Initial import

1 files changed, 1371 insertions, 0 deletions

diff --git a/net/sunrpc/svc_xprt.c b/net/sunrpc/svc_xprt.c
new file mode 100644
index 000000000..163ac45c3
--- /dev/null
+++ b/net/sunrpc/svc_xprt.c
@@ -0,0 +1,1371 @@
+/*
+ * linux/net/sunrpc/svc_xprt.c
+ *
+ * Author: Tom Tucker <tom@opengridcomputing.com>
+ */
+
+#include <linux/sched.h>
+#include <linux/errno.h>
+#include <linux/freezer.h>
+#include <linux/kthread.h>
+#include <linux/slab.h>
+#include <net/sock.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 <trace/events/sunrpc.h>
+
+#define RPCDBG_FACILITY	RPCDBG_SVCXPRT
+
+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(unsigned long closure);
+static void svc_delete_xprt(struct svc_xprt *xprt);
+static void svc_xprt_do_enqueue(struct svc_xprt *xprt);
+
+/* apparently the "standard" is that clients close
+ * idle connections after 5 minutes, servers after
+ * 6 minutes
+ *   http://www.connectathon.org/talks96/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.
+ */
+int svc_reg_xprt_class(struct svc_xprt_class *xcl)
+{
+	struct svc_xprt_class *cl;
+	int res = -EEXIST;
+
+	dprintk("svc: Adding svc transport class '%s'\n", xcl->xcl_name);
+
+	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);
+
+void svc_unreg_xprt_class(struct svc_xprt_class *xcl)
+{
+	dprintk("svc: Removing svc transport class '%s'\n", xcl->xcl_name);
+	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);
+
+/*
+ * Format the transport list for printing
+ */
+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;
+
+		sprintf(tmpstr, "%s %d\n", xcl->xcl_name, xcl->xcl_max_payload);
+		slen = strlen(tmpstr);
+		if (len + slen > maxlen)
+			break;
+		len += slen;
+		strcat(buf, tmpstr);
+	}
+	spin_unlock(&svc_xprt_class_lock);
+
+	return len;
+}
+
+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_net(xprt->xpt_net);
+	/* See comment on corresponding get in xs_setup_bc_tcp(): */
+	if (xprt->xpt_bc_xprt)
+		xprt_put(xprt->xpt_bc_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);
+	rpc_init_wait_queue(&xprt->xpt_bc_pending, "xpt_bc_pending");
+	xprt->xpt_net = get_net(net);
+}
+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 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);
+	}
+
+	return xcl->xcl_ops->xpo_create(serv, net, sap, len, flags);
+}
+
+/*
+ * svc_xprt_received conditionally queues the transport for processing
+ * by another thread. 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.
+ */
+static 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_do_enqueue with:
+	 */
+	svc_xprt_get(xprt);
+	smp_mb__before_atomic();
+	clear_bit(XPT_BUSY, &xprt->xpt_flags);
+	svc_xprt_do_enqueue(xprt);
+	svc_xprt_put(xprt);
+}
+
+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);
+}
+
+int svc_create_xprt(struct svc_serv *serv, const char *xprt_name,
+		    struct net *net, const int family,
+		    const unsigned short port, int flags)
+{
+	struct svc_xprt_class *xcl;
+
+	dprintk("svc: creating transport %s[%d]\n", xprt_name, port);
+	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);
+		}
+		svc_add_new_perm_xprt(serv, newxprt);
+		newport = svc_xprt_local_port(newxprt);
+		return newport;
+	}
+ err:
+	spin_unlock(&svc_xprt_class_lock);
+	dprintk("svc: transport %s not found\n", xprt_name);
+
+	/* This errno is exposed to user space.  Provide a reasonable
+	 * perror msg for a bad transport. */
+	return -EPROTONOSUPPORT;
+}
+EXPORT_SYMBOL_GPL(svc_create_xprt);
+
+/*
+ * 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_has_something_to_do(struct svc_xprt *xprt)
+{
+	if (xprt->xpt_flags & ((1<<XPT_CONN)|(1<<XPT_CLOSE)))
+		return true;
+	if (xprt->xpt_flags & ((1<<XPT_DATA)|(1<<XPT_DEFERRED)))
+		return xprt->xpt_ops->xpo_has_wspace(xprt);
+	return false;
+}
+
+static void svc_xprt_do_enqueue(struct svc_xprt *xprt)
+{
+	struct svc_pool *pool;
+	struct svc_rqst	*rqstp = NULL;
+	int cpu;
+	bool queued = false;
+
+	if (!svc_xprt_has_something_to_do(xprt))
+		goto out;
+
+	/* 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)) {
+		/* Don't enqueue transport while already enqueued */
+		dprintk("svc: transport %p busy, not enqueued\n", xprt);
+		goto out;
+	}
+
+	cpu = get_cpu();
+	pool = svc_pool_for_cpu(xprt->xpt_server, cpu);
+
+	atomic_long_inc(&pool->sp_stats.packets);
+
+redo_search:
+	/* find a thread for this xprt */
+	rcu_read_lock();
+	list_for_each_entry_rcu(rqstp, &pool->sp_all_threads, rq_all) {
+		/* Do a lockless check first */
+		if (test_bit(RQ_BUSY, &rqstp->rq_flags))
+			continue;
+
+		/*
+		 * Once the xprt has been queued, it can only be dequeued by
+		 * the task that intends to service it. All we can do at that
+		 * point is to try to wake this thread back up so that it can
+		 * do so.
+		 */
+		if (!queued) {
+			spin_lock_bh(&rqstp->rq_lock);
+			if (test_and_set_bit(RQ_BUSY, &rqstp->rq_flags)) {
+				/* already busy, move on... */
+				spin_unlock_bh(&rqstp->rq_lock);
+				continue;
+			}
+
+			/* this one will do */
+			rqstp->rq_xprt = xprt;
+			svc_xprt_get(xprt);
+			spin_unlock_bh(&rqstp->rq_lock);
+		}
+		rcu_read_unlock();
+
+		atomic_long_inc(&pool->sp_stats.threads_woken);
+		wake_up_process(rqstp->rq_task);
+		put_cpu();
+		goto out;
+	}
+	rcu_read_unlock();
+
+	/*
+	 * We didn't find an idle thread to use, so we need to queue the xprt.
+	 * Do so and then search again. If we find one, we can't hook this one
+	 * up to it directly but we can wake the thread up in the hopes that it
+	 * will pick it up once it searches for a xprt to service.
+	 */
+	if (!queued) {
+		queued = true;
+		dprintk("svc: transport %p put into queue\n", xprt);
+		spin_lock_bh(&pool->sp_lock);
+		list_add_tail(&xprt->xpt_ready, &pool->sp_sockets);
+		pool->sp_stats.sockets_queued++;
+		spin_unlock_bh(&pool->sp_lock);
+		goto redo_search;
+	}
+	rqstp = NULL;
+	put_cpu();
+out:
+	trace_svc_xprt_do_enqueue(xprt, rqstp);
+}
+
+/*
+ * Queue up a transport with data pending. If there are idle nfsd
+ * processes, wake 'em up.
+ *
+ */
+void svc_xprt_enqueue(struct svc_xprt *xprt)
+{
+	if (test_bit(XPT_BUSY, &xprt->xpt_flags))
+		return;
+	svc_xprt_do_enqueue(xprt);
+}
+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);
+
+		dprintk("svc: transport %p dequeued, inuse=%d\n",
+			xprt, atomic_read(&xprt->xpt_ref.refcount));
+	}
+	spin_unlock_bh(&pool->sp_lock);
+out:
+	trace_svc_xprt_dequeue(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)
+{
+	space += rqstp->rq_res.head[0].iov_len;
+
+	if (space < rqstp->rq_reserved) {
+		struct svc_xprt *xprt = rqstp->rq_xprt;
+		atomic_sub((rqstp->rq_reserved - space), &xprt->xpt_reserved);
+		rqstp->rq_reserved = space;
+
+		if (xprt->xpt_ops->xpo_adjust_wspace)
+			xprt->xpt_ops->xpo_adjust_wspace(xprt);
+		svc_xprt_enqueue(xprt);
+	}
+}
+EXPORT_SYMBOL_GPL(svc_reserve);
+
+static void svc_xprt_release(struct svc_rqst *rqstp)
+{
+	struct svc_xprt	*xprt = rqstp->rq_xprt;
+
+	rqstp->rq_xprt->xpt_ops->xpo_release_rqst(rqstp);
+
+	kfree(rqstp->rq_deferred);
+	rqstp->rq_deferred = NULL;
+
+	svc_free_res_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);
+	rqstp->rq_xprt = NULL;
+
+	svc_xprt_put(xprt);
+}
+
+/*
+ * 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_rqst	*rqstp;
+	struct svc_pool *pool;
+
+	pool = &serv->sv_pools[0];
+
+	rcu_read_lock();
+	list_for_each_entry_rcu(rqstp, &pool->sp_all_threads, rq_all) {
+		/* skip any that aren't queued */
+		if (test_bit(RQ_BUSY, &rqstp->rq_flags))
+			continue;
+		rcu_read_unlock();
+		dprintk("svc: daemon %p woken up.\n", rqstp);
+		wake_up_process(rqstp->rq_task);
+		trace_svc_wake_up(rqstp->rq_task->pid);
+		return;
+	}
+	rcu_read_unlock();
+
+	/* No free entries available */
+	set_bit(SP_TASK_PENDING, &pool->sp_flags);
+	smp_wmb();
+	trace_svc_wake_up(0);
+}
+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 int svc_alloc_arg(struct svc_rqst *rqstp)
+{
+	struct svc_serv *serv = rqstp->rq_server;
+	struct xdr_buf *arg;
+	int pages;
+	int i;
+
+	/* now allocate needed pages.  If we get a failure, sleep briefly */
+	pages = (serv->sv_max_mesg + PAGE_SIZE) / PAGE_SIZE;
+	WARN_ON_ONCE(pages >= RPCSVC_MAXPAGES);
+	if (pages >= RPCSVC_MAXPAGES)
+		/* use as many pages as possible */
+		pages = RPCSVC_MAXPAGES - 1;
+	for (i = 0; i < pages ; i++)
+		while (rqstp->rq_pages[i] == NULL) {
+			struct page *p = alloc_page(GFP_KERNEL);
+			if (!p) {
+				set_current_state(TASK_INTERRUPTIBLE);
+				if (signalled() || kthread_should_stop()) {
+					set_current_state(TASK_RUNNING);
+					return -EINTR;
+				}
+				schedule_timeout(msecs_to_jiffies(500));
+			}
+			rqstp->rq_pages[i] = p;
+		}
+	rqstp->rq_page_end = &rqstp->rq_pages[i];
+	rqstp->rq_pages[i++] = NULL; /* this might be seen in nfs_read_actor */
+
+	/* Make arg->head point to first page and arg->pages point to rest */
+	arg = &rqstp->rq_arg;
+	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;
+	return 0;
+}
+
+static bool
+rqst_should_sleep(struct svc_rqst *rqstp)
+{
+	struct svc_pool		*pool = rqstp->rq_pool;
+
+	/* did someone call svc_wake_up? */
+	if (test_and_clear_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 (signalled() || 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, long timeout)
+{
+	struct svc_xprt *xprt;
+	struct svc_pool		*pool = rqstp->rq_pool;
+	long			time_left = 0;
+
+	/* rq_xprt should be clear on entry */
+	WARN_ON_ONCE(rqstp->rq_xprt);
+
+	/* Normally we will wait up to 5 seconds for any required
+	 * cache information to be provided.
+	 */
+	rqstp->rq_chandle.thread_wait = 5*HZ;
+
+	xprt = svc_xprt_dequeue(pool);
+	if (xprt) {
+		rqstp->rq_xprt = xprt;
+
+		/* As there is a shortage of threads and this request
+		 * had to be queued, don't allow the thread to wait so
+		 * long for cache updates.
+		 */
+		rqstp->rq_chandle.thread_wait = 1*HZ;
+		clear_bit(SP_TASK_PENDING, &pool->sp_flags);
+		return xprt;
+	}
+
+	/*
+	 * We have to be able to interrupt this wait
+	 * to bring down the daemons ...
+	 */
+	set_current_state(TASK_INTERRUPTIBLE);
+	clear_bit(RQ_BUSY, &rqstp->rq_flags);
+	smp_mb();
+
+	if (likely(rqst_should_sleep(rqstp)))
+		time_left = schedule_timeout(timeout);
+	else
+		__set_current_state(TASK_RUNNING);
+
+	try_to_freeze();
+
+	spin_lock_bh(&rqstp->rq_lock);
+	set_bit(RQ_BUSY, &rqstp->rq_flags);
+	spin_unlock_bh(&rqstp->rq_lock);
+
+	xprt = rqstp->rq_xprt;
+	if (xprt != NULL)
+		return xprt;
+
+	if (!time_left)
+		atomic_long_inc(&pool->sp_stats.threads_timedout);
+
+	if (signalled() || kthread_should_stop())
+		return ERR_PTR(-EINTR);
+	return ERR_PTR(-EAGAIN);
+}
+
+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 */
+		setup_timer(&serv->sv_temptimer, svc_age_temp_xprts,
+			    (unsigned long)serv);
+		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)) {
+		dprintk("svc_recv: found XPT_CLOSE\n");
+		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)
+			svc_add_new_temp_xprt(serv, newxpt);
+		else
+			module_put(xprt->xpt_class->xcl_owner);
+	} else {
+		/* XPT_DATA|XPT_DEFERRED case: */
+		dprintk("svc: server %p, pool %u, transport %p, inuse=%d\n",
+			rqstp, rqstp->rq_pool->sp_id, xprt,
+			atomic_read(&xprt->xpt_ref.refcount));
+		rqstp->rq_deferred = svc_deferred_dequeue(xprt);
+		if (rqstp->rq_deferred)
+			len = svc_deferred_recv(rqstp);
+		else
+			len = xprt->xpt_ops->xpo_recvfrom(rqstp);
+		dprintk("svc: got len=%d\n", len);
+		rqstp->rq_reserved = serv->sv_max_mesg;
+		atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
+	}
+	/* clear XPT_BUSY: */
+	svc_xprt_received(xprt);
+out:
+	trace_svc_handle_xprt(xprt, len);
+	return len;
+}
+
+/*
+ * Receive the next request on any transport.  This code is carefully
+ * organised not to touch any cachelines in the shared svc_serv
+ * structure, only cachelines in the local svc_pool.
+ */
+int svc_recv(struct svc_rqst *rqstp, long timeout)
+{
+	struct svc_xprt		*xprt = NULL;
+	struct svc_serv		*serv = rqstp->rq_server;
+	int			len, err;
+
+	dprintk("svc: server %p waiting for data (to = %ld)\n",
+		rqstp, timeout);
+
+	if (rqstp->rq_xprt)
+		printk(KERN_ERR
+			"svc_recv: service %p, transport not NULL!\n",
+			 rqstp);
+
+	err = svc_alloc_arg(rqstp);
+	if (err)
+		goto out;
+
+	try_to_freeze();
+	cond_resched();
+	err = -EINTR;
+	if (signalled() || kthread_should_stop())
+		goto out;
+
+	xprt = svc_get_next_xprt(rqstp, timeout);
+	if (IS_ERR(xprt)) {
+		err = PTR_ERR(xprt);
+		goto out;
+	}
+
+	len = svc_handle_xprt(rqstp, xprt);
+
+	/* No data, incomplete (TCP) read, or accept() */
+	err = -EAGAIN;
+	if (len <= 0)
+		goto out_release;
+
+	clear_bit(XPT_OLD, &xprt->xpt_flags);
+
+	if (xprt->xpt_ops->xpo_secure_port(rqstp))
+		set_bit(RQ_SECURE, &rqstp->rq_flags);
+	else
+		clear_bit(RQ_SECURE, &rqstp->rq_flags);
+	rqstp->rq_chandle.defer = svc_defer;
+	rqstp->rq_xid = svc_getu32(&rqstp->rq_arg.head[0]);
+
+	if (serv->sv_stats)
+		serv->sv_stats->netcnt++;
+	trace_svc_recv(rqstp, len);
+	return len;
+out_release:
+	rqstp->rq_res.len = 0;
+	svc_xprt_release(rqstp);
+out:
+	trace_svc_recv(rqstp, err);
+	return err;
+}
+EXPORT_SYMBOL_GPL(svc_recv);
+
+/*
+ * Drop request
+ */
+void svc_drop(struct svc_rqst *rqstp)
+{
+	dprintk("svc: xprt %p dropped request\n", rqstp->rq_xprt);
+	svc_xprt_release(rqstp);
+}
+EXPORT_SYMBOL_GPL(svc_drop);
+
+/*
+ * Return reply to client.
+ */
+int svc_send(struct svc_rqst *rqstp)
+{
+	struct svc_xprt	*xprt;
+	int		len = -EFAULT;
+	struct xdr_buf	*xb;
+
+	xprt = rqstp->rq_xprt;
+	if (!xprt)
+		goto out;
+
+	/* release the receive skb before sending the reply */
+	rqstp->rq_xprt->xpt_ops->xpo_release_rqst(rqstp);
+
+	/* calculate over-all length */
+	xb = &rqstp->rq_res;
+	xb->len = xb->head[0].iov_len +
+		xb->page_len +
+		xb->tail[0].iov_len;
+
+	/* Grab mutex to serialize outgoing data. */
+	mutex_lock(&xprt->xpt_mutex);
+	if (test_bit(XPT_DEAD, &xprt->xpt_flags)
+			|| test_bit(XPT_CLOSE, &xprt->xpt_flags))
+		len = -ENOTCONN;
+	else
+		len = xprt->xpt_ops->xpo_sendto(rqstp);
+	mutex_unlock(&xprt->xpt_mutex);
+	rpc_wake_up(&xprt->xpt_bc_pending);
+	svc_xprt_release(rqstp);
+
+	if (len == -ECONNREFUSED || len == -ENOTCONN || len == -EAGAIN)
+		len = 0;
+out:
+	trace_svc_send(rqstp, len);
+	return len;
+}
+
+/*
+ * Timer function to close old temporary transports, using
+ * a mark-and-sweep algorithm.
+ */
+static void svc_age_temp_xprts(unsigned long closure)
+{
+	struct svc_serv *serv = (struct svc_serv *)closure;
+	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 (atomic_read(&xprt->xpt_ref.refcount) > 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);
+}
+
+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(&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;
+
+	/* Only do this once */
+	if (test_and_set_bit(XPT_DEAD, &xprt->xpt_flags))
+		BUG();
+
+	dprintk("svc: svc_delete_xprt(%p)\n", xprt);
+	xprt->xpt_ops->xpo_detach(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)
+		kfree(dr);
+
+	call_xpt_users(xprt);
+	svc_xprt_put(xprt);
+}
+
+void svc_close_xprt(struct svc_xprt *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_close_xprt);
+
+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(&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(&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);
+	}
+}
+
+/*
+ * 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_close_net(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++);
+	}
+}
+
+/*
+ * 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);
+		dprintk("revisit canceled\n");
+		svc_xprt_put(xprt);
+		kfree(dr);
+		return;
+	}
+	dprintk("revisit queued\n");
+	dr->xprt = NULL;
+	list_add(&dr->handle.recent, &xprt->xpt_deferred);
+	spin_unlock(&xprt->xpt_lock);
+	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;
+		dr->xprt_hlen = rqstp->rq_xprt_hlen;
+
+		/* 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);
+	}
+	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 int svc_deferred_recv(struct svc_rqst *rqstp)
+{
+	struct svc_deferred_req *dr = rqstp->rq_deferred;
+
+	/* setup iov_base past transport header */
+	rqstp->rq_arg.head[0].iov_base = dr->args + (dr->xprt_hlen>>2);
+	/* The iov_len does not include the transport header bytes */
+	rqstp->rq_arg.head[0].iov_len = (dr->argslen<<2) - dr->xprt_hlen;
+	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_xprt_hlen   = dr->xprt_hlen;
+	rqstp->rq_daddr       = dr->daddr;
+	rqstp->rq_respages    = rqstp->rq_pages;
+	return (dr->argslen<<2) - dr->xprt_hlen;
+}
+
+
+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 %lu %lu %lu %lu\n",
+		pool->sp_id,
+		(unsigned long)atomic_long_read(&pool->sp_stats.packets),
+		pool->sp_stats.sockets_queued,
+		(unsigned long)atomic_long_read(&pool->sp_stats.threads_woken),
+		(unsigned long)atomic_long_read(&pool->sp_stats.threads_timedout));
+
+	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);
+
+/*----------------------------------------------------------------------------*/