1 // SPDX-License-Identifier: GPL-2.0-only
3 * linux/net/sunrpc/svc_xprt.c
5 * Author: Tom Tucker <tom@opengridcomputing.com>
8 #include <linux/sched.h>
9 #include <linux/sched/mm.h>
10 #include <linux/errno.h>
11 #include <linux/freezer.h>
12 #include <linux/kthread.h>
13 #include <linux/slab.h>
15 #include <linux/sunrpc/addr.h>
16 #include <linux/sunrpc/stats.h>
17 #include <linux/sunrpc/svc_xprt.h>
18 #include <linux/sunrpc/svcsock.h>
19 #include <linux/sunrpc/xprt.h>
20 #include <linux/module.h>
21 #include <linux/netdevice.h>
22 #include <trace/events/sunrpc.h>
24 #define RPCDBG_FACILITY RPCDBG_SVCXPRT
26 static unsigned int svc_rpc_per_connection_limit __read_mostly;
27 module_param(svc_rpc_per_connection_limit, uint, 0644);
30 static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt);
31 static int svc_deferred_recv(struct svc_rqst *rqstp);
32 static struct cache_deferred_req *svc_defer(struct cache_req *req);
33 static void svc_age_temp_xprts(struct timer_list *t);
34 static void svc_delete_xprt(struct svc_xprt *xprt);
36 /* apparently the "standard" is that clients close
37 * idle connections after 5 minutes, servers after
39 * http://nfsv4bat.org/Documents/ConnectAThon/1996/nfstcp.pdf
41 static int svc_conn_age_period = 6*60;
43 /* List of registered transport classes */
44 static DEFINE_SPINLOCK(svc_xprt_class_lock);
45 static LIST_HEAD(svc_xprt_class_list);
47 /* SMP locking strategy:
49 * svc_pool->sp_lock protects most of the fields of that pool.
50 * svc_serv->sv_lock protects sv_tempsocks, sv_permsocks, sv_tmpcnt.
51 * when both need to be taken (rare), svc_serv->sv_lock is first.
52 * The "service mutex" protects svc_serv->sv_nrthread.
53 * svc_sock->sk_lock protects the svc_sock->sk_deferred list
54 * and the ->sk_info_authunix cache.
56 * The XPT_BUSY bit in xprt->xpt_flags prevents a transport being
57 * enqueued multiply. During normal transport processing this bit
58 * is set by svc_xprt_enqueue and cleared by svc_xprt_received.
59 * Providers should not manipulate this bit directly.
61 * Some flags can be set to certain values at any time
62 * providing that certain rules are followed:
65 * - Can be set or cleared at any time.
66 * - After a set, svc_xprt_enqueue must be called to enqueue
67 * the transport for processing.
68 * - After a clear, the transport must be read/accepted.
69 * If this succeeds, it must be set again.
71 * - Can set at any time. It is never cleared.
73 * - Can only be set while XPT_BUSY is held which ensures
74 * that no other thread will be using the transport or will
75 * try to set XPT_DEAD.
79 * svc_reg_xprt_class - Register a server-side RPC transport class
80 * @xcl: New transport class to be registered
82 * Returns zero on success; otherwise a negative errno is returned.
84 int svc_reg_xprt_class(struct svc_xprt_class *xcl)
86 struct svc_xprt_class *cl;
89 INIT_LIST_HEAD(&xcl->xcl_list);
90 spin_lock(&svc_xprt_class_lock);
91 /* Make sure there isn't already a class with the same name */
92 list_for_each_entry(cl, &svc_xprt_class_list, xcl_list) {
93 if (strcmp(xcl->xcl_name, cl->xcl_name) == 0)
96 list_add_tail(&xcl->xcl_list, &svc_xprt_class_list);
99 spin_unlock(&svc_xprt_class_lock);
102 EXPORT_SYMBOL_GPL(svc_reg_xprt_class);
105 * svc_unreg_xprt_class - Unregister a server-side RPC transport class
106 * @xcl: Transport class to be unregistered
109 void svc_unreg_xprt_class(struct svc_xprt_class *xcl)
111 spin_lock(&svc_xprt_class_lock);
112 list_del_init(&xcl->xcl_list);
113 spin_unlock(&svc_xprt_class_lock);
115 EXPORT_SYMBOL_GPL(svc_unreg_xprt_class);
118 * svc_print_xprts - Format the transport list for printing
119 * @buf: target buffer for formatted address
120 * @maxlen: length of target buffer
122 * Fills in @buf with a string containing a list of transport names, each name
123 * terminated with '\n'. If the buffer is too small, some entries may be
124 * missing, but it is guaranteed that all lines in the output buffer are
127 * Returns positive length of the filled-in string.
129 int svc_print_xprts(char *buf, int maxlen)
131 struct svc_xprt_class *xcl;
136 spin_lock(&svc_xprt_class_lock);
137 list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
140 slen = snprintf(tmpstr, sizeof(tmpstr), "%s %d\n",
141 xcl->xcl_name, xcl->xcl_max_payload);
142 if (slen >= sizeof(tmpstr) || len + slen >= maxlen)
147 spin_unlock(&svc_xprt_class_lock);
153 * svc_xprt_deferred_close - Close a transport
154 * @xprt: transport instance
156 * Used in contexts that need to defer the work of shutting down
157 * the transport to an nfsd thread.
159 void svc_xprt_deferred_close(struct svc_xprt *xprt)
161 if (!test_and_set_bit(XPT_CLOSE, &xprt->xpt_flags))
162 svc_xprt_enqueue(xprt);
164 EXPORT_SYMBOL_GPL(svc_xprt_deferred_close);
166 static void svc_xprt_free(struct kref *kref)
168 struct svc_xprt *xprt =
169 container_of(kref, struct svc_xprt, xpt_ref);
170 struct module *owner = xprt->xpt_class->xcl_owner;
171 if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags))
172 svcauth_unix_info_release(xprt);
173 put_cred(xprt->xpt_cred);
174 put_net_track(xprt->xpt_net, &xprt->ns_tracker);
175 /* See comment on corresponding get in xs_setup_bc_tcp(): */
176 if (xprt->xpt_bc_xprt)
177 xprt_put(xprt->xpt_bc_xprt);
178 if (xprt->xpt_bc_xps)
179 xprt_switch_put(xprt->xpt_bc_xps);
180 trace_svc_xprt_free(xprt);
181 xprt->xpt_ops->xpo_free(xprt);
185 void svc_xprt_put(struct svc_xprt *xprt)
187 kref_put(&xprt->xpt_ref, svc_xprt_free);
189 EXPORT_SYMBOL_GPL(svc_xprt_put);
192 * Called by transport drivers to initialize the transport independent
193 * portion of the transport instance.
195 void svc_xprt_init(struct net *net, struct svc_xprt_class *xcl,
196 struct svc_xprt *xprt, struct svc_serv *serv)
198 memset(xprt, 0, sizeof(*xprt));
199 xprt->xpt_class = xcl;
200 xprt->xpt_ops = xcl->xcl_ops;
201 kref_init(&xprt->xpt_ref);
202 xprt->xpt_server = serv;
203 INIT_LIST_HEAD(&xprt->xpt_list);
204 INIT_LIST_HEAD(&xprt->xpt_ready);
205 INIT_LIST_HEAD(&xprt->xpt_deferred);
206 INIT_LIST_HEAD(&xprt->xpt_users);
207 mutex_init(&xprt->xpt_mutex);
208 spin_lock_init(&xprt->xpt_lock);
209 set_bit(XPT_BUSY, &xprt->xpt_flags);
210 xprt->xpt_net = get_net_track(net, &xprt->ns_tracker, GFP_ATOMIC);
211 strcpy(xprt->xpt_remotebuf, "uninitialized");
213 EXPORT_SYMBOL_GPL(svc_xprt_init);
215 static struct svc_xprt *__svc_xpo_create(struct svc_xprt_class *xcl,
216 struct svc_serv *serv,
219 const unsigned short port,
222 struct sockaddr_in sin = {
223 .sin_family = AF_INET,
224 .sin_addr.s_addr = htonl(INADDR_ANY),
225 .sin_port = htons(port),
227 #if IS_ENABLED(CONFIG_IPV6)
228 struct sockaddr_in6 sin6 = {
229 .sin6_family = AF_INET6,
230 .sin6_addr = IN6ADDR_ANY_INIT,
231 .sin6_port = htons(port),
234 struct svc_xprt *xprt;
235 struct sockaddr *sap;
240 sap = (struct sockaddr *)&sin;
243 #if IS_ENABLED(CONFIG_IPV6)
245 sap = (struct sockaddr *)&sin6;
250 return ERR_PTR(-EAFNOSUPPORT);
253 xprt = xcl->xcl_ops->xpo_create(serv, net, sap, len, flags);
255 trace_svc_xprt_create_err(serv->sv_program->pg_name,
256 xcl->xcl_name, sap, len, xprt);
261 * svc_xprt_received - start next receiver thread
262 * @xprt: controlling transport
264 * The caller must hold the XPT_BUSY bit and must
265 * not thereafter touch transport data.
267 * Note: XPT_DATA only gets cleared when a read-attempt finds no (or
268 * insufficient) data.
270 void svc_xprt_received(struct svc_xprt *xprt)
272 if (!test_bit(XPT_BUSY, &xprt->xpt_flags)) {
273 WARN_ONCE(1, "xprt=0x%p already busy!", xprt);
277 /* As soon as we clear busy, the xprt could be closed and
278 * 'put', so we need a reference to call svc_xprt_enqueue with:
281 smp_mb__before_atomic();
282 clear_bit(XPT_BUSY, &xprt->xpt_flags);
283 svc_xprt_enqueue(xprt);
286 EXPORT_SYMBOL_GPL(svc_xprt_received);
288 void svc_add_new_perm_xprt(struct svc_serv *serv, struct svc_xprt *new)
290 clear_bit(XPT_TEMP, &new->xpt_flags);
291 spin_lock_bh(&serv->sv_lock);
292 list_add(&new->xpt_list, &serv->sv_permsocks);
293 spin_unlock_bh(&serv->sv_lock);
294 svc_xprt_received(new);
297 static int _svc_xprt_create(struct svc_serv *serv, const char *xprt_name,
298 struct net *net, const int family,
299 const unsigned short port, int flags,
300 const struct cred *cred)
302 struct svc_xprt_class *xcl;
304 spin_lock(&svc_xprt_class_lock);
305 list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
306 struct svc_xprt *newxprt;
307 unsigned short newport;
309 if (strcmp(xprt_name, xcl->xcl_name))
312 if (!try_module_get(xcl->xcl_owner))
315 spin_unlock(&svc_xprt_class_lock);
316 newxprt = __svc_xpo_create(xcl, serv, net, family, port, flags);
317 if (IS_ERR(newxprt)) {
318 module_put(xcl->xcl_owner);
319 return PTR_ERR(newxprt);
321 newxprt->xpt_cred = get_cred(cred);
322 svc_add_new_perm_xprt(serv, newxprt);
323 newport = svc_xprt_local_port(newxprt);
327 spin_unlock(&svc_xprt_class_lock);
328 /* This errno is exposed to user space. Provide a reasonable
329 * perror msg for a bad transport. */
330 return -EPROTONOSUPPORT;
334 * svc_xprt_create - Add a new listener to @serv
335 * @serv: target RPC service
336 * @xprt_name: transport class name
337 * @net: network namespace
338 * @family: network address family
339 * @port: listener port
340 * @flags: SVC_SOCK flags
341 * @cred: credential to bind to this transport
344 * %0: New listener added successfully
345 * %-EPROTONOSUPPORT: Requested transport type not supported
347 int svc_xprt_create(struct svc_serv *serv, const char *xprt_name,
348 struct net *net, const int family,
349 const unsigned short port, int flags,
350 const struct cred *cred)
354 err = _svc_xprt_create(serv, xprt_name, net, family, port, flags, cred);
355 if (err == -EPROTONOSUPPORT) {
356 request_module("svc%s", xprt_name);
357 err = _svc_xprt_create(serv, xprt_name, net, family, port, flags, cred);
361 EXPORT_SYMBOL_GPL(svc_xprt_create);
364 * Copy the local and remote xprt addresses to the rqstp structure
366 void svc_xprt_copy_addrs(struct svc_rqst *rqstp, struct svc_xprt *xprt)
368 memcpy(&rqstp->rq_addr, &xprt->xpt_remote, xprt->xpt_remotelen);
369 rqstp->rq_addrlen = xprt->xpt_remotelen;
372 * Destination address in request is needed for binding the
373 * source address in RPC replies/callbacks later.
375 memcpy(&rqstp->rq_daddr, &xprt->xpt_local, xprt->xpt_locallen);
376 rqstp->rq_daddrlen = xprt->xpt_locallen;
378 EXPORT_SYMBOL_GPL(svc_xprt_copy_addrs);
381 * svc_print_addr - Format rq_addr field for printing
382 * @rqstp: svc_rqst struct containing address to print
383 * @buf: target buffer for formatted address
384 * @len: length of target buffer
387 char *svc_print_addr(struct svc_rqst *rqstp, char *buf, size_t len)
389 return __svc_print_addr(svc_addr(rqstp), buf, len);
391 EXPORT_SYMBOL_GPL(svc_print_addr);
393 static bool svc_xprt_slots_in_range(struct svc_xprt *xprt)
395 unsigned int limit = svc_rpc_per_connection_limit;
396 int nrqsts = atomic_read(&xprt->xpt_nr_rqsts);
398 return limit == 0 || (nrqsts >= 0 && nrqsts < limit);
401 static bool svc_xprt_reserve_slot(struct svc_rqst *rqstp, struct svc_xprt *xprt)
403 if (!test_bit(RQ_DATA, &rqstp->rq_flags)) {
404 if (!svc_xprt_slots_in_range(xprt))
406 atomic_inc(&xprt->xpt_nr_rqsts);
407 set_bit(RQ_DATA, &rqstp->rq_flags);
412 static void svc_xprt_release_slot(struct svc_rqst *rqstp)
414 struct svc_xprt *xprt = rqstp->rq_xprt;
415 if (test_and_clear_bit(RQ_DATA, &rqstp->rq_flags)) {
416 atomic_dec(&xprt->xpt_nr_rqsts);
417 smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */
418 svc_xprt_enqueue(xprt);
422 static bool svc_xprt_ready(struct svc_xprt *xprt)
424 unsigned long xpt_flags;
427 * If another cpu has recently updated xpt_flags,
428 * sk_sock->flags, xpt_reserved, or xpt_nr_rqsts, we need to
429 * know about it; otherwise it's possible that both that cpu and
430 * this one could call svc_xprt_enqueue() without either
431 * svc_xprt_enqueue() recognizing that the conditions below
432 * are satisfied, and we could stall indefinitely:
435 xpt_flags = READ_ONCE(xprt->xpt_flags);
437 trace_svc_xprt_enqueue(xprt, xpt_flags);
438 if (xpt_flags & BIT(XPT_BUSY))
440 if (xpt_flags & (BIT(XPT_CONN) | BIT(XPT_CLOSE) | BIT(XPT_HANDSHAKE)))
442 if (xpt_flags & (BIT(XPT_DATA) | BIT(XPT_DEFERRED))) {
443 if (xprt->xpt_ops->xpo_has_wspace(xprt) &&
444 svc_xprt_slots_in_range(xprt))
446 trace_svc_xprt_no_write_space(xprt);
453 * svc_xprt_enqueue - Queue a transport on an idle nfsd thread
454 * @xprt: transport with data pending
457 void svc_xprt_enqueue(struct svc_xprt *xprt)
459 struct svc_pool *pool;
461 if (!svc_xprt_ready(xprt))
464 /* Mark transport as busy. It will remain in this state until
465 * the provider calls svc_xprt_received. We update XPT_BUSY
466 * atomically because it also guards against trying to enqueue
467 * the transport twice.
469 if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
472 pool = svc_pool_for_cpu(xprt->xpt_server);
474 percpu_counter_inc(&pool->sp_sockets_queued);
475 spin_lock_bh(&pool->sp_lock);
476 list_add_tail(&xprt->xpt_ready, &pool->sp_sockets);
477 spin_unlock_bh(&pool->sp_lock);
479 svc_pool_wake_idle_thread(pool);
481 EXPORT_SYMBOL_GPL(svc_xprt_enqueue);
484 * Dequeue the first transport, if there is one.
486 static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool)
488 struct svc_xprt *xprt = NULL;
490 if (list_empty(&pool->sp_sockets))
493 spin_lock_bh(&pool->sp_lock);
494 if (likely(!list_empty(&pool->sp_sockets))) {
495 xprt = list_first_entry(&pool->sp_sockets,
496 struct svc_xprt, xpt_ready);
497 list_del_init(&xprt->xpt_ready);
500 spin_unlock_bh(&pool->sp_lock);
506 * svc_reserve - change the space reserved for the reply to a request.
507 * @rqstp: The request in question
508 * @space: new max space to reserve
510 * Each request reserves some space on the output queue of the transport
511 * to make sure the reply fits. This function reduces that reserved
512 * space to be the amount of space used already, plus @space.
515 void svc_reserve(struct svc_rqst *rqstp, int space)
517 struct svc_xprt *xprt = rqstp->rq_xprt;
519 space += rqstp->rq_res.head[0].iov_len;
521 if (xprt && space < rqstp->rq_reserved) {
522 atomic_sub((rqstp->rq_reserved - space), &xprt->xpt_reserved);
523 rqstp->rq_reserved = space;
524 smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */
525 svc_xprt_enqueue(xprt);
528 EXPORT_SYMBOL_GPL(svc_reserve);
530 static void free_deferred(struct svc_xprt *xprt, struct svc_deferred_req *dr)
535 xprt->xpt_ops->xpo_release_ctxt(xprt, dr->xprt_ctxt);
539 static void svc_xprt_release(struct svc_rqst *rqstp)
541 struct svc_xprt *xprt = rqstp->rq_xprt;
543 xprt->xpt_ops->xpo_release_ctxt(xprt, rqstp->rq_xprt_ctxt);
544 rqstp->rq_xprt_ctxt = NULL;
546 free_deferred(xprt, rqstp->rq_deferred);
547 rqstp->rq_deferred = NULL;
549 svc_rqst_release_pages(rqstp);
550 rqstp->rq_res.page_len = 0;
551 rqstp->rq_res.page_base = 0;
553 /* Reset response buffer and release
555 * But first, check that enough space was reserved
556 * for the reply, otherwise we have a bug!
558 if ((rqstp->rq_res.len) > rqstp->rq_reserved)
559 printk(KERN_ERR "RPC request reserved %d but used %d\n",
563 rqstp->rq_res.head[0].iov_len = 0;
564 svc_reserve(rqstp, 0);
565 svc_xprt_release_slot(rqstp);
566 rqstp->rq_xprt = NULL;
571 * svc_wake_up - Wake up a service thread for non-transport work
574 * Some svc_serv's will have occasional work to do, even when a xprt is not
575 * waiting to be serviced. This function is there to "kick" a task in one of
576 * those services so that it can wake up and do that work. Note that we only
577 * bother with pool 0 as we don't need to wake up more than one thread for
580 void svc_wake_up(struct svc_serv *serv)
582 struct svc_pool *pool = &serv->sv_pools[0];
584 set_bit(SP_TASK_PENDING, &pool->sp_flags);
585 svc_pool_wake_idle_thread(pool);
587 EXPORT_SYMBOL_GPL(svc_wake_up);
589 int svc_port_is_privileged(struct sockaddr *sin)
591 switch (sin->sa_family) {
593 return ntohs(((struct sockaddr_in *)sin)->sin_port)
596 return ntohs(((struct sockaddr_in6 *)sin)->sin6_port)
604 * Make sure that we don't have too many active connections. If we have,
605 * something must be dropped. It's not clear what will happen if we allow
606 * "too many" connections, but when dealing with network-facing software,
607 * we have to code defensively. Here we do that by imposing hard limits.
609 * There's no point in trying to do random drop here for DoS
610 * prevention. The NFS clients does 1 reconnect in 15 seconds. An
611 * attacker can easily beat that.
613 * The only somewhat efficient mechanism would be if drop old
614 * connections from the same IP first. But right now we don't even
615 * record the client IP in svc_sock.
617 * single-threaded services that expect a lot of clients will probably
618 * need to set sv_maxconn to override the default value which is based
619 * on the number of threads
621 static void svc_check_conn_limits(struct svc_serv *serv)
623 unsigned int limit = serv->sv_maxconn ? serv->sv_maxconn :
624 (serv->sv_nrthreads+3) * 20;
626 if (serv->sv_tmpcnt > limit) {
627 struct svc_xprt *xprt = NULL;
628 spin_lock_bh(&serv->sv_lock);
629 if (!list_empty(&serv->sv_tempsocks)) {
630 /* Try to help the admin */
631 net_notice_ratelimited("%s: too many open connections, consider increasing the %s\n",
632 serv->sv_name, serv->sv_maxconn ?
633 "max number of connections" :
634 "number of threads");
636 * Always select the oldest connection. It's not fair,
639 xprt = list_entry(serv->sv_tempsocks.prev,
642 set_bit(XPT_CLOSE, &xprt->xpt_flags);
645 spin_unlock_bh(&serv->sv_lock);
648 svc_xprt_enqueue(xprt);
654 static bool svc_alloc_arg(struct svc_rqst *rqstp)
656 struct svc_serv *serv = rqstp->rq_server;
657 struct xdr_buf *arg = &rqstp->rq_arg;
658 unsigned long pages, filled, ret;
660 pages = (serv->sv_max_mesg + 2 * PAGE_SIZE) >> PAGE_SHIFT;
661 if (pages > RPCSVC_MAXPAGES) {
662 pr_warn_once("svc: warning: pages=%lu > RPCSVC_MAXPAGES=%lu\n",
663 pages, RPCSVC_MAXPAGES);
664 /* use as many pages as possible */
665 pages = RPCSVC_MAXPAGES;
668 for (filled = 0; filled < pages; filled = ret) {
669 ret = alloc_pages_bulk_array(GFP_KERNEL, pages,
672 /* Made progress, don't sleep yet */
675 set_current_state(TASK_IDLE);
676 if (kthread_should_stop()) {
677 set_current_state(TASK_RUNNING);
680 trace_svc_alloc_arg_err(pages, ret);
681 memalloc_retry_wait(GFP_KERNEL);
683 rqstp->rq_page_end = &rqstp->rq_pages[pages];
684 rqstp->rq_pages[pages] = NULL; /* this might be seen in nfsd_splice_actor() */
686 /* Make arg->head point to first page and arg->pages point to rest */
687 arg->head[0].iov_base = page_address(rqstp->rq_pages[0]);
688 arg->head[0].iov_len = PAGE_SIZE;
689 arg->pages = rqstp->rq_pages + 1;
691 /* save at least one page for response */
692 arg->page_len = (pages-2)*PAGE_SIZE;
693 arg->len = (pages-1)*PAGE_SIZE;
694 arg->tail[0].iov_len = 0;
696 rqstp->rq_xid = xdr_zero;
701 rqst_should_sleep(struct svc_rqst *rqstp)
703 struct svc_pool *pool = rqstp->rq_pool;
705 /* did someone call svc_wake_up? */
706 if (test_bit(SP_TASK_PENDING, &pool->sp_flags))
709 /* was a socket queued? */
710 if (!list_empty(&pool->sp_sockets))
713 /* are we shutting down? */
714 if (kthread_should_stop())
717 /* are we freezing? */
718 if (freezing(current))
724 static struct svc_xprt *svc_get_next_xprt(struct svc_rqst *rqstp)
726 struct svc_pool *pool = rqstp->rq_pool;
728 /* rq_xprt should be clear on entry */
729 WARN_ON_ONCE(rqstp->rq_xprt);
731 rqstp->rq_xprt = svc_xprt_dequeue(pool);
735 set_current_state(TASK_IDLE);
736 smp_mb__before_atomic();
737 clear_bit(SP_CONGESTED, &pool->sp_flags);
738 clear_bit(RQ_BUSY, &rqstp->rq_flags);
739 smp_mb__after_atomic();
741 if (likely(rqst_should_sleep(rqstp)))
744 __set_current_state(TASK_RUNNING);
748 set_bit(RQ_BUSY, &rqstp->rq_flags);
749 smp_mb__after_atomic();
750 clear_bit(SP_TASK_PENDING, &pool->sp_flags);
751 rqstp->rq_xprt = svc_xprt_dequeue(pool);
755 if (kthread_should_stop())
759 clear_bit(SP_TASK_PENDING, &pool->sp_flags);
760 /* Normally we will wait up to 5 seconds for any required
761 * cache information to be provided.
763 if (!test_bit(SP_CONGESTED, &pool->sp_flags))
764 rqstp->rq_chandle.thread_wait = 5*HZ;
766 rqstp->rq_chandle.thread_wait = 1*HZ;
767 trace_svc_xprt_dequeue(rqstp);
768 return rqstp->rq_xprt;
771 static void svc_add_new_temp_xprt(struct svc_serv *serv, struct svc_xprt *newxpt)
773 spin_lock_bh(&serv->sv_lock);
774 set_bit(XPT_TEMP, &newxpt->xpt_flags);
775 list_add(&newxpt->xpt_list, &serv->sv_tempsocks);
777 if (serv->sv_temptimer.function == NULL) {
778 /* setup timer to age temp transports */
779 serv->sv_temptimer.function = svc_age_temp_xprts;
780 mod_timer(&serv->sv_temptimer,
781 jiffies + svc_conn_age_period * HZ);
783 spin_unlock_bh(&serv->sv_lock);
784 svc_xprt_received(newxpt);
787 static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
789 struct svc_serv *serv = rqstp->rq_server;
792 if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) {
793 if (test_and_clear_bit(XPT_KILL_TEMP, &xprt->xpt_flags))
794 xprt->xpt_ops->xpo_kill_temp_xprt(xprt);
795 svc_delete_xprt(xprt);
796 /* Leave XPT_BUSY set on the dead xprt: */
799 if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) {
800 struct svc_xprt *newxpt;
802 * We know this module_get will succeed because the
803 * listener holds a reference too
805 __module_get(xprt->xpt_class->xcl_owner);
806 svc_check_conn_limits(xprt->xpt_server);
807 newxpt = xprt->xpt_ops->xpo_accept(xprt);
809 newxpt->xpt_cred = get_cred(xprt->xpt_cred);
810 svc_add_new_temp_xprt(serv, newxpt);
811 trace_svc_xprt_accept(newxpt, serv->sv_name);
813 module_put(xprt->xpt_class->xcl_owner);
815 svc_xprt_received(xprt);
816 } else if (test_bit(XPT_HANDSHAKE, &xprt->xpt_flags)) {
817 xprt->xpt_ops->xpo_handshake(xprt);
818 svc_xprt_received(xprt);
819 } else if (svc_xprt_reserve_slot(rqstp, xprt)) {
820 /* XPT_DATA|XPT_DEFERRED case: */
821 rqstp->rq_deferred = svc_deferred_dequeue(xprt);
822 if (rqstp->rq_deferred)
823 len = svc_deferred_recv(rqstp);
825 len = xprt->xpt_ops->xpo_recvfrom(rqstp);
826 rqstp->rq_reserved = serv->sv_max_mesg;
827 atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
829 svc_xprt_received(xprt);
836 * svc_recv - Receive and process the next request on any transport
837 * @rqstp: an idle RPC service thread
839 * This code is carefully organised not to touch any cachelines in
840 * the shared svc_serv structure, only cachelines in the local
843 void svc_recv(struct svc_rqst *rqstp)
845 struct svc_xprt *xprt = NULL;
846 struct svc_serv *serv = rqstp->rq_server;
849 if (!svc_alloc_arg(rqstp))
854 if (kthread_should_stop())
857 xprt = svc_get_next_xprt(rqstp);
861 len = svc_handle_xprt(rqstp, xprt);
863 /* No data, incomplete (TCP) read, or accept() */
867 trace_svc_xdr_recvfrom(&rqstp->rq_arg);
869 clear_bit(XPT_OLD, &xprt->xpt_flags);
871 rqstp->rq_chandle.defer = svc_defer;
874 serv->sv_stats->netcnt++;
875 percpu_counter_inc(&rqstp->rq_pool->sp_messages_arrived);
876 rqstp->rq_stime = ktime_get();
881 rqstp->rq_res.len = 0;
882 svc_xprt_release(rqstp);
884 EXPORT_SYMBOL_GPL(svc_recv);
889 void svc_drop(struct svc_rqst *rqstp)
891 trace_svc_drop(rqstp);
892 svc_xprt_release(rqstp);
894 EXPORT_SYMBOL_GPL(svc_drop);
897 * svc_send - Return reply to client
898 * @rqstp: RPC transaction context
901 void svc_send(struct svc_rqst *rqstp)
903 struct svc_xprt *xprt;
907 xprt = rqstp->rq_xprt;
911 /* calculate over-all length */
913 xb->len = xb->head[0].iov_len +
916 trace_svc_xdr_sendto(rqstp->rq_xid, xb);
917 trace_svc_stats_latency(rqstp);
919 status = xprt->xpt_ops->xpo_sendto(rqstp);
921 trace_svc_send(rqstp, status);
922 svc_xprt_release(rqstp);
926 * Timer function to close old temporary transports, using
927 * a mark-and-sweep algorithm.
929 static void svc_age_temp_xprts(struct timer_list *t)
931 struct svc_serv *serv = from_timer(serv, t, sv_temptimer);
932 struct svc_xprt *xprt;
933 struct list_head *le, *next;
935 dprintk("svc_age_temp_xprts\n");
937 if (!spin_trylock_bh(&serv->sv_lock)) {
938 /* busy, try again 1 sec later */
939 dprintk("svc_age_temp_xprts: busy\n");
940 mod_timer(&serv->sv_temptimer, jiffies + HZ);
944 list_for_each_safe(le, next, &serv->sv_tempsocks) {
945 xprt = list_entry(le, struct svc_xprt, xpt_list);
947 /* First time through, just mark it OLD. Second time
948 * through, close it. */
949 if (!test_and_set_bit(XPT_OLD, &xprt->xpt_flags))
951 if (kref_read(&xprt->xpt_ref) > 1 ||
952 test_bit(XPT_BUSY, &xprt->xpt_flags))
955 set_bit(XPT_CLOSE, &xprt->xpt_flags);
956 dprintk("queuing xprt %p for closing\n", xprt);
958 /* a thread will dequeue and close it soon */
959 svc_xprt_enqueue(xprt);
961 spin_unlock_bh(&serv->sv_lock);
963 mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ);
966 /* Close temporary transports whose xpt_local matches server_addr immediately
967 * instead of waiting for them to be picked up by the timer.
969 * This is meant to be called from a notifier_block that runs when an ip
970 * address is deleted.
972 void svc_age_temp_xprts_now(struct svc_serv *serv, struct sockaddr *server_addr)
974 struct svc_xprt *xprt;
975 struct list_head *le, *next;
976 LIST_HEAD(to_be_closed);
978 spin_lock_bh(&serv->sv_lock);
979 list_for_each_safe(le, next, &serv->sv_tempsocks) {
980 xprt = list_entry(le, struct svc_xprt, xpt_list);
981 if (rpc_cmp_addr(server_addr, (struct sockaddr *)
983 dprintk("svc_age_temp_xprts_now: found %p\n", xprt);
984 list_move(le, &to_be_closed);
987 spin_unlock_bh(&serv->sv_lock);
989 while (!list_empty(&to_be_closed)) {
990 le = to_be_closed.next;
992 xprt = list_entry(le, struct svc_xprt, xpt_list);
993 set_bit(XPT_CLOSE, &xprt->xpt_flags);
994 set_bit(XPT_KILL_TEMP, &xprt->xpt_flags);
995 dprintk("svc_age_temp_xprts_now: queuing xprt %p for closing\n",
997 svc_xprt_enqueue(xprt);
1000 EXPORT_SYMBOL_GPL(svc_age_temp_xprts_now);
1002 static void call_xpt_users(struct svc_xprt *xprt)
1004 struct svc_xpt_user *u;
1006 spin_lock(&xprt->xpt_lock);
1007 while (!list_empty(&xprt->xpt_users)) {
1008 u = list_first_entry(&xprt->xpt_users, struct svc_xpt_user, list);
1009 list_del_init(&u->list);
1012 spin_unlock(&xprt->xpt_lock);
1016 * Remove a dead transport
1018 static void svc_delete_xprt(struct svc_xprt *xprt)
1020 struct svc_serv *serv = xprt->xpt_server;
1021 struct svc_deferred_req *dr;
1023 if (test_and_set_bit(XPT_DEAD, &xprt->xpt_flags))
1026 trace_svc_xprt_detach(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);
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))
1036 spin_unlock_bh(&serv->sv_lock);
1038 while ((dr = svc_deferred_dequeue(xprt)) != NULL)
1039 free_deferred(xprt, dr);
1041 call_xpt_users(xprt);
1046 * svc_xprt_close - Close a client connection
1047 * @xprt: transport to disconnect
1050 void svc_xprt_close(struct svc_xprt *xprt)
1052 trace_svc_xprt_close(xprt);
1053 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1054 if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
1055 /* someone else will have to effect the close */
1058 * We expect svc_close_xprt() to work even when no threads are
1059 * running (e.g., while configuring the server before starting
1060 * any threads), so if the transport isn't busy, we delete
1063 svc_delete_xprt(xprt);
1065 EXPORT_SYMBOL_GPL(svc_xprt_close);
1067 static int svc_close_list(struct svc_serv *serv, struct list_head *xprt_list, struct net *net)
1069 struct svc_xprt *xprt;
1072 spin_lock_bh(&serv->sv_lock);
1073 list_for_each_entry(xprt, xprt_list, xpt_list) {
1074 if (xprt->xpt_net != net)
1077 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1078 svc_xprt_enqueue(xprt);
1080 spin_unlock_bh(&serv->sv_lock);
1084 static struct svc_xprt *svc_dequeue_net(struct svc_serv *serv, struct net *net)
1086 struct svc_pool *pool;
1087 struct svc_xprt *xprt;
1088 struct svc_xprt *tmp;
1091 for (i = 0; i < serv->sv_nrpools; i++) {
1092 pool = &serv->sv_pools[i];
1094 spin_lock_bh(&pool->sp_lock);
1095 list_for_each_entry_safe(xprt, tmp, &pool->sp_sockets, xpt_ready) {
1096 if (xprt->xpt_net != net)
1098 list_del_init(&xprt->xpt_ready);
1099 spin_unlock_bh(&pool->sp_lock);
1102 spin_unlock_bh(&pool->sp_lock);
1107 static void svc_clean_up_xprts(struct svc_serv *serv, struct net *net)
1109 struct svc_xprt *xprt;
1111 while ((xprt = svc_dequeue_net(serv, net))) {
1112 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1113 svc_delete_xprt(xprt);
1118 * svc_xprt_destroy_all - Destroy transports associated with @serv
1119 * @serv: RPC service to be shut down
1120 * @net: target network namespace
1122 * Server threads may still be running (especially in the case where the
1123 * service is still running in other network namespaces).
1125 * So we shut down sockets the same way we would on a running server, by
1126 * setting XPT_CLOSE, enqueuing, and letting a thread pick it up to do
1127 * the close. In the case there are no such other threads,
1128 * threads running, svc_clean_up_xprts() does a simple version of a
1129 * server's main event loop, and in the case where there are other
1130 * threads, we may need to wait a little while and then check again to
1131 * see if they're done.
1133 void svc_xprt_destroy_all(struct svc_serv *serv, struct net *net)
1137 while (svc_close_list(serv, &serv->sv_permsocks, net) +
1138 svc_close_list(serv, &serv->sv_tempsocks, net)) {
1140 svc_clean_up_xprts(serv, net);
1144 EXPORT_SYMBOL_GPL(svc_xprt_destroy_all);
1147 * Handle defer and revisit of requests
1150 static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
1152 struct svc_deferred_req *dr =
1153 container_of(dreq, struct svc_deferred_req, handle);
1154 struct svc_xprt *xprt = dr->xprt;
1156 spin_lock(&xprt->xpt_lock);
1157 set_bit(XPT_DEFERRED, &xprt->xpt_flags);
1158 if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) {
1159 spin_unlock(&xprt->xpt_lock);
1160 trace_svc_defer_drop(dr);
1161 free_deferred(xprt, dr);
1166 list_add(&dr->handle.recent, &xprt->xpt_deferred);
1167 spin_unlock(&xprt->xpt_lock);
1168 trace_svc_defer_queue(dr);
1169 svc_xprt_enqueue(xprt);
1174 * Save the request off for later processing. The request buffer looks
1177 * <xprt-header><rpc-header><rpc-pagelist><rpc-tail>
1179 * This code can only handle requests that consist of an xprt-header
1182 static struct cache_deferred_req *svc_defer(struct cache_req *req)
1184 struct svc_rqst *rqstp = container_of(req, struct svc_rqst, rq_chandle);
1185 struct svc_deferred_req *dr;
1187 if (rqstp->rq_arg.page_len || !test_bit(RQ_USEDEFERRAL, &rqstp->rq_flags))
1188 return NULL; /* if more than a page, give up FIXME */
1189 if (rqstp->rq_deferred) {
1190 dr = rqstp->rq_deferred;
1191 rqstp->rq_deferred = NULL;
1195 /* FIXME maybe discard if size too large */
1196 size = sizeof(struct svc_deferred_req) + rqstp->rq_arg.len;
1197 dr = kmalloc(size, GFP_KERNEL);
1201 dr->handle.owner = rqstp->rq_server;
1202 dr->prot = rqstp->rq_prot;
1203 memcpy(&dr->addr, &rqstp->rq_addr, rqstp->rq_addrlen);
1204 dr->addrlen = rqstp->rq_addrlen;
1205 dr->daddr = rqstp->rq_daddr;
1206 dr->argslen = rqstp->rq_arg.len >> 2;
1208 /* back up head to the start of the buffer and copy */
1209 skip = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len;
1210 memcpy(dr->args, rqstp->rq_arg.head[0].iov_base - skip,
1213 dr->xprt_ctxt = rqstp->rq_xprt_ctxt;
1214 rqstp->rq_xprt_ctxt = NULL;
1215 trace_svc_defer(rqstp);
1216 svc_xprt_get(rqstp->rq_xprt);
1217 dr->xprt = rqstp->rq_xprt;
1218 set_bit(RQ_DROPME, &rqstp->rq_flags);
1220 dr->handle.revisit = svc_revisit;
1225 * recv data from a deferred request into an active one
1227 static noinline int svc_deferred_recv(struct svc_rqst *rqstp)
1229 struct svc_deferred_req *dr = rqstp->rq_deferred;
1231 trace_svc_defer_recv(dr);
1233 /* setup iov_base past transport header */
1234 rqstp->rq_arg.head[0].iov_base = dr->args;
1235 /* The iov_len does not include the transport header bytes */
1236 rqstp->rq_arg.head[0].iov_len = dr->argslen << 2;
1237 rqstp->rq_arg.page_len = 0;
1238 /* The rq_arg.len includes the transport header bytes */
1239 rqstp->rq_arg.len = dr->argslen << 2;
1240 rqstp->rq_prot = dr->prot;
1241 memcpy(&rqstp->rq_addr, &dr->addr, dr->addrlen);
1242 rqstp->rq_addrlen = dr->addrlen;
1243 /* Save off transport header len in case we get deferred again */
1244 rqstp->rq_daddr = dr->daddr;
1245 rqstp->rq_respages = rqstp->rq_pages;
1246 rqstp->rq_xprt_ctxt = dr->xprt_ctxt;
1248 dr->xprt_ctxt = NULL;
1249 svc_xprt_received(rqstp->rq_xprt);
1250 return dr->argslen << 2;
1254 static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt)
1256 struct svc_deferred_req *dr = NULL;
1258 if (!test_bit(XPT_DEFERRED, &xprt->xpt_flags))
1260 spin_lock(&xprt->xpt_lock);
1261 if (!list_empty(&xprt->xpt_deferred)) {
1262 dr = list_entry(xprt->xpt_deferred.next,
1263 struct svc_deferred_req,
1265 list_del_init(&dr->handle.recent);
1267 clear_bit(XPT_DEFERRED, &xprt->xpt_flags);
1268 spin_unlock(&xprt->xpt_lock);
1273 * svc_find_xprt - find an RPC transport instance
1274 * @serv: pointer to svc_serv to search
1275 * @xcl_name: C string containing transport's class name
1276 * @net: owner net pointer
1277 * @af: Address family of transport's local address
1278 * @port: transport's IP port number
1280 * Return the transport instance pointer for the endpoint accepting
1281 * connections/peer traffic from the specified transport class,
1282 * address family and port.
1284 * Specifying 0 for the address family or port is effectively a
1285 * wild-card, and will result in matching the first transport in the
1286 * service's list that has a matching class name.
1288 struct svc_xprt *svc_find_xprt(struct svc_serv *serv, const char *xcl_name,
1289 struct net *net, const sa_family_t af,
1290 const unsigned short port)
1292 struct svc_xprt *xprt;
1293 struct svc_xprt *found = NULL;
1295 /* Sanity check the args */
1296 if (serv == NULL || xcl_name == NULL)
1299 spin_lock_bh(&serv->sv_lock);
1300 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1301 if (xprt->xpt_net != net)
1303 if (strcmp(xprt->xpt_class->xcl_name, xcl_name))
1305 if (af != AF_UNSPEC && af != xprt->xpt_local.ss_family)
1307 if (port != 0 && port != svc_xprt_local_port(xprt))
1313 spin_unlock_bh(&serv->sv_lock);
1316 EXPORT_SYMBOL_GPL(svc_find_xprt);
1318 static int svc_one_xprt_name(const struct svc_xprt *xprt,
1319 char *pos, int remaining)
1323 len = snprintf(pos, remaining, "%s %u\n",
1324 xprt->xpt_class->xcl_name,
1325 svc_xprt_local_port(xprt));
1326 if (len >= remaining)
1327 return -ENAMETOOLONG;
1332 * svc_xprt_names - format a buffer with a list of transport names
1333 * @serv: pointer to an RPC service
1334 * @buf: pointer to a buffer to be filled in
1335 * @buflen: length of buffer to be filled in
1337 * Fills in @buf with a string containing a list of transport names,
1338 * each name terminated with '\n'.
1340 * Returns positive length of the filled-in string on success; otherwise
1341 * a negative errno value is returned if an error occurs.
1343 int svc_xprt_names(struct svc_serv *serv, char *buf, const int buflen)
1345 struct svc_xprt *xprt;
1349 /* Sanity check args */
1353 spin_lock_bh(&serv->sv_lock);
1357 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1358 len = svc_one_xprt_name(xprt, pos, buflen - totlen);
1370 spin_unlock_bh(&serv->sv_lock);
1373 EXPORT_SYMBOL_GPL(svc_xprt_names);
1376 /*----------------------------------------------------------------------------*/
1378 static void *svc_pool_stats_start(struct seq_file *m, loff_t *pos)
1380 unsigned int pidx = (unsigned int)*pos;
1381 struct svc_serv *serv = m->private;
1383 dprintk("svc_pool_stats_start, *pidx=%u\n", pidx);
1386 return SEQ_START_TOKEN;
1387 return (pidx > serv->sv_nrpools ? NULL : &serv->sv_pools[pidx-1]);
1390 static void *svc_pool_stats_next(struct seq_file *m, void *p, loff_t *pos)
1392 struct svc_pool *pool = p;
1393 struct svc_serv *serv = m->private;
1395 dprintk("svc_pool_stats_next, *pos=%llu\n", *pos);
1397 if (p == SEQ_START_TOKEN) {
1398 pool = &serv->sv_pools[0];
1400 unsigned int pidx = (pool - &serv->sv_pools[0]);
1401 if (pidx < serv->sv_nrpools-1)
1402 pool = &serv->sv_pools[pidx+1];
1410 static void svc_pool_stats_stop(struct seq_file *m, void *p)
1414 static int svc_pool_stats_show(struct seq_file *m, void *p)
1416 struct svc_pool *pool = p;
1418 if (p == SEQ_START_TOKEN) {
1419 seq_puts(m, "# pool packets-arrived sockets-enqueued threads-woken threads-timedout\n");
1423 seq_printf(m, "%u %llu %llu %llu 0\n",
1425 percpu_counter_sum_positive(&pool->sp_messages_arrived),
1426 percpu_counter_sum_positive(&pool->sp_sockets_queued),
1427 percpu_counter_sum_positive(&pool->sp_threads_woken));
1432 static const struct seq_operations svc_pool_stats_seq_ops = {
1433 .start = svc_pool_stats_start,
1434 .next = svc_pool_stats_next,
1435 .stop = svc_pool_stats_stop,
1436 .show = svc_pool_stats_show,
1439 int svc_pool_stats_open(struct svc_serv *serv, struct file *file)
1443 err = seq_open(file, &svc_pool_stats_seq_ops);
1445 ((struct seq_file *) file->private_data)->private = serv;
1448 EXPORT_SYMBOL(svc_pool_stats_open);
1450 /*----------------------------------------------------------------------------*/