// SPDX-License-Identifier: GPL-2.0-only /* * linux/net/sunrpc/svc_xprt.c * * Author: Tom Tucker */ #include #include #include #include #include #include #include #include #include #include #include #include #include #include #include #define RPCDBG_FACILITY RPCDBG_SVCXPRT static unsigned int svc_rpc_per_connection_limit __read_mostly; module_param(svc_rpc_per_connection_limit, uint, 0644); static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt); static int svc_deferred_recv(struct svc_rqst *rqstp); static struct cache_deferred_req *svc_defer(struct cache_req *req); static void svc_age_temp_xprts(struct timer_list *t); static void svc_delete_xprt(struct svc_xprt *xprt); /* apparently the "standard" is that clients close * idle connections after 5 minutes, servers after * 6 minutes * http://nfsv4bat.org/Documents/ConnectAThon/1996/nfstcp.pdf */ static int svc_conn_age_period = 6*60; /* List of registered transport classes */ static DEFINE_SPINLOCK(svc_xprt_class_lock); static LIST_HEAD(svc_xprt_class_list); /* SMP locking strategy: * * svc_pool->sp_lock protects most of the fields of that pool. * svc_serv->sv_lock protects sv_tempsocks, sv_permsocks, sv_tmpcnt. * when both need to be taken (rare), svc_serv->sv_lock is first. * The "service mutex" protects svc_serv->sv_nrthread. * svc_sock->sk_lock protects the svc_sock->sk_deferred list * and the ->sk_info_authunix cache. * * The XPT_BUSY bit in xprt->xpt_flags prevents a transport being * enqueued multiply. During normal transport processing this bit * is set by svc_xprt_enqueue and cleared by svc_xprt_received. * Providers should not manipulate this bit directly. * * Some flags can be set to certain values at any time * providing that certain rules are followed: * * XPT_CONN, XPT_DATA: * - Can be set or cleared at any time. * - After a set, svc_xprt_enqueue must be called to enqueue * the transport for processing. * - After a clear, the transport must be read/accepted. * If this succeeds, it must be set again. * XPT_CLOSE: * - Can set at any time. It is never cleared. * XPT_DEAD: * - Can only be set while XPT_BUSY is held which ensures * that no other thread will be using the transport or will * try to set XPT_DEAD. */ /** * svc_reg_xprt_class - Register a server-side RPC transport class * @xcl: New transport class to be registered * * Returns zero on success; otherwise a negative errno is returned. */ int svc_reg_xprt_class(struct svc_xprt_class *xcl) { struct svc_xprt_class *cl; int res = -EEXIST; INIT_LIST_HEAD(&xcl->xcl_list); spin_lock(&svc_xprt_class_lock); /* Make sure there isn't already a class with the same name */ list_for_each_entry(cl, &svc_xprt_class_list, xcl_list) { if (strcmp(xcl->xcl_name, cl->xcl_name) == 0) goto out; } list_add_tail(&xcl->xcl_list, &svc_xprt_class_list); res = 0; out: spin_unlock(&svc_xprt_class_lock); return res; } EXPORT_SYMBOL_GPL(svc_reg_xprt_class); /** * svc_unreg_xprt_class - Unregister a server-side RPC transport class * @xcl: Transport class to be unregistered * */ void svc_unreg_xprt_class(struct svc_xprt_class *xcl) { spin_lock(&svc_xprt_class_lock); list_del_init(&xcl->xcl_list); spin_unlock(&svc_xprt_class_lock); } EXPORT_SYMBOL_GPL(svc_unreg_xprt_class); /** * svc_print_xprts - Format the transport list for printing * @buf: target buffer for formatted address * @maxlen: length of target buffer * * Fills in @buf with a string containing a list of transport names, each name * terminated with '\n'. If the buffer is too small, some entries may be * missing, but it is guaranteed that all lines in the output buffer are * complete. * * Returns positive length of the filled-in string. */ int svc_print_xprts(char *buf, int maxlen) { struct svc_xprt_class *xcl; char tmpstr[80]; int len = 0; buf[0] = '\0'; spin_lock(&svc_xprt_class_lock); list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) { int slen; slen = snprintf(tmpstr, sizeof(tmpstr), "%s %d\n", xcl->xcl_name, xcl->xcl_max_payload); if (slen >= sizeof(tmpstr) || len + slen >= maxlen) break; len += slen; strcat(buf, tmpstr); } spin_unlock(&svc_xprt_class_lock); return len; } /** * svc_xprt_deferred_close - Close a transport * @xprt: transport instance * * Used in contexts that need to defer the work of shutting down * the transport to an nfsd thread. */ void svc_xprt_deferred_close(struct svc_xprt *xprt) { if (!test_and_set_bit(XPT_CLOSE, &xprt->xpt_flags)) svc_xprt_enqueue(xprt); } EXPORT_SYMBOL_GPL(svc_xprt_deferred_close); static void svc_xprt_free(struct kref *kref) { struct svc_xprt *xprt = container_of(kref, struct svc_xprt, xpt_ref); struct module *owner = xprt->xpt_class->xcl_owner; if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags)) svcauth_unix_info_release(xprt); put_cred(xprt->xpt_cred); put_net_track(xprt->xpt_net, &xprt->ns_tracker); /* See comment on corresponding get in xs_setup_bc_tcp(): */ if (xprt->xpt_bc_xprt) xprt_put(xprt->xpt_bc_xprt); if (xprt->xpt_bc_xps) xprt_switch_put(xprt->xpt_bc_xps); trace_svc_xprt_free(xprt); xprt->xpt_ops->xpo_free(xprt); module_put(owner); } void svc_xprt_put(struct svc_xprt *xprt) { kref_put(&xprt->xpt_ref, svc_xprt_free); } EXPORT_SYMBOL_GPL(svc_xprt_put); /* * Called by transport drivers to initialize the transport independent * portion of the transport instance. */ void svc_xprt_init(struct net *net, struct svc_xprt_class *xcl, struct svc_xprt *xprt, struct svc_serv *serv) { memset(xprt, 0, sizeof(*xprt)); xprt->xpt_class = xcl; xprt->xpt_ops = xcl->xcl_ops; kref_init(&xprt->xpt_ref); xprt->xpt_server = serv; INIT_LIST_HEAD(&xprt->xpt_list); INIT_LIST_HEAD(&xprt->xpt_deferred); INIT_LIST_HEAD(&xprt->xpt_users); mutex_init(&xprt->xpt_mutex); spin_lock_init(&xprt->xpt_lock); set_bit(XPT_BUSY, &xprt->xpt_flags); xprt->xpt_net = get_net_track(net, &xprt->ns_tracker, GFP_ATOMIC); strcpy(xprt->xpt_remotebuf, "uninitialized"); } EXPORT_SYMBOL_GPL(svc_xprt_init); static struct svc_xprt *__svc_xpo_create(struct svc_xprt_class *xcl, struct svc_serv *serv, struct net *net, const int family, const unsigned short port, int flags) { struct sockaddr_in sin = { .sin_family = AF_INET, .sin_addr.s_addr = htonl(INADDR_ANY), .sin_port = htons(port), }; #if IS_ENABLED(CONFIG_IPV6) struct sockaddr_in6 sin6 = { .sin6_family = AF_INET6, .sin6_addr = IN6ADDR_ANY_INIT, .sin6_port = htons(port), }; #endif struct svc_xprt *xprt; struct sockaddr *sap; size_t len; switch (family) { case PF_INET: sap = (struct sockaddr *)&sin; len = sizeof(sin); break; #if IS_ENABLED(CONFIG_IPV6) case PF_INET6: sap = (struct sockaddr *)&sin6; len = sizeof(sin6); break; #endif default: return ERR_PTR(-EAFNOSUPPORT); } xprt = xcl->xcl_ops->xpo_create(serv, net, sap, len, flags); if (IS_ERR(xprt)) trace_svc_xprt_create_err(serv->sv_program->pg_name, xcl->xcl_name, sap, len, xprt); return xprt; } /** * svc_xprt_received - start next receiver thread * @xprt: controlling transport * * The caller must hold the XPT_BUSY bit and must * not thereafter touch transport data. * * Note: XPT_DATA only gets cleared when a read-attempt finds no (or * insufficient) data. */ void svc_xprt_received(struct svc_xprt *xprt) { if (!test_bit(XPT_BUSY, &xprt->xpt_flags)) { WARN_ONCE(1, "xprt=0x%p already busy!", xprt); return; } /* As soon as we clear busy, the xprt could be closed and * 'put', so we need a reference to call svc_xprt_enqueue with: */ svc_xprt_get(xprt); smp_mb__before_atomic(); clear_bit(XPT_BUSY, &xprt->xpt_flags); svc_xprt_enqueue(xprt); svc_xprt_put(xprt); } EXPORT_SYMBOL_GPL(svc_xprt_received); void svc_add_new_perm_xprt(struct svc_serv *serv, struct svc_xprt *new) { clear_bit(XPT_TEMP, &new->xpt_flags); spin_lock_bh(&serv->sv_lock); list_add(&new->xpt_list, &serv->sv_permsocks); spin_unlock_bh(&serv->sv_lock); svc_xprt_received(new); } static int _svc_xprt_create(struct svc_serv *serv, const char *xprt_name, struct net *net, const int family, const unsigned short port, int flags, const struct cred *cred) { struct svc_xprt_class *xcl; spin_lock(&svc_xprt_class_lock); list_for_each_entry(xcl, &svc_xprt_class_list, xcl_list) { struct svc_xprt *newxprt; unsigned short newport; if (strcmp(xprt_name, xcl->xcl_name)) continue; if (!try_module_get(xcl->xcl_owner)) goto err; spin_unlock(&svc_xprt_class_lock); newxprt = __svc_xpo_create(xcl, serv, net, family, port, flags); if (IS_ERR(newxprt)) { module_put(xcl->xcl_owner); return PTR_ERR(newxprt); } newxprt->xpt_cred = get_cred(cred); svc_add_new_perm_xprt(serv, newxprt); newport = svc_xprt_local_port(newxprt); return newport; } err: spin_unlock(&svc_xprt_class_lock); /* This errno is exposed to user space. Provide a reasonable * perror msg for a bad transport. */ return -EPROTONOSUPPORT; } /** * svc_xprt_create - Add a new listener to @serv * @serv: target RPC service * @xprt_name: transport class name * @net: network namespace * @family: network address family * @port: listener port * @flags: SVC_SOCK flags * @cred: credential to bind to this transport * * Return values: * %0: New listener added successfully * %-EPROTONOSUPPORT: Requested transport type not supported */ int svc_xprt_create(struct svc_serv *serv, const char *xprt_name, struct net *net, const int family, const unsigned short port, int flags, const struct cred *cred) { int err; err = _svc_xprt_create(serv, xprt_name, net, family, port, flags, cred); if (err == -EPROTONOSUPPORT) { request_module("svc%s", xprt_name); err = _svc_xprt_create(serv, xprt_name, net, family, port, flags, cred); } return err; } EXPORT_SYMBOL_GPL(svc_xprt_create); /* * Copy the local and remote xprt addresses to the rqstp structure */ void svc_xprt_copy_addrs(struct svc_rqst *rqstp, struct svc_xprt *xprt) { memcpy(&rqstp->rq_addr, &xprt->xpt_remote, xprt->xpt_remotelen); rqstp->rq_addrlen = xprt->xpt_remotelen; /* * Destination address in request is needed for binding the * source address in RPC replies/callbacks later. */ memcpy(&rqstp->rq_daddr, &xprt->xpt_local, xprt->xpt_locallen); rqstp->rq_daddrlen = xprt->xpt_locallen; } EXPORT_SYMBOL_GPL(svc_xprt_copy_addrs); /** * svc_print_addr - Format rq_addr field for printing * @rqstp: svc_rqst struct containing address to print * @buf: target buffer for formatted address * @len: length of target buffer * */ char *svc_print_addr(struct svc_rqst *rqstp, char *buf, size_t len) { return __svc_print_addr(svc_addr(rqstp), buf, len); } EXPORT_SYMBOL_GPL(svc_print_addr); static bool svc_xprt_slots_in_range(struct svc_xprt *xprt) { unsigned int limit = svc_rpc_per_connection_limit; int nrqsts = atomic_read(&xprt->xpt_nr_rqsts); return limit == 0 || (nrqsts >= 0 && nrqsts < limit); } static bool svc_xprt_reserve_slot(struct svc_rqst *rqstp, struct svc_xprt *xprt) { if (!test_bit(RQ_DATA, &rqstp->rq_flags)) { if (!svc_xprt_slots_in_range(xprt)) return false; atomic_inc(&xprt->xpt_nr_rqsts); set_bit(RQ_DATA, &rqstp->rq_flags); } return true; } static void svc_xprt_release_slot(struct svc_rqst *rqstp) { struct svc_xprt *xprt = rqstp->rq_xprt; if (test_and_clear_bit(RQ_DATA, &rqstp->rq_flags)) { atomic_dec(&xprt->xpt_nr_rqsts); smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */ svc_xprt_enqueue(xprt); } } static bool svc_xprt_ready(struct svc_xprt *xprt) { unsigned long xpt_flags; /* * If another cpu has recently updated xpt_flags, * sk_sock->flags, xpt_reserved, or xpt_nr_rqsts, we need to * know about it; otherwise it's possible that both that cpu and * this one could call svc_xprt_enqueue() without either * svc_xprt_enqueue() recognizing that the conditions below * are satisfied, and we could stall indefinitely: */ smp_rmb(); xpt_flags = READ_ONCE(xprt->xpt_flags); trace_svc_xprt_enqueue(xprt, xpt_flags); if (xpt_flags & BIT(XPT_BUSY)) return false; if (xpt_flags & (BIT(XPT_CONN) | BIT(XPT_CLOSE) | BIT(XPT_HANDSHAKE))) return true; if (xpt_flags & (BIT(XPT_DATA) | BIT(XPT_DEFERRED))) { if (xprt->xpt_ops->xpo_has_wspace(xprt) && svc_xprt_slots_in_range(xprt)) return true; trace_svc_xprt_no_write_space(xprt); return false; } return false; } /** * svc_xprt_enqueue - Queue a transport on an idle nfsd thread * @xprt: transport with data pending * */ void svc_xprt_enqueue(struct svc_xprt *xprt) { struct svc_pool *pool; if (!svc_xprt_ready(xprt)) return; /* Mark transport as busy. It will remain in this state until * the provider calls svc_xprt_received. We update XPT_BUSY * atomically because it also guards against trying to enqueue * the transport twice. */ if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags)) return; pool = svc_pool_for_cpu(xprt->xpt_server); percpu_counter_inc(&pool->sp_sockets_queued); lwq_enqueue(&xprt->xpt_ready, &pool->sp_xprts); svc_pool_wake_idle_thread(pool); } EXPORT_SYMBOL_GPL(svc_xprt_enqueue); /* * Dequeue the first transport, if there is one. */ static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool) { struct svc_xprt *xprt = NULL; xprt = lwq_dequeue(&pool->sp_xprts, struct svc_xprt, xpt_ready); if (xprt) svc_xprt_get(xprt); return xprt; } /** * svc_reserve - change the space reserved for the reply to a request. * @rqstp: The request in question * @space: new max space to reserve * * Each request reserves some space on the output queue of the transport * to make sure the reply fits. This function reduces that reserved * space to be the amount of space used already, plus @space. * */ void svc_reserve(struct svc_rqst *rqstp, int space) { struct svc_xprt *xprt = rqstp->rq_xprt; space += rqstp->rq_res.head[0].iov_len; if (xprt && space < rqstp->rq_reserved) { atomic_sub((rqstp->rq_reserved - space), &xprt->xpt_reserved); rqstp->rq_reserved = space; smp_wmb(); /* See smp_rmb() in svc_xprt_ready() */ svc_xprt_enqueue(xprt); } } EXPORT_SYMBOL_GPL(svc_reserve); static void free_deferred(struct svc_xprt *xprt, struct svc_deferred_req *dr) { if (!dr) return; xprt->xpt_ops->xpo_release_ctxt(xprt, dr->xprt_ctxt); kfree(dr); } static void svc_xprt_release(struct svc_rqst *rqstp) { struct svc_xprt *xprt = rqstp->rq_xprt; xprt->xpt_ops->xpo_release_ctxt(xprt, rqstp->rq_xprt_ctxt); rqstp->rq_xprt_ctxt = NULL; free_deferred(xprt, rqstp->rq_deferred); rqstp->rq_deferred = NULL; svc_rqst_release_pages(rqstp); rqstp->rq_res.page_len = 0; rqstp->rq_res.page_base = 0; /* Reset response buffer and release * the reservation. * But first, check that enough space was reserved * for the reply, otherwise we have a bug! */ if ((rqstp->rq_res.len) > rqstp->rq_reserved) printk(KERN_ERR "RPC request reserved %d but used %d\n", rqstp->rq_reserved, rqstp->rq_res.len); rqstp->rq_res.head[0].iov_len = 0; svc_reserve(rqstp, 0); svc_xprt_release_slot(rqstp); rqstp->rq_xprt = NULL; svc_xprt_put(xprt); } /** * svc_wake_up - Wake up a service thread for non-transport work * @serv: RPC service * * Some svc_serv's will have occasional work to do, even when a xprt is not * waiting to be serviced. This function is there to "kick" a task in one of * those services so that it can wake up and do that work. Note that we only * bother with pool 0 as we don't need to wake up more than one thread for * this purpose. */ void svc_wake_up(struct svc_serv *serv) { struct svc_pool *pool = &serv->sv_pools[0]; set_bit(SP_TASK_PENDING, &pool->sp_flags); svc_pool_wake_idle_thread(pool); } EXPORT_SYMBOL_GPL(svc_wake_up); int svc_port_is_privileged(struct sockaddr *sin) { switch (sin->sa_family) { case AF_INET: return ntohs(((struct sockaddr_in *)sin)->sin_port) < PROT_SOCK; case AF_INET6: return ntohs(((struct sockaddr_in6 *)sin)->sin6_port) < PROT_SOCK; default: return 0; } } /* * Make sure that we don't have too many active connections. If we have, * something must be dropped. It's not clear what will happen if we allow * "too many" connections, but when dealing with network-facing software, * we have to code defensively. Here we do that by imposing hard limits. * * There's no point in trying to do random drop here for DoS * prevention. The NFS clients does 1 reconnect in 15 seconds. An * attacker can easily beat that. * * The only somewhat efficient mechanism would be if drop old * connections from the same IP first. But right now we don't even * record the client IP in svc_sock. * * single-threaded services that expect a lot of clients will probably * need to set sv_maxconn to override the default value which is based * on the number of threads */ static void svc_check_conn_limits(struct svc_serv *serv) { unsigned int limit = serv->sv_maxconn ? serv->sv_maxconn : (serv->sv_nrthreads+3) * 20; if (serv->sv_tmpcnt > limit) { struct svc_xprt *xprt = NULL; spin_lock_bh(&serv->sv_lock); if (!list_empty(&serv->sv_tempsocks)) { /* Try to help the admin */ net_notice_ratelimited("%s: too many open connections, consider increasing the %s\n", serv->sv_name, serv->sv_maxconn ? "max number of connections" : "number of threads"); /* * Always select the oldest connection. It's not fair, * but so is life */ xprt = list_entry(serv->sv_tempsocks.prev, struct svc_xprt, xpt_list); set_bit(XPT_CLOSE, &xprt->xpt_flags); svc_xprt_get(xprt); } spin_unlock_bh(&serv->sv_lock); if (xprt) { svc_xprt_enqueue(xprt); svc_xprt_put(xprt); } } } static bool svc_alloc_arg(struct svc_rqst *rqstp) { struct svc_serv *serv = rqstp->rq_server; struct xdr_buf *arg = &rqstp->rq_arg; unsigned long pages, filled, ret; pages = (serv->sv_max_mesg + 2 * PAGE_SIZE) >> PAGE_SHIFT; if (pages > RPCSVC_MAXPAGES) { pr_warn_once("svc: warning: pages=%lu > RPCSVC_MAXPAGES=%lu\n", pages, RPCSVC_MAXPAGES); /* use as many pages as possible */ pages = RPCSVC_MAXPAGES; } for (filled = 0; filled < pages; filled = ret) { ret = alloc_pages_bulk_array(GFP_KERNEL, pages, rqstp->rq_pages); if (ret > filled) /* Made progress, don't sleep yet */ continue; set_current_state(TASK_IDLE); if (svc_thread_should_stop(rqstp)) { set_current_state(TASK_RUNNING); return false; } trace_svc_alloc_arg_err(pages, ret); memalloc_retry_wait(GFP_KERNEL); } rqstp->rq_page_end = &rqstp->rq_pages[pages]; rqstp->rq_pages[pages] = NULL; /* this might be seen in nfsd_splice_actor() */ /* Make arg->head point to first page and arg->pages point to rest */ arg->head[0].iov_base = page_address(rqstp->rq_pages[0]); arg->head[0].iov_len = PAGE_SIZE; arg->pages = rqstp->rq_pages + 1; arg->page_base = 0; /* save at least one page for response */ arg->page_len = (pages-2)*PAGE_SIZE; arg->len = (pages-1)*PAGE_SIZE; arg->tail[0].iov_len = 0; rqstp->rq_xid = xdr_zero; return true; } static bool svc_thread_should_sleep(struct svc_rqst *rqstp) { struct svc_pool *pool = rqstp->rq_pool; /* did someone call svc_wake_up? */ if (test_bit(SP_TASK_PENDING, &pool->sp_flags)) return false; /* was a socket queued? */ if (!lwq_empty(&pool->sp_xprts)) return false; /* are we shutting down? */ if (svc_thread_should_stop(rqstp)) return false; #if defined(CONFIG_SUNRPC_BACKCHANNEL) if (svc_is_backchannel(rqstp)) { if (!lwq_empty(&rqstp->rq_server->sv_cb_list)) return false; } #endif return true; } static void svc_thread_wait_for_work(struct svc_rqst *rqstp) { struct svc_pool *pool = rqstp->rq_pool; if (svc_thread_should_sleep(rqstp)) { set_current_state(TASK_IDLE | TASK_FREEZABLE); llist_add(&rqstp->rq_idle, &pool->sp_idle_threads); if (likely(svc_thread_should_sleep(rqstp))) schedule(); while (!llist_del_first_this(&pool->sp_idle_threads, &rqstp->rq_idle)) { /* Work just became available. This thread can only * handle it after removing rqstp from the idle * list. If that attempt failed, some other thread * must have queued itself after finding no * work to do, so that thread has taken responsibly * for this new work. This thread can safely sleep * until woken again. */ schedule(); set_current_state(TASK_IDLE | TASK_FREEZABLE); } __set_current_state(TASK_RUNNING); } else { cond_resched(); } try_to_freeze(); } static void svc_add_new_temp_xprt(struct svc_serv *serv, struct svc_xprt *newxpt) { spin_lock_bh(&serv->sv_lock); set_bit(XPT_TEMP, &newxpt->xpt_flags); list_add(&newxpt->xpt_list, &serv->sv_tempsocks); serv->sv_tmpcnt++; if (serv->sv_temptimer.function == NULL) { /* setup timer to age temp transports */ serv->sv_temptimer.function = svc_age_temp_xprts; mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ); } spin_unlock_bh(&serv->sv_lock); svc_xprt_received(newxpt); } static void svc_handle_xprt(struct svc_rqst *rqstp, struct svc_xprt *xprt) { struct svc_serv *serv = rqstp->rq_server; int len = 0; if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) { if (test_and_clear_bit(XPT_KILL_TEMP, &xprt->xpt_flags)) xprt->xpt_ops->xpo_kill_temp_xprt(xprt); svc_delete_xprt(xprt); /* Leave XPT_BUSY set on the dead xprt: */ goto out; } if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) { struct svc_xprt *newxpt; /* * We know this module_get will succeed because the * listener holds a reference too */ __module_get(xprt->xpt_class->xcl_owner); svc_check_conn_limits(xprt->xpt_server); newxpt = xprt->xpt_ops->xpo_accept(xprt); if (newxpt) { newxpt->xpt_cred = get_cred(xprt->xpt_cred); svc_add_new_temp_xprt(serv, newxpt); trace_svc_xprt_accept(newxpt, serv->sv_name); } else { module_put(xprt->xpt_class->xcl_owner); } svc_xprt_received(xprt); } else if (test_bit(XPT_HANDSHAKE, &xprt->xpt_flags)) { xprt->xpt_ops->xpo_handshake(xprt); svc_xprt_received(xprt); } else if (svc_xprt_reserve_slot(rqstp, xprt)) { /* XPT_DATA|XPT_DEFERRED case: */ rqstp->rq_deferred = svc_deferred_dequeue(xprt); if (rqstp->rq_deferred) len = svc_deferred_recv(rqstp); else len = xprt->xpt_ops->xpo_recvfrom(rqstp); rqstp->rq_reserved = serv->sv_max_mesg; atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved); if (len <= 0) goto out; trace_svc_xdr_recvfrom(&rqstp->rq_arg); clear_bit(XPT_OLD, &xprt->xpt_flags); rqstp->rq_chandle.defer = svc_defer; if (serv->sv_stats) serv->sv_stats->netcnt++; percpu_counter_inc(&rqstp->rq_pool->sp_messages_arrived); rqstp->rq_stime = ktime_get(); svc_process(rqstp); } else svc_xprt_received(xprt); out: rqstp->rq_res.len = 0; svc_xprt_release(rqstp); } static void svc_thread_wake_next(struct svc_rqst *rqstp) { if (!svc_thread_should_sleep(rqstp)) /* More work pending after I dequeued some, * wake another worker */ svc_pool_wake_idle_thread(rqstp->rq_pool); } /** * svc_recv - Receive and process the next request on any transport * @rqstp: an idle RPC service thread * * This code is carefully organised not to touch any cachelines in * the shared svc_serv structure, only cachelines in the local * svc_pool. */ void svc_recv(struct svc_rqst *rqstp) { struct svc_pool *pool = rqstp->rq_pool; if (!svc_alloc_arg(rqstp)) return; svc_thread_wait_for_work(rqstp); clear_bit(SP_TASK_PENDING, &pool->sp_flags); if (svc_thread_should_stop(rqstp)) { svc_thread_wake_next(rqstp); return; } rqstp->rq_xprt = svc_xprt_dequeue(pool); if (rqstp->rq_xprt) { struct svc_xprt *xprt = rqstp->rq_xprt; svc_thread_wake_next(rqstp); /* Normally we will wait up to 5 seconds for any required * cache information to be provided. When there are no * idle threads, we reduce the wait time. */ if (pool->sp_idle_threads.first) rqstp->rq_chandle.thread_wait = 5 * HZ; else rqstp->rq_chandle.thread_wait = 1 * HZ; trace_svc_xprt_dequeue(rqstp); svc_handle_xprt(rqstp, xprt); } #if defined(CONFIG_SUNRPC_BACKCHANNEL) if (svc_is_backchannel(rqstp)) { struct svc_serv *serv = rqstp->rq_server; struct rpc_rqst *req; req = lwq_dequeue(&serv->sv_cb_list, struct rpc_rqst, rq_bc_list); if (req) { svc_thread_wake_next(rqstp); svc_process_bc(req, rqstp); } } #endif } EXPORT_SYMBOL_GPL(svc_recv); /* * Drop request */ void svc_drop(struct svc_rqst *rqstp) { trace_svc_drop(rqstp); } EXPORT_SYMBOL_GPL(svc_drop); /** * svc_send - Return reply to client * @rqstp: RPC transaction context * */ void svc_send(struct svc_rqst *rqstp) { struct svc_xprt *xprt; struct xdr_buf *xb; int status; xprt = rqstp->rq_xprt; /* calculate over-all length */ xb = &rqstp->rq_res; xb->len = xb->head[0].iov_len + xb->page_len + xb->tail[0].iov_len; trace_svc_xdr_sendto(rqstp->rq_xid, xb); trace_svc_stats_latency(rqstp); status = xprt->xpt_ops->xpo_sendto(rqstp); trace_svc_send(rqstp, status); } /* * Timer function to close old temporary transports, using * a mark-and-sweep algorithm. */ static void svc_age_temp_xprts(struct timer_list *t) { struct svc_serv *serv = from_timer(serv, t, sv_temptimer); struct svc_xprt *xprt; struct list_head *le, *next; dprintk("svc_age_temp_xprts\n"); if (!spin_trylock_bh(&serv->sv_lock)) { /* busy, try again 1 sec later */ dprintk("svc_age_temp_xprts: busy\n"); mod_timer(&serv->sv_temptimer, jiffies + HZ); return; } list_for_each_safe(le, next, &serv->sv_tempsocks) { xprt = list_entry(le, struct svc_xprt, xpt_list); /* First time through, just mark it OLD. Second time * through, close it. */ if (!test_and_set_bit(XPT_OLD, &xprt->xpt_flags)) continue; if (kref_read(&xprt->xpt_ref) > 1 || test_bit(XPT_BUSY, &xprt->xpt_flags)) continue; list_del_init(le); set_bit(XPT_CLOSE, &xprt->xpt_flags); dprintk("queuing xprt %p for closing\n", xprt); /* a thread will dequeue and close it soon */ svc_xprt_enqueue(xprt); } spin_unlock_bh(&serv->sv_lock); mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ); } /* Close temporary transports whose xpt_local matches server_addr immediately * instead of waiting for them to be picked up by the timer. * * This is meant to be called from a notifier_block that runs when an ip * address is deleted. */ void svc_age_temp_xprts_now(struct svc_serv *serv, struct sockaddr *server_addr) { struct svc_xprt *xprt; struct list_head *le, *next; LIST_HEAD(to_be_closed); spin_lock_bh(&serv->sv_lock); list_for_each_safe(le, next, &serv->sv_tempsocks) { xprt = list_entry(le, struct svc_xprt, xpt_list); if (rpc_cmp_addr(server_addr, (struct sockaddr *) &xprt->xpt_local)) { dprintk("svc_age_temp_xprts_now: found %p\n", xprt); list_move(le, &to_be_closed); } } spin_unlock_bh(&serv->sv_lock); while (!list_empty(&to_be_closed)) { le = to_be_closed.next; list_del_init(le); xprt = list_entry(le, struct svc_xprt, xpt_list); set_bit(XPT_CLOSE, &xprt->xpt_flags); set_bit(XPT_KILL_TEMP, &xprt->xpt_flags); dprintk("svc_age_temp_xprts_now: queuing xprt %p for closing\n", xprt); svc_xprt_enqueue(xprt); } } EXPORT_SYMBOL_GPL(svc_age_temp_xprts_now); static void call_xpt_users(struct svc_xprt *xprt) { struct svc_xpt_user *u; spin_lock(&xprt->xpt_lock); while (!list_empty(&xprt->xpt_users)) { u = list_first_entry(&xprt->xpt_users, struct svc_xpt_user, list); list_del_init(&u->list); u->callback(u); } spin_unlock(&xprt->xpt_lock); } /* * Remove a dead transport */ static void svc_delete_xprt(struct svc_xprt *xprt) { struct svc_serv *serv = xprt->xpt_server; struct svc_deferred_req *dr; if (test_and_set_bit(XPT_DEAD, &xprt->xpt_flags)) return; trace_svc_xprt_detach(xprt); xprt->xpt_ops->xpo_detach(xprt); if (xprt->xpt_bc_xprt) xprt->xpt_bc_xprt->ops->close(xprt->xpt_bc_xprt); spin_lock_bh(&serv->sv_lock); list_del_init(&xprt->xpt_list); if (test_bit(XPT_TEMP, &xprt->xpt_flags)) serv->sv_tmpcnt--; spin_unlock_bh(&serv->sv_lock); while ((dr = svc_deferred_dequeue(xprt)) != NULL) free_deferred(xprt, dr); call_xpt_users(xprt); svc_xprt_put(xprt); } /** * svc_xprt_close - Close a client connection * @xprt: transport to disconnect * */ void svc_xprt_close(struct svc_xprt *xprt) { trace_svc_xprt_close(xprt); set_bit(XPT_CLOSE, &xprt->xpt_flags); if (test_and_set_bit(XPT_BUSY, &xprt->xpt_flags)) /* someone else will have to effect the close */ return; /* * We expect svc_close_xprt() to work even when no threads are * running (e.g., while configuring the server before starting * any threads), so if the transport isn't busy, we delete * it ourself: */ svc_delete_xprt(xprt); } EXPORT_SYMBOL_GPL(svc_xprt_close); static int svc_close_list(struct svc_serv *serv, struct list_head *xprt_list, struct net *net) { struct svc_xprt *xprt; int ret = 0; spin_lock_bh(&serv->sv_lock); list_for_each_entry(xprt, xprt_list, xpt_list) { if (xprt->xpt_net != net) continue; ret++; set_bit(XPT_CLOSE, &xprt->xpt_flags); svc_xprt_enqueue(xprt); } spin_unlock_bh(&serv->sv_lock); return ret; } static void svc_clean_up_xprts(struct svc_serv *serv, struct net *net) { struct svc_xprt *xprt; int i; for (i = 0; i < serv->sv_nrpools; i++) { struct svc_pool *pool = &serv->sv_pools[i]; struct llist_node *q, **t1, *t2; q = lwq_dequeue_all(&pool->sp_xprts); lwq_for_each_safe(xprt, t1, t2, &q, xpt_ready) { if (xprt->xpt_net == net) { set_bit(XPT_CLOSE, &xprt->xpt_flags); svc_delete_xprt(xprt); xprt = NULL; } } if (q) lwq_enqueue_batch(q, &pool->sp_xprts); } } /** * svc_xprt_destroy_all - Destroy transports associated with @serv * @serv: RPC service to be shut down * @net: target network namespace * * Server threads may still be running (especially in the case where the * service is still running in other network namespaces). * * So we shut down sockets the same way we would on a running server, by * setting XPT_CLOSE, enqueuing, and letting a thread pick it up to do * the close. In the case there are no such other threads, * threads running, svc_clean_up_xprts() does a simple version of a * server's main event loop, and in the case where there are other * threads, we may need to wait a little while and then check again to * see if they're done. */ void svc_xprt_destroy_all(struct svc_serv *serv, struct net *net) { int delay = 0; while (svc_close_list(serv, &serv->sv_permsocks, net) + svc_close_list(serv, &serv->sv_tempsocks, net)) { svc_clean_up_xprts(serv, net); msleep(delay++); } } EXPORT_SYMBOL_GPL(svc_xprt_destroy_all); /* * Handle defer and revisit of requests */ static void svc_revisit(struct cache_deferred_req *dreq, int too_many) { struct svc_deferred_req *dr = container_of(dreq, struct svc_deferred_req, handle); struct svc_xprt *xprt = dr->xprt; spin_lock(&xprt->xpt_lock); set_bit(XPT_DEFERRED, &xprt->xpt_flags); if (too_many || test_bit(XPT_DEAD, &xprt->xpt_flags)) { spin_unlock(&xprt->xpt_lock); trace_svc_defer_drop(dr); free_deferred(xprt, dr); svc_xprt_put(xprt); return; } dr->xprt = NULL; list_add(&dr->handle.recent, &xprt->xpt_deferred); spin_unlock(&xprt->xpt_lock); trace_svc_defer_queue(dr); svc_xprt_enqueue(xprt); svc_xprt_put(xprt); } /* * Save the request off for later processing. The request buffer looks * like this: * * * * This code can only handle requests that consist of an xprt-header * and rpc-header. */ static struct cache_deferred_req *svc_defer(struct cache_req *req) { struct svc_rqst *rqstp = container_of(req, struct svc_rqst, rq_chandle); struct svc_deferred_req *dr; if (rqstp->rq_arg.page_len || !test_bit(RQ_USEDEFERRAL, &rqstp->rq_flags)) return NULL; /* if more than a page, give up FIXME */ if (rqstp->rq_deferred) { dr = rqstp->rq_deferred; rqstp->rq_deferred = NULL; } else { size_t skip; size_t size; /* FIXME maybe discard if size too large */ size = sizeof(struct svc_deferred_req) + rqstp->rq_arg.len; dr = kmalloc(size, GFP_KERNEL); if (dr == NULL) return NULL; dr->handle.owner = rqstp->rq_server; dr->prot = rqstp->rq_prot; memcpy(&dr->addr, &rqstp->rq_addr, rqstp->rq_addrlen); dr->addrlen = rqstp->rq_addrlen; dr->daddr = rqstp->rq_daddr; dr->argslen = rqstp->rq_arg.len >> 2; /* back up head to the start of the buffer and copy */ skip = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len; memcpy(dr->args, rqstp->rq_arg.head[0].iov_base - skip, dr->argslen << 2); } dr->xprt_ctxt = rqstp->rq_xprt_ctxt; rqstp->rq_xprt_ctxt = NULL; trace_svc_defer(rqstp); svc_xprt_get(rqstp->rq_xprt); dr->xprt = rqstp->rq_xprt; set_bit(RQ_DROPME, &rqstp->rq_flags); dr->handle.revisit = svc_revisit; return &dr->handle; } /* * recv data from a deferred request into an active one */ static noinline int svc_deferred_recv(struct svc_rqst *rqstp) { struct svc_deferred_req *dr = rqstp->rq_deferred; trace_svc_defer_recv(dr); /* setup iov_base past transport header */ rqstp->rq_arg.head[0].iov_base = dr->args; /* The iov_len does not include the transport header bytes */ rqstp->rq_arg.head[0].iov_len = dr->argslen << 2; rqstp->rq_arg.page_len = 0; /* The rq_arg.len includes the transport header bytes */ rqstp->rq_arg.len = dr->argslen << 2; rqstp->rq_prot = dr->prot; memcpy(&rqstp->rq_addr, &dr->addr, dr->addrlen); rqstp->rq_addrlen = dr->addrlen; /* Save off transport header len in case we get deferred again */ rqstp->rq_daddr = dr->daddr; rqstp->rq_respages = rqstp->rq_pages; rqstp->rq_xprt_ctxt = dr->xprt_ctxt; dr->xprt_ctxt = NULL; svc_xprt_received(rqstp->rq_xprt); return dr->argslen << 2; } static struct svc_deferred_req *svc_deferred_dequeue(struct svc_xprt *xprt) { struct svc_deferred_req *dr = NULL; if (!test_bit(XPT_DEFERRED, &xprt->xpt_flags)) return NULL; spin_lock(&xprt->xpt_lock); if (!list_empty(&xprt->xpt_deferred)) { dr = list_entry(xprt->xpt_deferred.next, struct svc_deferred_req, handle.recent); list_del_init(&dr->handle.recent); } else clear_bit(XPT_DEFERRED, &xprt->xpt_flags); spin_unlock(&xprt->xpt_lock); return dr; } /** * svc_find_xprt - find an RPC transport instance * @serv: pointer to svc_serv to search * @xcl_name: C string containing transport's class name * @net: owner net pointer * @af: Address family of transport's local address * @port: transport's IP port number * * Return the transport instance pointer for the endpoint accepting * connections/peer traffic from the specified transport class, * address family and port. * * Specifying 0 for the address family or port is effectively a * wild-card, and will result in matching the first transport in the * service's list that has a matching class name. */ struct svc_xprt *svc_find_xprt(struct svc_serv *serv, const char *xcl_name, struct net *net, const sa_family_t af, const unsigned short port) { struct svc_xprt *xprt; struct svc_xprt *found = NULL; /* Sanity check the args */ if (serv == NULL || xcl_name == NULL) return found; spin_lock_bh(&serv->sv_lock); list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) { if (xprt->xpt_net != net) continue; if (strcmp(xprt->xpt_class->xcl_name, xcl_name)) continue; if (af != AF_UNSPEC && af != xprt->xpt_local.ss_family) continue; if (port != 0 && port != svc_xprt_local_port(xprt)) continue; found = xprt; svc_xprt_get(xprt); break; } spin_unlock_bh(&serv->sv_lock); return found; } EXPORT_SYMBOL_GPL(svc_find_xprt); static int svc_one_xprt_name(const struct svc_xprt *xprt, char *pos, int remaining) { int len; len = snprintf(pos, remaining, "%s %u\n", xprt->xpt_class->xcl_name, svc_xprt_local_port(xprt)); if (len >= remaining) return -ENAMETOOLONG; return len; } /** * svc_xprt_names - format a buffer with a list of transport names * @serv: pointer to an RPC service * @buf: pointer to a buffer to be filled in * @buflen: length of buffer to be filled in * * Fills in @buf with a string containing a list of transport names, * each name terminated with '\n'. * * Returns positive length of the filled-in string on success; otherwise * a negative errno value is returned if an error occurs. */ int svc_xprt_names(struct svc_serv *serv, char *buf, const int buflen) { struct svc_xprt *xprt; int len, totlen; char *pos; /* Sanity check args */ if (!serv) return 0; spin_lock_bh(&serv->sv_lock); pos = buf; totlen = 0; list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) { len = svc_one_xprt_name(xprt, pos, buflen - totlen); if (len < 0) { *buf = '\0'; totlen = len; } if (len <= 0) break; pos += len; totlen += len; } spin_unlock_bh(&serv->sv_lock); return totlen; } EXPORT_SYMBOL_GPL(svc_xprt_names); /*----------------------------------------------------------------------------*/ static void *svc_pool_stats_start(struct seq_file *m, loff_t *pos) { unsigned int pidx = (unsigned int)*pos; struct svc_info *si = m->private; dprintk("svc_pool_stats_start, *pidx=%u\n", pidx); mutex_lock(si->mutex); if (!pidx) return SEQ_START_TOKEN; if (!si->serv) return NULL; return pidx > si->serv->sv_nrpools ? NULL : &si->serv->sv_pools[pidx - 1]; } static void *svc_pool_stats_next(struct seq_file *m, void *p, loff_t *pos) { struct svc_pool *pool = p; struct svc_info *si = m->private; struct svc_serv *serv = si->serv; dprintk("svc_pool_stats_next, *pos=%llu\n", *pos); if (!serv) { pool = NULL; } else if (p == SEQ_START_TOKEN) { pool = &serv->sv_pools[0]; } else { unsigned int pidx = (pool - &serv->sv_pools[0]); if (pidx < serv->sv_nrpools-1) pool = &serv->sv_pools[pidx+1]; else pool = NULL; } ++*pos; return pool; } static void svc_pool_stats_stop(struct seq_file *m, void *p) { struct svc_info *si = m->private; mutex_unlock(si->mutex); } static int svc_pool_stats_show(struct seq_file *m, void *p) { struct svc_pool *pool = p; if (p == SEQ_START_TOKEN) { seq_puts(m, "# pool packets-arrived sockets-enqueued threads-woken threads-timedout\n"); return 0; } seq_printf(m, "%u %llu %llu %llu 0\n", pool->sp_id, percpu_counter_sum_positive(&pool->sp_messages_arrived), percpu_counter_sum_positive(&pool->sp_sockets_queued), percpu_counter_sum_positive(&pool->sp_threads_woken)); return 0; } static const struct seq_operations svc_pool_stats_seq_ops = { .start = svc_pool_stats_start, .next = svc_pool_stats_next, .stop = svc_pool_stats_stop, .show = svc_pool_stats_show, }; int svc_pool_stats_open(struct svc_info *info, struct file *file) { struct seq_file *seq; int err; err = seq_open(file, &svc_pool_stats_seq_ops); if (err) return err; seq = file->private_data; seq->private = info; return 0; } EXPORT_SYMBOL(svc_pool_stats_open); /*----------------------------------------------------------------------------*/