~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

TOMOYO Linux Cross Reference
Linux/net/sunrpc/svc_xprt.c

Version: ~ [ linux-5.1-rc1 ] ~ [ linux-5.0.2 ] ~ [ linux-4.20.16 ] ~ [ linux-4.19.29 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.106 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.163 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.176 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.136 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.63 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ linux-2.6.39.4 ] ~ [ linux-2.6.38.8 ] ~ [ linux-2.6.37.6 ] ~ [ linux-2.6.36.4 ] ~ [ linux-2.6.35.14 ] ~ [ linux-2.6.34.15 ] ~ [ linux-2.6.33.20 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  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/addr.h>
 14 #include <linux/sunrpc/stats.h>
 15 #include <linux/sunrpc/svc_xprt.h>
 16 #include <linux/sunrpc/svcsock.h>
 17 #include <linux/sunrpc/xprt.h>
 18 #include <linux/module.h>
 19 #include <linux/netdevice.h>
 20 #include <trace/events/sunrpc.h>
 21 
 22 #define RPCDBG_FACILITY RPCDBG_SVCXPRT
 23 
 24 static unsigned int svc_rpc_per_connection_limit __read_mostly;
 25 module_param(svc_rpc_per_connection_limit, uint, 0644);
 26 
 27 
 28 static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt);
 29 static int svc_deferred_recv(struct svc_rqst *rqstp);
 30 static struct cache_deferred_req *svc_defer(struct cache_req *req);
 31 static void svc_age_temp_xprts(struct timer_list *t);
 32 static void svc_delete_xprt(struct svc_xprt *xprt);
 33 
 34 /* apparently the "standard" is that clients close
 35  * idle connections after 5 minutes, servers after
 36  * 6 minutes
 37  *   http://www.connectathon.org/talks96/nfstcp.pdf
 38  */
 39 static int svc_conn_age_period = 6*60;
 40 
 41 /* List of registered transport classes */
 42 static DEFINE_SPINLOCK(svc_xprt_class_lock);
 43 static LIST_HEAD(svc_xprt_class_list);
 44 
 45 /* SMP locking strategy:
 46  *
 47  *      svc_pool->sp_lock protects most of the fields of that pool.
 48  *      svc_serv->sv_lock protects sv_tempsocks, sv_permsocks, sv_tmpcnt.
 49  *      when both need to be taken (rare), svc_serv->sv_lock is first.
 50  *      The "service mutex" protects svc_serv->sv_nrthread.
 51  *      svc_sock->sk_lock protects the svc_sock->sk_deferred list
 52  *             and the ->sk_info_authunix cache.
 53  *
 54  *      The XPT_BUSY bit in xprt->xpt_flags prevents a transport being
 55  *      enqueued multiply. During normal transport processing this bit
 56  *      is set by svc_xprt_enqueue and cleared by svc_xprt_received.
 57  *      Providers should not manipulate this bit directly.
 58  *
 59  *      Some flags can be set to certain values at any time
 60  *      providing that certain rules are followed:
 61  *
 62  *      XPT_CONN, XPT_DATA:
 63  *              - Can be set or cleared at any time.
 64  *              - After a set, svc_xprt_enqueue must be called to enqueue
 65  *                the transport for processing.
 66  *              - After a clear, the transport must be read/accepted.
 67  *                If this succeeds, it must be set again.
 68  *      XPT_CLOSE:
 69  *              - Can set at any time. It is never cleared.
 70  *      XPT_DEAD:
 71  *              - Can only be set while XPT_BUSY is held which ensures
 72  *                that no other thread will be using the transport or will
 73  *                try to set XPT_DEAD.
 74  */
 75 int svc_reg_xprt_class(struct svc_xprt_class *xcl)
 76 {
 77         struct svc_xprt_class *cl;
 78         int res = -EEXIST;
 79 
 80         dprintk("svc: Adding svc transport class '%s'\n", xcl->xcl_name);
 81 
 82         INIT_LIST_HEAD(&xcl->xcl_list);
 83         spin_lock(&svc_xprt_class_lock);
 84         /* Make sure there isn't already a class with the same name */
 85         list_for_each_entry(cl, &svc_xprt_class_list, xcl_list) {
 86                 if (strcmp(xcl->xcl_name, cl->xcl_name) == 0)
 87                         goto out;
 88         }
 89         list_add_tail(&xcl->xcl_list, &svc_xprt_class_list);
 90         res = 0;
 91 out:
 92         spin_unlock(&svc_xprt_class_lock);
 93         return res;
 94 }
 95 EXPORT_SYMBOL_GPL(svc_reg_xprt_class);
 96 
 97 void svc_unreg_xprt_class(struct svc_xprt_class *xcl)
 98 {
 99         dprintk("svc: Removing svc transport class '%s'\n", xcl->xcl_name);
100         spin_lock(&svc_xprt_class_lock);
101         list_del_init(&xcl->xcl_list);
102         spin_unlock(&svc_xprt_class_lock);
103 }
104 EXPORT_SYMBOL_GPL(svc_unreg_xprt_class);
105 
106 /*
107  * Format the transport list for printing
108  */
109 int svc_print_xprts(char *buf, int maxlen)
110 {
111         struct svc_xprt_class *xcl;
112         char tmpstr[80];
113         int len = 0;
114         buf[0] = '\0';
115 
116         spin_lock(&svc_xprt_class_lock);
117         list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
118                 int slen;
119 
120                 sprintf(tmpstr, "%s %d\n", xcl->xcl_name, xcl->xcl_max_payload);
121                 slen = strlen(tmpstr);
122                 if (len + slen > maxlen)
123                         break;
124                 len += slen;
125                 strcat(buf, tmpstr);
126         }
127         spin_unlock(&svc_xprt_class_lock);
128 
129         return len;
130 }
131 
132 static void svc_xprt_free(struct kref *kref)
133 {
134         struct svc_xprt *xprt =
135                 container_of(kref, struct svc_xprt, xpt_ref);
136         struct module *owner = xprt->xpt_class->xcl_owner;
137         if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags))
138                 svcauth_unix_info_release(xprt);
139         put_net(xprt->xpt_net);
140         /* See comment on corresponding get in xs_setup_bc_tcp(): */
141         if (xprt->xpt_bc_xprt)
142                 xprt_put(xprt->xpt_bc_xprt);
143         if (xprt->xpt_bc_xps)
144                 xprt_switch_put(xprt->xpt_bc_xps);
145         xprt->xpt_ops->xpo_free(xprt);
146         module_put(owner);
147 }
148 
149 void svc_xprt_put(struct svc_xprt *xprt)
150 {
151         kref_put(&xprt->xpt_ref, svc_xprt_free);
152 }
153 EXPORT_SYMBOL_GPL(svc_xprt_put);
154 
155 /*
156  * Called by transport drivers to initialize the transport independent
157  * portion of the transport instance.
158  */
159 void svc_xprt_init(struct net *net, struct svc_xprt_class *xcl,
160                    struct svc_xprt *xprt, struct svc_serv *serv)
161 {
162         memset(xprt, 0, sizeof(*xprt));
163         xprt->xpt_class = xcl;
164         xprt->xpt_ops = xcl->xcl_ops;
165         kref_init(&xprt->xpt_ref);
166         xprt->xpt_server = serv;
167         INIT_LIST_HEAD(&xprt->xpt_list);
168         INIT_LIST_HEAD(&xprt->xpt_ready);
169         INIT_LIST_HEAD(&xprt->xpt_deferred);
170         INIT_LIST_HEAD(&xprt->xpt_users);
171         mutex_init(&xprt->xpt_mutex);
172         spin_lock_init(&xprt->xpt_lock);
173         set_bit(XPT_BUSY, &xprt->xpt_flags);
174         xprt->xpt_net = get_net(net);
175         strcpy(xprt->xpt_remotebuf, "uninitialized");
176 }
177 EXPORT_SYMBOL_GPL(svc_xprt_init);
178 
179 static struct svc_xprt *__svc_xpo_create(struct svc_xprt_class *xcl,
180                                          struct svc_serv *serv,
181                                          struct net *net,
182                                          const int family,
183                                          const unsigned short port,
184                                          int flags)
185 {
186         struct sockaddr_in sin = {
187                 .sin_family             = AF_INET,
188                 .sin_addr.s_addr        = htonl(INADDR_ANY),
189                 .sin_port               = htons(port),
190         };
191 #if IS_ENABLED(CONFIG_IPV6)
192         struct sockaddr_in6 sin6 = {
193                 .sin6_family            = AF_INET6,
194                 .sin6_addr              = IN6ADDR_ANY_INIT,
195                 .sin6_port              = htons(port),
196         };
197 #endif
198         struct sockaddr *sap;
199         size_t len;
200 
201         switch (family) {
202         case PF_INET:
203                 sap = (struct sockaddr *)&sin;
204                 len = sizeof(sin);
205                 break;
206 #if IS_ENABLED(CONFIG_IPV6)
207         case PF_INET6:
208                 sap = (struct sockaddr *)&sin6;
209                 len = sizeof(sin6);
210                 break;
211 #endif
212         default:
213                 return ERR_PTR(-EAFNOSUPPORT);
214         }
215 
216         return xcl->xcl_ops->xpo_create(serv, net, sap, len, flags);
217 }
218 
219 /*
220  * svc_xprt_received conditionally queues the transport for processing
221  * by another thread. The caller must hold the XPT_BUSY bit and must
222  * not thereafter touch transport data.
223  *
224  * Note: XPT_DATA only gets cleared when a read-attempt finds no (or
225  * insufficient) data.
226  */
227 static void svc_xprt_received(struct svc_xprt *xprt)
228 {
229         if (!test_bit(XPT_BUSY, &xprt->xpt_flags)) {
230                 WARN_ONCE(1, "xprt=0x%p already busy!", xprt);
231                 return;
232         }
233 
234         /* As soon as we clear busy, the xprt could be closed and
235          * 'put', so we need a reference to call svc_enqueue_xprt with:
236          */
237         svc_xprt_get(xprt);
238         smp_mb__before_atomic();
239         clear_bit(XPT_BUSY, &xprt->xpt_flags);
240         xprt->xpt_server->sv_ops->svo_enqueue_xprt(xprt);
241         svc_xprt_put(xprt);
242 }
243 
244 void svc_add_new_perm_xprt(struct svc_serv *serv, struct svc_xprt *new)
245 {
246         clear_bit(XPT_TEMP, &new->xpt_flags);
247         spin_lock_bh(&serv->sv_lock);
248         list_add(&new->xpt_list, &serv->sv_permsocks);
249         spin_unlock_bh(&serv->sv_lock);
250         svc_xprt_received(new);
251 }
252 
253 static int _svc_create_xprt(struct svc_serv *serv, const char *xprt_name,
254                             struct net *net, const int family,
255                             const unsigned short port, int flags)
256 {
257         struct svc_xprt_class *xcl;
258 
259         spin_lock(&svc_xprt_class_lock);
260         list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
261                 struct svc_xprt *newxprt;
262                 unsigned short newport;
263 
264                 if (strcmp(xprt_name, xcl->xcl_name))
265                         continue;
266 
267                 if (!try_module_get(xcl->xcl_owner))
268                         goto err;
269 
270                 spin_unlock(&svc_xprt_class_lock);
271                 newxprt = __svc_xpo_create(xcl, serv, net, family, port, flags);
272                 if (IS_ERR(newxprt)) {
273                         module_put(xcl->xcl_owner);
274                         return PTR_ERR(newxprt);
275                 }
276                 svc_add_new_perm_xprt(serv, newxprt);
277                 newport = svc_xprt_local_port(newxprt);
278                 return newport;
279         }
280  err:
281         spin_unlock(&svc_xprt_class_lock);
282         /* This errno is exposed to user space.  Provide a reasonable
283          * perror msg for a bad transport. */
284         return -EPROTONOSUPPORT;
285 }
286 
287 int svc_create_xprt(struct svc_serv *serv, const char *xprt_name,
288                     struct net *net, const int family,
289                     const unsigned short port, int flags)
290 {
291         int err;
292 
293         dprintk("svc: creating transport %s[%d]\n", xprt_name, port);
294         err = _svc_create_xprt(serv, xprt_name, net, family, port, flags);
295         if (err == -EPROTONOSUPPORT) {
296                 request_module("svc%s", xprt_name);
297                 err = _svc_create_xprt(serv, xprt_name, net, family, port, flags);
298         }
299         if (err < 0)
300                 dprintk("svc: transport %s not found, err %d\n",
301                         xprt_name, -err);
302         return err;
303 }
304 EXPORT_SYMBOL_GPL(svc_create_xprt);
305 
306 /*
307  * Copy the local and remote xprt addresses to the rqstp structure
308  */
309 void svc_xprt_copy_addrs(struct svc_rqst *rqstp, struct svc_xprt *xprt)
310 {
311         memcpy(&rqstp->rq_addr, &xprt->xpt_remote, xprt->xpt_remotelen);
312         rqstp->rq_addrlen = xprt->xpt_remotelen;
313 
314         /*
315          * Destination address in request is needed for binding the
316          * source address in RPC replies/callbacks later.
317          */
318         memcpy(&rqstp->rq_daddr, &xprt->xpt_local, xprt->xpt_locallen);
319         rqstp->rq_daddrlen = xprt->xpt_locallen;
320 }
321 EXPORT_SYMBOL_GPL(svc_xprt_copy_addrs);
322 
323 /**
324  * svc_print_addr - Format rq_addr field for printing
325  * @rqstp: svc_rqst struct containing address to print
326  * @buf: target buffer for formatted address
327  * @len: length of target buffer
328  *
329  */
330 char *svc_print_addr(struct svc_rqst *rqstp, char *buf, size_t len)
331 {
332         return __svc_print_addr(svc_addr(rqstp), buf, len);
333 }
334 EXPORT_SYMBOL_GPL(svc_print_addr);
335 
336 static bool svc_xprt_slots_in_range(struct svc_xprt *xprt)
337 {
338         unsigned int limit = svc_rpc_per_connection_limit;
339         int nrqsts = atomic_read(&xprt->xpt_nr_rqsts);
340 
341         return limit == 0 || (nrqsts >= 0 && nrqsts < limit);
342 }
343 
344 static bool svc_xprt_reserve_slot(struct svc_rqst *rqstp, struct svc_xprt *xprt)
345 {
346         if (!test_bit(RQ_DATA, &rqstp->rq_flags)) {
347                 if (!svc_xprt_slots_in_range(xprt))
348                         return false;
349                 atomic_inc(&xprt->xpt_nr_rqsts);
350                 set_bit(RQ_DATA, &rqstp->rq_flags);
351         }
352         return true;
353 }
354 
355 static void svc_xprt_release_slot(struct svc_rqst *rqstp)
356 {
357         struct svc_xprt *xprt = rqstp->rq_xprt;
358         if (test_and_clear_bit(RQ_DATA, &rqstp->rq_flags)) {
359                 atomic_dec(&xprt->xpt_nr_rqsts);
360                 smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */
361                 svc_xprt_enqueue(xprt);
362         }
363 }
364 
365 static bool svc_xprt_ready(struct svc_xprt *xprt)
366 {
367         unsigned long xpt_flags;
368 
369         /*
370          * If another cpu has recently updated xpt_flags,
371          * sk_sock->flags, xpt_reserved, or xpt_nr_rqsts, we need to
372          * know about it; otherwise it's possible that both that cpu and
373          * this one could call svc_xprt_enqueue() without either
374          * svc_xprt_enqueue() recognizing that the conditions below
375          * are satisfied, and we could stall indefinitely:
376          */
377         smp_rmb();
378         xpt_flags = READ_ONCE(xprt->xpt_flags);
379 
380         if (xpt_flags & (BIT(XPT_CONN) | BIT(XPT_CLOSE)))
381                 return true;
382         if (xpt_flags & (BIT(XPT_DATA) | BIT(XPT_DEFERRED))) {
383                 if (xprt->xpt_ops->xpo_has_wspace(xprt) &&
384                     svc_xprt_slots_in_range(xprt))
385                         return true;
386                 trace_svc_xprt_no_write_space(xprt);
387                 return false;
388         }
389         return false;
390 }
391 
392 void svc_xprt_do_enqueue(struct svc_xprt *xprt)
393 {
394         struct svc_pool *pool;
395         struct svc_rqst *rqstp = NULL;
396         int cpu;
397 
398         if (!svc_xprt_ready(xprt))
399                 return;
400 
401         /* Mark transport as busy. It will remain in this state until
402          * the provider calls svc_xprt_received. We update XPT_BUSY
403          * atomically because it also guards against trying to enqueue
404          * the transport twice.
405          */
406         if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
407                 return;
408 
409         cpu = get_cpu();
410         pool = svc_pool_for_cpu(xprt->xpt_server, cpu);
411 
412         atomic_long_inc(&pool->sp_stats.packets);
413 
414         spin_lock_bh(&pool->sp_lock);
415         list_add_tail(&xprt->xpt_ready, &pool->sp_sockets);
416         pool->sp_stats.sockets_queued++;
417         spin_unlock_bh(&pool->sp_lock);
418 
419         /* find a thread for this xprt */
420         rcu_read_lock();
421         list_for_each_entry_rcu(rqstp, &pool->sp_all_threads, rq_all) {
422                 if (test_and_set_bit(RQ_BUSY, &rqstp->rq_flags))
423                         continue;
424                 atomic_long_inc(&pool->sp_stats.threads_woken);
425                 rqstp->rq_qtime = ktime_get();
426                 wake_up_process(rqstp->rq_task);
427                 goto out_unlock;
428         }
429         set_bit(SP_CONGESTED, &pool->sp_flags);
430         rqstp = NULL;
431 out_unlock:
432         rcu_read_unlock();
433         put_cpu();
434         trace_svc_xprt_do_enqueue(xprt, rqstp);
435 }
436 EXPORT_SYMBOL_GPL(svc_xprt_do_enqueue);
437 
438 /*
439  * Queue up a transport with data pending. If there are idle nfsd
440  * processes, wake 'em up.
441  *
442  */
443 void svc_xprt_enqueue(struct svc_xprt *xprt)
444 {
445         if (test_bit(XPT_BUSY, &xprt->xpt_flags))
446                 return;
447         xprt->xpt_server->sv_ops->svo_enqueue_xprt(xprt);
448 }
449 EXPORT_SYMBOL_GPL(svc_xprt_enqueue);
450 
451 /*
452  * Dequeue the first transport, if there is one.
453  */
454 static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool)
455 {
456         struct svc_xprt *xprt = NULL;
457 
458         if (list_empty(&pool->sp_sockets))
459                 goto out;
460 
461         spin_lock_bh(&pool->sp_lock);
462         if (likely(!list_empty(&pool->sp_sockets))) {
463                 xprt = list_first_entry(&pool->sp_sockets,
464                                         struct svc_xprt, xpt_ready);
465                 list_del_init(&xprt->xpt_ready);
466                 svc_xprt_get(xprt);
467         }
468         spin_unlock_bh(&pool->sp_lock);
469 out:
470         return xprt;
471 }
472 
473 /**
474  * svc_reserve - change the space reserved for the reply to a request.
475  * @rqstp:  The request in question
476  * @space: new max space to reserve
477  *
478  * Each request reserves some space on the output queue of the transport
479  * to make sure the reply fits.  This function reduces that reserved
480  * space to be the amount of space used already, plus @space.
481  *
482  */
483 void svc_reserve(struct svc_rqst *rqstp, int space)
484 {
485         struct svc_xprt *xprt = rqstp->rq_xprt;
486 
487         space += rqstp->rq_res.head[0].iov_len;
488 
489         if (xprt && space < rqstp->rq_reserved) {
490                 atomic_sub((rqstp->rq_reserved - space), &xprt->xpt_reserved);
491                 rqstp->rq_reserved = space;
492                 smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */
493                 svc_xprt_enqueue(xprt);
494         }
495 }
496 EXPORT_SYMBOL_GPL(svc_reserve);
497 
498 static void svc_xprt_release(struct svc_rqst *rqstp)
499 {
500         struct svc_xprt *xprt = rqstp->rq_xprt;
501 
502         xprt->xpt_ops->xpo_release_rqst(rqstp);
503 
504         kfree(rqstp->rq_deferred);
505         rqstp->rq_deferred = NULL;
506 
507         svc_free_res_pages(rqstp);
508         rqstp->rq_res.page_len = 0;
509         rqstp->rq_res.page_base = 0;
510 
511         /* Reset response buffer and release
512          * the reservation.
513          * But first, check that enough space was reserved
514          * for the reply, otherwise we have a bug!
515          */
516         if ((rqstp->rq_res.len) >  rqstp->rq_reserved)
517                 printk(KERN_ERR "RPC request reserved %d but used %d\n",
518                        rqstp->rq_reserved,
519                        rqstp->rq_res.len);
520 
521         rqstp->rq_res.head[0].iov_len = 0;
522         svc_reserve(rqstp, 0);
523         svc_xprt_release_slot(rqstp);
524         rqstp->rq_xprt = NULL;
525         svc_xprt_put(xprt);
526 }
527 
528 /*
529  * Some svc_serv's will have occasional work to do, even when a xprt is not
530  * waiting to be serviced. This function is there to "kick" a task in one of
531  * those services so that it can wake up and do that work. Note that we only
532  * bother with pool 0 as we don't need to wake up more than one thread for
533  * this purpose.
534  */
535 void svc_wake_up(struct svc_serv *serv)
536 {
537         struct svc_rqst *rqstp;
538         struct svc_pool *pool;
539 
540         pool = &serv->sv_pools[0];
541 
542         rcu_read_lock();
543         list_for_each_entry_rcu(rqstp, &pool->sp_all_threads, rq_all) {
544                 /* skip any that aren't queued */
545                 if (test_bit(RQ_BUSY, &rqstp->rq_flags))
546                         continue;
547                 rcu_read_unlock();
548                 wake_up_process(rqstp->rq_task);
549                 trace_svc_wake_up(rqstp->rq_task->pid);
550                 return;
551         }
552         rcu_read_unlock();
553 
554         /* No free entries available */
555         set_bit(SP_TASK_PENDING, &pool->sp_flags);
556         smp_wmb();
557         trace_svc_wake_up(0);
558 }
559 EXPORT_SYMBOL_GPL(svc_wake_up);
560 
561 int svc_port_is_privileged(struct sockaddr *sin)
562 {
563         switch (sin->sa_family) {
564         case AF_INET:
565                 return ntohs(((struct sockaddr_in *)sin)->sin_port)
566                         < PROT_SOCK;
567         case AF_INET6:
568                 return ntohs(((struct sockaddr_in6 *)sin)->sin6_port)
569                         < PROT_SOCK;
570         default:
571                 return 0;
572         }
573 }
574 
575 /*
576  * Make sure that we don't have too many active connections. If we have,
577  * something must be dropped. It's not clear what will happen if we allow
578  * "too many" connections, but when dealing with network-facing software,
579  * we have to code defensively. Here we do that by imposing hard limits.
580  *
581  * There's no point in trying to do random drop here for DoS
582  * prevention. The NFS clients does 1 reconnect in 15 seconds. An
583  * attacker can easily beat that.
584  *
585  * The only somewhat efficient mechanism would be if drop old
586  * connections from the same IP first. But right now we don't even
587  * record the client IP in svc_sock.
588  *
589  * single-threaded services that expect a lot of clients will probably
590  * need to set sv_maxconn to override the default value which is based
591  * on the number of threads
592  */
593 static void svc_check_conn_limits(struct svc_serv *serv)
594 {
595         unsigned int limit = serv->sv_maxconn ? serv->sv_maxconn :
596                                 (serv->sv_nrthreads+3) * 20;
597 
598         if (serv->sv_tmpcnt > limit) {
599                 struct svc_xprt *xprt = NULL;
600                 spin_lock_bh(&serv->sv_lock);
601                 if (!list_empty(&serv->sv_tempsocks)) {
602                         /* Try to help the admin */
603                         net_notice_ratelimited("%s: too many open connections, consider increasing the %s\n",
604                                                serv->sv_name, serv->sv_maxconn ?
605                                                "max number of connections" :
606                                                "number of threads");
607                         /*
608                          * Always select the oldest connection. It's not fair,
609                          * but so is life
610                          */
611                         xprt = list_entry(serv->sv_tempsocks.prev,
612                                           struct svc_xprt,
613                                           xpt_list);
614                         set_bit(XPT_CLOSE, &xprt->xpt_flags);
615                         svc_xprt_get(xprt);
616                 }
617                 spin_unlock_bh(&serv->sv_lock);
618 
619                 if (xprt) {
620                         svc_xprt_enqueue(xprt);
621                         svc_xprt_put(xprt);
622                 }
623         }
624 }
625 
626 static int svc_alloc_arg(struct svc_rqst *rqstp)
627 {
628         struct svc_serv *serv = rqstp->rq_server;
629         struct xdr_buf *arg;
630         int pages;
631         int i;
632 
633         /* now allocate needed pages.  If we get a failure, sleep briefly */
634         pages = (serv->sv_max_mesg + 2 * PAGE_SIZE) >> PAGE_SHIFT;
635         if (pages > RPCSVC_MAXPAGES) {
636                 pr_warn_once("svc: warning: pages=%u > RPCSVC_MAXPAGES=%lu\n",
637                              pages, RPCSVC_MAXPAGES);
638                 /* use as many pages as possible */
639                 pages = RPCSVC_MAXPAGES;
640         }
641         for (i = 0; i < pages ; i++)
642                 while (rqstp->rq_pages[i] == NULL) {
643                         struct page *p = alloc_page(GFP_KERNEL);
644                         if (!p) {
645                                 set_current_state(TASK_INTERRUPTIBLE);
646                                 if (signalled() || kthread_should_stop()) {
647                                         set_current_state(TASK_RUNNING);
648                                         return -EINTR;
649                                 }
650                                 schedule_timeout(msecs_to_jiffies(500));
651                         }
652                         rqstp->rq_pages[i] = p;
653                 }
654         rqstp->rq_page_end = &rqstp->rq_pages[i];
655         rqstp->rq_pages[i++] = NULL; /* this might be seen in nfs_read_actor */
656 
657         /* Make arg->head point to first page and arg->pages point to rest */
658         arg = &rqstp->rq_arg;
659         arg->head[0].iov_base = page_address(rqstp->rq_pages[0]);
660         arg->head[0].iov_len = PAGE_SIZE;
661         arg->pages = rqstp->rq_pages + 1;
662         arg->page_base = 0;
663         /* save at least one page for response */
664         arg->page_len = (pages-2)*PAGE_SIZE;
665         arg->len = (pages-1)*PAGE_SIZE;
666         arg->tail[0].iov_len = 0;
667         return 0;
668 }
669 
670 static bool
671 rqst_should_sleep(struct svc_rqst *rqstp)
672 {
673         struct svc_pool         *pool = rqstp->rq_pool;
674 
675         /* did someone call svc_wake_up? */
676         if (test_and_clear_bit(SP_TASK_PENDING, &pool->sp_flags))
677                 return false;
678 
679         /* was a socket queued? */
680         if (!list_empty(&pool->sp_sockets))
681                 return false;
682 
683         /* are we shutting down? */
684         if (signalled() || kthread_should_stop())
685                 return false;
686 
687         /* are we freezing? */
688         if (freezing(current))
689                 return false;
690 
691         return true;
692 }
693 
694 static struct svc_xprt *svc_get_next_xprt(struct svc_rqst *rqstp, long timeout)
695 {
696         struct svc_pool         *pool = rqstp->rq_pool;
697         long                    time_left = 0;
698 
699         /* rq_xprt should be clear on entry */
700         WARN_ON_ONCE(rqstp->rq_xprt);
701 
702         rqstp->rq_xprt = svc_xprt_dequeue(pool);
703         if (rqstp->rq_xprt)
704                 goto out_found;
705 
706         /*
707          * We have to be able to interrupt this wait
708          * to bring down the daemons ...
709          */
710         set_current_state(TASK_INTERRUPTIBLE);
711         smp_mb__before_atomic();
712         clear_bit(SP_CONGESTED, &pool->sp_flags);
713         clear_bit(RQ_BUSY, &rqstp->rq_flags);
714         smp_mb__after_atomic();
715 
716         if (likely(rqst_should_sleep(rqstp)))
717                 time_left = schedule_timeout(timeout);
718         else
719                 __set_current_state(TASK_RUNNING);
720 
721         try_to_freeze();
722 
723         set_bit(RQ_BUSY, &rqstp->rq_flags);
724         smp_mb__after_atomic();
725         rqstp->rq_xprt = svc_xprt_dequeue(pool);
726         if (rqstp->rq_xprt)
727                 goto out_found;
728 
729         if (!time_left)
730                 atomic_long_inc(&pool->sp_stats.threads_timedout);
731 
732         if (signalled() || kthread_should_stop())
733                 return ERR_PTR(-EINTR);
734         return ERR_PTR(-EAGAIN);
735 out_found:
736         /* Normally we will wait up to 5 seconds for any required
737          * cache information to be provided.
738          */
739         if (!test_bit(SP_CONGESTED, &pool->sp_flags))
740                 rqstp->rq_chandle.thread_wait = 5*HZ;
741         else
742                 rqstp->rq_chandle.thread_wait = 1*HZ;
743         trace_svc_xprt_dequeue(rqstp);
744         return rqstp->rq_xprt;
745 }
746 
747 static void svc_add_new_temp_xprt(struct svc_serv *serv, struct svc_xprt *newxpt)
748 {
749         spin_lock_bh(&serv->sv_lock);
750         set_bit(XPT_TEMP, &newxpt->xpt_flags);
751         list_add(&newxpt->xpt_list, &serv->sv_tempsocks);
752         serv->sv_tmpcnt++;
753         if (serv->sv_temptimer.function == NULL) {
754                 /* setup timer to age temp transports */
755                 serv->sv_temptimer.function = svc_age_temp_xprts;
756                 mod_timer(&serv->sv_temptimer,
757                           jiffies + svc_conn_age_period * HZ);
758         }
759         spin_unlock_bh(&serv->sv_lock);
760         svc_xprt_received(newxpt);
761 }
762 
763 static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
764 {
765         struct svc_serv *serv = rqstp->rq_server;
766         int len = 0;
767 
768         if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) {
769                 dprintk("svc_recv: found XPT_CLOSE\n");
770                 if (test_and_clear_bit(XPT_KILL_TEMP, &xprt->xpt_flags))
771                         xprt->xpt_ops->xpo_kill_temp_xprt(xprt);
772                 svc_delete_xprt(xprt);
773                 /* Leave XPT_BUSY set on the dead xprt: */
774                 goto out;
775         }
776         if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) {
777                 struct svc_xprt *newxpt;
778                 /*
779                  * We know this module_get will succeed because the
780                  * listener holds a reference too
781                  */
782                 __module_get(xprt->xpt_class->xcl_owner);
783                 svc_check_conn_limits(xprt->xpt_server);
784                 newxpt = xprt->xpt_ops->xpo_accept(xprt);
785                 if (newxpt)
786                         svc_add_new_temp_xprt(serv, newxpt);
787                 else
788                         module_put(xprt->xpt_class->xcl_owner);
789         } else if (svc_xprt_reserve_slot(rqstp, xprt)) {
790                 /* XPT_DATA|XPT_DEFERRED case: */
791                 dprintk("svc: server %p, pool %u, transport %p, inuse=%d\n",
792                         rqstp, rqstp->rq_pool->sp_id, xprt,
793                         kref_read(&xprt->xpt_ref));
794                 rqstp->rq_deferred = svc_deferred_dequeue(xprt);
795                 if (rqstp->rq_deferred)
796                         len = svc_deferred_recv(rqstp);
797                 else
798                         len = xprt->xpt_ops->xpo_recvfrom(rqstp);
799                 rqstp->rq_stime = ktime_get();
800                 rqstp->rq_reserved = serv->sv_max_mesg;
801                 atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
802         }
803         /* clear XPT_BUSY: */
804         svc_xprt_received(xprt);
805 out:
806         trace_svc_handle_xprt(xprt, len);
807         return len;
808 }
809 
810 /*
811  * Receive the next request on any transport.  This code is carefully
812  * organised not to touch any cachelines in the shared svc_serv
813  * structure, only cachelines in the local svc_pool.
814  */
815 int svc_recv(struct svc_rqst *rqstp, long timeout)
816 {
817         struct svc_xprt         *xprt = NULL;
818         struct svc_serv         *serv = rqstp->rq_server;
819         int                     len, err;
820 
821         dprintk("svc: server %p waiting for data (to = %ld)\n",
822                 rqstp, timeout);
823 
824         if (rqstp->rq_xprt)
825                 printk(KERN_ERR
826                         "svc_recv: service %p, transport not NULL!\n",
827                          rqstp);
828 
829         err = svc_alloc_arg(rqstp);
830         if (err)
831                 goto out;
832 
833         try_to_freeze();
834         cond_resched();
835         err = -EINTR;
836         if (signalled() || kthread_should_stop())
837                 goto out;
838 
839         xprt = svc_get_next_xprt(rqstp, timeout);
840         if (IS_ERR(xprt)) {
841                 err = PTR_ERR(xprt);
842                 goto out;
843         }
844 
845         len = svc_handle_xprt(rqstp, xprt);
846 
847         /* No data, incomplete (TCP) read, or accept() */
848         err = -EAGAIN;
849         if (len <= 0)
850                 goto out_release;
851 
852         clear_bit(XPT_OLD, &xprt->xpt_flags);
853 
854         xprt->xpt_ops->xpo_secure_port(rqstp);
855         rqstp->rq_chandle.defer = svc_defer;
856         rqstp->rq_xid = svc_getu32(&rqstp->rq_arg.head[0]);
857 
858         if (serv->sv_stats)
859                 serv->sv_stats->netcnt++;
860         trace_svc_recv(rqstp, len);
861         return len;
862 out_release:
863         rqstp->rq_res.len = 0;
864         svc_xprt_release(rqstp);
865 out:
866         return err;
867 }
868 EXPORT_SYMBOL_GPL(svc_recv);
869 
870 /*
871  * Drop request
872  */
873 void svc_drop(struct svc_rqst *rqstp)
874 {
875         trace_svc_drop(rqstp);
876         dprintk("svc: xprt %p dropped request\n", rqstp->rq_xprt);
877         svc_xprt_release(rqstp);
878 }
879 EXPORT_SYMBOL_GPL(svc_drop);
880 
881 /*
882  * Return reply to client.
883  */
884 int svc_send(struct svc_rqst *rqstp)
885 {
886         struct svc_xprt *xprt;
887         int             len = -EFAULT;
888         struct xdr_buf  *xb;
889 
890         xprt = rqstp->rq_xprt;
891         if (!xprt)
892                 goto out;
893 
894         /* release the receive skb before sending the reply */
895         xprt->xpt_ops->xpo_release_rqst(rqstp);
896 
897         /* calculate over-all length */
898         xb = &rqstp->rq_res;
899         xb->len = xb->head[0].iov_len +
900                 xb->page_len +
901                 xb->tail[0].iov_len;
902 
903         /* Grab mutex to serialize outgoing data. */
904         mutex_lock(&xprt->xpt_mutex);
905         trace_svc_stats_latency(rqstp);
906         if (test_bit(XPT_DEAD, &xprt->xpt_flags)
907                         || test_bit(XPT_CLOSE, &xprt->xpt_flags))
908                 len = -ENOTCONN;
909         else
910                 len = xprt->xpt_ops->xpo_sendto(rqstp);
911         mutex_unlock(&xprt->xpt_mutex);
912         trace_svc_send(rqstp, len);
913         svc_xprt_release(rqstp);
914 
915         if (len == -ECONNREFUSED || len == -ENOTCONN || len == -EAGAIN)
916                 len = 0;
917 out:
918         return len;
919 }
920 
921 /*
922  * Timer function to close old temporary transports, using
923  * a mark-and-sweep algorithm.
924  */
925 static void svc_age_temp_xprts(struct timer_list *t)
926 {
927         struct svc_serv *serv = from_timer(serv, t, sv_temptimer);
928         struct svc_xprt *xprt;
929         struct list_head *le, *next;
930 
931         dprintk("svc_age_temp_xprts\n");
932 
933         if (!spin_trylock_bh(&serv->sv_lock)) {
934                 /* busy, try again 1 sec later */
935                 dprintk("svc_age_temp_xprts: busy\n");
936                 mod_timer(&serv->sv_temptimer, jiffies + HZ);
937                 return;
938         }
939 
940         list_for_each_safe(le, next, &serv->sv_tempsocks) {
941                 xprt = list_entry(le, struct svc_xprt, xpt_list);
942 
943                 /* First time through, just mark it OLD. Second time
944                  * through, close it. */
945                 if (!test_and_set_bit(XPT_OLD, &xprt->xpt_flags))
946                         continue;
947                 if (kref_read(&xprt->xpt_ref) > 1 ||
948                     test_bit(XPT_BUSY, &xprt->xpt_flags))
949                         continue;
950                 list_del_init(le);
951                 set_bit(XPT_CLOSE, &xprt->xpt_flags);
952                 dprintk("queuing xprt %p for closing\n", xprt);
953 
954                 /* a thread will dequeue and close it soon */
955                 svc_xprt_enqueue(xprt);
956         }
957         spin_unlock_bh(&serv->sv_lock);
958 
959         mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ);
960 }
961 
962 /* Close temporary transports whose xpt_local matches server_addr immediately
963  * instead of waiting for them to be picked up by the timer.
964  *
965  * This is meant to be called from a notifier_block that runs when an ip
966  * address is deleted.
967  */
968 void svc_age_temp_xprts_now(struct svc_serv *serv, struct sockaddr *server_addr)
969 {
970         struct svc_xprt *xprt;
971         struct list_head *le, *next;
972         LIST_HEAD(to_be_closed);
973 
974         spin_lock_bh(&serv->sv_lock);
975         list_for_each_safe(le, next, &serv->sv_tempsocks) {
976                 xprt = list_entry(le, struct svc_xprt, xpt_list);
977                 if (rpc_cmp_addr(server_addr, (struct sockaddr *)
978                                 &xprt->xpt_local)) {
979                         dprintk("svc_age_temp_xprts_now: found %p\n", xprt);
980                         list_move(le, &to_be_closed);
981                 }
982         }
983         spin_unlock_bh(&serv->sv_lock);
984 
985         while (!list_empty(&to_be_closed)) {
986                 le = to_be_closed.next;
987                 list_del_init(le);
988                 xprt = list_entry(le, struct svc_xprt, xpt_list);
989                 set_bit(XPT_CLOSE, &xprt->xpt_flags);
990                 set_bit(XPT_KILL_TEMP, &xprt->xpt_flags);
991                 dprintk("svc_age_temp_xprts_now: queuing xprt %p for closing\n",
992                                 xprt);
993                 svc_xprt_enqueue(xprt);
994         }
995 }
996 EXPORT_SYMBOL_GPL(svc_age_temp_xprts_now);
997 
998 static void call_xpt_users(struct svc_xprt *xprt)
999 {
1000         struct svc_xpt_user *u;
1001 
1002         spin_lock(&xprt->xpt_lock);
1003         while (!list_empty(&xprt->xpt_users)) {
1004                 u = list_first_entry(&xprt->xpt_users, struct svc_xpt_user, list);
1005                 list_del_init(&u->list);
1006                 u->callback(u);
1007         }
1008         spin_unlock(&xprt->xpt_lock);
1009 }
1010 
1011 /*
1012  * Remove a dead transport
1013  */
1014 static void svc_delete_xprt(struct svc_xprt *xprt)
1015 {
1016         struct svc_serv *serv = xprt->xpt_server;
1017         struct svc_deferred_req *dr;
1018 
1019         /* Only do this once */
1020         if (test_and_set_bit(XPT_DEAD, &xprt->xpt_flags))
1021                 BUG();
1022 
1023         dprintk("svc: svc_delete_xprt(%p)\n", xprt);
1024         xprt->xpt_ops->xpo_detach(xprt);
1025 
1026         spin_lock_bh(&serv->sv_lock);
1027         list_del_init(&xprt->xpt_list);
1028         WARN_ON_ONCE(!list_empty(&xprt->xpt_ready));
1029         if (test_bit(XPT_TEMP, &xprt->xpt_flags))
1030                 serv->sv_tmpcnt--;
1031         spin_unlock_bh(&serv->sv_lock);
1032 
1033         while ((dr = svc_deferred_dequeue(xprt)) != NULL)
1034                 kfree(dr);
1035 
1036         call_xpt_users(xprt);
1037         svc_xprt_put(xprt);
1038 }
1039 
1040 void svc_close_xprt(struct svc_xprt *xprt)
1041 {
1042         set_bit(XPT_CLOSE, &xprt->xpt_flags);
1043         if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
1044                 /* someone else will have to effect the close */
1045                 return;
1046         /*
1047          * We expect svc_close_xprt() to work even when no threads are
1048          * running (e.g., while configuring the server before starting
1049          * any threads), so if the transport isn't busy, we delete
1050          * it ourself:
1051          */
1052         svc_delete_xprt(xprt);
1053 }
1054 EXPORT_SYMBOL_GPL(svc_close_xprt);
1055 
1056 static int svc_close_list(struct svc_serv *serv, struct list_head *xprt_list, struct net *net)
1057 {
1058         struct svc_xprt *xprt;
1059         int ret = 0;
1060 
1061         spin_lock(&serv->sv_lock);
1062         list_for_each_entry(xprt, xprt_list, xpt_list) {
1063                 if (xprt->xpt_net != net)
1064                         continue;
1065                 ret++;
1066                 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1067                 svc_xprt_enqueue(xprt);
1068         }
1069         spin_unlock(&serv->sv_lock);
1070         return ret;
1071 }
1072 
1073 static struct svc_xprt *svc_dequeue_net(struct svc_serv *serv, struct net *net)
1074 {
1075         struct svc_pool *pool;
1076         struct svc_xprt *xprt;
1077         struct svc_xprt *tmp;
1078         int i;
1079 
1080         for (i = 0; i < serv->sv_nrpools; i++) {
1081                 pool = &serv->sv_pools[i];
1082 
1083                 spin_lock_bh(&pool->sp_lock);
1084                 list_for_each_entry_safe(xprt, tmp, &pool->sp_sockets, xpt_ready) {
1085                         if (xprt->xpt_net != net)
1086                                 continue;
1087                         list_del_init(&xprt->xpt_ready);
1088                         spin_unlock_bh(&pool->sp_lock);
1089                         return xprt;
1090                 }
1091                 spin_unlock_bh(&pool->sp_lock);
1092         }
1093         return NULL;
1094 }
1095 
1096 static void svc_clean_up_xprts(struct svc_serv *serv, struct net *net)
1097 {
1098         struct svc_xprt *xprt;
1099 
1100         while ((xprt = svc_dequeue_net(serv, net))) {
1101                 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1102                 svc_delete_xprt(xprt);
1103         }
1104 }
1105 
1106 /*
1107  * Server threads may still be running (especially in the case where the
1108  * service is still running in other network namespaces).
1109  *
1110  * So we shut down sockets the same way we would on a running server, by
1111  * setting XPT_CLOSE, enqueuing, and letting a thread pick it up to do
1112  * the close.  In the case there are no such other threads,
1113  * threads running, svc_clean_up_xprts() does a simple version of a
1114  * server's main event loop, and in the case where there are other
1115  * threads, we may need to wait a little while and then check again to
1116  * see if they're done.
1117  */
1118 void svc_close_net(struct svc_serv *serv, struct net *net)
1119 {
1120         int delay = 0;
1121 
1122         while (svc_close_list(serv, &serv->sv_permsocks, net) +
1123                svc_close_list(serv, &serv->sv_tempsocks, net)) {
1124 
1125                 svc_clean_up_xprts(serv, net);
1126                 msleep(delay++);
1127         }
1128 }
1129 
1130 /*
1131  * Handle defer and revisit of requests
1132  */
1133 
1134 static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
1135 {
1136         struct svc_deferred_req *dr =
1137                 container_of(dreq, struct svc_deferred_req, handle);
1138         struct svc_xprt *xprt = dr->xprt;
1139 
1140         spin_lock(&xprt->xpt_lock);
1141         set_bit(XPT_DEFERRED, &xprt->xpt_flags);
1142         if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) {
1143                 spin_unlock(&xprt->xpt_lock);
1144                 dprintk("revisit canceled\n");
1145                 svc_xprt_put(xprt);
1146                 trace_svc_drop_deferred(dr);
1147                 kfree(dr);
1148                 return;
1149         }
1150         dprintk("revisit queued\n");
1151         dr->xprt = NULL;
1152         list_add(&dr->handle.recent, &xprt->xpt_deferred);
1153         spin_unlock(&xprt->xpt_lock);
1154         svc_xprt_enqueue(xprt);
1155         svc_xprt_put(xprt);
1156 }
1157 
1158 /*
1159  * Save the request off for later processing. The request buffer looks
1160  * like this:
1161  *
1162  * <xprt-header><rpc-header><rpc-pagelist><rpc-tail>
1163  *
1164  * This code can only handle requests that consist of an xprt-header
1165  * and rpc-header.
1166  */
1167 static struct cache_deferred_req *svc_defer(struct cache_req *req)
1168 {
1169         struct svc_rqst *rqstp = container_of(req, struct svc_rqst, rq_chandle);
1170         struct svc_deferred_req *dr;
1171 
1172         if (rqstp->rq_arg.page_len || !test_bit(RQ_USEDEFERRAL, &rqstp->rq_flags))
1173                 return NULL; /* if more than a page, give up FIXME */
1174         if (rqstp->rq_deferred) {
1175                 dr = rqstp->rq_deferred;
1176                 rqstp->rq_deferred = NULL;
1177         } else {
1178                 size_t skip;
1179                 size_t size;
1180                 /* FIXME maybe discard if size too large */
1181                 size = sizeof(struct svc_deferred_req) + rqstp->rq_arg.len;
1182                 dr = kmalloc(size, GFP_KERNEL);
1183                 if (dr == NULL)
1184                         return NULL;
1185 
1186                 dr->handle.owner = rqstp->rq_server;
1187                 dr->prot = rqstp->rq_prot;
1188                 memcpy(&dr->addr, &rqstp->rq_addr, rqstp->rq_addrlen);
1189                 dr->addrlen = rqstp->rq_addrlen;
1190                 dr->daddr = rqstp->rq_daddr;
1191                 dr->argslen = rqstp->rq_arg.len >> 2;
1192                 dr->xprt_hlen = rqstp->rq_xprt_hlen;
1193 
1194                 /* back up head to the start of the buffer and copy */
1195                 skip = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len;
1196                 memcpy(dr->args, rqstp->rq_arg.head[0].iov_base - skip,
1197                        dr->argslen << 2);
1198         }
1199         svc_xprt_get(rqstp->rq_xprt);
1200         dr->xprt = rqstp->rq_xprt;
1201         set_bit(RQ_DROPME, &rqstp->rq_flags);
1202 
1203         dr->handle.revisit = svc_revisit;
1204         trace_svc_defer(rqstp);
1205         return &dr->handle;
1206 }
1207 
1208 /*
1209  * recv data from a deferred request into an active one
1210  */
1211 static int svc_deferred_recv(struct svc_rqst *rqstp)
1212 {
1213         struct svc_deferred_req *dr = rqstp->rq_deferred;
1214 
1215         /* setup iov_base past transport header */
1216         rqstp->rq_arg.head[0].iov_base = dr->args + (dr->xprt_hlen>>2);
1217         /* The iov_len does not include the transport header bytes */
1218         rqstp->rq_arg.head[0].iov_len = (dr->argslen<<2) - dr->xprt_hlen;
1219         rqstp->rq_arg.page_len = 0;
1220         /* The rq_arg.len includes the transport header bytes */
1221         rqstp->rq_arg.len     = dr->argslen<<2;
1222         rqstp->rq_prot        = dr->prot;
1223         memcpy(&rqstp->rq_addr, &dr->addr, dr->addrlen);
1224         rqstp->rq_addrlen     = dr->addrlen;
1225         /* Save off transport header len in case we get deferred again */
1226         rqstp->rq_xprt_hlen   = dr->xprt_hlen;
1227         rqstp->rq_daddr       = dr->daddr;
1228         rqstp->rq_respages    = rqstp->rq_pages;
1229         return (dr->argslen<<2) - dr->xprt_hlen;
1230 }
1231 
1232 
1233 static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt)
1234 {
1235         struct svc_deferred_req *dr = NULL;
1236 
1237         if (!test_bit(XPT_DEFERRED, &xprt->xpt_flags))
1238                 return NULL;
1239         spin_lock(&xprt->xpt_lock);
1240         if (!list_empty(&xprt->xpt_deferred)) {
1241                 dr = list_entry(xprt->xpt_deferred.next,
1242                                 struct svc_deferred_req,
1243                                 handle.recent);
1244                 list_del_init(&dr->handle.recent);
1245                 trace_svc_revisit_deferred(dr);
1246         } else
1247                 clear_bit(XPT_DEFERRED, &xprt->xpt_flags);
1248         spin_unlock(&xprt->xpt_lock);
1249         return dr;
1250 }
1251 
1252 /**
1253  * svc_find_xprt - find an RPC transport instance
1254  * @serv: pointer to svc_serv to search
1255  * @xcl_name: C string containing transport's class name
1256  * @net: owner net pointer
1257  * @af: Address family of transport's local address
1258  * @port: transport's IP port number
1259  *
1260  * Return the transport instance pointer for the endpoint accepting
1261  * connections/peer traffic from the specified transport class,
1262  * address family and port.
1263  *
1264  * Specifying 0 for the address family or port is effectively a
1265  * wild-card, and will result in matching the first transport in the
1266  * service's list that has a matching class name.
1267  */
1268 struct svc_xprt *svc_find_xprt(struct svc_serv *serv, const char *xcl_name,
1269                                struct net *net, const sa_family_t af,
1270                                const unsigned short port)
1271 {
1272         struct svc_xprt *xprt;
1273         struct svc_xprt *found = NULL;
1274 
1275         /* Sanity check the args */
1276         if (serv == NULL || xcl_name == NULL)
1277                 return found;
1278 
1279         spin_lock_bh(&serv->sv_lock);
1280         list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1281                 if (xprt->xpt_net != net)
1282                         continue;
1283                 if (strcmp(xprt->xpt_class->xcl_name, xcl_name))
1284                         continue;
1285                 if (af != AF_UNSPEC && af != xprt->xpt_local.ss_family)
1286                         continue;
1287                 if (port != 0 && port != svc_xprt_local_port(xprt))
1288                         continue;
1289                 found = xprt;
1290                 svc_xprt_get(xprt);
1291                 break;
1292         }
1293         spin_unlock_bh(&serv->sv_lock);
1294         return found;
1295 }
1296 EXPORT_SYMBOL_GPL(svc_find_xprt);
1297 
1298 static int svc_one_xprt_name(const struct svc_xprt *xprt,
1299                              char *pos, int remaining)
1300 {
1301         int len;
1302 
1303         len = snprintf(pos, remaining, "%s %u\n",
1304                         xprt->xpt_class->xcl_name,
1305                         svc_xprt_local_port(xprt));
1306         if (len >= remaining)
1307                 return -ENAMETOOLONG;
1308         return len;
1309 }
1310 
1311 /**
1312  * svc_xprt_names - format a buffer with a list of transport names
1313  * @serv: pointer to an RPC service
1314  * @buf: pointer to a buffer to be filled in
1315  * @buflen: length of buffer to be filled in
1316  *
1317  * Fills in @buf with a string containing a list of transport names,
1318  * each name terminated with '\n'.
1319  *
1320  * Returns positive length of the filled-in string on success; otherwise
1321  * a negative errno value is returned if an error occurs.
1322  */
1323 int svc_xprt_names(struct svc_serv *serv, char *buf, const int buflen)
1324 {
1325         struct svc_xprt *xprt;
1326         int len, totlen;
1327         char *pos;
1328 
1329         /* Sanity check args */
1330         if (!serv)
1331                 return 0;
1332 
1333         spin_lock_bh(&serv->sv_lock);
1334 
1335         pos = buf;
1336         totlen = 0;
1337         list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1338                 len = svc_one_xprt_name(xprt, pos, buflen - totlen);
1339                 if (len < 0) {
1340                         *buf = '\0';
1341                         totlen = len;
1342                 }
1343                 if (len <= 0)
1344                         break;
1345 
1346                 pos += len;
1347                 totlen += len;
1348         }
1349 
1350         spin_unlock_bh(&serv->sv_lock);
1351         return totlen;
1352 }
1353 EXPORT_SYMBOL_GPL(svc_xprt_names);
1354 
1355 
1356 /*----------------------------------------------------------------------------*/
1357 
1358 static void *svc_pool_stats_start(struct seq_file *m, loff_t *pos)
1359 {
1360         unsigned int pidx = (unsigned int)*pos;
1361         struct svc_serv *serv = m->private;
1362 
1363         dprintk("svc_pool_stats_start, *pidx=%u\n", pidx);
1364 
1365         if (!pidx)
1366                 return SEQ_START_TOKEN;
1367         return (pidx > serv->sv_nrpools ? NULL : &serv->sv_pools[pidx-1]);
1368 }
1369 
1370 static void *svc_pool_stats_next(struct seq_file *m, void *p, loff_t *pos)
1371 {
1372         struct svc_pool *pool = p;
1373         struct svc_serv *serv = m->private;
1374 
1375         dprintk("svc_pool_stats_next, *pos=%llu\n", *pos);
1376 
1377         if (p == SEQ_START_TOKEN) {
1378                 pool = &serv->sv_pools[0];
1379         } else {
1380                 unsigned int pidx = (pool - &serv->sv_pools[0]);
1381                 if (pidx < serv->sv_nrpools-1)
1382                         pool = &serv->sv_pools[pidx+1];
1383                 else
1384                         pool = NULL;
1385         }
1386         ++*pos;
1387         return pool;
1388 }
1389 
1390 static void svc_pool_stats_stop(struct seq_file *m, void *p)
1391 {
1392 }
1393 
1394 static int svc_pool_stats_show(struct seq_file *m, void *p)
1395 {
1396         struct svc_pool *pool = p;
1397 
1398         if (p == SEQ_START_TOKEN) {
1399                 seq_puts(m, "# pool packets-arrived sockets-enqueued threads-woken threads-timedout\n");
1400                 return 0;
1401         }
1402 
1403         seq_printf(m, "%u %lu %lu %lu %lu\n",
1404                 pool->sp_id,
1405                 (unsigned long)atomic_long_read(&pool->sp_stats.packets),
1406                 pool->sp_stats.sockets_queued,
1407                 (unsigned long)atomic_long_read(&pool->sp_stats.threads_woken),
1408                 (unsigned long)atomic_long_read(&pool->sp_stats.threads_timedout));
1409 
1410         return 0;
1411 }
1412 
1413 static const struct seq_operations svc_pool_stats_seq_ops = {
1414         .start  = svc_pool_stats_start,
1415         .next   = svc_pool_stats_next,
1416         .stop   = svc_pool_stats_stop,
1417         .show   = svc_pool_stats_show,
1418 };
1419 
1420 int svc_pool_stats_open(struct svc_serv *serv, struct file *file)
1421 {
1422         int err;
1423 
1424         err = seq_open(file, &svc_pool_stats_seq_ops);
1425         if (!err)
1426                 ((struct seq_file *) file->private_data)->private = serv;
1427         return err;
1428 }
1429 EXPORT_SYMBOL(svc_pool_stats_open);
1430 
1431 /*----------------------------------------------------------------------------*/
1432 

~ [ source navigation ] ~ [ diff markup ] ~ [ identifier search ] ~

kernel.org | git.kernel.org | LWN.net | Project Home | Wiki (Japanese) | Wiki (English) | SVN repository | Mail admin

Linux® is a registered trademark of Linus Torvalds in the United States and other countries.
TOMOYO® is a registered trademark of NTT DATA CORPORATION.

osdn.jp