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.
77 int svc_reg_xprt_class(struct svc_xprt_class *xcl)
79 struct svc_xprt_class *cl;
82 dprintk("svc: Adding svc transport class '%s'\n", xcl->xcl_name);
84 INIT_LIST_HEAD(&xcl->xcl_list);
85 spin_lock(&svc_xprt_class_lock);
86 /* Make sure there isn't already a class with the same name */
87 list_for_each_entry(cl, &svc_xprt_class_list, xcl_list) {
88 if (strcmp(xcl->xcl_name, cl->xcl_name) == 0)
91 list_add_tail(&xcl->xcl_list, &svc_xprt_class_list);
94 spin_unlock(&svc_xprt_class_lock);
97 EXPORT_SYMBOL_GPL(svc_reg_xprt_class);
99 void svc_unreg_xprt_class(struct svc_xprt_class *xcl)
101 dprintk("svc: Removing svc transport class '%s'\n", xcl->xcl_name);
102 spin_lock(&svc_xprt_class_lock);
103 list_del_init(&xcl->xcl_list);
104 spin_unlock(&svc_xprt_class_lock);
106 EXPORT_SYMBOL_GPL(svc_unreg_xprt_class);
109 * svc_print_xprts - Format the transport list for printing
110 * @buf: target buffer for formatted address
111 * @maxlen: length of target buffer
113 * Fills in @buf with a string containing a list of transport names, each name
114 * terminated with '\n'. If the buffer is too small, some entries may be
115 * missing, but it is guaranteed that all lines in the output buffer are
118 * Returns positive length of the filled-in string.
120 int svc_print_xprts(char *buf, int maxlen)
122 struct svc_xprt_class *xcl;
127 spin_lock(&svc_xprt_class_lock);
128 list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
131 slen = snprintf(tmpstr, sizeof(tmpstr), "%s %d\n",
132 xcl->xcl_name, xcl->xcl_max_payload);
133 if (slen >= sizeof(tmpstr) || len + slen >= maxlen)
138 spin_unlock(&svc_xprt_class_lock);
144 * svc_xprt_deferred_close - Close a transport
145 * @xprt: transport instance
147 * Used in contexts that need to defer the work of shutting down
148 * the transport to an nfsd thread.
150 void svc_xprt_deferred_close(struct svc_xprt *xprt)
152 if (!test_and_set_bit(XPT_CLOSE, &xprt->xpt_flags))
153 svc_xprt_enqueue(xprt);
155 EXPORT_SYMBOL_GPL(svc_xprt_deferred_close);
157 static void svc_xprt_free(struct kref *kref)
159 struct svc_xprt *xprt =
160 container_of(kref, struct svc_xprt, xpt_ref);
161 struct module *owner = xprt->xpt_class->xcl_owner;
162 if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags))
163 svcauth_unix_info_release(xprt);
164 put_cred(xprt->xpt_cred);
165 put_net_track(xprt->xpt_net, &xprt->ns_tracker);
166 /* See comment on corresponding get in xs_setup_bc_tcp(): */
167 if (xprt->xpt_bc_xprt)
168 xprt_put(xprt->xpt_bc_xprt);
169 if (xprt->xpt_bc_xps)
170 xprt_switch_put(xprt->xpt_bc_xps);
171 trace_svc_xprt_free(xprt);
172 xprt->xpt_ops->xpo_free(xprt);
176 void svc_xprt_put(struct svc_xprt *xprt)
178 kref_put(&xprt->xpt_ref, svc_xprt_free);
180 EXPORT_SYMBOL_GPL(svc_xprt_put);
183 * Called by transport drivers to initialize the transport independent
184 * portion of the transport instance.
186 void svc_xprt_init(struct net *net, struct svc_xprt_class *xcl,
187 struct svc_xprt *xprt, struct svc_serv *serv)
189 memset(xprt, 0, sizeof(*xprt));
190 xprt->xpt_class = xcl;
191 xprt->xpt_ops = xcl->xcl_ops;
192 kref_init(&xprt->xpt_ref);
193 xprt->xpt_server = serv;
194 INIT_LIST_HEAD(&xprt->xpt_list);
195 INIT_LIST_HEAD(&xprt->xpt_ready);
196 INIT_LIST_HEAD(&xprt->xpt_deferred);
197 INIT_LIST_HEAD(&xprt->xpt_users);
198 mutex_init(&xprt->xpt_mutex);
199 spin_lock_init(&xprt->xpt_lock);
200 set_bit(XPT_BUSY, &xprt->xpt_flags);
201 xprt->xpt_net = get_net_track(net, &xprt->ns_tracker, GFP_ATOMIC);
202 strcpy(xprt->xpt_remotebuf, "uninitialized");
204 EXPORT_SYMBOL_GPL(svc_xprt_init);
206 static struct svc_xprt *__svc_xpo_create(struct svc_xprt_class *xcl,
207 struct svc_serv *serv,
210 const unsigned short port,
213 struct sockaddr_in sin = {
214 .sin_family = AF_INET,
215 .sin_addr.s_addr = htonl(INADDR_ANY),
216 .sin_port = htons(port),
218 #if IS_ENABLED(CONFIG_IPV6)
219 struct sockaddr_in6 sin6 = {
220 .sin6_family = AF_INET6,
221 .sin6_addr = IN6ADDR_ANY_INIT,
222 .sin6_port = htons(port),
225 struct svc_xprt *xprt;
226 struct sockaddr *sap;
231 sap = (struct sockaddr *)&sin;
234 #if IS_ENABLED(CONFIG_IPV6)
236 sap = (struct sockaddr *)&sin6;
241 return ERR_PTR(-EAFNOSUPPORT);
244 xprt = xcl->xcl_ops->xpo_create(serv, net, sap, len, flags);
246 trace_svc_xprt_create_err(serv->sv_program->pg_name,
247 xcl->xcl_name, sap, len, xprt);
252 * svc_xprt_received - start next receiver thread
253 * @xprt: controlling transport
255 * The caller must hold the XPT_BUSY bit and must
256 * not thereafter touch transport data.
258 * Note: XPT_DATA only gets cleared when a read-attempt finds no (or
259 * insufficient) data.
261 void svc_xprt_received(struct svc_xprt *xprt)
263 if (!test_bit(XPT_BUSY, &xprt->xpt_flags)) {
264 WARN_ONCE(1, "xprt=0x%p already busy!", xprt);
268 /* As soon as we clear busy, the xprt could be closed and
269 * 'put', so we need a reference to call svc_xprt_enqueue with:
272 smp_mb__before_atomic();
273 clear_bit(XPT_BUSY, &xprt->xpt_flags);
274 svc_xprt_enqueue(xprt);
277 EXPORT_SYMBOL_GPL(svc_xprt_received);
279 void svc_add_new_perm_xprt(struct svc_serv *serv, struct svc_xprt *new)
281 clear_bit(XPT_TEMP, &new->xpt_flags);
282 spin_lock_bh(&serv->sv_lock);
283 list_add(&new->xpt_list, &serv->sv_permsocks);
284 spin_unlock_bh(&serv->sv_lock);
285 svc_xprt_received(new);
288 static int _svc_xprt_create(struct svc_serv *serv, const char *xprt_name,
289 struct net *net, const int family,
290 const unsigned short port, int flags,
291 const struct cred *cred)
293 struct svc_xprt_class *xcl;
295 spin_lock(&svc_xprt_class_lock);
296 list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) {
297 struct svc_xprt *newxprt;
298 unsigned short newport;
300 if (strcmp(xprt_name, xcl->xcl_name))
303 if (!try_module_get(xcl->xcl_owner))
306 spin_unlock(&svc_xprt_class_lock);
307 newxprt = __svc_xpo_create(xcl, serv, net, family, port, flags);
308 if (IS_ERR(newxprt)) {
309 module_put(xcl->xcl_owner);
310 return PTR_ERR(newxprt);
312 newxprt->xpt_cred = get_cred(cred);
313 svc_add_new_perm_xprt(serv, newxprt);
314 newport = svc_xprt_local_port(newxprt);
318 spin_unlock(&svc_xprt_class_lock);
319 /* This errno is exposed to user space. Provide a reasonable
320 * perror msg for a bad transport. */
321 return -EPROTONOSUPPORT;
325 * svc_xprt_create - Add a new listener to @serv
326 * @serv: target RPC service
327 * @xprt_name: transport class name
328 * @net: network namespace
329 * @family: network address family
330 * @port: listener port
331 * @flags: SVC_SOCK flags
332 * @cred: credential to bind to this transport
335 * %0: New listener added successfully
336 * %-EPROTONOSUPPORT: Requested transport type not supported
338 int svc_xprt_create(struct svc_serv *serv, const char *xprt_name,
339 struct net *net, const int family,
340 const unsigned short port, int flags,
341 const struct cred *cred)
345 err = _svc_xprt_create(serv, xprt_name, net, family, port, flags, cred);
346 if (err == -EPROTONOSUPPORT) {
347 request_module("svc%s", xprt_name);
348 err = _svc_xprt_create(serv, xprt_name, net, family, port, flags, cred);
352 EXPORT_SYMBOL_GPL(svc_xprt_create);
355 * Copy the local and remote xprt addresses to the rqstp structure
357 void svc_xprt_copy_addrs(struct svc_rqst *rqstp, struct svc_xprt *xprt)
359 memcpy(&rqstp->rq_addr, &xprt->xpt_remote, xprt->xpt_remotelen);
360 rqstp->rq_addrlen = xprt->xpt_remotelen;
363 * Destination address in request is needed for binding the
364 * source address in RPC replies/callbacks later.
366 memcpy(&rqstp->rq_daddr, &xprt->xpt_local, xprt->xpt_locallen);
367 rqstp->rq_daddrlen = xprt->xpt_locallen;
369 EXPORT_SYMBOL_GPL(svc_xprt_copy_addrs);
372 * svc_print_addr - Format rq_addr field for printing
373 * @rqstp: svc_rqst struct containing address to print
374 * @buf: target buffer for formatted address
375 * @len: length of target buffer
378 char *svc_print_addr(struct svc_rqst *rqstp, char *buf, size_t len)
380 return __svc_print_addr(svc_addr(rqstp), buf, len);
382 EXPORT_SYMBOL_GPL(svc_print_addr);
384 static bool svc_xprt_slots_in_range(struct svc_xprt *xprt)
386 unsigned int limit = svc_rpc_per_connection_limit;
387 int nrqsts = atomic_read(&xprt->xpt_nr_rqsts);
389 return limit == 0 || (nrqsts >= 0 && nrqsts < limit);
392 static bool svc_xprt_reserve_slot(struct svc_rqst *rqstp, struct svc_xprt *xprt)
394 if (!test_bit(RQ_DATA, &rqstp->rq_flags)) {
395 if (!svc_xprt_slots_in_range(xprt))
397 atomic_inc(&xprt->xpt_nr_rqsts);
398 set_bit(RQ_DATA, &rqstp->rq_flags);
403 static void svc_xprt_release_slot(struct svc_rqst *rqstp)
405 struct svc_xprt *xprt = rqstp->rq_xprt;
406 if (test_and_clear_bit(RQ_DATA, &rqstp->rq_flags)) {
407 atomic_dec(&xprt->xpt_nr_rqsts);
408 smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */
409 svc_xprt_enqueue(xprt);
413 static bool svc_xprt_ready(struct svc_xprt *xprt)
415 unsigned long xpt_flags;
418 * If another cpu has recently updated xpt_flags,
419 * sk_sock->flags, xpt_reserved, or xpt_nr_rqsts, we need to
420 * know about it; otherwise it's possible that both that cpu and
421 * this one could call svc_xprt_enqueue() without either
422 * svc_xprt_enqueue() recognizing that the conditions below
423 * are satisfied, and we could stall indefinitely:
426 xpt_flags = READ_ONCE(xprt->xpt_flags);
428 if (xpt_flags & BIT(XPT_BUSY))
430 if (xpt_flags & (BIT(XPT_CONN) | BIT(XPT_CLOSE) | BIT(XPT_HANDSHAKE)))
432 if (xpt_flags & (BIT(XPT_DATA) | BIT(XPT_DEFERRED))) {
433 if (xprt->xpt_ops->xpo_has_wspace(xprt) &&
434 svc_xprt_slots_in_range(xprt))
436 trace_svc_xprt_no_write_space(xprt);
443 * svc_xprt_enqueue - Queue a transport on an idle nfsd thread
444 * @xprt: transport with data pending
447 void svc_xprt_enqueue(struct svc_xprt *xprt)
449 struct svc_pool *pool;
450 struct svc_rqst *rqstp = NULL;
452 if (!svc_xprt_ready(xprt))
455 /* Mark transport as busy. It will remain in this state until
456 * the provider calls svc_xprt_received. We update XPT_BUSY
457 * atomically because it also guards against trying to enqueue
458 * the transport twice.
460 if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
463 pool = svc_pool_for_cpu(xprt->xpt_server);
465 percpu_counter_inc(&pool->sp_sockets_queued);
466 spin_lock_bh(&pool->sp_lock);
467 list_add_tail(&xprt->xpt_ready, &pool->sp_sockets);
468 spin_unlock_bh(&pool->sp_lock);
470 /* find a thread for this xprt */
472 list_for_each_entry_rcu(rqstp, &pool->sp_all_threads, rq_all) {
473 if (test_and_set_bit(RQ_BUSY, &rqstp->rq_flags))
475 percpu_counter_inc(&pool->sp_threads_woken);
476 rqstp->rq_qtime = ktime_get();
477 wake_up_process(rqstp->rq_task);
480 set_bit(SP_CONGESTED, &pool->sp_flags);
484 trace_svc_xprt_enqueue(xprt, rqstp);
486 EXPORT_SYMBOL_GPL(svc_xprt_enqueue);
489 * Dequeue the first transport, if there is one.
491 static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool)
493 struct svc_xprt *xprt = NULL;
495 if (list_empty(&pool->sp_sockets))
498 spin_lock_bh(&pool->sp_lock);
499 if (likely(!list_empty(&pool->sp_sockets))) {
500 xprt = list_first_entry(&pool->sp_sockets,
501 struct svc_xprt, xpt_ready);
502 list_del_init(&xprt->xpt_ready);
505 spin_unlock_bh(&pool->sp_lock);
511 * svc_reserve - change the space reserved for the reply to a request.
512 * @rqstp: The request in question
513 * @space: new max space to reserve
515 * Each request reserves some space on the output queue of the transport
516 * to make sure the reply fits. This function reduces that reserved
517 * space to be the amount of space used already, plus @space.
520 void svc_reserve(struct svc_rqst *rqstp, int space)
522 struct svc_xprt *xprt = rqstp->rq_xprt;
524 space += rqstp->rq_res.head[0].iov_len;
526 if (xprt && space < rqstp->rq_reserved) {
527 atomic_sub((rqstp->rq_reserved - space), &xprt->xpt_reserved);
528 rqstp->rq_reserved = space;
529 smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */
530 svc_xprt_enqueue(xprt);
533 EXPORT_SYMBOL_GPL(svc_reserve);
535 static void free_deferred(struct svc_xprt *xprt, struct svc_deferred_req *dr)
540 xprt->xpt_ops->xpo_release_ctxt(xprt, dr->xprt_ctxt);
544 static void svc_xprt_release(struct svc_rqst *rqstp)
546 struct svc_xprt *xprt = rqstp->rq_xprt;
548 xprt->xpt_ops->xpo_release_ctxt(xprt, rqstp->rq_xprt_ctxt);
549 rqstp->rq_xprt_ctxt = NULL;
551 free_deferred(xprt, rqstp->rq_deferred);
552 rqstp->rq_deferred = NULL;
554 svc_rqst_release_pages(rqstp);
555 rqstp->rq_res.page_len = 0;
556 rqstp->rq_res.page_base = 0;
558 /* Reset response buffer and release
560 * But first, check that enough space was reserved
561 * for the reply, otherwise we have a bug!
563 if ((rqstp->rq_res.len) > rqstp->rq_reserved)
564 printk(KERN_ERR "RPC request reserved %d but used %d\n",
568 rqstp->rq_res.head[0].iov_len = 0;
569 svc_reserve(rqstp, 0);
570 svc_xprt_release_slot(rqstp);
571 rqstp->rq_xprt = NULL;
576 * Some svc_serv's will have occasional work to do, even when a xprt is not
577 * waiting to be serviced. This function is there to "kick" a task in one of
578 * those services so that it can wake up and do that work. Note that we only
579 * bother with pool 0 as we don't need to wake up more than one thread for
582 void svc_wake_up(struct svc_serv *serv)
584 struct svc_rqst *rqstp;
585 struct svc_pool *pool;
587 pool = &serv->sv_pools[0];
590 list_for_each_entry_rcu(rqstp, &pool->sp_all_threads, rq_all) {
591 /* skip any that aren't queued */
592 if (test_bit(RQ_BUSY, &rqstp->rq_flags))
595 wake_up_process(rqstp->rq_task);
596 trace_svc_wake_up(rqstp->rq_task->pid);
601 /* No free entries available */
602 set_bit(SP_TASK_PENDING, &pool->sp_flags);
604 trace_svc_wake_up(0);
606 EXPORT_SYMBOL_GPL(svc_wake_up);
608 int svc_port_is_privileged(struct sockaddr *sin)
610 switch (sin->sa_family) {
612 return ntohs(((struct sockaddr_in *)sin)->sin_port)
615 return ntohs(((struct sockaddr_in6 *)sin)->sin6_port)
623 * Make sure that we don't have too many active connections. If we have,
624 * something must be dropped. It's not clear what will happen if we allow
625 * "too many" connections, but when dealing with network-facing software,
626 * we have to code defensively. Here we do that by imposing hard limits.
628 * There's no point in trying to do random drop here for DoS
629 * prevention. The NFS clients does 1 reconnect in 15 seconds. An
630 * attacker can easily beat that.
632 * The only somewhat efficient mechanism would be if drop old
633 * connections from the same IP first. But right now we don't even
634 * record the client IP in svc_sock.
636 * single-threaded services that expect a lot of clients will probably
637 * need to set sv_maxconn to override the default value which is based
638 * on the number of threads
640 static void svc_check_conn_limits(struct svc_serv *serv)
642 unsigned int limit = serv->sv_maxconn ? serv->sv_maxconn :
643 (serv->sv_nrthreads+3) * 20;
645 if (serv->sv_tmpcnt > limit) {
646 struct svc_xprt *xprt = NULL;
647 spin_lock_bh(&serv->sv_lock);
648 if (!list_empty(&serv->sv_tempsocks)) {
649 /* Try to help the admin */
650 net_notice_ratelimited("%s: too many open connections, consider increasing the %s\n",
651 serv->sv_name, serv->sv_maxconn ?
652 "max number of connections" :
653 "number of threads");
655 * Always select the oldest connection. It's not fair,
658 xprt = list_entry(serv->sv_tempsocks.prev,
661 set_bit(XPT_CLOSE, &xprt->xpt_flags);
664 spin_unlock_bh(&serv->sv_lock);
667 svc_xprt_enqueue(xprt);
673 static int svc_alloc_arg(struct svc_rqst *rqstp)
675 struct svc_serv *serv = rqstp->rq_server;
676 struct xdr_buf *arg = &rqstp->rq_arg;
677 unsigned long pages, filled, ret;
679 pages = (serv->sv_max_mesg + 2 * PAGE_SIZE) >> PAGE_SHIFT;
680 if (pages > RPCSVC_MAXPAGES) {
681 pr_warn_once("svc: warning: pages=%lu > RPCSVC_MAXPAGES=%lu\n",
682 pages, RPCSVC_MAXPAGES);
683 /* use as many pages as possible */
684 pages = RPCSVC_MAXPAGES;
687 for (filled = 0; filled < pages; filled = ret) {
688 ret = alloc_pages_bulk_array(GFP_KERNEL, pages,
691 /* Made progress, don't sleep yet */
694 set_current_state(TASK_INTERRUPTIBLE);
695 if (signalled() || kthread_should_stop()) {
696 set_current_state(TASK_RUNNING);
699 trace_svc_alloc_arg_err(pages, ret);
700 memalloc_retry_wait(GFP_KERNEL);
702 rqstp->rq_page_end = &rqstp->rq_pages[pages];
703 rqstp->rq_pages[pages] = NULL; /* this might be seen in nfsd_splice_actor() */
705 /* Make arg->head point to first page and arg->pages point to rest */
706 arg->head[0].iov_base = page_address(rqstp->rq_pages[0]);
707 arg->head[0].iov_len = PAGE_SIZE;
708 arg->pages = rqstp->rq_pages + 1;
710 /* save at least one page for response */
711 arg->page_len = (pages-2)*PAGE_SIZE;
712 arg->len = (pages-1)*PAGE_SIZE;
713 arg->tail[0].iov_len = 0;
715 rqstp->rq_xid = xdr_zero;
720 rqst_should_sleep(struct svc_rqst *rqstp)
722 struct svc_pool *pool = rqstp->rq_pool;
724 /* did someone call svc_wake_up? */
725 if (test_and_clear_bit(SP_TASK_PENDING, &pool->sp_flags))
728 /* was a socket queued? */
729 if (!list_empty(&pool->sp_sockets))
732 /* are we shutting down? */
733 if (signalled() || kthread_should_stop())
736 /* are we freezing? */
737 if (freezing(current))
743 static struct svc_xprt *svc_get_next_xprt(struct svc_rqst *rqstp, long timeout)
745 struct svc_pool *pool = rqstp->rq_pool;
748 /* rq_xprt should be clear on entry */
749 WARN_ON_ONCE(rqstp->rq_xprt);
751 rqstp->rq_xprt = svc_xprt_dequeue(pool);
756 * We have to be able to interrupt this wait
757 * to bring down the daemons ...
759 set_current_state(TASK_INTERRUPTIBLE);
760 smp_mb__before_atomic();
761 clear_bit(SP_CONGESTED, &pool->sp_flags);
762 clear_bit(RQ_BUSY, &rqstp->rq_flags);
763 smp_mb__after_atomic();
765 if (likely(rqst_should_sleep(rqstp)))
766 time_left = schedule_timeout(timeout);
768 __set_current_state(TASK_RUNNING);
772 set_bit(RQ_BUSY, &rqstp->rq_flags);
773 smp_mb__after_atomic();
774 rqstp->rq_xprt = svc_xprt_dequeue(pool);
779 percpu_counter_inc(&pool->sp_threads_timedout);
781 if (signalled() || kthread_should_stop())
782 return ERR_PTR(-EINTR);
783 return ERR_PTR(-EAGAIN);
785 /* Normally we will wait up to 5 seconds for any required
786 * cache information to be provided.
788 if (!test_bit(SP_CONGESTED, &pool->sp_flags))
789 rqstp->rq_chandle.thread_wait = 5*HZ;
791 rqstp->rq_chandle.thread_wait = 1*HZ;
792 trace_svc_xprt_dequeue(rqstp);
793 return rqstp->rq_xprt;
796 static void svc_add_new_temp_xprt(struct svc_serv *serv, struct svc_xprt *newxpt)
798 spin_lock_bh(&serv->sv_lock);
799 set_bit(XPT_TEMP, &newxpt->xpt_flags);
800 list_add(&newxpt->xpt_list, &serv->sv_tempsocks);
802 if (serv->sv_temptimer.function == NULL) {
803 /* setup timer to age temp transports */
804 serv->sv_temptimer.function = svc_age_temp_xprts;
805 mod_timer(&serv->sv_temptimer,
806 jiffies + svc_conn_age_period * HZ);
808 spin_unlock_bh(&serv->sv_lock);
809 svc_xprt_received(newxpt);
812 static int svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt)
814 struct svc_serv *serv = rqstp->rq_server;
817 if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) {
818 if (test_and_clear_bit(XPT_KILL_TEMP, &xprt->xpt_flags))
819 xprt->xpt_ops->xpo_kill_temp_xprt(xprt);
820 svc_delete_xprt(xprt);
821 /* Leave XPT_BUSY set on the dead xprt: */
824 if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) {
825 struct svc_xprt *newxpt;
827 * We know this module_get will succeed because the
828 * listener holds a reference too
830 __module_get(xprt->xpt_class->xcl_owner);
831 svc_check_conn_limits(xprt->xpt_server);
832 newxpt = xprt->xpt_ops->xpo_accept(xprt);
834 newxpt->xpt_cred = get_cred(xprt->xpt_cred);
835 svc_add_new_temp_xprt(serv, newxpt);
836 trace_svc_xprt_accept(newxpt, serv->sv_name);
838 module_put(xprt->xpt_class->xcl_owner);
840 svc_xprt_received(xprt);
841 } else if (test_bit(XPT_HANDSHAKE, &xprt->xpt_flags)) {
842 xprt->xpt_ops->xpo_handshake(xprt);
843 svc_xprt_received(xprt);
844 } else if (svc_xprt_reserve_slot(rqstp, xprt)) {
845 /* XPT_DATA|XPT_DEFERRED case: */
846 dprintk("svc: server %p, pool %u, transport %p, inuse=%d\n",
847 rqstp, rqstp->rq_pool->sp_id, xprt,
848 kref_read(&xprt->xpt_ref));
849 rqstp->rq_deferred = svc_deferred_dequeue(xprt);
850 if (rqstp->rq_deferred)
851 len = svc_deferred_recv(rqstp);
853 len = xprt->xpt_ops->xpo_recvfrom(rqstp);
854 rqstp->rq_stime = ktime_get();
855 rqstp->rq_reserved = serv->sv_max_mesg;
856 atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
858 svc_xprt_received(xprt);
865 * Receive the next request on any transport. This code is carefully
866 * organised not to touch any cachelines in the shared svc_serv
867 * structure, only cachelines in the local svc_pool.
869 int svc_recv(struct svc_rqst *rqstp, long timeout)
871 struct svc_xprt *xprt = NULL;
872 struct svc_serv *serv = rqstp->rq_server;
875 err = svc_alloc_arg(rqstp);
882 if (signalled() || kthread_should_stop())
885 xprt = svc_get_next_xprt(rqstp, timeout);
891 len = svc_handle_xprt(rqstp, xprt);
893 /* No data, incomplete (TCP) read, or accept() */
897 trace_svc_xdr_recvfrom(&rqstp->rq_arg);
899 clear_bit(XPT_OLD, &xprt->xpt_flags);
901 rqstp->rq_chandle.defer = svc_defer;
904 serv->sv_stats->netcnt++;
907 rqstp->rq_res.len = 0;
908 svc_xprt_release(rqstp);
912 EXPORT_SYMBOL_GPL(svc_recv);
917 void svc_drop(struct svc_rqst *rqstp)
919 trace_svc_drop(rqstp);
920 svc_xprt_release(rqstp);
922 EXPORT_SYMBOL_GPL(svc_drop);
925 * svc_send - Return reply to client
926 * @rqstp: RPC transaction context
929 void svc_send(struct svc_rqst *rqstp)
931 struct svc_xprt *xprt;
935 xprt = rqstp->rq_xprt;
939 /* calculate over-all length */
941 xb->len = xb->head[0].iov_len +
944 trace_svc_xdr_sendto(rqstp->rq_xid, xb);
945 trace_svc_stats_latency(rqstp);
947 status = xprt->xpt_ops->xpo_sendto(rqstp);
949 trace_svc_send(rqstp, status);
950 svc_xprt_release(rqstp);
954 * Timer function to close old temporary transports, using
955 * a mark-and-sweep algorithm.
957 static void svc_age_temp_xprts(struct timer_list *t)
959 struct svc_serv *serv = from_timer(serv, t, sv_temptimer);
960 struct svc_xprt *xprt;
961 struct list_head *le, *next;
963 dprintk("svc_age_temp_xprts\n");
965 if (!spin_trylock_bh(&serv->sv_lock)) {
966 /* busy, try again 1 sec later */
967 dprintk("svc_age_temp_xprts: busy\n");
968 mod_timer(&serv->sv_temptimer, jiffies + HZ);
972 list_for_each_safe(le, next, &serv->sv_tempsocks) {
973 xprt = list_entry(le, struct svc_xprt, xpt_list);
975 /* First time through, just mark it OLD. Second time
976 * through, close it. */
977 if (!test_and_set_bit(XPT_OLD, &xprt->xpt_flags))
979 if (kref_read(&xprt->xpt_ref) > 1 ||
980 test_bit(XPT_BUSY, &xprt->xpt_flags))
983 set_bit(XPT_CLOSE, &xprt->xpt_flags);
984 dprintk("queuing xprt %p for closing\n", xprt);
986 /* a thread will dequeue and close it soon */
987 svc_xprt_enqueue(xprt);
989 spin_unlock_bh(&serv->sv_lock);
991 mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ);
994 /* Close temporary transports whose xpt_local matches server_addr immediately
995 * instead of waiting for them to be picked up by the timer.
997 * This is meant to be called from a notifier_block that runs when an ip
998 * address is deleted.
1000 void svc_age_temp_xprts_now(struct svc_serv *serv, struct sockaddr *server_addr)
1002 struct svc_xprt *xprt;
1003 struct list_head *le, *next;
1004 LIST_HEAD(to_be_closed);
1006 spin_lock_bh(&serv->sv_lock);
1007 list_for_each_safe(le, next, &serv->sv_tempsocks) {
1008 xprt = list_entry(le, struct svc_xprt, xpt_list);
1009 if (rpc_cmp_addr(server_addr, (struct sockaddr *)
1010 &xprt->xpt_local)) {
1011 dprintk("svc_age_temp_xprts_now: found %p\n", xprt);
1012 list_move(le, &to_be_closed);
1015 spin_unlock_bh(&serv->sv_lock);
1017 while (!list_empty(&to_be_closed)) {
1018 le = to_be_closed.next;
1020 xprt = list_entry(le, struct svc_xprt, xpt_list);
1021 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1022 set_bit(XPT_KILL_TEMP, &xprt->xpt_flags);
1023 dprintk("svc_age_temp_xprts_now: queuing xprt %p for closing\n",
1025 svc_xprt_enqueue(xprt);
1028 EXPORT_SYMBOL_GPL(svc_age_temp_xprts_now);
1030 static void call_xpt_users(struct svc_xprt *xprt)
1032 struct svc_xpt_user *u;
1034 spin_lock(&xprt->xpt_lock);
1035 while (!list_empty(&xprt->xpt_users)) {
1036 u = list_first_entry(&xprt->xpt_users, struct svc_xpt_user, list);
1037 list_del_init(&u->list);
1040 spin_unlock(&xprt->xpt_lock);
1044 * Remove a dead transport
1046 static void svc_delete_xprt(struct svc_xprt *xprt)
1048 struct svc_serv *serv = xprt->xpt_server;
1049 struct svc_deferred_req *dr;
1051 if (test_and_set_bit(XPT_DEAD, &xprt->xpt_flags))
1054 trace_svc_xprt_detach(xprt);
1055 xprt->xpt_ops->xpo_detach(xprt);
1056 if (xprt->xpt_bc_xprt)
1057 xprt->xpt_bc_xprt->ops->close(xprt->xpt_bc_xprt);
1059 spin_lock_bh(&serv->sv_lock);
1060 list_del_init(&xprt->xpt_list);
1061 WARN_ON_ONCE(!list_empty(&xprt->xpt_ready));
1062 if (test_bit(XPT_TEMP, &xprt->xpt_flags))
1064 spin_unlock_bh(&serv->sv_lock);
1066 while ((dr = svc_deferred_dequeue(xprt)) != NULL)
1067 free_deferred(xprt, dr);
1069 call_xpt_users(xprt);
1074 * svc_xprt_close - Close a client connection
1075 * @xprt: transport to disconnect
1078 void svc_xprt_close(struct svc_xprt *xprt)
1080 trace_svc_xprt_close(xprt);
1081 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1082 if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags))
1083 /* someone else will have to effect the close */
1086 * We expect svc_close_xprt() to work even when no threads are
1087 * running (e.g., while configuring the server before starting
1088 * any threads), so if the transport isn't busy, we delete
1091 svc_delete_xprt(xprt);
1093 EXPORT_SYMBOL_GPL(svc_xprt_close);
1095 static int svc_close_list(struct svc_serv *serv, struct list_head *xprt_list, struct net *net)
1097 struct svc_xprt *xprt;
1100 spin_lock_bh(&serv->sv_lock);
1101 list_for_each_entry(xprt, xprt_list, xpt_list) {
1102 if (xprt->xpt_net != net)
1105 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1106 svc_xprt_enqueue(xprt);
1108 spin_unlock_bh(&serv->sv_lock);
1112 static struct svc_xprt *svc_dequeue_net(struct svc_serv *serv, struct net *net)
1114 struct svc_pool *pool;
1115 struct svc_xprt *xprt;
1116 struct svc_xprt *tmp;
1119 for (i = 0; i < serv->sv_nrpools; i++) {
1120 pool = &serv->sv_pools[i];
1122 spin_lock_bh(&pool->sp_lock);
1123 list_for_each_entry_safe(xprt, tmp, &pool->sp_sockets, xpt_ready) {
1124 if (xprt->xpt_net != net)
1126 list_del_init(&xprt->xpt_ready);
1127 spin_unlock_bh(&pool->sp_lock);
1130 spin_unlock_bh(&pool->sp_lock);
1135 static void svc_clean_up_xprts(struct svc_serv *serv, struct net *net)
1137 struct svc_xprt *xprt;
1139 while ((xprt = svc_dequeue_net(serv, net))) {
1140 set_bit(XPT_CLOSE, &xprt->xpt_flags);
1141 svc_delete_xprt(xprt);
1146 * svc_xprt_destroy_all - Destroy transports associated with @serv
1147 * @serv: RPC service to be shut down
1148 * @net: target network namespace
1150 * Server threads may still be running (especially in the case where the
1151 * service is still running in other network namespaces).
1153 * So we shut down sockets the same way we would on a running server, by
1154 * setting XPT_CLOSE, enqueuing, and letting a thread pick it up to do
1155 * the close. In the case there are no such other threads,
1156 * threads running, svc_clean_up_xprts() does a simple version of a
1157 * server's main event loop, and in the case where there are other
1158 * threads, we may need to wait a little while and then check again to
1159 * see if they're done.
1161 void svc_xprt_destroy_all(struct svc_serv *serv, struct net *net)
1165 while (svc_close_list(serv, &serv->sv_permsocks, net) +
1166 svc_close_list(serv, &serv->sv_tempsocks, net)) {
1168 svc_clean_up_xprts(serv, net);
1172 EXPORT_SYMBOL_GPL(svc_xprt_destroy_all);
1175 * Handle defer and revisit of requests
1178 static void svc_revisit(struct cache_deferred_req *dreq, int too_many)
1180 struct svc_deferred_req *dr =
1181 container_of(dreq, struct svc_deferred_req, handle);
1182 struct svc_xprt *xprt = dr->xprt;
1184 spin_lock(&xprt->xpt_lock);
1185 set_bit(XPT_DEFERRED, &xprt->xpt_flags);
1186 if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) {
1187 spin_unlock(&xprt->xpt_lock);
1188 trace_svc_defer_drop(dr);
1189 free_deferred(xprt, dr);
1194 list_add(&dr->handle.recent, &xprt->xpt_deferred);
1195 spin_unlock(&xprt->xpt_lock);
1196 trace_svc_defer_queue(dr);
1197 svc_xprt_enqueue(xprt);
1202 * Save the request off for later processing. The request buffer looks
1205 * <xprt-header><rpc-header><rpc-pagelist><rpc-tail>
1207 * This code can only handle requests that consist of an xprt-header
1210 static struct cache_deferred_req *svc_defer(struct cache_req *req)
1212 struct svc_rqst *rqstp = container_of(req, struct svc_rqst, rq_chandle);
1213 struct svc_deferred_req *dr;
1215 if (rqstp->rq_arg.page_len || !test_bit(RQ_USEDEFERRAL, &rqstp->rq_flags))
1216 return NULL; /* if more than a page, give up FIXME */
1217 if (rqstp->rq_deferred) {
1218 dr = rqstp->rq_deferred;
1219 rqstp->rq_deferred = NULL;
1223 /* FIXME maybe discard if size too large */
1224 size = sizeof(struct svc_deferred_req) + rqstp->rq_arg.len;
1225 dr = kmalloc(size, GFP_KERNEL);
1229 dr->handle.owner = rqstp->rq_server;
1230 dr->prot = rqstp->rq_prot;
1231 memcpy(&dr->addr, &rqstp->rq_addr, rqstp->rq_addrlen);
1232 dr->addrlen = rqstp->rq_addrlen;
1233 dr->daddr = rqstp->rq_daddr;
1234 dr->argslen = rqstp->rq_arg.len >> 2;
1236 /* back up head to the start of the buffer and copy */
1237 skip = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len;
1238 memcpy(dr->args, rqstp->rq_arg.head[0].iov_base - skip,
1241 dr->xprt_ctxt = rqstp->rq_xprt_ctxt;
1242 rqstp->rq_xprt_ctxt = NULL;
1243 trace_svc_defer(rqstp);
1244 svc_xprt_get(rqstp->rq_xprt);
1245 dr->xprt = rqstp->rq_xprt;
1246 set_bit(RQ_DROPME, &rqstp->rq_flags);
1248 dr->handle.revisit = svc_revisit;
1253 * recv data from a deferred request into an active one
1255 static noinline int svc_deferred_recv(struct svc_rqst *rqstp)
1257 struct svc_deferred_req *dr = rqstp->rq_deferred;
1259 trace_svc_defer_recv(dr);
1261 /* setup iov_base past transport header */
1262 rqstp->rq_arg.head[0].iov_base = dr->args;
1263 /* The iov_len does not include the transport header bytes */
1264 rqstp->rq_arg.head[0].iov_len = dr->argslen << 2;
1265 rqstp->rq_arg.page_len = 0;
1266 /* The rq_arg.len includes the transport header bytes */
1267 rqstp->rq_arg.len = dr->argslen << 2;
1268 rqstp->rq_prot = dr->prot;
1269 memcpy(&rqstp->rq_addr, &dr->addr, dr->addrlen);
1270 rqstp->rq_addrlen = dr->addrlen;
1271 /* Save off transport header len in case we get deferred again */
1272 rqstp->rq_daddr = dr->daddr;
1273 rqstp->rq_respages = rqstp->rq_pages;
1274 rqstp->rq_xprt_ctxt = dr->xprt_ctxt;
1276 dr->xprt_ctxt = NULL;
1277 svc_xprt_received(rqstp->rq_xprt);
1278 return dr->argslen << 2;
1282 static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt)
1284 struct svc_deferred_req *dr = NULL;
1286 if (!test_bit(XPT_DEFERRED, &xprt->xpt_flags))
1288 spin_lock(&xprt->xpt_lock);
1289 if (!list_empty(&xprt->xpt_deferred)) {
1290 dr = list_entry(xprt->xpt_deferred.next,
1291 struct svc_deferred_req,
1293 list_del_init(&dr->handle.recent);
1295 clear_bit(XPT_DEFERRED, &xprt->xpt_flags);
1296 spin_unlock(&xprt->xpt_lock);
1301 * svc_find_xprt - find an RPC transport instance
1302 * @serv: pointer to svc_serv to search
1303 * @xcl_name: C string containing transport's class name
1304 * @net: owner net pointer
1305 * @af: Address family of transport's local address
1306 * @port: transport's IP port number
1308 * Return the transport instance pointer for the endpoint accepting
1309 * connections/peer traffic from the specified transport class,
1310 * address family and port.
1312 * Specifying 0 for the address family or port is effectively a
1313 * wild-card, and will result in matching the first transport in the
1314 * service's list that has a matching class name.
1316 struct svc_xprt *svc_find_xprt(struct svc_serv *serv, const char *xcl_name,
1317 struct net *net, const sa_family_t af,
1318 const unsigned short port)
1320 struct svc_xprt *xprt;
1321 struct svc_xprt *found = NULL;
1323 /* Sanity check the args */
1324 if (serv == NULL || xcl_name == NULL)
1327 spin_lock_bh(&serv->sv_lock);
1328 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1329 if (xprt->xpt_net != net)
1331 if (strcmp(xprt->xpt_class->xcl_name, xcl_name))
1333 if (af != AF_UNSPEC && af != xprt->xpt_local.ss_family)
1335 if (port != 0 && port != svc_xprt_local_port(xprt))
1341 spin_unlock_bh(&serv->sv_lock);
1344 EXPORT_SYMBOL_GPL(svc_find_xprt);
1346 static int svc_one_xprt_name(const struct svc_xprt *xprt,
1347 char *pos, int remaining)
1351 len = snprintf(pos, remaining, "%s %u\n",
1352 xprt->xpt_class->xcl_name,
1353 svc_xprt_local_port(xprt));
1354 if (len >= remaining)
1355 return -ENAMETOOLONG;
1360 * svc_xprt_names - format a buffer with a list of transport names
1361 * @serv: pointer to an RPC service
1362 * @buf: pointer to a buffer to be filled in
1363 * @buflen: length of buffer to be filled in
1365 * Fills in @buf with a string containing a list of transport names,
1366 * each name terminated with '\n'.
1368 * Returns positive length of the filled-in string on success; otherwise
1369 * a negative errno value is returned if an error occurs.
1371 int svc_xprt_names(struct svc_serv *serv, char *buf, const int buflen)
1373 struct svc_xprt *xprt;
1377 /* Sanity check args */
1381 spin_lock_bh(&serv->sv_lock);
1385 list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1386 len = svc_one_xprt_name(xprt, pos, buflen - totlen);
1398 spin_unlock_bh(&serv->sv_lock);
1401 EXPORT_SYMBOL_GPL(svc_xprt_names);
1404 /*----------------------------------------------------------------------------*/
1406 static void *svc_pool_stats_start(struct seq_file *m, loff_t *pos)
1408 unsigned int pidx = (unsigned int)*pos;
1409 struct svc_serv *serv = m->private;
1411 dprintk("svc_pool_stats_start, *pidx=%u\n", pidx);
1414 return SEQ_START_TOKEN;
1415 return (pidx > serv->sv_nrpools ? NULL : &serv->sv_pools[pidx-1]);
1418 static void *svc_pool_stats_next(struct seq_file *m, void *p, loff_t *pos)
1420 struct svc_pool *pool = p;
1421 struct svc_serv *serv = m->private;
1423 dprintk("svc_pool_stats_next, *pos=%llu\n", *pos);
1425 if (p == SEQ_START_TOKEN) {
1426 pool = &serv->sv_pools[0];
1428 unsigned int pidx = (pool - &serv->sv_pools[0]);
1429 if (pidx < serv->sv_nrpools-1)
1430 pool = &serv->sv_pools[pidx+1];
1438 static void svc_pool_stats_stop(struct seq_file *m, void *p)
1442 static int svc_pool_stats_show(struct seq_file *m, void *p)
1444 struct svc_pool *pool = p;
1446 if (p == SEQ_START_TOKEN) {
1447 seq_puts(m, "# pool packets-arrived sockets-enqueued threads-woken threads-timedout\n");
1451 seq_printf(m, "%u %llu %llu %llu %llu\n",
1453 percpu_counter_sum_positive(&pool->sp_sockets_queued),
1454 percpu_counter_sum_positive(&pool->sp_sockets_queued),
1455 percpu_counter_sum_positive(&pool->sp_threads_woken),
1456 percpu_counter_sum_positive(&pool->sp_threads_timedout));
1461 static const struct seq_operations svc_pool_stats_seq_ops = {
1462 .start = svc_pool_stats_start,
1463 .next = svc_pool_stats_next,
1464 .stop = svc_pool_stats_stop,
1465 .show = svc_pool_stats_show,
1468 int svc_pool_stats_open(struct svc_serv *serv, struct file *file)
1472 err = seq_open(file, &svc_pool_stats_seq_ops);
1474 ((struct seq_file *) file->private_data)->private = serv;
1477 EXPORT_SYMBOL(svc_pool_stats_open);
1479 /*----------------------------------------------------------------------------*/