprt->xpt_ops->xpo_detach(xprt);
1028         if (xprt->xpt_bc_xprt)
1029                 xprt->xpt_bc_xprt->ops->close(xprt->xpt_bc_xprt);
1030 
1031         spin_lock_bh(&serv->sv_lock);
1032         list_del_init(&xprt->xpt_list);
1033         WARN_ON_ONCE(!list_empty(&xprt->xpt_ready));
1034         if (test_bit(XPT_TEMP, &xprt->xpt_flags))
1035                 serv->sv_tmpcnt--;
1036         spin_unlock_bh(&serv->sv_lock);
1037 
1038         while ((dr = svc_deferred_dequeue(xprt)) != NULL)
1039                 kfree(dr);
1040 
1041         call_xpt_users(xprt);
1042         svc_xprt_put(xprt);
1043 }
1044 
1045 void svc_close_xprt(struct svc_xprt *xprt)
1046 {
1047         set_bit(XPT_CLOSE, &xprt->xpt_flags);
1048         if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
1049                 /* someone else will have to effect the close */
1050                 return;
1051         /*
1052          * We expect svc_close_xprt() to work even when no threads are
1053          * running (e.g., while configuring the server before starting
1054          * any threads), so if the transport isn't busy, we delete
1055          * it ourself:
1056          */
1057         svc_delete_xprt(xprt);
1058 }
1059 EXPORT_SYMBOL_GPL(svc_close_xprt);
1060 
1061 static int svc_close_list(struct svc_serv *serv, struct list_head *xprt_list, struct net *net)
1062 {
1063         struct svc_xprt *xprt;
1064         int ret = 0;
1065 
1066         spin_lock(&serv->sv_lock);
1067         list_for_each_entry(xprt, xprt_list, xpt_list) {
1068                 if (xprt->xpt_net != net)
1069                         continue;
1070                 ret++;
1071                 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1072                 svc_xprt_enqueue(xprt);
1073         }
1074         spin_unlock(&serv->sv_lock);
1075         return ret;
1076 }
1077 
1078 static struct svc_xprt *svc_dequeue_net(struct svc_serv *serv, struct net *net)
1079 {
1080         struct svc_pool *pool;
1081         struct svc_xprt *xprt;
1082         struct svc_xprt *tmp;
1083         int i;
1084 
1085         for (i = 0; i < serv->sv_nrpools; i++) {
1086                 pool = &serv->sv_pools[i];
1087 
1088                 spin_lock_bh(&pool->sp_lock);
1089                 list_for_each_entry_safe(xprt, tmp, &pool->sp_sockets, xpt_ready) {
1090                         if (xprt->xpt_net != net)
1091                                 continue;
1092                         list_del_init(&xprt->xpt_ready);
1093                         spin_unlock_bh(&pool->sp_lock);
1094                         return xprt;
1095                 }
1096                 spin_unlock_bh(&pool->sp_lock);
1097         }
1098         return NULL;
1099 }
1100 
1101 static void svc_clean_up_xprts(struct svc_serv *serv, struct net *net)
1102 {
1103         struct svc_xprt *xprt;
1104 
1105         while ((xprt = svc_dequeue_net(serv, net))) {
1106                 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1107                 svc_delete_xprt(xprt);
1108         }
1109 }
1110 
1111 /*
1112  * Server threads may still be running (especially in the case where the
1113  * service is still running in other network namespaces).
1114  *
1115  * So we shut down sockets the same way we would on a running server, by
1116  * setting XPT_CLOSE, enqueuing, and letting a thread pick it up to do
1117  * the close.  In the case there are no such other threads,
1118  * threads running, svc_clean_up_xprts() does a simple version of a
1119  * server's main event loop, and in the case where there are other
1120  * threads, we may need to wait a little while and then check again to
1121  * see if they're done.
1122  */
1123 void svc_close_net(struct svc_serv *serv, struct net *net)
1124 {
1125         int delay = 0;
1126 
1127         while (svc_close_list(serv, &serv->sv_permsocks, net) +
1128                svc_close_list(serv, &serv->sv_tempsocks, net)) {
1129 
1130                 svc_clean_up_xprts(serv, net);
1131                 msleep(delay++);
1132         }
1133 }
1134 
1135 /*
1136  * Handle defer and revisit of requests
1137  */
1138 
1139 static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
1140 {
1141         struct svc_deferred_req *dr =
1142                 container_of(dreq, struct svc_deferred_req, handle);
1143         struct svc_xprt *xprt = dr->xprt;
1144 
1145         spin_lock(&xprt->xpt_lock);
1146         set_bit(XPT_DEFERRED, &xprt->xpt_flags);
1147         if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) {
1148                 spin_unlock(&xprt->xpt_lock);
1149                 dprintk("revisit canceled\n");
1150                 svc_xprt_put(xprt);
1151                 trace_svc_drop_deferred(dr);
1152                 kfree(dr);
1153                 return;
1154         }
1155         dprintk("revisit queued\n");
1156         dr->xprt = NULL;
1157         list_add(&dr->handle.recent, &xprt->xpt_deferred);
1158         spin_unlock(&xprt->xpt_lock);
1159         svc_xprt_enqueue(xprt);
1160         svc_xprt_put(xprt);
1161 }
1162 
1163 /*
1164  * Save the request off for later processing. The request buffer looks
1165  * like this:
1166  *
1167  * <xprt-header><rpc-header><rpc-pagelist><rpc-tail>
1168  *
1169  * This code can only handle requests that consist of an xprt-header
1170  * and rpc-header.
1171  */
1172 static struct cache_deferred_req *svc_defer(struct cache_req *req)
1173 {
1174         struct svc_rqst *rqstp = container_of(req, struct svc_rqst, rq_chandle);
1175         struct svc_deferred_req *dr;
1176 
1177         if (rqstp->rq_arg.page_len || !test_bit(RQ_USEDEFERRAL, &rqstp->rq_flags))
1178                 return NULL; /* if more than a page, give up FIXME */
1179         if (rqstp->rq_deferred) {
1180                 dr = rqstp->rq_deferred;
1181                 rqstp->rq_deferred = NULL;
1182         } else {
1183                 size_t skip;
1184                 size_t size;
1185                 /* FIXME maybe discard if size too large */
1186                 size = sizeof(struct svc_deferred_req) + rqstp->rq_arg.len;
1187                 dr = kmalloc(size, GFP_KERNEL);
1188                 if (dr == NULL)
1189                         return NULL;
1190 
1191                 dr->handle.owner = rqstp->rq_server;
1192                 dr->prot = rqstp->rq_prot;
1193                 memcpy(&dr->addr, &rqstp->rq_addr, rqstp->rq_addrlen);
1194                 dr->addrlen = rqstp->rq_addrlen;
1195                 dr->daddr = rqstp->rq_daddr;
1196                 dr->argslen = rqstp->rq_arg.len >> 2;
1197                 dr->xprt_hlen = rqstp->rq_xprt_hlen;
1198 
1199                 /* back up head to the start of the buffer and copy */
1200                 skip = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len;
1201                 memcpy(dr->args, rqstp->rq_arg.head[0].iov_base - skip,
1202                        dr->argslen << 2);
1203         }
1204         svc_xprt_get(rqstp->rq_xprt);
1205         dr->xprt = rqstp->rq_xprt;
1206         set_bit(RQ_DROPME, &rqstp->rq_flags);
1207 
1208         dr->handle.revisit = svc_revisit;
1209         trace_svc_defer(rqstp);
1210         return &dr->handle;
1211 }
1212 
1213 /*
1214  * recv data from a deferred request into an active one
1215  */
1216 static int svc_deferred_recv(struct svc_rqst *rqstp)
1217 {
1218         struct svc_deferred_req *dr = rqstp->rq_deferred;
1219 
1220         /* setup iov_base past transport header */
1221         rqstp->rq_arg.head[0].iov_base = dr->args + (dr->xprt_hlen>>2);
1222         /* The iov_len does not include the transport header bytes */
1223         rqstp->rq_arg.head[0].iov_len = (dr->argslen<<2) - dr->xprt_hlen;
1224         rqstp->rq_arg.page_len = 0;
1225         /* The rq_arg.len includes the transport header bytes */
1226         rqstp->rq_arg.len     = dr->argslen<<2;
1227         rqstp->rq_prot        = dr->prot;
1228         memcpy(&rqstp->rq_addr, &dr->addr, dr->addrlen);
1229         rqstp->rq_addrlen     = dr->addrlen;
1230         /* Save off transport header len in case we get deferred again */
1231         rqstp->rq_xprt_hlen   = dr->xprt_hlen;
1232         rqstp->rq_daddr       = dr->daddr;
1233         rqstp->rq_respages    = rqstp->rq_pages;
1234         return (dr->argslen<<2) - dr->xprt_hlen;
1235 }
1236 
1237 
1238 static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt)
1239 {
1240         struct svc_deferred_req *dr = NULL;
1241 
1242         if (!test_bit(XPT_DEFERRED, &xprt->xpt_flags))
1243                 return NULL;
1244         spin_lock(&xprt->xpt_lock);
1245         if (!list_empty(&xprt->xpt_deferred)) {
1246                 dr = list_entry(xprt->xpt_deferred.next,
1247                                 struct svc_deferred_req,
1248                                 handle.recent);
1249                 list_del_init(&dr->handle.recent);
1250                 trace_svc_revisit_deferred(dr);
1251         } else
1252                 clear_bit(XPT_DEFERRED, &xprt->xpt_flags);
1253         spin_unlock(&xprt->xpt_lock);
1254         return dr;
1255 }
1256 
1257 /**
1258  * svc_find_xprt - find an RPC transport instance
1259  * @serv: pointer to svc_serv to search
1260  * @xcl_name: C string containing transport's class name
1261  * @net: owner net pointer
1262  * @af: Address family of transport's local address
1263  * @port: transport's IP port number
1264  *
1265  * Return the transport instance pointer for the endpoint accepting
1266  * connections/peer traffic from the specified transport class,
1267  * address family and port.
1268  *
1269  * Specifying 0 for the address family or port is effectively a
1270  * wild-card, and will result in matching the first transport in the
1271  * service's list that has a matching class name.
1272  */
1273 struct svc_xprt *svc_find_xprt(struct svc_serv *serv, const char *xcl_name,
1274                                struct net *net, const sa_family_t af,
1275                                const unsigned short port)
1276 {
1277         struct svc_xprt *xprt;
1278         struct svc_xprt *found = NULL;
1279 
1280         /* Sanity check the args */
1281         if (serv == NULL || xcl_name == NULL)
1282                 return found;
1283 
1284         spin_lock_bh(&serv->sv_lock);
1285         list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1286                 if (xprt->xpt_net != net)
1287                         continue;
1288                 if (strcmp(xprt->xpt_class->xcl_name, xcl_name))
1289                         continue;
1290                 if (af != AF_UNSPEC && af != xprt->xpt_local.ss_family)
1291                         continue;
1292                 if (port != 0 && port != svc_xprt_local_port(xprt))
1293                         continue;
1294                 found = xprt;
1295                 svc_xprt_get(xprt);
1296                 break;
1297         }
1298         spin_unlock_bh(&serv->sv_lock);
1299         return found;
1300 }
1301 EXPORT_SYMBOL_GPL(svc_find_xprt);
1302 
1303 static int svc_one_xprt_name(const struct svc_xprt *xprt,
1304                              char *pos, int remaining)
1305 {
1306         int len;
1307 
1308         len = snprintf(pos, remaining, "%s %u\n",
1309                         xprt->xpt_class->xcl_name,
1310                         svc_xprt_local_port(xprt));
1311         if (len >= remaining)
1312                 return -ENAMETOOLONG;
1313         return len;
1314 }
1315 
1316 /**
1317  * svc_xprt_names - format a buffer with a list of transport names
1318  * @serv: pointer to an RPC service
1319  * @buf: pointer to a buffer to be filled in
1320  * @buflen: length of buffer to be filled in
1321  *
1322  * Fills in @buf with a string containing a list of transport names,
1323  * each name terminated with '\n'.
1324  *
1325  * Returns positive length of the filled-in string on success; otherwise
1326  * a negative errno value is returned if an error occurs.
1327  */
1328 int svc_xprt_names(struct svc_serv *serv, char *buf, const int buflen)
1329 {
1330         struct svc_xprt *xprt;
1331         int len, totlen;
1332         char *pos;
1333 
1334         /* Sanity check args */
1335         if (!serv)
1336                 return 0;
1337 
1338         spin_lock_bh(&serv->sv_lock);
1339 
1340         pos = buf;
1341         totlen = 0;
1342         list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1343                 len = svc_one_xprt_name(xprt, pos, buflen - totlen);
1344                 if (len < 0) {
1345                         *buf = '\0';
1346                         totlen = len;
1347                 }
1348                 if (len <= 0)
1349                         break;
1350 
1351                 pos += len;
1352                 totlen += len;
1353         }
1354 
1355         spin_unlock_bh(&serv->sv_lock);
1356         return totlen;
1357 }
1358 EXPORT_SYMBOL_GPL(svc_xprt_names);
1359 
1360 
1361 /*----------------------------------------------------------------------------*/
1362 
1363 static void *svc_pool_stats_start(struct seq_file *m, loff_t *pos)
1364 {
1365         unsigned int pidx = (unsigned int)*pos;
1366         struct svc_serv *serv = m->private;
1367 
1368         dprintk("svc_pool_stats_start, *pidx=%u\n", pidx);
1369 
1370         if (!pidx)
1371                 return SEQ_START_TOKEN;
1372         return (pidx > serv->sv_nrpools ? NULL : &serv->sv_pools[pidx-1]);
1373 }
1374 
1375 static void *svc_pool_stats_next(struct seq_file *m, void *p, loff_t *pos)
1376 {
1377         struct svc_pool *pool = p;
1378         struct svc_serv *serv = m->private;
1379 
1380         dprintk("svc_pool_stats_next, *pos=%llu\n", *pos);
1381 
1382         if (p == SEQ_START_TOKEN) {
1383                 pool = &serv->sv_pools[0];
1384         } else {
1385                 unsigned int pidx = (pool - &serv->sv_pools[0]);
1386                 if (pidx < serv->sv_nrpools-1)
1387                         pool = &serv->sv_pools[pidx+1];
1388                 else
1389                         pool = NULL;
1390         }
1391         ++*pos;
1392         return pool;
1393 }
1394 
1395 static void svc_pool_stats_stop(struct seq_file *m, void *p)
1396 {
1397 }
1398 
1399 static int svc_pool_stats_show(struct seq_file *m, void *p)
1400 {
1401         struct svc_pool *pool = p;
1402 
1403         if (p == SEQ_START_TOKEN) {
1404                 seq_puts(m, "# pool packets-arrived sockets-enqueued threads-woken threads-timedout\n");
1405                 return 0;
1406         }
1407 
1408         seq_printf(m, "%u %lu %lu %lu %lu\n",
1409                 pool->sp_id,
1410                 (unsigned long)atomic_long_read(&pool->sp_stats.packets),
1411                 pool->sp_stats.sockets_queued,
1412                 (unsigned long)atomic_long_read(&pool->sp_stats.threads_woken),
1413                 (unsigned long)atomic_long_read(&pool->sp_stats.threads_timedout));
1414 
1415         return 0;
1416 }
1417 
1418 static const struct seq_operations svc_pool_stats_seq_ops = {
1419         .start  = svc_pool_stats_start,
1420         .next   = svc_pool_stats_next,
1421         .stop   = svc_pool_stats_stop,
1422         .show   = svc_pool_stats_show,
1423 };
1424 
1425 int svc_pool_stats_open(struct svc_serv *serv, struct file *file)
1426 {
1427         int err;
1428 
1429         err = seq_open(file, &svc_pool_stats_seq_ops);
1430         if (!err)
1431                 ((struct seq_file *) file->private_data)->private = serv;
1432         return err;
1433 }
1434 EXPORT_SYMBOL(svc_pool_stats_open);
1435 
1436 /*----------------------------------------------------------------------------*/
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root/net/sunrpc/svc_xprt.c

DEFINITIONS
