Adding upstream version 6.6.15.upstream/6.6.15

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1644 insertions, 0 deletions

diff --git a/net/sunrpc/svcsock.c b/net/sunrpc/svcsock.c
new file mode 100644
index 0000000000..e0ce427627
--- /dev/null
+++ b/net/sunrpc/svcsock.c
@@ -0,0 +1,1644 @@
+// SPDX-License-Identifier: GPL-2.0-only
+/*
+ * linux/net/sunrpc/svcsock.c
+ *
+ * These are the RPC server socket internals.
+ *
+ * The server scheduling algorithm does not always distribute the load
+ * evenly when servicing a single client. May need to modify the
+ * svc_xprt_enqueue procedure...
+ *
+ * TCP support is largely untested and may be a little slow. The problem
+ * is that we currently do two separate recvfrom's, one for the 4-byte
+ * record length, and the second for the actual record. This could possibly
+ * be improved by always reading a minimum size of around 100 bytes and
+ * tucking any superfluous bytes away in a temporary store. Still, that
+ * leaves write requests out in the rain. An alternative may be to peek at
+ * the first skb in the queue, and if it matches the next TCP sequence
+ * number, to extract the record marker. Yuck.
+ *
+ * Copyright (C) 1995, 1996 Olaf Kirch <okir@monad.swb.de>
+ */
+
+#include <linux/kernel.h>
+#include <linux/sched.h>
+#include <linux/module.h>
+#include <linux/errno.h>
+#include <linux/fcntl.h>
+#include <linux/net.h>
+#include <linux/in.h>
+#include <linux/inet.h>
+#include <linux/udp.h>
+#include <linux/tcp.h>
+#include <linux/unistd.h>
+#include <linux/slab.h>
+#include <linux/netdevice.h>
+#include <linux/skbuff.h>
+#include <linux/file.h>
+#include <linux/freezer.h>
+#include <linux/bvec.h>
+
+#include <net/sock.h>
+#include <net/checksum.h>
+#include <net/ip.h>
+#include <net/ipv6.h>
+#include <net/udp.h>
+#include <net/tcp.h>
+#include <net/tcp_states.h>
+#include <net/tls_prot.h>
+#include <net/handshake.h>
+#include <linux/uaccess.h>
+#include <linux/highmem.h>
+#include <asm/ioctls.h>
+#include <linux/key.h>
+
+#include <linux/sunrpc/types.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/xdr.h>
+#include <linux/sunrpc/msg_prot.h>
+#include <linux/sunrpc/svcsock.h>
+#include <linux/sunrpc/stats.h>
+#include <linux/sunrpc/xprt.h>
+
+#include <trace/events/sock.h>
+#include <trace/events/sunrpc.h>
+
+#include "socklib.h"
+#include "sunrpc.h"
+
+#define RPCDBG_FACILITY	RPCDBG_SVCXPRT
+
+/* To-do: to avoid tying up an nfsd thread while waiting for a
+ * handshake request, the request could instead be deferred.
+ */
+enum {
+	SVC_HANDSHAKE_TO	= 5U * HZ
+};
+
+static struct svc_sock *svc_setup_socket(struct svc_serv *, struct socket *,
+					 int flags);
+static int		svc_udp_recvfrom(struct svc_rqst *);
+static int		svc_udp_sendto(struct svc_rqst *);
+static void		svc_sock_detach(struct svc_xprt *);
+static void		svc_tcp_sock_detach(struct svc_xprt *);
+static void		svc_sock_free(struct svc_xprt *);
+
+static struct svc_xprt *svc_create_socket(struct svc_serv *, int,
+					  struct net *, struct sockaddr *,
+					  int, int);
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+static struct lock_class_key svc_key[2];
+static struct lock_class_key svc_slock_key[2];
+
+static void svc_reclassify_socket(struct socket *sock)
+{
+	struct sock *sk = sock->sk;
+
+	if (WARN_ON_ONCE(!sock_allow_reclassification(sk)))
+		return;
+
+	switch (sk->sk_family) {
+	case AF_INET:
+		sock_lock_init_class_and_name(sk, "slock-AF_INET-NFSD",
+					      &svc_slock_key[0],
+					      "sk_xprt.xpt_lock-AF_INET-NFSD",
+					      &svc_key[0]);
+		break;
+
+	case AF_INET6:
+		sock_lock_init_class_and_name(sk, "slock-AF_INET6-NFSD",
+					      &svc_slock_key[1],
+					      "sk_xprt.xpt_lock-AF_INET6-NFSD",
+					      &svc_key[1]);
+		break;
+
+	default:
+		BUG();
+	}
+}
+#else
+static void svc_reclassify_socket(struct socket *sock)
+{
+}
+#endif
+
+/**
+ * svc_tcp_release_ctxt - Release transport-related resources
+ * @xprt: the transport which owned the context
+ * @ctxt: the context from rqstp->rq_xprt_ctxt or dr->xprt_ctxt
+ *
+ */
+static void svc_tcp_release_ctxt(struct svc_xprt *xprt, void *ctxt)
+{
+}
+
+/**
+ * svc_udp_release_ctxt - Release transport-related resources
+ * @xprt: the transport which owned the context
+ * @ctxt: the context from rqstp->rq_xprt_ctxt or dr->xprt_ctxt
+ *
+ */
+static void svc_udp_release_ctxt(struct svc_xprt *xprt, void *ctxt)
+{
+	struct sk_buff *skb = ctxt;
+
+	if (skb)
+		consume_skb(skb);
+}
+
+union svc_pktinfo_u {
+	struct in_pktinfo pkti;
+	struct in6_pktinfo pkti6;
+};
+#define SVC_PKTINFO_SPACE \
+	CMSG_SPACE(sizeof(union svc_pktinfo_u))
+
+static void svc_set_cmsg_data(struct svc_rqst *rqstp, struct cmsghdr *cmh)
+{
+	struct svc_sock *svsk =
+		container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
+	switch (svsk->sk_sk->sk_family) {
+	case AF_INET: {
+			struct in_pktinfo *pki = CMSG_DATA(cmh);
+
+			cmh->cmsg_level = SOL_IP;
+			cmh->cmsg_type = IP_PKTINFO;
+			pki->ipi_ifindex = 0;
+			pki->ipi_spec_dst.s_addr =
+				 svc_daddr_in(rqstp)->sin_addr.s_addr;
+			cmh->cmsg_len = CMSG_LEN(sizeof(*pki));
+		}
+		break;
+
+	case AF_INET6: {
+			struct in6_pktinfo *pki = CMSG_DATA(cmh);
+			struct sockaddr_in6 *daddr = svc_daddr_in6(rqstp);
+
+			cmh->cmsg_level = SOL_IPV6;
+			cmh->cmsg_type = IPV6_PKTINFO;
+			pki->ipi6_ifindex = daddr->sin6_scope_id;
+			pki->ipi6_addr = daddr->sin6_addr;
+			cmh->cmsg_len = CMSG_LEN(sizeof(*pki));
+		}
+		break;
+	}
+}
+
+static int svc_sock_result_payload(struct svc_rqst *rqstp, unsigned int offset,
+				   unsigned int length)
+{
+	return 0;
+}
+
+/*
+ * Report socket names for nfsdfs
+ */
+static int svc_one_sock_name(struct svc_sock *svsk, char *buf, int remaining)
+{
+	const struct sock *sk = svsk->sk_sk;
+	const char *proto_name = sk->sk_protocol == IPPROTO_UDP ?
+							"udp" : "tcp";
+	int len;
+
+	switch (sk->sk_family) {
+	case PF_INET:
+		len = snprintf(buf, remaining, "ipv4 %s %pI4 %d\n",
+				proto_name,
+				&inet_sk(sk)->inet_rcv_saddr,
+				inet_sk(sk)->inet_num);
+		break;
+#if IS_ENABLED(CONFIG_IPV6)
+	case PF_INET6:
+		len = snprintf(buf, remaining, "ipv6 %s %pI6 %d\n",
+				proto_name,
+				&sk->sk_v6_rcv_saddr,
+				inet_sk(sk)->inet_num);
+		break;
+#endif
+	default:
+		len = snprintf(buf, remaining, "*unknown-%d*\n",
+				sk->sk_family);
+	}
+
+	if (len >= remaining) {
+		*buf = '\0';
+		return -ENAMETOOLONG;
+	}
+	return len;
+}
+
+static int
+svc_tcp_sock_process_cmsg(struct socket *sock, struct msghdr *msg,
+			  struct cmsghdr *cmsg, int ret)
+{
+	u8 content_type = tls_get_record_type(sock->sk, cmsg);
+	u8 level, description;
+
+	switch (content_type) {
+	case 0:
+		break;
+	case TLS_RECORD_TYPE_DATA:
+		/* TLS sets EOR at the end of each application data
+		 * record, even though there might be more frames
+		 * waiting to be decrypted.
+		 */
+		msg->msg_flags &= ~MSG_EOR;
+		break;
+	case TLS_RECORD_TYPE_ALERT:
+		tls_alert_recv(sock->sk, msg, &level, &description);
+		ret = (level == TLS_ALERT_LEVEL_FATAL) ?
+			-ENOTCONN : -EAGAIN;
+		break;
+	default:
+		/* discard this record type */
+		ret = -EAGAIN;
+	}
+	return ret;
+}
+
+static int
+svc_tcp_sock_recv_cmsg(struct svc_sock *svsk, struct msghdr *msg)
+{
+	union {
+		struct cmsghdr	cmsg;
+		u8		buf[CMSG_SPACE(sizeof(u8))];
+	} u;
+	struct socket *sock = svsk->sk_sock;
+	int ret;
+
+	msg->msg_control = &u;
+	msg->msg_controllen = sizeof(u);
+	ret = sock_recvmsg(sock, msg, MSG_DONTWAIT);
+	if (unlikely(msg->msg_controllen != sizeof(u)))
+		ret = svc_tcp_sock_process_cmsg(sock, msg, &u.cmsg, ret);
+	return ret;
+}
+
+#if ARCH_IMPLEMENTS_FLUSH_DCACHE_PAGE
+static void svc_flush_bvec(const struct bio_vec *bvec, size_t size, size_t seek)
+{
+	struct bvec_iter bi = {
+		.bi_size	= size + seek,
+	};
+	struct bio_vec bv;
+
+	bvec_iter_advance(bvec, &bi, seek & PAGE_MASK);
+	for_each_bvec(bv, bvec, bi, bi)
+		flush_dcache_page(bv.bv_page);
+}
+#else
+static inline void svc_flush_bvec(const struct bio_vec *bvec, size_t size,
+				  size_t seek)
+{
+}
+#endif
+
+/*
+ * Read from @rqstp's transport socket. The incoming message fills whole
+ * pages in @rqstp's rq_pages array until the last page of the message
+ * has been received into a partial page.
+ */
+static ssize_t svc_tcp_read_msg(struct svc_rqst *rqstp, size_t buflen,
+				size_t seek)
+{
+	struct svc_sock *svsk =
+		container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
+	struct bio_vec *bvec = rqstp->rq_bvec;
+	struct msghdr msg = { NULL };
+	unsigned int i;
+	ssize_t len;
+	size_t t;
+
+	clear_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
+
+	for (i = 0, t = 0; t < buflen; i++, t += PAGE_SIZE)
+		bvec_set_page(&bvec[i], rqstp->rq_pages[i], PAGE_SIZE, 0);
+	rqstp->rq_respages = &rqstp->rq_pages[i];
+	rqstp->rq_next_page = rqstp->rq_respages + 1;
+
+	iov_iter_bvec(&msg.msg_iter, ITER_DEST, bvec, i, buflen);
+	if (seek) {
+		iov_iter_advance(&msg.msg_iter, seek);
+		buflen -= seek;
+	}
+	len = svc_tcp_sock_recv_cmsg(svsk, &msg);
+	if (len > 0)
+		svc_flush_bvec(bvec, len, seek);
+
+	/* If we read a full record, then assume there may be more
+	 * data to read (stream based sockets only!)
+	 */
+	if (len == buflen)
+		set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
+
+	return len;
+}
+
+/*
+ * Set socket snd and rcv buffer lengths
+ */
+static void svc_sock_setbufsize(struct svc_sock *svsk, unsigned int nreqs)
+{
+	unsigned int max_mesg = svsk->sk_xprt.xpt_server->sv_max_mesg;
+	struct socket *sock = svsk->sk_sock;
+
+	nreqs = min(nreqs, INT_MAX / 2 / max_mesg);
+
+	lock_sock(sock->sk);
+	sock->sk->sk_sndbuf = nreqs * max_mesg * 2;
+	sock->sk->sk_rcvbuf = nreqs * max_mesg * 2;
+	sock->sk->sk_write_space(sock->sk);
+	release_sock(sock->sk);
+}
+
+static void svc_sock_secure_port(struct svc_rqst *rqstp)
+{
+	if (svc_port_is_privileged(svc_addr(rqstp)))
+		set_bit(RQ_SECURE, &rqstp->rq_flags);
+	else
+		clear_bit(RQ_SECURE, &rqstp->rq_flags);
+}
+
+/*
+ * INET callback when data has been received on the socket.
+ */
+static void svc_data_ready(struct sock *sk)
+{
+	struct svc_sock	*svsk = (struct svc_sock *)sk->sk_user_data;
+
+	trace_sk_data_ready(sk);
+
+	if (svsk) {
+		/* Refer to svc_setup_socket() for details. */
+		rmb();
+		svsk->sk_odata(sk);
+		trace_svcsock_data_ready(&svsk->sk_xprt, 0);
+		if (test_bit(XPT_HANDSHAKE, &svsk->sk_xprt.xpt_flags))
+			return;
+		if (!test_and_set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags))
+			svc_xprt_enqueue(&svsk->sk_xprt);
+	}
+}
+
+/*
+ * INET callback when space is newly available on the socket.
+ */
+static void svc_write_space(struct sock *sk)
+{
+	struct svc_sock	*svsk = (struct svc_sock *)(sk->sk_user_data);
+
+	if (svsk) {
+		/* Refer to svc_setup_socket() for details. */
+		rmb();
+		trace_svcsock_write_space(&svsk->sk_xprt, 0);
+		svsk->sk_owspace(sk);
+		svc_xprt_enqueue(&svsk->sk_xprt);
+	}
+}
+
+static int svc_tcp_has_wspace(struct svc_xprt *xprt)
+{
+	struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
+
+	if (test_bit(XPT_LISTENER, &xprt->xpt_flags))
+		return 1;
+	return !test_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
+}
+
+static void svc_tcp_kill_temp_xprt(struct svc_xprt *xprt)
+{
+	struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
+
+	sock_no_linger(svsk->sk_sock->sk);
+}
+
+/**
+ * svc_tcp_handshake_done - Handshake completion handler
+ * @data: address of xprt to wake
+ * @status: status of handshake
+ * @peerid: serial number of key containing the remote peer's identity
+ *
+ * If a security policy is specified as an export option, we don't
+ * have a specific export here to check. So we set a "TLS session
+ * is present" flag on the xprt and let an upper layer enforce local
+ * security policy.
+ */
+static void svc_tcp_handshake_done(void *data, int status, key_serial_t peerid)
+{
+	struct svc_xprt *xprt = data;
+	struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
+
+	if (!status) {
+		if (peerid != TLS_NO_PEERID)
+			set_bit(XPT_PEER_AUTH, &xprt->xpt_flags);
+		set_bit(XPT_TLS_SESSION, &xprt->xpt_flags);
+	}
+	clear_bit(XPT_HANDSHAKE, &xprt->xpt_flags);
+	complete_all(&svsk->sk_handshake_done);
+}
+
+/**
+ * svc_tcp_handshake - Perform a transport-layer security handshake
+ * @xprt: connected transport endpoint
+ *
+ */
+static void svc_tcp_handshake(struct svc_xprt *xprt)
+{
+	struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
+	struct sock *sk = svsk->sk_sock->sk;
+	struct tls_handshake_args args = {
+		.ta_sock	= svsk->sk_sock,
+		.ta_done	= svc_tcp_handshake_done,
+		.ta_data	= xprt,
+	};
+	int ret;
+
+	trace_svc_tls_upcall(xprt);
+
+	clear_bit(XPT_TLS_SESSION, &xprt->xpt_flags);
+	init_completion(&svsk->sk_handshake_done);
+
+	ret = tls_server_hello_x509(&args, GFP_KERNEL);
+	if (ret) {
+		trace_svc_tls_not_started(xprt);
+		goto out_failed;
+	}
+
+	ret = wait_for_completion_interruptible_timeout(&svsk->sk_handshake_done,
+							SVC_HANDSHAKE_TO);
+	if (ret <= 0) {
+		if (tls_handshake_cancel(sk)) {
+			trace_svc_tls_timed_out(xprt);
+			goto out_close;
+		}
+	}
+
+	if (!test_bit(XPT_TLS_SESSION, &xprt->xpt_flags)) {
+		trace_svc_tls_unavailable(xprt);
+		goto out_close;
+	}
+
+	/* Mark the transport ready in case the remote sent RPC
+	 * traffic before the kernel received the handshake
+	 * completion downcall.
+	 */
+	set_bit(XPT_DATA, &xprt->xpt_flags);
+	svc_xprt_enqueue(xprt);
+	return;
+
+out_close:
+	set_bit(XPT_CLOSE, &xprt->xpt_flags);
+out_failed:
+	clear_bit(XPT_HANDSHAKE, &xprt->xpt_flags);
+	set_bit(XPT_DATA, &xprt->xpt_flags);
+	svc_xprt_enqueue(xprt);
+}
+
+/*
+ * See net/ipv6/ip_sockglue.c : ip_cmsg_recv_pktinfo
+ */
+static int svc_udp_get_dest_address4(struct svc_rqst *rqstp,
+				     struct cmsghdr *cmh)
+{
+	struct in_pktinfo *pki = CMSG_DATA(cmh);
+	struct sockaddr_in *daddr = svc_daddr_in(rqstp);
+
+	if (cmh->cmsg_type != IP_PKTINFO)
+		return 0;
+
+	daddr->sin_family = AF_INET;
+	daddr->sin_addr.s_addr = pki->ipi_spec_dst.s_addr;
+	return 1;
+}
+
+/*
+ * See net/ipv6/datagram.c : ip6_datagram_recv_ctl
+ */
+static int svc_udp_get_dest_address6(struct svc_rqst *rqstp,
+				     struct cmsghdr *cmh)
+{
+	struct in6_pktinfo *pki = CMSG_DATA(cmh);
+	struct sockaddr_in6 *daddr = svc_daddr_in6(rqstp);
+
+	if (cmh->cmsg_type != IPV6_PKTINFO)
+		return 0;
+
+	daddr->sin6_family = AF_INET6;
+	daddr->sin6_addr = pki->ipi6_addr;
+	daddr->sin6_scope_id = pki->ipi6_ifindex;
+	return 1;
+}
+
+/*
+ * Copy the UDP datagram's destination address to the rqstp structure.
+ * The 'destination' address in this case is the address to which the
+ * peer sent the datagram, i.e. our local address. For multihomed
+ * hosts, this can change from msg to msg. Note that only the IP
+ * address changes, the port number should remain the same.
+ */
+static int svc_udp_get_dest_address(struct svc_rqst *rqstp,
+				    struct cmsghdr *cmh)
+{
+	switch (cmh->cmsg_level) {
+	case SOL_IP:
+		return svc_udp_get_dest_address4(rqstp, cmh);
+	case SOL_IPV6:
+		return svc_udp_get_dest_address6(rqstp, cmh);
+	}
+
+	return 0;
+}
+
+/**
+ * svc_udp_recvfrom - Receive a datagram from a UDP socket.
+ * @rqstp: request structure into which to receive an RPC Call
+ *
+ * Called in a loop when XPT_DATA has been set.
+ *
+ * Returns:
+ *   On success, the number of bytes in a received RPC Call, or
+ *   %0 if a complete RPC Call message was not ready to return
+ */
+static int svc_udp_recvfrom(struct svc_rqst *rqstp)
+{
+	struct svc_sock	*svsk =
+		container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
+	struct svc_serv	*serv = svsk->sk_xprt.xpt_server;
+	struct sk_buff	*skb;
+	union {
+		struct cmsghdr	hdr;
+		long		all[SVC_PKTINFO_SPACE / sizeof(long)];
+	} buffer;
+	struct cmsghdr *cmh = &buffer.hdr;
+	struct msghdr msg = {
+		.msg_name = svc_addr(rqstp),
+		.msg_control = cmh,
+		.msg_controllen = sizeof(buffer),
+		.msg_flags = MSG_DONTWAIT,
+	};
+	size_t len;
+	int err;
+
+	if (test_and_clear_bit(XPT_CHNGBUF, &svsk->sk_xprt.xpt_flags))
+	    /* udp sockets need large rcvbuf as all pending
+	     * requests are still in that buffer.  sndbuf must
+	     * also be large enough that there is enough space
+	     * for one reply per thread.  We count all threads
+	     * rather than threads in a particular pool, which
+	     * provides an upper bound on the number of threads
+	     * which will access the socket.
+	     */
+	    svc_sock_setbufsize(svsk, serv->sv_nrthreads + 3);
+
+	clear_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
+	err = kernel_recvmsg(svsk->sk_sock, &msg, NULL,
+			     0, 0, MSG_PEEK | MSG_DONTWAIT);
+	if (err < 0)
+		goto out_recv_err;
+	skb = skb_recv_udp(svsk->sk_sk, MSG_DONTWAIT, &err);
+	if (!skb)
+		goto out_recv_err;
+
+	len = svc_addr_len(svc_addr(rqstp));
+	rqstp->rq_addrlen = len;
+	if (skb->tstamp == 0) {
+		skb->tstamp = ktime_get_real();
+		/* Don't enable netstamp, sunrpc doesn't
+		   need that much accuracy */
+	}
+	sock_write_timestamp(svsk->sk_sk, skb->tstamp);
+	set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags); /* there may be more data... */
+
+	len = skb->len;
+	rqstp->rq_arg.len = len;
+	trace_svcsock_udp_recv(&svsk->sk_xprt, len);
+
+	rqstp->rq_prot = IPPROTO_UDP;
+
+	if (!svc_udp_get_dest_address(rqstp, cmh))
+		goto out_cmsg_err;
+	rqstp->rq_daddrlen = svc_addr_len(svc_daddr(rqstp));
+
+	if (skb_is_nonlinear(skb)) {
+		/* we have to copy */
+		local_bh_disable();
+		if (csum_partial_copy_to_xdr(&rqstp->rq_arg, skb))
+			goto out_bh_enable;
+		local_bh_enable();
+		consume_skb(skb);
+	} else {
+		/* we can use it in-place */
+		rqstp->rq_arg.head[0].iov_base = skb->data;
+		rqstp->rq_arg.head[0].iov_len = len;
+		if (skb_checksum_complete(skb))
+			goto out_free;
+		rqstp->rq_xprt_ctxt = skb;
+	}
+
+	rqstp->rq_arg.page_base = 0;
+	if (len <= rqstp->rq_arg.head[0].iov_len) {
+		rqstp->rq_arg.head[0].iov_len = len;
+		rqstp->rq_arg.page_len = 0;
+		rqstp->rq_respages = rqstp->rq_pages+1;
+	} else {
+		rqstp->rq_arg.page_len = len - rqstp->rq_arg.head[0].iov_len;
+		rqstp->rq_respages = rqstp->rq_pages + 1 +
+			DIV_ROUND_UP(rqstp->rq_arg.page_len, PAGE_SIZE);
+	}
+	rqstp->rq_next_page = rqstp->rq_respages+1;
+
+	if (serv->sv_stats)
+		serv->sv_stats->netudpcnt++;
+
+	svc_sock_secure_port(rqstp);
+	svc_xprt_received(rqstp->rq_xprt);
+	return len;
+
+out_recv_err:
+	if (err != -EAGAIN) {
+		/* possibly an icmp error */
+		set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
+	}
+	trace_svcsock_udp_recv_err(&svsk->sk_xprt, err);
+	goto out_clear_busy;
+out_cmsg_err:
+	net_warn_ratelimited("svc: received unknown control message %d/%d; dropping RPC reply datagram\n",
+			     cmh->cmsg_level, cmh->cmsg_type);
+	goto out_free;
+out_bh_enable:
+	local_bh_enable();
+out_free:
+	kfree_skb(skb);
+out_clear_busy:
+	svc_xprt_received(rqstp->rq_xprt);
+	return 0;
+}
+
+/**
+ * svc_udp_sendto - Send out a reply on a UDP socket
+ * @rqstp: completed svc_rqst
+ *
+ * xpt_mutex ensures @rqstp's whole message is written to the socket
+ * without interruption.
+ *
+ * Returns the number of bytes sent, or a negative errno.
+ */
+static int svc_udp_sendto(struct svc_rqst *rqstp)
+{
+	struct svc_xprt *xprt = rqstp->rq_xprt;
+	struct svc_sock	*svsk = container_of(xprt, struct svc_sock, sk_xprt);
+	struct xdr_buf *xdr = &rqstp->rq_res;
+	union {
+		struct cmsghdr	hdr;
+		long		all[SVC_PKTINFO_SPACE / sizeof(long)];
+	} buffer;
+	struct cmsghdr *cmh = &buffer.hdr;
+	struct msghdr msg = {
+		.msg_name	= &rqstp->rq_addr,
+		.msg_namelen	= rqstp->rq_addrlen,
+		.msg_control	= cmh,
+		.msg_flags	= MSG_SPLICE_PAGES,
+		.msg_controllen	= sizeof(buffer),
+	};
+	unsigned int count;
+	int err;
+
+	svc_udp_release_ctxt(xprt, rqstp->rq_xprt_ctxt);
+	rqstp->rq_xprt_ctxt = NULL;
+
+	svc_set_cmsg_data(rqstp, cmh);
+
+	mutex_lock(&xprt->xpt_mutex);
+
+	if (svc_xprt_is_dead(xprt))
+		goto out_notconn;
+
+	count = xdr_buf_to_bvec(rqstp->rq_bvec,
+				ARRAY_SIZE(rqstp->rq_bvec), xdr);
+
+	iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, rqstp->rq_bvec,
+		      count, rqstp->rq_res.len);
+	err = sock_sendmsg(svsk->sk_sock, &msg);
+	if (err == -ECONNREFUSED) {
+		/* ICMP error on earlier request. */
+		iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, rqstp->rq_bvec,
+			      count, rqstp->rq_res.len);
+		err = sock_sendmsg(svsk->sk_sock, &msg);
+	}
+
+	trace_svcsock_udp_send(xprt, err);
+
+	mutex_unlock(&xprt->xpt_mutex);
+	return err;
+
+out_notconn:
+	mutex_unlock(&xprt->xpt_mutex);
+	return -ENOTCONN;
+}
+
+static int svc_udp_has_wspace(struct svc_xprt *xprt)
+{
+	struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
+	struct svc_serv	*serv = xprt->xpt_server;
+	unsigned long required;
+
+	/*
+	 * Set the SOCK_NOSPACE flag before checking the available
+	 * sock space.
+	 */
+	set_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
+	required = atomic_read(&svsk->sk_xprt.xpt_reserved) + serv->sv_max_mesg;
+	if (required*2 > sock_wspace(svsk->sk_sk))
+		return 0;
+	clear_bit(SOCK_NOSPACE, &svsk->sk_sock->flags);
+	return 1;
+}
+
+static struct svc_xprt *svc_udp_accept(struct svc_xprt *xprt)
+{
+	BUG();
+	return NULL;
+}
+
+static void svc_udp_kill_temp_xprt(struct svc_xprt *xprt)
+{
+}
+
+static struct svc_xprt *svc_udp_create(struct svc_serv *serv,
+				       struct net *net,
+				       struct sockaddr *sa, int salen,
+				       int flags)
+{
+	return svc_create_socket(serv, IPPROTO_UDP, net, sa, salen, flags);
+}
+
+static const struct svc_xprt_ops svc_udp_ops = {
+	.xpo_create = svc_udp_create,
+	.xpo_recvfrom = svc_udp_recvfrom,
+	.xpo_sendto = svc_udp_sendto,
+	.xpo_result_payload = svc_sock_result_payload,
+	.xpo_release_ctxt = svc_udp_release_ctxt,
+	.xpo_detach = svc_sock_detach,
+	.xpo_free = svc_sock_free,
+	.xpo_has_wspace = svc_udp_has_wspace,
+	.xpo_accept = svc_udp_accept,
+	.xpo_kill_temp_xprt = svc_udp_kill_temp_xprt,
+};
+
+static struct svc_xprt_class svc_udp_class = {
+	.xcl_name = "udp",
+	.xcl_owner = THIS_MODULE,
+	.xcl_ops = &svc_udp_ops,
+	.xcl_max_payload = RPCSVC_MAXPAYLOAD_UDP,
+	.xcl_ident = XPRT_TRANSPORT_UDP,
+};
+
+static void svc_udp_init(struct svc_sock *svsk, struct svc_serv *serv)
+{
+	svc_xprt_init(sock_net(svsk->sk_sock->sk), &svc_udp_class,
+		      &svsk->sk_xprt, serv);
+	clear_bit(XPT_CACHE_AUTH, &svsk->sk_xprt.xpt_flags);
+	svsk->sk_sk->sk_data_ready = svc_data_ready;
+	svsk->sk_sk->sk_write_space = svc_write_space;
+
+	/* initialise setting must have enough space to
+	 * receive and respond to one request.
+	 * svc_udp_recvfrom will re-adjust if necessary
+	 */
+	svc_sock_setbufsize(svsk, 3);
+
+	/* data might have come in before data_ready set up */
+	set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
+	set_bit(XPT_CHNGBUF, &svsk->sk_xprt.xpt_flags);
+
+	/* make sure we get destination address info */
+	switch (svsk->sk_sk->sk_family) {
+	case AF_INET:
+		ip_sock_set_pktinfo(svsk->sk_sock->sk);
+		break;
+	case AF_INET6:
+		ip6_sock_set_recvpktinfo(svsk->sk_sock->sk);
+		break;
+	default:
+		BUG();
+	}
+}
+
+/*
+ * A data_ready event on a listening socket means there's a connection
+ * pending. Do not use state_change as a substitute for it.
+ */
+static void svc_tcp_listen_data_ready(struct sock *sk)
+{
+	struct svc_sock	*svsk = (struct svc_sock *)sk->sk_user_data;
+
+	trace_sk_data_ready(sk);
+
+	/*
+	 * This callback may called twice when a new connection
+	 * is established as a child socket inherits everything
+	 * from a parent LISTEN socket.
+	 * 1) data_ready method of the parent socket will be called
+	 *    when one of child sockets become ESTABLISHED.
+	 * 2) data_ready method of the child socket may be called
+	 *    when it receives data before the socket is accepted.
+	 * In case of 2, we should ignore it silently and DO NOT
+	 * dereference svsk.
+	 */
+	if (sk->sk_state != TCP_LISTEN)
+		return;
+
+	if (svsk) {
+		/* Refer to svc_setup_socket() for details. */
+		rmb();
+		svsk->sk_odata(sk);
+		set_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags);
+		svc_xprt_enqueue(&svsk->sk_xprt);
+	}
+}
+
+/*
+ * A state change on a connected socket means it's dying or dead.
+ */
+static void svc_tcp_state_change(struct sock *sk)
+{
+	struct svc_sock	*svsk = (struct svc_sock *)sk->sk_user_data;
+
+	if (svsk) {
+		/* Refer to svc_setup_socket() for details. */
+		rmb();
+		svsk->sk_ostate(sk);
+		trace_svcsock_tcp_state(&svsk->sk_xprt, svsk->sk_sock);
+		if (sk->sk_state != TCP_ESTABLISHED)
+			svc_xprt_deferred_close(&svsk->sk_xprt);
+	}
+}
+
+/*
+ * Accept a TCP connection
+ */
+static struct svc_xprt *svc_tcp_accept(struct svc_xprt *xprt)
+{
+	struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
+	struct sockaddr_storage addr;
+	struct sockaddr	*sin = (struct sockaddr *) &addr;
+	struct svc_serv	*serv = svsk->sk_xprt.xpt_server;
+	struct socket	*sock = svsk->sk_sock;
+	struct socket	*newsock;
+	struct svc_sock	*newsvsk;
+	int		err, slen;
+
+	if (!sock)
+		return NULL;
+
+	clear_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags);
+	err = kernel_accept(sock, &newsock, O_NONBLOCK);
+	if (err < 0) {
+		if (err != -EAGAIN)
+			trace_svcsock_accept_err(xprt, serv->sv_name, err);
+		return NULL;
+	}
+	if (IS_ERR(sock_alloc_file(newsock, O_NONBLOCK, NULL)))
+		return NULL;
+
+	set_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags);
+
+	err = kernel_getpeername(newsock, sin);
+	if (err < 0) {
+		trace_svcsock_getpeername_err(xprt, serv->sv_name, err);
+		goto failed;		/* aborted connection or whatever */
+	}
+	slen = err;
+
+	/* Reset the inherited callbacks before calling svc_setup_socket */
+	newsock->sk->sk_state_change = svsk->sk_ostate;
+	newsock->sk->sk_data_ready = svsk->sk_odata;
+	newsock->sk->sk_write_space = svsk->sk_owspace;
+
+	/* make sure that a write doesn't block forever when
+	 * low on memory
+	 */
+	newsock->sk->sk_sndtimeo = HZ*30;
+
+	newsvsk = svc_setup_socket(serv, newsock,
+				 (SVC_SOCK_ANONYMOUS | SVC_SOCK_TEMPORARY));
+	if (IS_ERR(newsvsk))
+		goto failed;
+	svc_xprt_set_remote(&newsvsk->sk_xprt, sin, slen);
+	err = kernel_getsockname(newsock, sin);
+	slen = err;
+	if (unlikely(err < 0))
+		slen = offsetof(struct sockaddr, sa_data);
+	svc_xprt_set_local(&newsvsk->sk_xprt, sin, slen);
+
+	if (sock_is_loopback(newsock->sk))
+		set_bit(XPT_LOCAL, &newsvsk->sk_xprt.xpt_flags);
+	else
+		clear_bit(XPT_LOCAL, &newsvsk->sk_xprt.xpt_flags);
+	if (serv->sv_stats)
+		serv->sv_stats->nettcpconn++;
+
+	return &newsvsk->sk_xprt;
+
+failed:
+	sockfd_put(newsock);
+	return NULL;
+}
+
+static size_t svc_tcp_restore_pages(struct svc_sock *svsk,
+				    struct svc_rqst *rqstp)
+{
+	size_t len = svsk->sk_datalen;
+	unsigned int i, npages;
+
+	if (!len)
+		return 0;
+	npages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
+	for (i = 0; i < npages; i++) {
+		if (rqstp->rq_pages[i] != NULL)
+			put_page(rqstp->rq_pages[i]);
+		BUG_ON(svsk->sk_pages[i] == NULL);
+		rqstp->rq_pages[i] = svsk->sk_pages[i];
+		svsk->sk_pages[i] = NULL;
+	}
+	rqstp->rq_arg.head[0].iov_base = page_address(rqstp->rq_pages[0]);
+	return len;
+}
+
+static void svc_tcp_save_pages(struct svc_sock *svsk, struct svc_rqst *rqstp)
+{
+	unsigned int i, len, npages;
+
+	if (svsk->sk_datalen == 0)
+		return;
+	len = svsk->sk_datalen;
+	npages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
+	for (i = 0; i < npages; i++) {
+		svsk->sk_pages[i] = rqstp->rq_pages[i];
+		rqstp->rq_pages[i] = NULL;
+	}
+}
+
+static void svc_tcp_clear_pages(struct svc_sock *svsk)
+{
+	unsigned int i, len, npages;
+
+	if (svsk->sk_datalen == 0)
+		goto out;
+	len = svsk->sk_datalen;
+	npages = (len + PAGE_SIZE - 1) >> PAGE_SHIFT;
+	for (i = 0; i < npages; i++) {
+		if (svsk->sk_pages[i] == NULL) {
+			WARN_ON_ONCE(1);
+			continue;
+		}
+		put_page(svsk->sk_pages[i]);
+		svsk->sk_pages[i] = NULL;
+	}
+out:
+	svsk->sk_tcplen = 0;
+	svsk->sk_datalen = 0;
+}
+
+/*
+ * Receive fragment record header into sk_marker.
+ */
+static ssize_t svc_tcp_read_marker(struct svc_sock *svsk,
+				   struct svc_rqst *rqstp)
+{
+	ssize_t want, len;
+
+	/* If we haven't gotten the record length yet,
+	 * get the next four bytes.
+	 */
+	if (svsk->sk_tcplen < sizeof(rpc_fraghdr)) {
+		struct msghdr	msg = { NULL };
+		struct kvec	iov;
+
+		want = sizeof(rpc_fraghdr) - svsk->sk_tcplen;
+		iov.iov_base = ((char *)&svsk->sk_marker) + svsk->sk_tcplen;
+		iov.iov_len  = want;
+		iov_iter_kvec(&msg.msg_iter, ITER_DEST, &iov, 1, want);
+		len = svc_tcp_sock_recv_cmsg(svsk, &msg);
+		if (len < 0)
+			return len;
+		svsk->sk_tcplen += len;
+		if (len < want) {
+			/* call again to read the remaining bytes */
+			goto err_short;
+		}
+		trace_svcsock_marker(&svsk->sk_xprt, svsk->sk_marker);
+		if (svc_sock_reclen(svsk) + svsk->sk_datalen >
+		    svsk->sk_xprt.xpt_server->sv_max_mesg)
+			goto err_too_large;
+	}
+	return svc_sock_reclen(svsk);
+
+err_too_large:
+	net_notice_ratelimited("svc: %s %s RPC fragment too large: %d\n",
+			       __func__, svsk->sk_xprt.xpt_server->sv_name,
+			       svc_sock_reclen(svsk));
+	svc_xprt_deferred_close(&svsk->sk_xprt);
+err_short:
+	return -EAGAIN;
+}
+
+static int receive_cb_reply(struct svc_sock *svsk, struct svc_rqst *rqstp)
+{
+	struct rpc_xprt *bc_xprt = svsk->sk_xprt.xpt_bc_xprt;
+	struct rpc_rqst *req = NULL;
+	struct kvec *src, *dst;
+	__be32 *p = (__be32 *)rqstp->rq_arg.head[0].iov_base;
+	__be32 xid;
+	__be32 calldir;
+
+	xid = *p++;
+	calldir = *p;
+
+	if (!bc_xprt)
+		return -EAGAIN;
+	spin_lock(&bc_xprt->queue_lock);
+	req = xprt_lookup_rqst(bc_xprt, xid);
+	if (!req)
+		goto unlock_notfound;
+
+	memcpy(&req->rq_private_buf, &req->rq_rcv_buf, sizeof(struct xdr_buf));
+	/*
+	 * XXX!: cheating for now!  Only copying HEAD.
+	 * But we know this is good enough for now (in fact, for any
+	 * callback reply in the forseeable future).
+	 */
+	dst = &req->rq_private_buf.head[0];
+	src = &rqstp->rq_arg.head[0];
+	if (dst->iov_len < src->iov_len)
+		goto unlock_eagain; /* whatever; just giving up. */
+	memcpy(dst->iov_base, src->iov_base, src->iov_len);
+	xprt_complete_rqst(req->rq_task, rqstp->rq_arg.len);
+	rqstp->rq_arg.len = 0;
+	spin_unlock(&bc_xprt->queue_lock);
+	return 0;
+unlock_notfound:
+	printk(KERN_NOTICE
+		"%s: Got unrecognized reply: "
+		"calldir 0x%x xpt_bc_xprt %p xid %08x\n",
+		__func__, ntohl(calldir),
+		bc_xprt, ntohl(xid));
+unlock_eagain:
+	spin_unlock(&bc_xprt->queue_lock);
+	return -EAGAIN;
+}
+
+static void svc_tcp_fragment_received(struct svc_sock *svsk)
+{
+	/* If we have more data, signal svc_xprt_enqueue() to try again */
+	svsk->sk_tcplen = 0;
+	svsk->sk_marker = xdr_zero;
+
+	smp_wmb();
+	tcp_set_rcvlowat(svsk->sk_sk, 1);
+}
+
+/**
+ * svc_tcp_recvfrom - Receive data from a TCP socket
+ * @rqstp: request structure into which to receive an RPC Call
+ *
+ * Called in a loop when XPT_DATA has been set.
+ *
+ * Read the 4-byte stream record marker, then use the record length
+ * in that marker to set up exactly the resources needed to receive
+ * the next RPC message into @rqstp.
+ *
+ * Returns:
+ *   On success, the number of bytes in a received RPC Call, or
+ *   %0 if a complete RPC Call message was not ready to return
+ *
+ * The zero return case handles partial receives and callback Replies.
+ * The state of a partial receive is preserved in the svc_sock for
+ * the next call to svc_tcp_recvfrom.
+ */
+static int svc_tcp_recvfrom(struct svc_rqst *rqstp)
+{
+	struct svc_sock	*svsk =
+		container_of(rqstp->rq_xprt, struct svc_sock, sk_xprt);
+	struct svc_serv	*serv = svsk->sk_xprt.xpt_server;
+	size_t want, base;
+	ssize_t len;
+	__be32 *p;
+	__be32 calldir;
+
+	clear_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
+	len = svc_tcp_read_marker(svsk, rqstp);
+	if (len < 0)
+		goto error;
+
+	base = svc_tcp_restore_pages(svsk, rqstp);
+	want = len - (svsk->sk_tcplen - sizeof(rpc_fraghdr));
+	len = svc_tcp_read_msg(rqstp, base + want, base);
+	if (len >= 0) {
+		trace_svcsock_tcp_recv(&svsk->sk_xprt, len);
+		svsk->sk_tcplen += len;
+		svsk->sk_datalen += len;
+	}
+	if (len != want || !svc_sock_final_rec(svsk))
+		goto err_incomplete;
+	if (svsk->sk_datalen < 8)
+		goto err_nuts;
+
+	rqstp->rq_arg.len = svsk->sk_datalen;
+	rqstp->rq_arg.page_base = 0;
+	if (rqstp->rq_arg.len <= rqstp->rq_arg.head[0].iov_len) {
+		rqstp->rq_arg.head[0].iov_len = rqstp->rq_arg.len;
+		rqstp->rq_arg.page_len = 0;
+	} else
+		rqstp->rq_arg.page_len = rqstp->rq_arg.len - rqstp->rq_arg.head[0].iov_len;
+
+	rqstp->rq_xprt_ctxt   = NULL;
+	rqstp->rq_prot	      = IPPROTO_TCP;
+	if (test_bit(XPT_LOCAL, &svsk->sk_xprt.xpt_flags))
+		set_bit(RQ_LOCAL, &rqstp->rq_flags);
+	else
+		clear_bit(RQ_LOCAL, &rqstp->rq_flags);
+
+	p = (__be32 *)rqstp->rq_arg.head[0].iov_base;
+	calldir = p[1];
+	if (calldir)
+		len = receive_cb_reply(svsk, rqstp);
+
+	/* Reset TCP read info */
+	svsk->sk_datalen = 0;
+	svc_tcp_fragment_received(svsk);
+
+	if (len < 0)
+		goto error;
+
+	svc_xprt_copy_addrs(rqstp, &svsk->sk_xprt);
+	if (serv->sv_stats)
+		serv->sv_stats->nettcpcnt++;
+
+	svc_sock_secure_port(rqstp);
+	svc_xprt_received(rqstp->rq_xprt);
+	return rqstp->rq_arg.len;
+
+err_incomplete:
+	svc_tcp_save_pages(svsk, rqstp);
+	if (len < 0 && len != -EAGAIN)
+		goto err_delete;
+	if (len == want)
+		svc_tcp_fragment_received(svsk);
+	else {
+		/* Avoid more ->sk_data_ready() calls until the rest
+		 * of the message has arrived. This reduces service
+		 * thread wake-ups on large incoming messages. */
+		tcp_set_rcvlowat(svsk->sk_sk,
+				 svc_sock_reclen(svsk) - svsk->sk_tcplen);
+
+		trace_svcsock_tcp_recv_short(&svsk->sk_xprt,
+				svc_sock_reclen(svsk),
+				svsk->sk_tcplen - sizeof(rpc_fraghdr));
+	}
+	goto err_noclose;
+error:
+	if (len != -EAGAIN)
+		goto err_delete;
+	trace_svcsock_tcp_recv_eagain(&svsk->sk_xprt, 0);
+	goto err_noclose;
+err_nuts:
+	svsk->sk_datalen = 0;
+err_delete:
+	trace_svcsock_tcp_recv_err(&svsk->sk_xprt, len);
+	svc_xprt_deferred_close(&svsk->sk_xprt);
+err_noclose:
+	svc_xprt_received(rqstp->rq_xprt);
+	return 0;	/* record not complete */
+}
+
+/*
+ * MSG_SPLICE_PAGES is used exclusively to reduce the number of
+ * copy operations in this path. Therefore the caller must ensure
+ * that the pages backing @xdr are unchanging.
+ *
+ * Note that the send is non-blocking. The caller has incremented
+ * the reference count on each page backing the RPC message, and
+ * the network layer will "put" these pages when transmission is
+ * complete.
+ *
+ * This is safe for our RPC services because the memory backing
+ * the head and tail components is never kmalloc'd. These always
+ * come from pages in the svc_rqst::rq_pages array.
+ */
+static int svc_tcp_sendmsg(struct svc_sock *svsk, struct svc_rqst *rqstp,
+			   rpc_fraghdr marker, unsigned int *sentp)
+{
+	struct msghdr msg = {
+		.msg_flags	= MSG_SPLICE_PAGES,
+	};
+	unsigned int count;
+	void *buf;
+	int ret;
+
+	*sentp = 0;
+
+	/* The stream record marker is copied into a temporary page
+	 * fragment buffer so that it can be included in rq_bvec.
+	 */
+	buf = page_frag_alloc(&svsk->sk_frag_cache, sizeof(marker),
+			      GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+	memcpy(buf, &marker, sizeof(marker));
+	bvec_set_virt(rqstp->rq_bvec, buf, sizeof(marker));
+
+	count = xdr_buf_to_bvec(rqstp->rq_bvec + 1,
+				ARRAY_SIZE(rqstp->rq_bvec) - 1, &rqstp->rq_res);
+
+	iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, rqstp->rq_bvec,
+		      1 + count, sizeof(marker) + rqstp->rq_res.len);
+	ret = sock_sendmsg(svsk->sk_sock, &msg);
+	if (ret < 0)
+		return ret;
+	*sentp += ret;
+	return 0;
+}
+
+/**
+ * svc_tcp_sendto - Send out a reply on a TCP socket
+ * @rqstp: completed svc_rqst
+ *
+ * xpt_mutex ensures @rqstp's whole message is written to the socket
+ * without interruption.
+ *
+ * Returns the number of bytes sent, or a negative errno.
+ */
+static int svc_tcp_sendto(struct svc_rqst *rqstp)
+{
+	struct svc_xprt *xprt = rqstp->rq_xprt;
+	struct svc_sock	*svsk = container_of(xprt, struct svc_sock, sk_xprt);
+	struct xdr_buf *xdr = &rqstp->rq_res;
+	rpc_fraghdr marker = cpu_to_be32(RPC_LAST_STREAM_FRAGMENT |
+					 (u32)xdr->len);
+	unsigned int sent;
+	int err;
+
+	svc_tcp_release_ctxt(xprt, rqstp->rq_xprt_ctxt);
+	rqstp->rq_xprt_ctxt = NULL;
+
+	mutex_lock(&xprt->xpt_mutex);
+	if (svc_xprt_is_dead(xprt))
+		goto out_notconn;
+	err = svc_tcp_sendmsg(svsk, rqstp, marker, &sent);
+	trace_svcsock_tcp_send(xprt, err < 0 ? (long)err : sent);
+	if (err < 0 || sent != (xdr->len + sizeof(marker)))
+		goto out_close;
+	mutex_unlock(&xprt->xpt_mutex);
+	return sent;
+
+out_notconn:
+	mutex_unlock(&xprt->xpt_mutex);
+	return -ENOTCONN;
+out_close:
+	pr_notice("rpc-srv/tcp: %s: %s %d when sending %d bytes - shutting down socket\n",
+		  xprt->xpt_server->sv_name,
+		  (err < 0) ? "got error" : "sent",
+		  (err < 0) ? err : sent, xdr->len);
+	svc_xprt_deferred_close(xprt);
+	mutex_unlock(&xprt->xpt_mutex);
+	return -EAGAIN;
+}
+
+static struct svc_xprt *svc_tcp_create(struct svc_serv *serv,
+				       struct net *net,
+				       struct sockaddr *sa, int salen,
+				       int flags)
+{
+	return svc_create_socket(serv, IPPROTO_TCP, net, sa, salen, flags);
+}
+
+static const struct svc_xprt_ops svc_tcp_ops = {
+	.xpo_create = svc_tcp_create,
+	.xpo_recvfrom = svc_tcp_recvfrom,
+	.xpo_sendto = svc_tcp_sendto,
+	.xpo_result_payload = svc_sock_result_payload,
+	.xpo_release_ctxt = svc_tcp_release_ctxt,
+	.xpo_detach = svc_tcp_sock_detach,
+	.xpo_free = svc_sock_free,
+	.xpo_has_wspace = svc_tcp_has_wspace,
+	.xpo_accept = svc_tcp_accept,
+	.xpo_kill_temp_xprt = svc_tcp_kill_temp_xprt,
+	.xpo_handshake = svc_tcp_handshake,
+};
+
+static struct svc_xprt_class svc_tcp_class = {
+	.xcl_name = "tcp",
+	.xcl_owner = THIS_MODULE,
+	.xcl_ops = &svc_tcp_ops,
+	.xcl_max_payload = RPCSVC_MAXPAYLOAD_TCP,
+	.xcl_ident = XPRT_TRANSPORT_TCP,
+};
+
+void svc_init_xprt_sock(void)
+{
+	svc_reg_xprt_class(&svc_tcp_class);
+	svc_reg_xprt_class(&svc_udp_class);
+}
+
+void svc_cleanup_xprt_sock(void)
+{
+	svc_unreg_xprt_class(&svc_tcp_class);
+	svc_unreg_xprt_class(&svc_udp_class);
+}
+
+static void svc_tcp_init(struct svc_sock *svsk, struct svc_serv *serv)
+{
+	struct sock	*sk = svsk->sk_sk;
+
+	svc_xprt_init(sock_net(svsk->sk_sock->sk), &svc_tcp_class,
+		      &svsk->sk_xprt, serv);
+	set_bit(XPT_CACHE_AUTH, &svsk->sk_xprt.xpt_flags);
+	set_bit(XPT_CONG_CTRL, &svsk->sk_xprt.xpt_flags);
+	if (sk->sk_state == TCP_LISTEN) {
+		strcpy(svsk->sk_xprt.xpt_remotebuf, "listener");
+		set_bit(XPT_LISTENER, &svsk->sk_xprt.xpt_flags);
+		sk->sk_data_ready = svc_tcp_listen_data_ready;
+		set_bit(XPT_CONN, &svsk->sk_xprt.xpt_flags);
+	} else {
+		sk->sk_state_change = svc_tcp_state_change;
+		sk->sk_data_ready = svc_data_ready;
+		sk->sk_write_space = svc_write_space;
+
+		svsk->sk_marker = xdr_zero;
+		svsk->sk_tcplen = 0;
+		svsk->sk_datalen = 0;
+		memset(&svsk->sk_pages[0], 0, sizeof(svsk->sk_pages));
+
+		tcp_sock_set_nodelay(sk);
+
+		set_bit(XPT_DATA, &svsk->sk_xprt.xpt_flags);
+		switch (sk->sk_state) {
+		case TCP_SYN_RECV:
+		case TCP_ESTABLISHED:
+			break;
+		default:
+			svc_xprt_deferred_close(&svsk->sk_xprt);
+		}
+	}
+}
+
+void svc_sock_update_bufs(struct svc_serv *serv)
+{
+	/*
+	 * The number of server threads has changed. Update
+	 * rcvbuf and sndbuf accordingly on all sockets
+	 */
+	struct svc_sock *svsk;
+
+	spin_lock_bh(&serv->sv_lock);
+	list_for_each_entry(svsk, &serv->sv_permsocks, sk_xprt.xpt_list)
+		set_bit(XPT_CHNGBUF, &svsk->sk_xprt.xpt_flags);
+	spin_unlock_bh(&serv->sv_lock);
+}
+EXPORT_SYMBOL_GPL(svc_sock_update_bufs);
+
+/*
+ * Initialize socket for RPC use and create svc_sock struct
+ */
+static struct svc_sock *svc_setup_socket(struct svc_serv *serv,
+						struct socket *sock,
+						int flags)
+{
+	struct svc_sock	*svsk;
+	struct sock	*inet;
+	int		pmap_register = !(flags & SVC_SOCK_ANONYMOUS);
+
+	svsk = kzalloc(sizeof(*svsk), GFP_KERNEL);
+	if (!svsk)
+		return ERR_PTR(-ENOMEM);
+
+	inet = sock->sk;
+
+	if (pmap_register) {
+		int err;
+
+		err = svc_register(serv, sock_net(sock->sk), inet->sk_family,
+				     inet->sk_protocol,
+				     ntohs(inet_sk(inet)->inet_sport));
+		if (err < 0) {
+			kfree(svsk);
+			return ERR_PTR(err);
+		}
+	}
+
+	svsk->sk_sock = sock;
+	svsk->sk_sk = inet;
+	svsk->sk_ostate = inet->sk_state_change;
+	svsk->sk_odata = inet->sk_data_ready;
+	svsk->sk_owspace = inet->sk_write_space;
+	/*
+	 * This barrier is necessary in order to prevent race condition
+	 * with svc_data_ready(), svc_tcp_listen_data_ready(), and others
+	 * when calling callbacks above.
+	 */
+	wmb();
+	inet->sk_user_data = svsk;
+
+	/* Initialize the socket */
+	if (sock->type == SOCK_DGRAM)
+		svc_udp_init(svsk, serv);
+	else
+		svc_tcp_init(svsk, serv);
+
+	trace_svcsock_new(svsk, sock);
+	return svsk;
+}
+
+/**
+ * svc_addsock - add a listener socket to an RPC service
+ * @serv: pointer to RPC service to which to add a new listener
+ * @net: caller's network namespace
+ * @fd: file descriptor of the new listener
+ * @name_return: pointer to buffer to fill in with name of listener
+ * @len: size of the buffer
+ * @cred: credential
+ *
+ * Fills in socket name and returns positive length of name if successful.
+ * Name is terminated with '\n'.  On error, returns a negative errno
+ * value.
+ */
+int svc_addsock(struct svc_serv *serv, struct net *net, const int fd,
+		char *name_return, const size_t len, const struct cred *cred)
+{
+	int err = 0;
+	struct socket *so = sockfd_lookup(fd, &err);
+	struct svc_sock *svsk = NULL;
+	struct sockaddr_storage addr;
+	struct sockaddr *sin = (struct sockaddr *)&addr;
+	int salen;
+
+	if (!so)
+		return err;
+	err = -EINVAL;
+	if (sock_net(so->sk) != net)
+		goto out;
+	err = -EAFNOSUPPORT;
+	if ((so->sk->sk_family != PF_INET) && (so->sk->sk_family != PF_INET6))
+		goto out;
+	err =  -EPROTONOSUPPORT;
+	if (so->sk->sk_protocol != IPPROTO_TCP &&
+	    so->sk->sk_protocol != IPPROTO_UDP)
+		goto out;
+	err = -EISCONN;
+	if (so->state > SS_UNCONNECTED)
+		goto out;
+	err = -ENOENT;
+	if (!try_module_get(THIS_MODULE))
+		goto out;
+	svsk = svc_setup_socket(serv, so, SVC_SOCK_DEFAULTS);
+	if (IS_ERR(svsk)) {
+		module_put(THIS_MODULE);
+		err = PTR_ERR(svsk);
+		goto out;
+	}
+	salen = kernel_getsockname(svsk->sk_sock, sin);
+	if (salen >= 0)
+		svc_xprt_set_local(&svsk->sk_xprt, sin, salen);
+	svsk->sk_xprt.xpt_cred = get_cred(cred);
+	svc_add_new_perm_xprt(serv, &svsk->sk_xprt);
+	return svc_one_sock_name(svsk, name_return, len);
+out:
+	sockfd_put(so);
+	return err;
+}
+EXPORT_SYMBOL_GPL(svc_addsock);
+
+/*
+ * Create socket for RPC service.
+ */
+static struct svc_xprt *svc_create_socket(struct svc_serv *serv,
+					  int protocol,
+					  struct net *net,
+					  struct sockaddr *sin, int len,
+					  int flags)
+{
+	struct svc_sock	*svsk;
+	struct socket	*sock;
+	int		error;
+	int		type;
+	struct sockaddr_storage addr;
+	struct sockaddr *newsin = (struct sockaddr *)&addr;
+	int		newlen;
+	int		family;
+
+	if (protocol != IPPROTO_UDP && protocol != IPPROTO_TCP) {
+		printk(KERN_WARNING "svc: only UDP and TCP "
+				"sockets supported\n");
+		return ERR_PTR(-EINVAL);
+	}
+
+	type = (protocol == IPPROTO_UDP)? SOCK_DGRAM : SOCK_STREAM;
+	switch (sin->sa_family) {
+	case AF_INET6:
+		family = PF_INET6;
+		break;
+	case AF_INET:
+		family = PF_INET;
+		break;
+	default:
+		return ERR_PTR(-EINVAL);
+	}
+
+	error = __sock_create(net, family, type, protocol, &sock, 1);
+	if (error < 0)
+		return ERR_PTR(error);
+
+	svc_reclassify_socket(sock);
+
+	/*
+	 * If this is an PF_INET6 listener, we want to avoid
+	 * getting requests from IPv4 remotes.  Those should
+	 * be shunted to a PF_INET listener via rpcbind.
+	 */
+	if (family == PF_INET6)
+		ip6_sock_set_v6only(sock->sk);
+	if (type == SOCK_STREAM)
+		sock->sk->sk_reuse = SK_CAN_REUSE; /* allow address reuse */
+	error = kernel_bind(sock, sin, len);
+	if (error < 0)
+		goto bummer;
+
+	error = kernel_getsockname(sock, newsin);
+	if (error < 0)
+		goto bummer;
+	newlen = error;
+
+	if (protocol == IPPROTO_TCP) {
+		if ((error = kernel_listen(sock, 64)) < 0)
+			goto bummer;
+	}
+
+	svsk = svc_setup_socket(serv, sock, flags);
+	if (IS_ERR(svsk)) {
+		error = PTR_ERR(svsk);
+		goto bummer;
+	}
+	svc_xprt_set_local(&svsk->sk_xprt, newsin, newlen);
+	return (struct svc_xprt *)svsk;
+bummer:
+	sock_release(sock);
+	return ERR_PTR(error);
+}
+
+/*
+ * Detach the svc_sock from the socket so that no
+ * more callbacks occur.
+ */
+static void svc_sock_detach(struct svc_xprt *xprt)
+{
+	struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
+	struct sock *sk = svsk->sk_sk;
+
+	/* put back the old socket callbacks */
+	lock_sock(sk);
+	sk->sk_state_change = svsk->sk_ostate;
+	sk->sk_data_ready = svsk->sk_odata;
+	sk->sk_write_space = svsk->sk_owspace;
+	sk->sk_user_data = NULL;
+	release_sock(sk);
+}
+
+/*
+ * Disconnect the socket, and reset the callbacks
+ */
+static void svc_tcp_sock_detach(struct svc_xprt *xprt)
+{
+	struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
+
+	tls_handshake_close(svsk->sk_sock);
+
+	svc_sock_detach(xprt);
+
+	if (!test_bit(XPT_LISTENER, &xprt->xpt_flags)) {
+		svc_tcp_clear_pages(svsk);
+		kernel_sock_shutdown(svsk->sk_sock, SHUT_RDWR);
+	}
+}
+
+/*
+ * Free the svc_sock's socket resources and the svc_sock itself.
+ */
+static void svc_sock_free(struct svc_xprt *xprt)
+{
+	struct svc_sock *svsk = container_of(xprt, struct svc_sock, sk_xprt);
+	struct page_frag_cache *pfc = &svsk->sk_frag_cache;
+	struct socket *sock = svsk->sk_sock;
+
+	trace_svcsock_free(svsk, sock);
+
+	tls_handshake_cancel(sock->sk);
+	if (sock->file)
+		sockfd_put(sock);
+	else
+		sock_release(sock);
+	if (pfc->va)
+		__page_frag_cache_drain(virt_to_head_page(pfc->va),
+					pfc->pagecnt_bias);
+	kfree(svsk);
+}