svc_xprt.c 32.7 KB
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/*
 * linux/net/sunrpc/svc_xprt.c
 *
 * Author: Tom Tucker <tom@opengridcomputing.com>
 */

#include <linux/sched.h>
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#include <linux/smp_lock.h>
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#include <linux/errno.h>
#include <linux/freezer.h>
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#include <linux/kthread.h>
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#include <net/sock.h>
#include <linux/sunrpc/stats.h>
#include <linux/sunrpc/svc_xprt.h>
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#include <linux/sunrpc/svcsock.h>
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#define RPCDBG_FACILITY	RPCDBG_SVCXPRT

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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);

/* 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;

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/* List of registered transport classes */
static DEFINE_SPINLOCK(svc_xprt_class_lock);
static LIST_HEAD(svc_xprt_class_list);

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/* 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.
 *	BKL 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.
 */

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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);

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/*
 * Format the transport list for printing
 */
int svc_print_xprts(char *buf, int maxlen)
{
	struct list_head *le;
	char tmpstr[80];
	int len = 0;
	buf[0] = '\0';

	spin_lock(&svc_xprt_class_lock);
	list_for_each(le, &svc_xprt_class_list) {
		int slen;
		struct svc_xprt_class *xcl =
			list_entry(le, struct svc_xprt_class, xcl_list);

		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;
}

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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;
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	if (test_bit(XPT_CACHE_AUTH, &xprt->xpt_flags) &&
	    xprt->xpt_auth_cache != NULL)
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		svcauth_unix_info_release(xprt->xpt_auth_cache);
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	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);

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/*
 * Called by transport drivers to initialize the transport independent
 * portion of the transport instance.
 */
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void svc_xprt_init(struct svc_xprt_class *xcl, struct svc_xprt *xprt,
		   struct svc_serv *serv)
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{
	memset(xprt, 0, sizeof(*xprt));
	xprt->xpt_class = xcl;
	xprt->xpt_ops = xcl->xcl_ops;
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	kref_init(&xprt->xpt_ref);
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	xprt->xpt_server = serv;
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	INIT_LIST_HEAD(&xprt->xpt_list);
	INIT_LIST_HEAD(&xprt->xpt_ready);
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	INIT_LIST_HEAD(&xprt->xpt_deferred);
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	mutex_init(&xprt->xpt_mutex);
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	spin_lock_init(&xprt->xpt_lock);
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	set_bit(XPT_BUSY, &xprt->xpt_flags);
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	rpc_init_wait_queue(&xprt->xpt_bc_pending, "xpt_bc_pending");
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}
EXPORT_SYMBOL_GPL(svc_xprt_init);
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static struct svc_xprt *__svc_xpo_create(struct svc_xprt_class *xcl,
					 struct svc_serv *serv,
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					 const int family,
					 const unsigned short port,
					 int flags)
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{
	struct sockaddr_in sin = {
		.sin_family		= AF_INET,
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		.sin_addr.s_addr	= htonl(INADDR_ANY),
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		.sin_port		= htons(port),
	};
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#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
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	struct sockaddr_in6 sin6 = {
		.sin6_family		= AF_INET6,
		.sin6_addr		= IN6ADDR_ANY_INIT,
		.sin6_port		= htons(port),
	};
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#endif	/* defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) */
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	struct sockaddr *sap;
	size_t len;

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	switch (family) {
	case PF_INET:
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		sap = (struct sockaddr *)&sin;
		len = sizeof(sin);
		break;
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#if defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE)
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	case PF_INET6:
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		sap = (struct sockaddr *)&sin6;
		len = sizeof(sin6);
		break;
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#endif	/* defined(CONFIG_IPV6) || defined(CONFIG_IPV6_MODULE) */
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	default:
		return ERR_PTR(-EAFNOSUPPORT);
	}

	return xcl->xcl_ops->xpo_create(serv, sap, len, flags);
}

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int svc_create_xprt(struct svc_serv *serv, const char *xprt_name,
		    const int family, const unsigned short port,
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		    int flags)
{
	struct svc_xprt_class *xcl;

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	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) {
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		struct svc_xprt *newxprt;

		if (strcmp(xprt_name, xcl->xcl_name))
			continue;

		if (!try_module_get(xcl->xcl_owner))
			goto err;

		spin_unlock(&svc_xprt_class_lock);
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		newxprt = __svc_xpo_create(xcl, serv, family, port, flags);
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		if (IS_ERR(newxprt)) {
			module_put(xcl->xcl_owner);
			return PTR_ERR(newxprt);
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		}
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		clear_bit(XPT_TEMP, &newxprt->xpt_flags);
		spin_lock_bh(&serv->sv_lock);
		list_add(&newxprt->xpt_list, &serv->sv_permsocks);
		spin_unlock_bh(&serv->sv_lock);
		clear_bit(XPT_BUSY, &newxprt->xpt_flags);
		return svc_xprt_local_port(newxprt);
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	}
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 err:
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	spin_unlock(&svc_xprt_class_lock);
	dprintk("svc: transport %s not found\n", xprt_name);
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	/* This errno is exposed to user space.  Provide a reasonable
	 * perror msg for a bad transport. */
	return -EPROTONOSUPPORT;
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}
EXPORT_SYMBOL_GPL(svc_create_xprt);
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/*
 * Copy the local and remote xprt addresses to the rqstp structure
 */
void svc_xprt_copy_addrs(struct svc_rqst *rqstp, struct svc_xprt *xprt)
{
	struct sockaddr *sin;

	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.
	 */
	sin = (struct sockaddr *)&xprt->xpt_local;
	switch (sin->sa_family) {
	case AF_INET:
		rqstp->rq_daddr.addr = ((struct sockaddr_in *)sin)->sin_addr;
		break;
	case AF_INET6:
		rqstp->rq_daddr.addr6 = ((struct sockaddr_in6 *)sin)->sin6_addr;
		break;
	}
}
EXPORT_SYMBOL_GPL(svc_xprt_copy_addrs);

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/**
 * 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);

/*
 * Queue up an idle server thread.  Must have pool->sp_lock held.
 * Note: this is really a stack rather than a queue, so that we only
 * use as many different threads as we need, and the rest don't pollute
 * the cache.
 */
static void svc_thread_enqueue(struct svc_pool *pool, struct svc_rqst *rqstp)
{
	list_add(&rqstp->rq_list, &pool->sp_threads);
}

/*
 * Dequeue an nfsd thread.  Must have pool->sp_lock held.
 */
static void svc_thread_dequeue(struct svc_pool *pool, struct svc_rqst *rqstp)
{
	list_del(&rqstp->rq_list);
}

/*
 * Queue up a transport with data pending. If there are idle nfsd
 * processes, wake 'em up.
 *
 */
void svc_xprt_enqueue(struct svc_xprt *xprt)
{
	struct svc_serv	*serv = xprt->xpt_server;
	struct svc_pool *pool;
	struct svc_rqst	*rqstp;
	int cpu;

	if (!(xprt->xpt_flags &
	      ((1<<XPT_CONN)|(1<<XPT_DATA)|(1<<XPT_CLOSE)|(1<<XPT_DEFERRED))))
		return;

	cpu = get_cpu();
	pool = svc_pool_for_cpu(xprt->xpt_server, cpu);
	put_cpu();

	spin_lock_bh(&pool->sp_lock);

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	if (!list_empty(&pool->sp_threads) &&
	    !list_empty(&pool->sp_sockets))
		printk(KERN_ERR
		       "svc_xprt_enqueue: "
		       "threads and transports both waiting??\n");

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	if (test_bit(XPT_DEAD, &xprt->xpt_flags)) {
		/* Don't enqueue dead transports */
		dprintk("svc: transport %p is dead, not enqueued\n", xprt);
		goto out_unlock;
	}

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	pool->sp_stats.packets++;

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	/* 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_unlock;
	}
	BUG_ON(xprt->xpt_pool != NULL);
	xprt->xpt_pool = pool;

	/* Handle pending connection */
	if (test_bit(XPT_CONN, &xprt->xpt_flags))
		goto process;

	/* Handle close in-progress */
	if (test_bit(XPT_CLOSE, &xprt->xpt_flags))
		goto process;

	/* Check if we have space to reply to a request */
	if (!xprt->xpt_ops->xpo_has_wspace(xprt)) {
		/* Don't enqueue while not enough space for reply */
		dprintk("svc: no write space, transport %p  not enqueued\n",
			xprt);
		xprt->xpt_pool = NULL;
		clear_bit(XPT_BUSY, &xprt->xpt_flags);
		goto out_unlock;
	}

 process:
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	if (!list_empty(&pool->sp_threads)) {
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		rqstp = list_entry(pool->sp_threads.next,
				   struct svc_rqst,
				   rq_list);
		dprintk("svc: transport %p served by daemon %p\n",
			xprt, rqstp);
		svc_thread_dequeue(pool, rqstp);
		if (rqstp->rq_xprt)
			printk(KERN_ERR
				"svc_xprt_enqueue: server %p, rq_xprt=%p!\n",
				rqstp, rqstp->rq_xprt);
		rqstp->rq_xprt = xprt;
		svc_xprt_get(xprt);
		rqstp->rq_reserved = serv->sv_max_mesg;
		atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
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		pool->sp_stats.threads_woken++;
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		BUG_ON(xprt->xpt_pool != pool);
		wake_up(&rqstp->rq_wait);
	} else {
		dprintk("svc: transport %p put into queue\n", xprt);
		list_add_tail(&xprt->xpt_ready, &pool->sp_sockets);
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		pool->sp_stats.sockets_queued++;
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		BUG_ON(xprt->xpt_pool != pool);
	}

out_unlock:
	spin_unlock_bh(&pool->sp_lock);
}
EXPORT_SYMBOL_GPL(svc_xprt_enqueue);

/*
 * Dequeue the first transport.  Must be called with the pool->sp_lock held.
 */
static struct svc_xprt *svc_xprt_dequeue(struct svc_pool *pool)
{
	struct svc_xprt	*xprt;

	if (list_empty(&pool->sp_sockets))
		return NULL;

	xprt = list_entry(pool->sp_sockets.next,
			  struct svc_xprt, xpt_ready);
	list_del_init(&xprt->xpt_ready);

	dprintk("svc: transport %p dequeued, inuse=%d\n",
		xprt, atomic_read(&xprt->xpt_ref.refcount));

	return xprt;
}

/*
 * 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.
 */
void svc_xprt_received(struct svc_xprt *xprt)
{
	BUG_ON(!test_bit(XPT_BUSY, &xprt->xpt_flags));
	xprt->xpt_pool = NULL;
	clear_bit(XPT_BUSY, &xprt->xpt_flags);
	svc_xprt_enqueue(xprt);
}
EXPORT_SYMBOL_GPL(svc_xprt_received);

/**
 * 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;

		svc_xprt_enqueue(xprt);
	}
}
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EXPORT_SYMBOL_GPL(svc_reserve);
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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);

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	kfree(rqstp->rq_deferred);
	rqstp->rq_deferred = NULL;

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	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);
}

/*
 * External function to wake up a server waiting for data
 * This really only makes sense for services like lockd
 * which have exactly one thread anyway.
 */
void svc_wake_up(struct svc_serv *serv)
{
	struct svc_rqst	*rqstp;
	unsigned int i;
	struct svc_pool *pool;

	for (i = 0; i < serv->sv_nrpools; i++) {
		pool = &serv->sv_pools[i];

		spin_lock_bh(&pool->sp_lock);
		if (!list_empty(&pool->sp_threads)) {
			rqstp = list_entry(pool->sp_threads.next,
					   struct svc_rqst,
					   rq_list);
			dprintk("svc: daemon %p woken up.\n", rqstp);
			/*
			svc_thread_dequeue(pool, rqstp);
			rqstp->rq_xprt = NULL;
			 */
			wake_up(&rqstp->rq_wait);
		}
		spin_unlock_bh(&pool->sp_lock);
	}
}
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EXPORT_SYMBOL_GPL(svc_wake_up);
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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;
	}
}

/*
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 * 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.
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 *
 * 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.
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 *
 * 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
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 */
static void svc_check_conn_limits(struct svc_serv *serv)
{
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	unsigned int limit = serv->sv_maxconn ? serv->sv_maxconn :
				(serv->sv_nrthreads+3) * 20;

	if (serv->sv_tmpcnt > limit) {
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		struct svc_xprt *xprt = NULL;
		spin_lock_bh(&serv->sv_lock);
		if (!list_empty(&serv->sv_tempsocks)) {
			if (net_ratelimit()) {
				/* Try to help the admin */
				printk(KERN_NOTICE "%s: too many open  "
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				       "connections, consider increasing %s\n",
				       serv->sv_name, serv->sv_maxconn ?
				       "the max number of connections." :
				       "the number of threads.");
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			}
			/*
			 * 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);
		}
	}
}

/*
 * 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;
	struct svc_pool		*pool = rqstp->rq_pool;
	int			len, i;
	int			pages;
	struct xdr_buf		*arg;
	DECLARE_WAITQUEUE(wait, current);
605
	long			time_left;
606 607 608 609 610 611 612 613 614 615 616 617 618 619 620 621 622 623 624

	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);
	if (waitqueue_active(&rqstp->rq_wait))
		printk(KERN_ERR
			"svc_recv: service %p, wait queue active!\n",
			 rqstp);

	/* now allocate needed pages.  If we get a failure, sleep briefly */
	pages = (serv->sv_max_mesg + PAGE_SIZE) / PAGE_SIZE;
	for (i = 0; i < pages ; i++)
		while (rqstp->rq_pages[i] == NULL) {
			struct page *p = alloc_page(GFP_KERNEL);
			if (!p) {
625 626 627
				set_current_state(TASK_INTERRUPTIBLE);
				if (signalled() || kthread_should_stop()) {
					set_current_state(TASK_RUNNING);
628
					return -EINTR;
629 630
				}
				schedule_timeout(msecs_to_jiffies(500));
631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649
			}
			rqstp->rq_pages[i] = p;
		}
	rqstp->rq_pages[i++] = NULL; /* this might be seen in nfs_read_actor */
	BUG_ON(pages >= RPCSVC_MAXPAGES);

	/* 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;

	try_to_freeze();
	cond_resched();
650
	if (signalled() || kthread_should_stop())
651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668
		return -EINTR;

	spin_lock_bh(&pool->sp_lock);
	xprt = svc_xprt_dequeue(pool);
	if (xprt) {
		rqstp->rq_xprt = xprt;
		svc_xprt_get(xprt);
		rqstp->rq_reserved = serv->sv_max_mesg;
		atomic_add(rqstp->rq_reserved, &xprt->xpt_reserved);
	} else {
		/* No data pending. Go to sleep */
		svc_thread_enqueue(pool, rqstp);

		/*
		 * We have to be able to interrupt this wait
		 * to bring down the daemons ...
		 */
		set_current_state(TASK_INTERRUPTIBLE);
669 670 671 672 673 674 675 676 677 678 679 680 681 682

		/*
		 * checking kthread_should_stop() here allows us to avoid
		 * locking and signalling when stopping kthreads that call
		 * svc_recv. If the thread has already been woken up, then
		 * we can exit here without sleeping. If not, then it
		 * it'll be woken up quickly during the schedule_timeout
		 */
		if (kthread_should_stop()) {
			set_current_state(TASK_RUNNING);
			spin_unlock_bh(&pool->sp_lock);
			return -EINTR;
		}

683 684 685
		add_wait_queue(&rqstp->rq_wait, &wait);
		spin_unlock_bh(&pool->sp_lock);

686
		time_left = schedule_timeout(timeout);
687 688 689 690 691

		try_to_freeze();

		spin_lock_bh(&pool->sp_lock);
		remove_wait_queue(&rqstp->rq_wait, &wait);
692 693
		if (!time_left)
			pool->sp_stats.threads_timedout++;
694 695 696 697 698 699

		xprt = rqstp->rq_xprt;
		if (!xprt) {
			svc_thread_dequeue(pool, rqstp);
			spin_unlock_bh(&pool->sp_lock);
			dprintk("svc: server %p, no data yet\n", rqstp);
700 701 702 703
			if (signalled() || kthread_should_stop())
				return -EINTR;
			else
				return -EAGAIN;
704 705 706 707 708
		}
	}
	spin_unlock_bh(&pool->sp_lock);

	len = 0;
709 710 711 712
	if (test_bit(XPT_CLOSE, &xprt->xpt_flags)) {
		dprintk("svc_recv: found XPT_CLOSE\n");
		svc_delete_xprt(xprt);
	} else if (test_bit(XPT_LISTENER, &xprt->xpt_flags)) {
713 714 715 716 717 718 719 720 721 722 723 724 725 726 727 728 729 730 731 732 733 734 735 736 737
		struct svc_xprt *newxpt;
		newxpt = xprt->xpt_ops->xpo_accept(xprt);
		if (newxpt) {
			/*
			 * We know this module_get will succeed because the
			 * listener holds a reference too
			 */
			__module_get(newxpt->xpt_class->xcl_owner);
			svc_check_conn_limits(xprt->xpt_server);
			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);
		}
		svc_xprt_received(xprt);
738
	} else {
739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765
		dprintk("svc: server %p, pool %u, transport %p, inuse=%d\n",
			rqstp, pool->sp_id, xprt,
			atomic_read(&xprt->xpt_ref.refcount));
		rqstp->rq_deferred = svc_deferred_dequeue(xprt);
		if (rqstp->rq_deferred) {
			svc_xprt_received(xprt);
			len = svc_deferred_recv(rqstp);
		} else
			len = xprt->xpt_ops->xpo_recvfrom(rqstp);
		dprintk("svc: got len=%d\n", len);
	}

	/* No data, incomplete (TCP) read, or accept() */
	if (len == 0 || len == -EAGAIN) {
		rqstp->rq_res.len = 0;
		svc_xprt_release(rqstp);
		return -EAGAIN;
	}
	clear_bit(XPT_OLD, &xprt->xpt_flags);

	rqstp->rq_secure = svc_port_is_privileged(svc_addr(rqstp));
	rqstp->rq_chandle.defer = svc_defer;

	if (serv->sv_stats)
		serv->sv_stats->netcnt++;
	return len;
}
766
EXPORT_SYMBOL_GPL(svc_recv);
767 768 769 770 771 772 773 774 775

/*
 * Drop request
 */
void svc_drop(struct svc_rqst *rqstp)
{
	dprintk("svc: xprt %p dropped request\n", rqstp->rq_xprt);
	svc_xprt_release(rqstp);
}
776
EXPORT_SYMBOL_GPL(svc_drop);
777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806

/*
 * Return reply to client.
 */
int svc_send(struct svc_rqst *rqstp)
{
	struct svc_xprt	*xprt;
	int		len;
	struct xdr_buf	*xb;

	xprt = rqstp->rq_xprt;
	if (!xprt)
		return -EFAULT;

	/* 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))
		len = -ENOTCONN;
	else
		len = xprt->xpt_ops->xpo_sendto(rqstp);
	mutex_unlock(&xprt->xpt_mutex);
807
	rpc_wake_up(&xprt->xpt_bc_pending);
808 809 810 811 812 813 814 815 816 817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838 839 840 841
	svc_xprt_release(rqstp);

	if (len == -ECONNREFUSED || len == -ENOTCONN || len == -EAGAIN)
		return 0;
	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;
	LIST_HEAD(to_be_aged);

	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;
842 843
		if (atomic_read(&xprt->xpt_ref.refcount) > 1 ||
		    test_bit(XPT_BUSY, &xprt->xpt_flags))
844 845 846 847 848 849 850 851 852 853 854 855 856 857 858 859 860 861 862 863 864 865 866 867 868 869 870 871 872 873
			continue;
		svc_xprt_get(xprt);
		list_move(le, &to_be_aged);
		set_bit(XPT_CLOSE, &xprt->xpt_flags);
		set_bit(XPT_DETACHED, &xprt->xpt_flags);
	}
	spin_unlock_bh(&serv->sv_lock);

	while (!list_empty(&to_be_aged)) {
		le = to_be_aged.next;
		/* fiddling the xpt_list node is safe 'cos we're XPT_DETACHED */
		list_del_init(le);
		xprt = list_entry(le, struct svc_xprt, xpt_list);

		dprintk("queuing xprt %p for closing\n", xprt);

		/* a thread will dequeue and close it soon */
		svc_xprt_enqueue(xprt);
		svc_xprt_put(xprt);
	}

	mod_timer(&serv->sv_temptimer, jiffies + svc_conn_age_period * HZ);
}

/*
 * Remove a dead transport
 */
void svc_delete_xprt(struct svc_xprt *xprt)
{
	struct svc_serv	*serv = xprt->xpt_server;
874 875 876 877 878
	struct svc_deferred_req *dr;

	/* Only do this once */
	if (test_and_set_bit(XPT_DEAD, &xprt->xpt_flags))
		return;
879 880 881 882 883 884 885 886 887 888 889 890 891 892

	dprintk("svc: svc_delete_xprt(%p)\n", xprt);
	xprt->xpt_ops->xpo_detach(xprt);

	spin_lock_bh(&serv->sv_lock);
	if (!test_and_set_bit(XPT_DETACHED, &xprt->xpt_flags))
		list_del_init(&xprt->xpt_list);
	/*
	 * We used to delete the transport from whichever list
	 * it's sk_xprt.xpt_ready node was on, but we don't actually
	 * need to.  This is because the only time we're called
	 * while still attached to a queue, the queue itself
	 * is about to be destroyed (in svc_destroy).
	 */
893 894 895
	if (test_bit(XPT_TEMP, &xprt->xpt_flags))
		serv->sv_tmpcnt--;

896
	while ((dr = svc_deferred_dequeue(xprt)) != NULL)
897 898 899
		kfree(dr);

	svc_xprt_put(xprt);
900 901 902 903 904 905 906 907 908 909 910 911 912 913 914
	spin_unlock_bh(&serv->sv_lock);
}

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;

	svc_xprt_get(xprt);
	svc_delete_xprt(xprt);
	clear_bit(XPT_BUSY, &xprt->xpt_flags);
	svc_xprt_put(xprt);
}
915
EXPORT_SYMBOL_GPL(svc_close_xprt);
916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944

void svc_close_all(struct list_head *xprt_list)
{
	struct svc_xprt *xprt;
	struct svc_xprt *tmp;

	list_for_each_entry_safe(xprt, tmp, xprt_list, xpt_list) {
		set_bit(XPT_CLOSE, &xprt->xpt_flags);
		if (test_bit(XPT_BUSY, &xprt->xpt_flags)) {
			/* Waiting to be processed, but no threads left,
			 * So just remove it from the waiting list
			 */
			list_del_init(&xprt->xpt_ready);
			clear_bit(XPT_BUSY, &xprt->xpt_flags);
		}
		svc_close_xprt(xprt);
	}
}

/*
 * 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;

945 946 947 948 949
	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");
950 951 952 953 954 955 956 957 958 959 960 961
		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);
}

962 963 964 965 966 967 968 969 970
/*
 * 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.
 */
971 972 973 974 975
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;

976
	if (rqstp->rq_arg.page_len || !rqstp->rq_usedeferral)
977 978 979 980 981
		return NULL; /* if more than a page, give up FIXME */
	if (rqstp->rq_deferred) {
		dr = rqstp->rq_deferred;
		rqstp->rq_deferred = NULL;
	} else {
982 983
		size_t skip;
		size_t size;
984
		/* FIXME maybe discard if size too large */
985
		size = sizeof(struct svc_deferred_req) + rqstp->rq_arg.len;
986 987 988 989 990 991 992 993 994 995
		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;
996 997 998 999 1000 1001
		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);
1002 1003 1004 1005 1006 1007 1008 1009 1010 1011 1012 1013 1014 1015 1016
	}
	svc_xprt_get(rqstp->rq_xprt);
	dr->xprt = rqstp->rq_xprt;

	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;

1017 1018 1019 1020
	/* 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;
1021
	rqstp->rq_arg.page_len = 0;
1022 1023
	/* The rq_arg.len includes the transport header bytes */
	rqstp->rq_arg.len     = dr->argslen<<2;
1024 1025 1026
	rqstp->rq_prot        = dr->prot;
	memcpy(&rqstp->rq_addr, &dr->addr, dr->addrlen);
	rqstp->rq_addrlen     = dr->addrlen;
1027 1028
	/* Save off transport header len in case we get deferred again */
	rqstp->rq_xprt_hlen   = dr->xprt_hlen;
1029 1030
	rqstp->rq_daddr       = dr->daddr;
	rqstp->rq_respages    = rqstp->rq_pages;
1031
	return (dr->argslen<<2) - dr->xprt_hlen;
1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052
}


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);
	clear_bit(XPT_DEFERRED, &xprt->xpt_flags);
	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);
		set_bit(XPT_DEFERRED, &xprt->xpt_flags);
	}
	spin_unlock(&xprt->xpt_lock);
	return dr;
}
1053

1054 1055 1056 1057 1058 1059 1060
/**
 * svc_find_xprt - find an RPC transport instance
 * @serv: pointer to svc_serv to search
 * @xcl_name: C string containing transport's class name
 * @af: Address family of transport's local address
 * @port: transport's IP port number
 *
1061 1062 1063 1064 1065 1066 1067 1068
 * 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.
 */
1069 1070
struct svc_xprt *svc_find_xprt(struct svc_serv *serv, const char *xcl_name,
			       const sa_family_t af, const unsigned short port)
1071 1072 1073 1074 1075
{
	struct svc_xprt *xprt;
	struct svc_xprt *found = NULL;

	/* Sanity check the args */
1076
	if (serv == NULL || xcl_name == NULL)
1077 1078 1079 1080 1081 1082 1083 1084
		return found;

	spin_lock_bh(&serv->sv_lock);
	list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
		if (strcmp(xprt->xpt_class->xcl_name, xcl_name))
			continue;
		if (af != AF_UNSPEC && af != xprt->xpt_local.ss_family)
			continue;
1085
		if (port != 0 && port != svc_xprt_local_port(xprt))
1086 1087
			continue;
		found = xprt;
1088
		svc_xprt_get(xprt);
1089 1090 1091 1092 1093 1094
		break;
	}
	spin_unlock_bh(&serv->sv_lock);
	return found;
}
EXPORT_SYMBOL_GPL(svc_find_xprt);
1095

1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119
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.
1120
 */
1121
int svc_xprt_names(struct svc_serv *serv, char *buf, const int buflen)
1122 1123
{
	struct svc_xprt *xprt;
1124 1125
	int len, totlen;
	char *pos;
1126 1127 1128 1129 1130 1131

	/* Sanity check args */
	if (!serv)
		return 0;

	spin_lock_bh(&serv->sv_lock);
1132 1133 1134

	pos = buf;
	totlen = 0;
1135
	list_for_each_entry(xprt, &serv->sv_permsocks, xpt_list) {
1136 1137 1138 1139 1140 1141
		len = svc_one_xprt_name(xprt, pos, buflen - totlen);
		if (len < 0) {
			*buf = '\0';
			totlen = len;
		}
		if (len <= 0)
1142
			break;
1143 1144

		pos += len;
1145 1146
		totlen += len;
	}
1147

1148 1149 1150 1151
	spin_unlock_bh(&serv->sv_lock);
	return totlen;
}
EXPORT_SYMBOL_GPL(svc_xprt_names);
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/*----------------------------------------------------------------------------*/

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) {
1197
		seq_puts(m, "# pool packets-arrived sockets-enqueued threads-woken threads-timedout\n");
1198 1199 1200
		return 0;
	}

1201
	seq_printf(m, "%u %lu %lu %lu %lu\n",
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		pool->sp_id,
		pool->sp_stats.packets,
		pool->sp_stats.sockets_queued,
		pool->sp_stats.threads_woken,
		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);

/*----------------------------------------------------------------------------*/