diff options
Diffstat (limited to 'net/sunrpc/svc_xprt.c')
| -rw-r--r-- | net/sunrpc/svc_xprt.c | 1450 |
1 files changed, 1450 insertions, 0 deletions
diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c new file mode 100644 index 0000000000..5cfe5c7408 --- /dev/null +++ b/net/sunrpc/svc_xprt.c @@ -0,0 +1,1450 @@ +// SPDX-License-Identifier: GPL-2.0-only +/* + * linux/net/sunrpc/svc_xprt.c + * + * Author: Tom Tucker <tom@opengridcomputing.com> + */ + +#include <linux/sched.h> +#include <linux/sched/mm.h> +#include <linux/errno.h> +#include <linux/freezer.h> +#include <linux/kthread.h> +#include <linux/slab.h> +#include <net/sock.h> +#include <linux/sunrpc/addr.h> +#include <linux/sunrpc/stats.h> +#include <linux/sunrpc/svc_xprt.h> +#include <linux/sunrpc/svcsock.h> +#include <linux/sunrpc/xprt.h> +#include <linux/module.h> +#include <linux/netdevice.h> +#include <trace/events/sunrpc.h> + +#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_ready); + 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); + spin_lock_bh(&pool->sp_lock); + list_add_tail(&xprt->xpt_ready, &pool->sp_sockets); + spin_unlock_bh(&pool->sp_lock); + + 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; + + if (list_empty(&pool->sp_sockets)) + goto out; + + spin_lock_bh(&pool->sp_lock); + if (likely(!list_empty(&pool->sp_sockets))) { + xprt = list_first_entry(&pool->sp_sockets, + struct svc_xprt, xpt_ready); + list_del_init(&xprt->xpt_ready); + svc_xprt_get(xprt); + } + spin_unlock_bh(&pool->sp_lock); +out: + 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 (kthread_should_stop()) { + 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 +rqst_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 (!list_empty(&pool->sp_sockets)) + return false; + + /* are we shutting down? */ + if (kthread_should_stop()) + return false; + + /* are we freezing? */ + if (freezing(current)) + return false; + + return true; +} + +static struct svc_xprt *svc_get_next_xprt(struct svc_rqst *rqstp) +{ + struct svc_pool *pool = rqstp->rq_pool; + + /* rq_xprt should be clear on entry */ + WARN_ON_ONCE(rqstp->rq_xprt); + + rqstp->rq_xprt = svc_xprt_dequeue(pool); + if (rqstp->rq_xprt) + goto out_found; + + set_current_state(TASK_IDLE); + smp_mb__before_atomic(); + clear_bit(SP_CONGESTED, &pool->sp_flags); + clear_bit(RQ_BUSY, &rqstp->rq_flags); + smp_mb__after_atomic(); + + if (likely(rqst_should_sleep(rqstp))) + schedule(); + else + __set_current_state(TASK_RUNNING); + + try_to_freeze(); + + set_bit(RQ_BUSY, &rqstp->rq_flags); + smp_mb__after_atomic(); + clear_bit(SP_TASK_PENDING, &pool->sp_flags); + rqstp->rq_xprt = svc_xprt_dequeue(pool); + if (rqstp->rq_xprt) + goto out_found; + + if (kthread_should_stop()) + return NULL; + return NULL; +out_found: + clear_bit(SP_TASK_PENDING, &pool->sp_flags); + /* Normally we will wait up to 5 seconds for any required + * cache information to be provided. + */ + if (!test_bit(SP_CONGESTED, &pool->sp_flags)) + rqstp->rq_chandle.thread_wait = 5*HZ; + else + rqstp->rq_chandle.thread_wait = 1*HZ; + trace_svc_xprt_dequeue(rqstp); + return rqstp->rq_xprt; +} + +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 int 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); + } else + svc_xprt_received(xprt); + +out: + return len; +} + +/** + * 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_xprt *xprt = NULL; + struct svc_serv *serv = rqstp->rq_server; + int len; + + if (!svc_alloc_arg(rqstp)) + goto out; + + try_to_freeze(); + cond_resched(); + if (kthread_should_stop()) + goto out; + + xprt = svc_get_next_xprt(rqstp); + if (!xprt) + goto out; + + len = svc_handle_xprt(rqstp, xprt); + + /* No data, incomplete (TCP) read, or accept() */ + if (len <= 0) + goto out_release; + + 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); +out: + return; +out_release: + rqstp->rq_res.len = 0; + svc_xprt_release(rqstp); +} +EXPORT_SYMBOL_GPL(svc_recv); + +/* + * Drop request + */ +void svc_drop(struct svc_rqst *rqstp) +{ + trace_svc_drop(rqstp); + svc_xprt_release(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; + if (!xprt) + return; + + /* 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); + svc_xprt_release(rqstp); +} + +/* + * 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); + WARN_ON_ONCE(!list_empty(&xprt->xpt_ready)); + 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 struct svc_xprt *svc_dequeue_net(struct svc_serv *serv, struct net *net) +{ + struct svc_pool *pool; + struct svc_xprt *xprt; + struct svc_xprt *tmp; + int i; + + for (i = 0; i < serv->sv_nrpools; i++) { + pool = &serv->sv_pools[i]; + + spin_lock_bh(&pool->sp_lock); + list_for_each_entry_safe(xprt, tmp, &pool->sp_sockets, xpt_ready) { + if (xprt->xpt_net != net) + continue; + list_del_init(&xprt->xpt_ready); + spin_unlock_bh(&pool->sp_lock); + return xprt; + } + spin_unlock_bh(&pool->sp_lock); + } + return NULL; +} + +static void svc_clean_up_xprts(struct svc_serv *serv, struct net *net) +{ + struct svc_xprt *xprt; + + while ((xprt = svc_dequeue_net(serv, net))) { + set_bit(XPT_CLOSE, &xprt->xpt_flags); + svc_delete_xprt(xprt); + } +} + +/** + * 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: + * + * <xprt-header><rpc-header><rpc-pagelist><rpc-tail> + * + * 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_serv *serv = m->private; + + dprintk("svc_pool_stats_start, *pidx=%u\n", pidx); + + if (!pidx) + return SEQ_START_TOKEN; + return (pidx > serv->sv_nrpools ? NULL : &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_serv *serv = m->private; + + dprintk("svc_pool_stats_next, *pos=%llu\n", *pos); + + 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) +{ +} + +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_serv *serv, struct file *file) +{ + int err; + + err = seq_open(file, &svc_pool_stats_seq_ops); + if (!err) + ((struct seq_file *) file->private_data)->private = serv; + return err; +} +EXPORT_SYMBOL(svc_pool_stats_open); + +/*----------------------------------------------------------------------------*/ |