Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / net / sunrpc / xprtsock.c
diff --git a/kernel/net/sunrpc/xprtsock.c b/kernel/net/sunrpc/xprtsock.c
new file mode 100644 (file)
index 0000000..66891e3
--- /dev/null
@@ -0,0 +1,3034 @@
+/*
+ * linux/net/sunrpc/xprtsock.c
+ *
+ * Client-side transport implementation for sockets.
+ *
+ * TCP callback races fixes (C) 1998 Red Hat
+ * TCP send fixes (C) 1998 Red Hat
+ * TCP NFS related read + write fixes
+ *  (C) 1999 Dave Airlie, University of Limerick, Ireland <airlied@linux.ie>
+ *
+ * Rewrite of larges part of the code in order to stabilize TCP stuff.
+ * Fix behaviour when socket buffer is full.
+ *  (C) 1999 Trond Myklebust <trond.myklebust@fys.uio.no>
+ *
+ * IP socket transport implementation, (C) 2005 Chuck Lever <cel@netapp.com>
+ *
+ * IPv6 support contributed by Gilles Quillard, Bull Open Source, 2005.
+ *   <gilles.quillard@bull.net>
+ */
+
+#include <linux/types.h>
+#include <linux/string.h>
+#include <linux/slab.h>
+#include <linux/module.h>
+#include <linux/capability.h>
+#include <linux/pagemap.h>
+#include <linux/errno.h>
+#include <linux/socket.h>
+#include <linux/in.h>
+#include <linux/net.h>
+#include <linux/mm.h>
+#include <linux/un.h>
+#include <linux/udp.h>
+#include <linux/tcp.h>
+#include <linux/sunrpc/clnt.h>
+#include <linux/sunrpc/addr.h>
+#include <linux/sunrpc/sched.h>
+#include <linux/sunrpc/svcsock.h>
+#include <linux/sunrpc/xprtsock.h>
+#include <linux/file.h>
+#ifdef CONFIG_SUNRPC_BACKCHANNEL
+#include <linux/sunrpc/bc_xprt.h>
+#endif
+
+#include <net/sock.h>
+#include <net/checksum.h>
+#include <net/udp.h>
+#include <net/tcp.h>
+
+#include <trace/events/sunrpc.h>
+
+#include "sunrpc.h"
+
+static void xs_close(struct rpc_xprt *xprt);
+
+/*
+ * xprtsock tunables
+ */
+static unsigned int xprt_udp_slot_table_entries = RPC_DEF_SLOT_TABLE;
+static unsigned int xprt_tcp_slot_table_entries = RPC_MIN_SLOT_TABLE;
+static unsigned int xprt_max_tcp_slot_table_entries = RPC_MAX_SLOT_TABLE;
+
+static unsigned int xprt_min_resvport = RPC_DEF_MIN_RESVPORT;
+static unsigned int xprt_max_resvport = RPC_DEF_MAX_RESVPORT;
+
+#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
+
+#define XS_TCP_LINGER_TO       (15U * HZ)
+static unsigned int xs_tcp_fin_timeout __read_mostly = XS_TCP_LINGER_TO;
+
+/*
+ * We can register our own files under /proc/sys/sunrpc by
+ * calling register_sysctl_table() again.  The files in that
+ * directory become the union of all files registered there.
+ *
+ * We simply need to make sure that we don't collide with
+ * someone else's file names!
+ */
+
+static unsigned int min_slot_table_size = RPC_MIN_SLOT_TABLE;
+static unsigned int max_slot_table_size = RPC_MAX_SLOT_TABLE;
+static unsigned int max_tcp_slot_table_limit = RPC_MAX_SLOT_TABLE_LIMIT;
+static unsigned int xprt_min_resvport_limit = RPC_MIN_RESVPORT;
+static unsigned int xprt_max_resvport_limit = RPC_MAX_RESVPORT;
+
+static struct ctl_table_header *sunrpc_table_header;
+
+/*
+ * FIXME: changing the UDP slot table size should also resize the UDP
+ *        socket buffers for existing UDP transports
+ */
+static struct ctl_table xs_tunables_table[] = {
+       {
+               .procname       = "udp_slot_table_entries",
+               .data           = &xprt_udp_slot_table_entries,
+               .maxlen         = sizeof(unsigned int),
+               .mode           = 0644,
+               .proc_handler   = proc_dointvec_minmax,
+               .extra1         = &min_slot_table_size,
+               .extra2         = &max_slot_table_size
+       },
+       {
+               .procname       = "tcp_slot_table_entries",
+               .data           = &xprt_tcp_slot_table_entries,
+               .maxlen         = sizeof(unsigned int),
+               .mode           = 0644,
+               .proc_handler   = proc_dointvec_minmax,
+               .extra1         = &min_slot_table_size,
+               .extra2         = &max_slot_table_size
+       },
+       {
+               .procname       = "tcp_max_slot_table_entries",
+               .data           = &xprt_max_tcp_slot_table_entries,
+               .maxlen         = sizeof(unsigned int),
+               .mode           = 0644,
+               .proc_handler   = proc_dointvec_minmax,
+               .extra1         = &min_slot_table_size,
+               .extra2         = &max_tcp_slot_table_limit
+       },
+       {
+               .procname       = "min_resvport",
+               .data           = &xprt_min_resvport,
+               .maxlen         = sizeof(unsigned int),
+               .mode           = 0644,
+               .proc_handler   = proc_dointvec_minmax,
+               .extra1         = &xprt_min_resvport_limit,
+               .extra2         = &xprt_max_resvport_limit
+       },
+       {
+               .procname       = "max_resvport",
+               .data           = &xprt_max_resvport,
+               .maxlen         = sizeof(unsigned int),
+               .mode           = 0644,
+               .proc_handler   = proc_dointvec_minmax,
+               .extra1         = &xprt_min_resvport_limit,
+               .extra2         = &xprt_max_resvport_limit
+       },
+       {
+               .procname       = "tcp_fin_timeout",
+               .data           = &xs_tcp_fin_timeout,
+               .maxlen         = sizeof(xs_tcp_fin_timeout),
+               .mode           = 0644,
+               .proc_handler   = proc_dointvec_jiffies,
+       },
+       { },
+};
+
+static struct ctl_table sunrpc_table[] = {
+       {
+               .procname       = "sunrpc",
+               .mode           = 0555,
+               .child          = xs_tunables_table
+       },
+       { },
+};
+
+#endif
+
+/*
+ * Wait duration for a reply from the RPC portmapper.
+ */
+#define XS_BIND_TO             (60U * HZ)
+
+/*
+ * Delay if a UDP socket connect error occurs.  This is most likely some
+ * kind of resource problem on the local host.
+ */
+#define XS_UDP_REEST_TO                (2U * HZ)
+
+/*
+ * The reestablish timeout allows clients to delay for a bit before attempting
+ * to reconnect to a server that just dropped our connection.
+ *
+ * We implement an exponential backoff when trying to reestablish a TCP
+ * transport connection with the server.  Some servers like to drop a TCP
+ * connection when they are overworked, so we start with a short timeout and
+ * increase over time if the server is down or not responding.
+ */
+#define XS_TCP_INIT_REEST_TO   (3U * HZ)
+#define XS_TCP_MAX_REEST_TO    (5U * 60 * HZ)
+
+/*
+ * TCP idle timeout; client drops the transport socket if it is idle
+ * for this long.  Note that we also timeout UDP sockets to prevent
+ * holding port numbers when there is no RPC traffic.
+ */
+#define XS_IDLE_DISC_TO                (5U * 60 * HZ)
+
+#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
+# undef  RPC_DEBUG_DATA
+# define RPCDBG_FACILITY       RPCDBG_TRANS
+#endif
+
+#ifdef RPC_DEBUG_DATA
+static void xs_pktdump(char *msg, u32 *packet, unsigned int count)
+{
+       u8 *buf = (u8 *) packet;
+       int j;
+
+       dprintk("RPC:       %s\n", msg);
+       for (j = 0; j < count && j < 128; j += 4) {
+               if (!(j & 31)) {
+                       if (j)
+                               dprintk("\n");
+                       dprintk("0x%04x ", j);
+               }
+               dprintk("%02x%02x%02x%02x ",
+                       buf[j], buf[j+1], buf[j+2], buf[j+3]);
+       }
+       dprintk("\n");
+}
+#else
+static inline void xs_pktdump(char *msg, u32 *packet, unsigned int count)
+{
+       /* NOP */
+}
+#endif
+
+static inline struct rpc_xprt *xprt_from_sock(struct sock *sk)
+{
+       return (struct rpc_xprt *) sk->sk_user_data;
+}
+
+static inline struct sockaddr *xs_addr(struct rpc_xprt *xprt)
+{
+       return (struct sockaddr *) &xprt->addr;
+}
+
+static inline struct sockaddr_un *xs_addr_un(struct rpc_xprt *xprt)
+{
+       return (struct sockaddr_un *) &xprt->addr;
+}
+
+static inline struct sockaddr_in *xs_addr_in(struct rpc_xprt *xprt)
+{
+       return (struct sockaddr_in *) &xprt->addr;
+}
+
+static inline struct sockaddr_in6 *xs_addr_in6(struct rpc_xprt *xprt)
+{
+       return (struct sockaddr_in6 *) &xprt->addr;
+}
+
+static void xs_format_common_peer_addresses(struct rpc_xprt *xprt)
+{
+       struct sockaddr *sap = xs_addr(xprt);
+       struct sockaddr_in6 *sin6;
+       struct sockaddr_in *sin;
+       struct sockaddr_un *sun;
+       char buf[128];
+
+       switch (sap->sa_family) {
+       case AF_LOCAL:
+               sun = xs_addr_un(xprt);
+               strlcpy(buf, sun->sun_path, sizeof(buf));
+               xprt->address_strings[RPC_DISPLAY_ADDR] =
+                                               kstrdup(buf, GFP_KERNEL);
+               break;
+       case AF_INET:
+               (void)rpc_ntop(sap, buf, sizeof(buf));
+               xprt->address_strings[RPC_DISPLAY_ADDR] =
+                                               kstrdup(buf, GFP_KERNEL);
+               sin = xs_addr_in(xprt);
+               snprintf(buf, sizeof(buf), "%08x", ntohl(sin->sin_addr.s_addr));
+               break;
+       case AF_INET6:
+               (void)rpc_ntop(sap, buf, sizeof(buf));
+               xprt->address_strings[RPC_DISPLAY_ADDR] =
+                                               kstrdup(buf, GFP_KERNEL);
+               sin6 = xs_addr_in6(xprt);
+               snprintf(buf, sizeof(buf), "%pi6", &sin6->sin6_addr);
+               break;
+       default:
+               BUG();
+       }
+
+       xprt->address_strings[RPC_DISPLAY_HEX_ADDR] = kstrdup(buf, GFP_KERNEL);
+}
+
+static void xs_format_common_peer_ports(struct rpc_xprt *xprt)
+{
+       struct sockaddr *sap = xs_addr(xprt);
+       char buf[128];
+
+       snprintf(buf, sizeof(buf), "%u", rpc_get_port(sap));
+       xprt->address_strings[RPC_DISPLAY_PORT] = kstrdup(buf, GFP_KERNEL);
+
+       snprintf(buf, sizeof(buf), "%4hx", rpc_get_port(sap));
+       xprt->address_strings[RPC_DISPLAY_HEX_PORT] = kstrdup(buf, GFP_KERNEL);
+}
+
+static void xs_format_peer_addresses(struct rpc_xprt *xprt,
+                                    const char *protocol,
+                                    const char *netid)
+{
+       xprt->address_strings[RPC_DISPLAY_PROTO] = protocol;
+       xprt->address_strings[RPC_DISPLAY_NETID] = netid;
+       xs_format_common_peer_addresses(xprt);
+       xs_format_common_peer_ports(xprt);
+}
+
+static void xs_update_peer_port(struct rpc_xprt *xprt)
+{
+       kfree(xprt->address_strings[RPC_DISPLAY_HEX_PORT]);
+       kfree(xprt->address_strings[RPC_DISPLAY_PORT]);
+
+       xs_format_common_peer_ports(xprt);
+}
+
+static void xs_free_peer_addresses(struct rpc_xprt *xprt)
+{
+       unsigned int i;
+
+       for (i = 0; i < RPC_DISPLAY_MAX; i++)
+               switch (i) {
+               case RPC_DISPLAY_PROTO:
+               case RPC_DISPLAY_NETID:
+                       continue;
+               default:
+                       kfree(xprt->address_strings[i]);
+               }
+}
+
+#define XS_SENDMSG_FLAGS       (MSG_DONTWAIT | MSG_NOSIGNAL)
+
+static int xs_send_kvec(struct socket *sock, struct sockaddr *addr, int addrlen, struct kvec *vec, unsigned int base, int more)
+{
+       struct msghdr msg = {
+               .msg_name       = addr,
+               .msg_namelen    = addrlen,
+               .msg_flags      = XS_SENDMSG_FLAGS | (more ? MSG_MORE : 0),
+       };
+       struct kvec iov = {
+               .iov_base       = vec->iov_base + base,
+               .iov_len        = vec->iov_len - base,
+       };
+
+       if (iov.iov_len != 0)
+               return kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len);
+       return kernel_sendmsg(sock, &msg, NULL, 0, 0);
+}
+
+static int xs_send_pagedata(struct socket *sock, struct xdr_buf *xdr, unsigned int base, int more, bool zerocopy, int *sent_p)
+{
+       ssize_t (*do_sendpage)(struct socket *sock, struct page *page,
+                       int offset, size_t size, int flags);
+       struct page **ppage;
+       unsigned int remainder;
+       int err;
+
+       remainder = xdr->page_len - base;
+       base += xdr->page_base;
+       ppage = xdr->pages + (base >> PAGE_SHIFT);
+       base &= ~PAGE_MASK;
+       do_sendpage = sock->ops->sendpage;
+       if (!zerocopy)
+               do_sendpage = sock_no_sendpage;
+       for(;;) {
+               unsigned int len = min_t(unsigned int, PAGE_SIZE - base, remainder);
+               int flags = XS_SENDMSG_FLAGS;
+
+               remainder -= len;
+               if (remainder != 0 || more)
+                       flags |= MSG_MORE;
+               err = do_sendpage(sock, *ppage, base, len, flags);
+               if (remainder == 0 || err != len)
+                       break;
+               *sent_p += err;
+               ppage++;
+               base = 0;
+       }
+       if (err > 0) {
+               *sent_p += err;
+               err = 0;
+       }
+       return err;
+}
+
+/**
+ * xs_sendpages - write pages directly to a socket
+ * @sock: socket to send on
+ * @addr: UDP only -- address of destination
+ * @addrlen: UDP only -- length of destination address
+ * @xdr: buffer containing this request
+ * @base: starting position in the buffer
+ * @zerocopy: true if it is safe to use sendpage()
+ * @sent_p: return the total number of bytes successfully queued for sending
+ *
+ */
+static int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base, bool zerocopy, int *sent_p)
+{
+       unsigned int remainder = xdr->len - base;
+       int err = 0;
+       int sent = 0;
+
+       if (unlikely(!sock))
+               return -ENOTSOCK;
+
+       clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags);
+       if (base != 0) {
+               addr = NULL;
+               addrlen = 0;
+       }
+
+       if (base < xdr->head[0].iov_len || addr != NULL) {
+               unsigned int len = xdr->head[0].iov_len - base;
+               remainder -= len;
+               err = xs_send_kvec(sock, addr, addrlen, &xdr->head[0], base, remainder != 0);
+               if (remainder == 0 || err != len)
+                       goto out;
+               *sent_p += err;
+               base = 0;
+       } else
+               base -= xdr->head[0].iov_len;
+
+       if (base < xdr->page_len) {
+               unsigned int len = xdr->page_len - base;
+               remainder -= len;
+               err = xs_send_pagedata(sock, xdr, base, remainder != 0, zerocopy, &sent);
+               *sent_p += sent;
+               if (remainder == 0 || sent != len)
+                       goto out;
+               base = 0;
+       } else
+               base -= xdr->page_len;
+
+       if (base >= xdr->tail[0].iov_len)
+               return 0;
+       err = xs_send_kvec(sock, NULL, 0, &xdr->tail[0], base, 0);
+out:
+       if (err > 0) {
+               *sent_p += err;
+               err = 0;
+       }
+       return err;
+}
+
+static void xs_nospace_callback(struct rpc_task *task)
+{
+       struct sock_xprt *transport = container_of(task->tk_rqstp->rq_xprt, struct sock_xprt, xprt);
+
+       transport->inet->sk_write_pending--;
+       clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
+}
+
+/**
+ * xs_nospace - place task on wait queue if transmit was incomplete
+ * @task: task to put to sleep
+ *
+ */
+static int xs_nospace(struct rpc_task *task)
+{
+       struct rpc_rqst *req = task->tk_rqstp;
+       struct rpc_xprt *xprt = req->rq_xprt;
+       struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
+       struct sock *sk = transport->inet;
+       int ret = -EAGAIN;
+
+       dprintk("RPC: %5u xmit incomplete (%u left of %u)\n",
+                       task->tk_pid, req->rq_slen - req->rq_bytes_sent,
+                       req->rq_slen);
+
+       /* Protect against races with write_space */
+       spin_lock_bh(&xprt->transport_lock);
+
+       /* Don't race with disconnect */
+       if (xprt_connected(xprt)) {
+               if (test_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags)) {
+                       /*
+                        * Notify TCP that we're limited by the application
+                        * window size
+                        */
+                       set_bit(SOCK_NOSPACE, &transport->sock->flags);
+                       sk->sk_write_pending++;
+                       /* ...and wait for more buffer space */
+                       xprt_wait_for_buffer_space(task, xs_nospace_callback);
+               }
+       } else {
+               clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
+               ret = -ENOTCONN;
+       }
+
+       spin_unlock_bh(&xprt->transport_lock);
+
+       /* Race breaker in case memory is freed before above code is called */
+       sk->sk_write_space(sk);
+       return ret;
+}
+
+/*
+ * Construct a stream transport record marker in @buf.
+ */
+static inline void xs_encode_stream_record_marker(struct xdr_buf *buf)
+{
+       u32 reclen = buf->len - sizeof(rpc_fraghdr);
+       rpc_fraghdr *base = buf->head[0].iov_base;
+       *base = cpu_to_be32(RPC_LAST_STREAM_FRAGMENT | reclen);
+}
+
+/**
+ * xs_local_send_request - write an RPC request to an AF_LOCAL socket
+ * @task: RPC task that manages the state of an RPC request
+ *
+ * Return values:
+ *        0:   The request has been sent
+ *   EAGAIN:   The socket was blocked, please call again later to
+ *             complete the request
+ * ENOTCONN:   Caller needs to invoke connect logic then call again
+ *    other:   Some other error occured, the request was not sent
+ */
+static int xs_local_send_request(struct rpc_task *task)
+{
+       struct rpc_rqst *req = task->tk_rqstp;
+       struct rpc_xprt *xprt = req->rq_xprt;
+       struct sock_xprt *transport =
+                               container_of(xprt, struct sock_xprt, xprt);
+       struct xdr_buf *xdr = &req->rq_snd_buf;
+       int status;
+       int sent = 0;
+
+       xs_encode_stream_record_marker(&req->rq_snd_buf);
+
+       xs_pktdump("packet data:",
+                       req->rq_svec->iov_base, req->rq_svec->iov_len);
+
+       status = xs_sendpages(transport->sock, NULL, 0, xdr, req->rq_bytes_sent,
+                             true, &sent);
+       dprintk("RPC:       %s(%u) = %d\n",
+                       __func__, xdr->len - req->rq_bytes_sent, status);
+       if (likely(sent > 0) || status == 0) {
+               req->rq_bytes_sent += sent;
+               req->rq_xmit_bytes_sent += sent;
+               if (likely(req->rq_bytes_sent >= req->rq_slen)) {
+                       req->rq_bytes_sent = 0;
+                       return 0;
+               }
+               status = -EAGAIN;
+       }
+
+       switch (status) {
+       case -ENOBUFS:
+       case -EAGAIN:
+               status = xs_nospace(task);
+               break;
+       default:
+               dprintk("RPC:       sendmsg returned unrecognized error %d\n",
+                       -status);
+       case -EPIPE:
+               xs_close(xprt);
+               status = -ENOTCONN;
+       }
+
+       return status;
+}
+
+/**
+ * xs_udp_send_request - write an RPC request to a UDP socket
+ * @task: address of RPC task that manages the state of an RPC request
+ *
+ * Return values:
+ *        0:   The request has been sent
+ *   EAGAIN:   The socket was blocked, please call again later to
+ *             complete the request
+ * ENOTCONN:   Caller needs to invoke connect logic then call again
+ *    other:   Some other error occurred, the request was not sent
+ */
+static int xs_udp_send_request(struct rpc_task *task)
+{
+       struct rpc_rqst *req = task->tk_rqstp;
+       struct rpc_xprt *xprt = req->rq_xprt;
+       struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
+       struct xdr_buf *xdr = &req->rq_snd_buf;
+       int sent = 0;
+       int status;
+
+       xs_pktdump("packet data:",
+                               req->rq_svec->iov_base,
+                               req->rq_svec->iov_len);
+
+       if (!xprt_bound(xprt))
+               return -ENOTCONN;
+       status = xs_sendpages(transport->sock, xs_addr(xprt), xprt->addrlen,
+                             xdr, req->rq_bytes_sent, true, &sent);
+
+       dprintk("RPC:       xs_udp_send_request(%u) = %d\n",
+                       xdr->len - req->rq_bytes_sent, status);
+
+       /* firewall is blocking us, don't return -EAGAIN or we end up looping */
+       if (status == -EPERM)
+               goto process_status;
+
+       if (sent > 0 || status == 0) {
+               req->rq_xmit_bytes_sent += sent;
+               if (sent >= req->rq_slen)
+                       return 0;
+               /* Still some bytes left; set up for a retry later. */
+               status = -EAGAIN;
+       }
+
+process_status:
+       switch (status) {
+       case -ENOTSOCK:
+               status = -ENOTCONN;
+               /* Should we call xs_close() here? */
+               break;
+       case -EAGAIN:
+               status = xs_nospace(task);
+               break;
+       default:
+               dprintk("RPC:       sendmsg returned unrecognized error %d\n",
+                       -status);
+       case -ENETUNREACH:
+       case -ENOBUFS:
+       case -EPIPE:
+       case -ECONNREFUSED:
+       case -EPERM:
+               /* When the server has died, an ICMP port unreachable message
+                * prompts ECONNREFUSED. */
+               clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
+       }
+
+       return status;
+}
+
+/**
+ * xs_tcp_shutdown - gracefully shut down a TCP socket
+ * @xprt: transport
+ *
+ * Initiates a graceful shutdown of the TCP socket by calling the
+ * equivalent of shutdown(SHUT_RDWR);
+ */
+static void xs_tcp_shutdown(struct rpc_xprt *xprt)
+{
+       struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
+       struct socket *sock = transport->sock;
+
+       if (sock != NULL) {
+               kernel_sock_shutdown(sock, SHUT_RDWR);
+               trace_rpc_socket_shutdown(xprt, sock);
+       }
+}
+
+/**
+ * xs_tcp_send_request - write an RPC request to a TCP socket
+ * @task: address of RPC task that manages the state of an RPC request
+ *
+ * Return values:
+ *        0:   The request has been sent
+ *   EAGAIN:   The socket was blocked, please call again later to
+ *             complete the request
+ * ENOTCONN:   Caller needs to invoke connect logic then call again
+ *    other:   Some other error occurred, the request was not sent
+ *
+ * XXX: In the case of soft timeouts, should we eventually give up
+ *     if sendmsg is not able to make progress?
+ */
+static int xs_tcp_send_request(struct rpc_task *task)
+{
+       struct rpc_rqst *req = task->tk_rqstp;
+       struct rpc_xprt *xprt = req->rq_xprt;
+       struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
+       struct xdr_buf *xdr = &req->rq_snd_buf;
+       bool zerocopy = true;
+       int status;
+       int sent;
+
+       xs_encode_stream_record_marker(&req->rq_snd_buf);
+
+       xs_pktdump("packet data:",
+                               req->rq_svec->iov_base,
+                               req->rq_svec->iov_len);
+       /* Don't use zero copy if this is a resend. If the RPC call
+        * completes while the socket holds a reference to the pages,
+        * then we may end up resending corrupted data.
+        */
+       if (task->tk_flags & RPC_TASK_SENT)
+               zerocopy = false;
+
+       /* Continue transmitting the packet/record. We must be careful
+        * to cope with writespace callbacks arriving _after_ we have
+        * called sendmsg(). */
+       while (1) {
+               sent = 0;
+               status = xs_sendpages(transport->sock, NULL, 0, xdr,
+                                     req->rq_bytes_sent, zerocopy, &sent);
+
+               dprintk("RPC:       xs_tcp_send_request(%u) = %d\n",
+                               xdr->len - req->rq_bytes_sent, status);
+
+               if (unlikely(sent == 0 && status < 0))
+                       break;
+
+               /* If we've sent the entire packet, immediately
+                * reset the count of bytes sent. */
+               req->rq_bytes_sent += sent;
+               req->rq_xmit_bytes_sent += sent;
+               if (likely(req->rq_bytes_sent >= req->rq_slen)) {
+                       req->rq_bytes_sent = 0;
+                       return 0;
+               }
+
+               if (sent != 0)
+                       continue;
+               status = -EAGAIN;
+               break;
+       }
+
+       switch (status) {
+       case -ENOTSOCK:
+               status = -ENOTCONN;
+               /* Should we call xs_close() here? */
+               break;
+       case -ENOBUFS:
+       case -EAGAIN:
+               status = xs_nospace(task);
+               break;
+       default:
+               dprintk("RPC:       sendmsg returned unrecognized error %d\n",
+                       -status);
+       case -ECONNRESET:
+       case -ECONNREFUSED:
+       case -ENOTCONN:
+       case -EADDRINUSE:
+       case -EPIPE:
+               clear_bit(SOCK_ASYNC_NOSPACE, &transport->sock->flags);
+       }
+
+       return status;
+}
+
+/**
+ * xs_tcp_release_xprt - clean up after a tcp transmission
+ * @xprt: transport
+ * @task: rpc task
+ *
+ * This cleans up if an error causes us to abort the transmission of a request.
+ * In this case, the socket may need to be reset in order to avoid confusing
+ * the server.
+ */
+static void xs_tcp_release_xprt(struct rpc_xprt *xprt, struct rpc_task *task)
+{
+       struct rpc_rqst *req;
+
+       if (task != xprt->snd_task)
+               return;
+       if (task == NULL)
+               goto out_release;
+       req = task->tk_rqstp;
+       if (req == NULL)
+               goto out_release;
+       if (req->rq_bytes_sent == 0)
+               goto out_release;
+       if (req->rq_bytes_sent == req->rq_snd_buf.len)
+               goto out_release;
+       set_bit(XPRT_CLOSE_WAIT, &xprt->state);
+out_release:
+       xprt_release_xprt(xprt, task);
+}
+
+static void xs_save_old_callbacks(struct sock_xprt *transport, struct sock *sk)
+{
+       transport->old_data_ready = sk->sk_data_ready;
+       transport->old_state_change = sk->sk_state_change;
+       transport->old_write_space = sk->sk_write_space;
+       transport->old_error_report = sk->sk_error_report;
+}
+
+static void xs_restore_old_callbacks(struct sock_xprt *transport, struct sock *sk)
+{
+       sk->sk_data_ready = transport->old_data_ready;
+       sk->sk_state_change = transport->old_state_change;
+       sk->sk_write_space = transport->old_write_space;
+       sk->sk_error_report = transport->old_error_report;
+}
+
+static void xs_sock_reset_connection_flags(struct rpc_xprt *xprt)
+{
+       smp_mb__before_atomic();
+       clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
+       clear_bit(XPRT_CLOSING, &xprt->state);
+       smp_mb__after_atomic();
+}
+
+static void xs_sock_mark_closed(struct rpc_xprt *xprt)
+{
+       xs_sock_reset_connection_flags(xprt);
+       /* Mark transport as closed and wake up all pending tasks */
+       xprt_disconnect_done(xprt);
+}
+
+/**
+ * xs_error_report - callback to handle TCP socket state errors
+ * @sk: socket
+ *
+ * Note: we don't call sock_error() since there may be a rpc_task
+ * using the socket, and so we don't want to clear sk->sk_err.
+ */
+static void xs_error_report(struct sock *sk)
+{
+       struct rpc_xprt *xprt;
+       int err;
+
+       read_lock_bh(&sk->sk_callback_lock);
+       if (!(xprt = xprt_from_sock(sk)))
+               goto out;
+
+       err = -sk->sk_err;
+       if (err == 0)
+               goto out;
+       /* Is this a reset event? */
+       if (sk->sk_state == TCP_CLOSE)
+               xs_sock_mark_closed(xprt);
+       dprintk("RPC:       xs_error_report client %p, error=%d...\n",
+                       xprt, -err);
+       trace_rpc_socket_error(xprt, sk->sk_socket, err);
+       xprt_wake_pending_tasks(xprt, err);
+ out:
+       read_unlock_bh(&sk->sk_callback_lock);
+}
+
+static void xs_reset_transport(struct sock_xprt *transport)
+{
+       struct socket *sock = transport->sock;
+       struct sock *sk = transport->inet;
+       struct rpc_xprt *xprt = &transport->xprt;
+
+       if (sk == NULL)
+               return;
+
+       write_lock_bh(&sk->sk_callback_lock);
+       transport->inet = NULL;
+       transport->sock = NULL;
+
+       sk->sk_user_data = NULL;
+
+       xs_restore_old_callbacks(transport, sk);
+       write_unlock_bh(&sk->sk_callback_lock);
+       xs_sock_reset_connection_flags(xprt);
+
+       trace_rpc_socket_close(xprt, sock);
+       sock_release(sock);
+}
+
+/**
+ * xs_close - close a socket
+ * @xprt: transport
+ *
+ * This is used when all requests are complete; ie, no DRC state remains
+ * on the server we want to save.
+ *
+ * The caller _must_ be holding XPRT_LOCKED in order to avoid issues with
+ * xs_reset_transport() zeroing the socket from underneath a writer.
+ */
+static void xs_close(struct rpc_xprt *xprt)
+{
+       struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
+
+       dprintk("RPC:       xs_close xprt %p\n", xprt);
+
+       xs_reset_transport(transport);
+       xprt->reestablish_timeout = 0;
+
+       xprt_disconnect_done(xprt);
+}
+
+static void xs_xprt_free(struct rpc_xprt *xprt)
+{
+       xs_free_peer_addresses(xprt);
+       xprt_free(xprt);
+}
+
+/**
+ * xs_destroy - prepare to shutdown a transport
+ * @xprt: doomed transport
+ *
+ */
+static void xs_destroy(struct rpc_xprt *xprt)
+{
+       dprintk("RPC:       xs_destroy xprt %p\n", xprt);
+
+       xs_close(xprt);
+       xs_xprt_free(xprt);
+       module_put(THIS_MODULE);
+}
+
+static int xs_local_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
+{
+       struct xdr_skb_reader desc = {
+               .skb            = skb,
+               .offset         = sizeof(rpc_fraghdr),
+               .count          = skb->len - sizeof(rpc_fraghdr),
+       };
+
+       if (xdr_partial_copy_from_skb(xdr, 0, &desc, xdr_skb_read_bits) < 0)
+               return -1;
+       if (desc.count)
+               return -1;
+       return 0;
+}
+
+/**
+ * xs_local_data_ready - "data ready" callback for AF_LOCAL sockets
+ * @sk: socket with data to read
+ * @len: how much data to read
+ *
+ * Currently this assumes we can read the whole reply in a single gulp.
+ */
+static void xs_local_data_ready(struct sock *sk)
+{
+       struct rpc_task *task;
+       struct rpc_xprt *xprt;
+       struct rpc_rqst *rovr;
+       struct sk_buff *skb;
+       int err, repsize, copied;
+       u32 _xid;
+       __be32 *xp;
+
+       read_lock_bh(&sk->sk_callback_lock);
+       dprintk("RPC:       %s...\n", __func__);
+       xprt = xprt_from_sock(sk);
+       if (xprt == NULL)
+               goto out;
+
+       skb = skb_recv_datagram(sk, 0, 1, &err);
+       if (skb == NULL)
+               goto out;
+
+       repsize = skb->len - sizeof(rpc_fraghdr);
+       if (repsize < 4) {
+               dprintk("RPC:       impossible RPC reply size %d\n", repsize);
+               goto dropit;
+       }
+
+       /* Copy the XID from the skb... */
+       xp = skb_header_pointer(skb, sizeof(rpc_fraghdr), sizeof(_xid), &_xid);
+       if (xp == NULL)
+               goto dropit;
+
+       /* Look up and lock the request corresponding to the given XID */
+       spin_lock(&xprt->transport_lock);
+       rovr = xprt_lookup_rqst(xprt, *xp);
+       if (!rovr)
+               goto out_unlock;
+       task = rovr->rq_task;
+
+       copied = rovr->rq_private_buf.buflen;
+       if (copied > repsize)
+               copied = repsize;
+
+       if (xs_local_copy_to_xdr(&rovr->rq_private_buf, skb)) {
+               dprintk("RPC:       sk_buff copy failed\n");
+               goto out_unlock;
+       }
+
+       xprt_complete_rqst(task, copied);
+
+ out_unlock:
+       spin_unlock(&xprt->transport_lock);
+ dropit:
+       skb_free_datagram(sk, skb);
+ out:
+       read_unlock_bh(&sk->sk_callback_lock);
+}
+
+/**
+ * xs_udp_data_ready - "data ready" callback for UDP sockets
+ * @sk: socket with data to read
+ * @len: how much data to read
+ *
+ */
+static void xs_udp_data_ready(struct sock *sk)
+{
+       struct rpc_task *task;
+       struct rpc_xprt *xprt;
+       struct rpc_rqst *rovr;
+       struct sk_buff *skb;
+       int err, repsize, copied;
+       u32 _xid;
+       __be32 *xp;
+
+       read_lock_bh(&sk->sk_callback_lock);
+       dprintk("RPC:       xs_udp_data_ready...\n");
+       if (!(xprt = xprt_from_sock(sk)))
+               goto out;
+
+       if ((skb = skb_recv_datagram(sk, 0, 1, &err)) == NULL)
+               goto out;
+
+       repsize = skb->len - sizeof(struct udphdr);
+       if (repsize < 4) {
+               dprintk("RPC:       impossible RPC reply size %d!\n", repsize);
+               goto dropit;
+       }
+
+       /* Copy the XID from the skb... */
+       xp = skb_header_pointer(skb, sizeof(struct udphdr),
+                               sizeof(_xid), &_xid);
+       if (xp == NULL)
+               goto dropit;
+
+       /* Look up and lock the request corresponding to the given XID */
+       spin_lock(&xprt->transport_lock);
+       rovr = xprt_lookup_rqst(xprt, *xp);
+       if (!rovr)
+               goto out_unlock;
+       task = rovr->rq_task;
+
+       if ((copied = rovr->rq_private_buf.buflen) > repsize)
+               copied = repsize;
+
+       /* Suck it into the iovec, verify checksum if not done by hw. */
+       if (csum_partial_copy_to_xdr(&rovr->rq_private_buf, skb)) {
+               UDPX_INC_STATS_BH(sk, UDP_MIB_INERRORS);
+               goto out_unlock;
+       }
+
+       UDPX_INC_STATS_BH(sk, UDP_MIB_INDATAGRAMS);
+
+       xprt_adjust_cwnd(xprt, task, copied);
+       xprt_complete_rqst(task, copied);
+
+ out_unlock:
+       spin_unlock(&xprt->transport_lock);
+ dropit:
+       skb_free_datagram(sk, skb);
+ out:
+       read_unlock_bh(&sk->sk_callback_lock);
+}
+
+/*
+ * Helper function to force a TCP close if the server is sending
+ * junk and/or it has put us in CLOSE_WAIT
+ */
+static void xs_tcp_force_close(struct rpc_xprt *xprt)
+{
+       xprt_force_disconnect(xprt);
+}
+
+static inline void xs_tcp_read_fraghdr(struct rpc_xprt *xprt, struct xdr_skb_reader *desc)
+{
+       struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
+       size_t len, used;
+       char *p;
+
+       p = ((char *) &transport->tcp_fraghdr) + transport->tcp_offset;
+       len = sizeof(transport->tcp_fraghdr) - transport->tcp_offset;
+       used = xdr_skb_read_bits(desc, p, len);
+       transport->tcp_offset += used;
+       if (used != len)
+               return;
+
+       transport->tcp_reclen = ntohl(transport->tcp_fraghdr);
+       if (transport->tcp_reclen & RPC_LAST_STREAM_FRAGMENT)
+               transport->tcp_flags |= TCP_RCV_LAST_FRAG;
+       else
+               transport->tcp_flags &= ~TCP_RCV_LAST_FRAG;
+       transport->tcp_reclen &= RPC_FRAGMENT_SIZE_MASK;
+
+       transport->tcp_flags &= ~TCP_RCV_COPY_FRAGHDR;
+       transport->tcp_offset = 0;
+
+       /* Sanity check of the record length */
+       if (unlikely(transport->tcp_reclen < 8)) {
+               dprintk("RPC:       invalid TCP record fragment length\n");
+               xs_tcp_force_close(xprt);
+               return;
+       }
+       dprintk("RPC:       reading TCP record fragment of length %d\n",
+                       transport->tcp_reclen);
+}
+
+static void xs_tcp_check_fraghdr(struct sock_xprt *transport)
+{
+       if (transport->tcp_offset == transport->tcp_reclen) {
+               transport->tcp_flags |= TCP_RCV_COPY_FRAGHDR;
+               transport->tcp_offset = 0;
+               if (transport->tcp_flags & TCP_RCV_LAST_FRAG) {
+                       transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
+                       transport->tcp_flags |= TCP_RCV_COPY_XID;
+                       transport->tcp_copied = 0;
+               }
+       }
+}
+
+static inline void xs_tcp_read_xid(struct sock_xprt *transport, struct xdr_skb_reader *desc)
+{
+       size_t len, used;
+       char *p;
+
+       len = sizeof(transport->tcp_xid) - transport->tcp_offset;
+       dprintk("RPC:       reading XID (%Zu bytes)\n", len);
+       p = ((char *) &transport->tcp_xid) + transport->tcp_offset;
+       used = xdr_skb_read_bits(desc, p, len);
+       transport->tcp_offset += used;
+       if (used != len)
+               return;
+       transport->tcp_flags &= ~TCP_RCV_COPY_XID;
+       transport->tcp_flags |= TCP_RCV_READ_CALLDIR;
+       transport->tcp_copied = 4;
+       dprintk("RPC:       reading %s XID %08x\n",
+                       (transport->tcp_flags & TCP_RPC_REPLY) ? "reply for"
+                                                             : "request with",
+                       ntohl(transport->tcp_xid));
+       xs_tcp_check_fraghdr(transport);
+}
+
+static inline void xs_tcp_read_calldir(struct sock_xprt *transport,
+                                      struct xdr_skb_reader *desc)
+{
+       size_t len, used;
+       u32 offset;
+       char *p;
+
+       /*
+        * We want transport->tcp_offset to be 8 at the end of this routine
+        * (4 bytes for the xid and 4 bytes for the call/reply flag).
+        * When this function is called for the first time,
+        * transport->tcp_offset is 4 (after having already read the xid).
+        */
+       offset = transport->tcp_offset - sizeof(transport->tcp_xid);
+       len = sizeof(transport->tcp_calldir) - offset;
+       dprintk("RPC:       reading CALL/REPLY flag (%Zu bytes)\n", len);
+       p = ((char *) &transport->tcp_calldir) + offset;
+       used = xdr_skb_read_bits(desc, p, len);
+       transport->tcp_offset += used;
+       if (used != len)
+               return;
+       transport->tcp_flags &= ~TCP_RCV_READ_CALLDIR;
+       /*
+        * We don't yet have the XDR buffer, so we will write the calldir
+        * out after we get the buffer from the 'struct rpc_rqst'
+        */
+       switch (ntohl(transport->tcp_calldir)) {
+       case RPC_REPLY:
+               transport->tcp_flags |= TCP_RCV_COPY_CALLDIR;
+               transport->tcp_flags |= TCP_RCV_COPY_DATA;
+               transport->tcp_flags |= TCP_RPC_REPLY;
+               break;
+       case RPC_CALL:
+               transport->tcp_flags |= TCP_RCV_COPY_CALLDIR;
+               transport->tcp_flags |= TCP_RCV_COPY_DATA;
+               transport->tcp_flags &= ~TCP_RPC_REPLY;
+               break;
+       default:
+               dprintk("RPC:       invalid request message type\n");
+               xs_tcp_force_close(&transport->xprt);
+       }
+       xs_tcp_check_fraghdr(transport);
+}
+
+static inline void xs_tcp_read_common(struct rpc_xprt *xprt,
+                                    struct xdr_skb_reader *desc,
+                                    struct rpc_rqst *req)
+{
+       struct sock_xprt *transport =
+                               container_of(xprt, struct sock_xprt, xprt);
+       struct xdr_buf *rcvbuf;
+       size_t len;
+       ssize_t r;
+
+       rcvbuf = &req->rq_private_buf;
+
+       if (transport->tcp_flags & TCP_RCV_COPY_CALLDIR) {
+               /*
+                * Save the RPC direction in the XDR buffer
+                */
+               memcpy(rcvbuf->head[0].iov_base + transport->tcp_copied,
+                       &transport->tcp_calldir,
+                       sizeof(transport->tcp_calldir));
+               transport->tcp_copied += sizeof(transport->tcp_calldir);
+               transport->tcp_flags &= ~TCP_RCV_COPY_CALLDIR;
+       }
+
+       len = desc->count;
+       if (len > transport->tcp_reclen - transport->tcp_offset) {
+               struct xdr_skb_reader my_desc;
+
+               len = transport->tcp_reclen - transport->tcp_offset;
+               memcpy(&my_desc, desc, sizeof(my_desc));
+               my_desc.count = len;
+               r = xdr_partial_copy_from_skb(rcvbuf, transport->tcp_copied,
+                                         &my_desc, xdr_skb_read_bits);
+               desc->count -= r;
+               desc->offset += r;
+       } else
+               r = xdr_partial_copy_from_skb(rcvbuf, transport->tcp_copied,
+                                         desc, xdr_skb_read_bits);
+
+       if (r > 0) {
+               transport->tcp_copied += r;
+               transport->tcp_offset += r;
+       }
+       if (r != len) {
+               /* Error when copying to the receive buffer,
+                * usually because we weren't able to allocate
+                * additional buffer pages. All we can do now
+                * is turn off TCP_RCV_COPY_DATA, so the request
+                * will not receive any additional updates,
+                * and time out.
+                * Any remaining data from this record will
+                * be discarded.
+                */
+               transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
+               dprintk("RPC:       XID %08x truncated request\n",
+                               ntohl(transport->tcp_xid));
+               dprintk("RPC:       xprt = %p, tcp_copied = %lu, "
+                               "tcp_offset = %u, tcp_reclen = %u\n",
+                               xprt, transport->tcp_copied,
+                               transport->tcp_offset, transport->tcp_reclen);
+               return;
+       }
+
+       dprintk("RPC:       XID %08x read %Zd bytes\n",
+                       ntohl(transport->tcp_xid), r);
+       dprintk("RPC:       xprt = %p, tcp_copied = %lu, tcp_offset = %u, "
+                       "tcp_reclen = %u\n", xprt, transport->tcp_copied,
+                       transport->tcp_offset, transport->tcp_reclen);
+
+       if (transport->tcp_copied == req->rq_private_buf.buflen)
+               transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
+       else if (transport->tcp_offset == transport->tcp_reclen) {
+               if (transport->tcp_flags & TCP_RCV_LAST_FRAG)
+                       transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
+       }
+}
+
+/*
+ * Finds the request corresponding to the RPC xid and invokes the common
+ * tcp read code to read the data.
+ */
+static inline int xs_tcp_read_reply(struct rpc_xprt *xprt,
+                                   struct xdr_skb_reader *desc)
+{
+       struct sock_xprt *transport =
+                               container_of(xprt, struct sock_xprt, xprt);
+       struct rpc_rqst *req;
+
+       dprintk("RPC:       read reply XID %08x\n", ntohl(transport->tcp_xid));
+
+       /* Find and lock the request corresponding to this xid */
+       spin_lock(&xprt->transport_lock);
+       req = xprt_lookup_rqst(xprt, transport->tcp_xid);
+       if (!req) {
+               dprintk("RPC:       XID %08x request not found!\n",
+                               ntohl(transport->tcp_xid));
+               spin_unlock(&xprt->transport_lock);
+               return -1;
+       }
+
+       xs_tcp_read_common(xprt, desc, req);
+
+       if (!(transport->tcp_flags & TCP_RCV_COPY_DATA))
+               xprt_complete_rqst(req->rq_task, transport->tcp_copied);
+
+       spin_unlock(&xprt->transport_lock);
+       return 0;
+}
+
+#if defined(CONFIG_SUNRPC_BACKCHANNEL)
+/*
+ * Obtains an rpc_rqst previously allocated and invokes the common
+ * tcp read code to read the data.  The result is placed in the callback
+ * queue.
+ * If we're unable to obtain the rpc_rqst we schedule the closing of the
+ * connection and return -1.
+ */
+static int xs_tcp_read_callback(struct rpc_xprt *xprt,
+                                      struct xdr_skb_reader *desc)
+{
+       struct sock_xprt *transport =
+                               container_of(xprt, struct sock_xprt, xprt);
+       struct rpc_rqst *req;
+
+       /* Look up and lock the request corresponding to the given XID */
+       spin_lock(&xprt->transport_lock);
+       req = xprt_lookup_bc_request(xprt, transport->tcp_xid);
+       if (req == NULL) {
+               spin_unlock(&xprt->transport_lock);
+               printk(KERN_WARNING "Callback slot table overflowed\n");
+               xprt_force_disconnect(xprt);
+               return -1;
+       }
+
+       dprintk("RPC:       read callback  XID %08x\n", ntohl(req->rq_xid));
+       xs_tcp_read_common(xprt, desc, req);
+
+       if (!(transport->tcp_flags & TCP_RCV_COPY_DATA))
+               xprt_complete_bc_request(req, transport->tcp_copied);
+       spin_unlock(&xprt->transport_lock);
+
+       return 0;
+}
+
+static inline int _xs_tcp_read_data(struct rpc_xprt *xprt,
+                                       struct xdr_skb_reader *desc)
+{
+       struct sock_xprt *transport =
+                               container_of(xprt, struct sock_xprt, xprt);
+
+       return (transport->tcp_flags & TCP_RPC_REPLY) ?
+               xs_tcp_read_reply(xprt, desc) :
+               xs_tcp_read_callback(xprt, desc);
+}
+#else
+static inline int _xs_tcp_read_data(struct rpc_xprt *xprt,
+                                       struct xdr_skb_reader *desc)
+{
+       return xs_tcp_read_reply(xprt, desc);
+}
+#endif /* CONFIG_SUNRPC_BACKCHANNEL */
+
+/*
+ * Read data off the transport.  This can be either an RPC_CALL or an
+ * RPC_REPLY.  Relay the processing to helper functions.
+ */
+static void xs_tcp_read_data(struct rpc_xprt *xprt,
+                                   struct xdr_skb_reader *desc)
+{
+       struct sock_xprt *transport =
+                               container_of(xprt, struct sock_xprt, xprt);
+
+       if (_xs_tcp_read_data(xprt, desc) == 0)
+               xs_tcp_check_fraghdr(transport);
+       else {
+               /*
+                * The transport_lock protects the request handling.
+                * There's no need to hold it to update the tcp_flags.
+                */
+               transport->tcp_flags &= ~TCP_RCV_COPY_DATA;
+       }
+}
+
+static inline void xs_tcp_read_discard(struct sock_xprt *transport, struct xdr_skb_reader *desc)
+{
+       size_t len;
+
+       len = transport->tcp_reclen - transport->tcp_offset;
+       if (len > desc->count)
+               len = desc->count;
+       desc->count -= len;
+       desc->offset += len;
+       transport->tcp_offset += len;
+       dprintk("RPC:       discarded %Zu bytes\n", len);
+       xs_tcp_check_fraghdr(transport);
+}
+
+static int xs_tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, unsigned int offset, size_t len)
+{
+       struct rpc_xprt *xprt = rd_desc->arg.data;
+       struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
+       struct xdr_skb_reader desc = {
+               .skb    = skb,
+               .offset = offset,
+               .count  = len,
+       };
+
+       dprintk("RPC:       xs_tcp_data_recv started\n");
+       do {
+               trace_xs_tcp_data_recv(transport);
+               /* Read in a new fragment marker if necessary */
+               /* Can we ever really expect to get completely empty fragments? */
+               if (transport->tcp_flags & TCP_RCV_COPY_FRAGHDR) {
+                       xs_tcp_read_fraghdr(xprt, &desc);
+                       continue;
+               }
+               /* Read in the xid if necessary */
+               if (transport->tcp_flags & TCP_RCV_COPY_XID) {
+                       xs_tcp_read_xid(transport, &desc);
+                       continue;
+               }
+               /* Read in the call/reply flag */
+               if (transport->tcp_flags & TCP_RCV_READ_CALLDIR) {
+                       xs_tcp_read_calldir(transport, &desc);
+                       continue;
+               }
+               /* Read in the request data */
+               if (transport->tcp_flags & TCP_RCV_COPY_DATA) {
+                       xs_tcp_read_data(xprt, &desc);
+                       continue;
+               }
+               /* Skip over any trailing bytes on short reads */
+               xs_tcp_read_discard(transport, &desc);
+       } while (desc.count);
+       trace_xs_tcp_data_recv(transport);
+       dprintk("RPC:       xs_tcp_data_recv done\n");
+       return len - desc.count;
+}
+
+/**
+ * xs_tcp_data_ready - "data ready" callback for TCP sockets
+ * @sk: socket with data to read
+ * @bytes: how much data to read
+ *
+ */
+static void xs_tcp_data_ready(struct sock *sk)
+{
+       struct rpc_xprt *xprt;
+       read_descriptor_t rd_desc;
+       int read;
+       unsigned long total = 0;
+
+       dprintk("RPC:       xs_tcp_data_ready...\n");
+
+       read_lock_bh(&sk->sk_callback_lock);
+       if (!(xprt = xprt_from_sock(sk))) {
+               read = 0;
+               goto out;
+       }
+       /* Any data means we had a useful conversation, so
+        * the we don't need to delay the next reconnect
+        */
+       if (xprt->reestablish_timeout)
+               xprt->reestablish_timeout = 0;
+
+       /* We use rd_desc to pass struct xprt to xs_tcp_data_recv */
+       rd_desc.arg.data = xprt;
+       do {
+               rd_desc.count = 65536;
+               read = tcp_read_sock(sk, &rd_desc, xs_tcp_data_recv);
+               if (read > 0)
+                       total += read;
+       } while (read > 0);
+out:
+       trace_xs_tcp_data_ready(xprt, read, total);
+       read_unlock_bh(&sk->sk_callback_lock);
+}
+
+/**
+ * xs_tcp_state_change - callback to handle TCP socket state changes
+ * @sk: socket whose state has changed
+ *
+ */
+static void xs_tcp_state_change(struct sock *sk)
+{
+       struct rpc_xprt *xprt;
+
+       read_lock_bh(&sk->sk_callback_lock);
+       if (!(xprt = xprt_from_sock(sk)))
+               goto out;
+       dprintk("RPC:       xs_tcp_state_change client %p...\n", xprt);
+       dprintk("RPC:       state %x conn %d dead %d zapped %d sk_shutdown %d\n",
+                       sk->sk_state, xprt_connected(xprt),
+                       sock_flag(sk, SOCK_DEAD),
+                       sock_flag(sk, SOCK_ZAPPED),
+                       sk->sk_shutdown);
+
+       trace_rpc_socket_state_change(xprt, sk->sk_socket);
+       switch (sk->sk_state) {
+       case TCP_ESTABLISHED:
+               spin_lock(&xprt->transport_lock);
+               if (!xprt_test_and_set_connected(xprt)) {
+                       struct sock_xprt *transport = container_of(xprt,
+                                       struct sock_xprt, xprt);
+
+                       /* Reset TCP record info */
+                       transport->tcp_offset = 0;
+                       transport->tcp_reclen = 0;
+                       transport->tcp_copied = 0;
+                       transport->tcp_flags =
+                               TCP_RCV_COPY_FRAGHDR | TCP_RCV_COPY_XID;
+                       xprt->connect_cookie++;
+
+                       xprt_wake_pending_tasks(xprt, -EAGAIN);
+               }
+               spin_unlock(&xprt->transport_lock);
+               break;
+       case TCP_FIN_WAIT1:
+               /* The client initiated a shutdown of the socket */
+               xprt->connect_cookie++;
+               xprt->reestablish_timeout = 0;
+               set_bit(XPRT_CLOSING, &xprt->state);
+               smp_mb__before_atomic();
+               clear_bit(XPRT_CONNECTED, &xprt->state);
+               clear_bit(XPRT_CLOSE_WAIT, &xprt->state);
+               smp_mb__after_atomic();
+               break;
+       case TCP_CLOSE_WAIT:
+               /* The server initiated a shutdown of the socket */
+               xprt->connect_cookie++;
+               clear_bit(XPRT_CONNECTED, &xprt->state);
+               xs_tcp_force_close(xprt);
+       case TCP_CLOSING:
+               /*
+                * If the server closed down the connection, make sure that
+                * we back off before reconnecting
+                */
+               if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
+                       xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
+               break;
+       case TCP_LAST_ACK:
+               set_bit(XPRT_CLOSING, &xprt->state);
+               smp_mb__before_atomic();
+               clear_bit(XPRT_CONNECTED, &xprt->state);
+               smp_mb__after_atomic();
+               break;
+       case TCP_CLOSE:
+               xs_sock_mark_closed(xprt);
+       }
+ out:
+       read_unlock_bh(&sk->sk_callback_lock);
+}
+
+static void xs_write_space(struct sock *sk)
+{
+       struct socket *sock;
+       struct rpc_xprt *xprt;
+
+       if (unlikely(!(sock = sk->sk_socket)))
+               return;
+       clear_bit(SOCK_NOSPACE, &sock->flags);
+
+       if (unlikely(!(xprt = xprt_from_sock(sk))))
+               return;
+       if (test_and_clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags) == 0)
+               return;
+
+       xprt_write_space(xprt);
+}
+
+/**
+ * xs_udp_write_space - callback invoked when socket buffer space
+ *                             becomes available
+ * @sk: socket whose state has changed
+ *
+ * Called when more output buffer space is available for this socket.
+ * We try not to wake our writers until they can make "significant"
+ * progress, otherwise we'll waste resources thrashing kernel_sendmsg
+ * with a bunch of small requests.
+ */
+static void xs_udp_write_space(struct sock *sk)
+{
+       read_lock_bh(&sk->sk_callback_lock);
+
+       /* from net/core/sock.c:sock_def_write_space */
+       if (sock_writeable(sk))
+               xs_write_space(sk);
+
+       read_unlock_bh(&sk->sk_callback_lock);
+}
+
+/**
+ * xs_tcp_write_space - callback invoked when socket buffer space
+ *                             becomes available
+ * @sk: socket whose state has changed
+ *
+ * Called when more output buffer space is available for this socket.
+ * We try not to wake our writers until they can make "significant"
+ * progress, otherwise we'll waste resources thrashing kernel_sendmsg
+ * with a bunch of small requests.
+ */
+static void xs_tcp_write_space(struct sock *sk)
+{
+       read_lock_bh(&sk->sk_callback_lock);
+
+       /* from net/core/stream.c:sk_stream_write_space */
+       if (sk_stream_is_writeable(sk))
+               xs_write_space(sk);
+
+       read_unlock_bh(&sk->sk_callback_lock);
+}
+
+static void xs_udp_do_set_buffer_size(struct rpc_xprt *xprt)
+{
+       struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
+       struct sock *sk = transport->inet;
+
+       if (transport->rcvsize) {
+               sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
+               sk->sk_rcvbuf = transport->rcvsize * xprt->max_reqs * 2;
+       }
+       if (transport->sndsize) {
+               sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
+               sk->sk_sndbuf = transport->sndsize * xprt->max_reqs * 2;
+               sk->sk_write_space(sk);
+       }
+}
+
+/**
+ * xs_udp_set_buffer_size - set send and receive limits
+ * @xprt: generic transport
+ * @sndsize: requested size of send buffer, in bytes
+ * @rcvsize: requested size of receive buffer, in bytes
+ *
+ * Set socket send and receive buffer size limits.
+ */
+static void xs_udp_set_buffer_size(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize)
+{
+       struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
+
+       transport->sndsize = 0;
+       if (sndsize)
+               transport->sndsize = sndsize + 1024;
+       transport->rcvsize = 0;
+       if (rcvsize)
+               transport->rcvsize = rcvsize + 1024;
+
+       xs_udp_do_set_buffer_size(xprt);
+}
+
+/**
+ * xs_udp_timer - called when a retransmit timeout occurs on a UDP transport
+ * @task: task that timed out
+ *
+ * Adjust the congestion window after a retransmit timeout has occurred.
+ */
+static void xs_udp_timer(struct rpc_xprt *xprt, struct rpc_task *task)
+{
+       xprt_adjust_cwnd(xprt, task, -ETIMEDOUT);
+}
+
+static unsigned short xs_get_random_port(void)
+{
+       unsigned short range = xprt_max_resvport - xprt_min_resvport;
+       unsigned short rand = (unsigned short) prandom_u32() % range;
+       return rand + xprt_min_resvport;
+}
+
+/**
+ * xs_set_reuseaddr_port - set the socket's port and address reuse options
+ * @sock: socket
+ *
+ * Note that this function has to be called on all sockets that share the
+ * same port, and it must be called before binding.
+ */
+static void xs_sock_set_reuseport(struct socket *sock)
+{
+       int opt = 1;
+
+       kernel_setsockopt(sock, SOL_SOCKET, SO_REUSEPORT,
+                       (char *)&opt, sizeof(opt));
+}
+
+static unsigned short xs_sock_getport(struct socket *sock)
+{
+       struct sockaddr_storage buf;
+       int buflen;
+       unsigned short port = 0;
+
+       if (kernel_getsockname(sock, (struct sockaddr *)&buf, &buflen) < 0)
+               goto out;
+       switch (buf.ss_family) {
+       case AF_INET6:
+               port = ntohs(((struct sockaddr_in6 *)&buf)->sin6_port);
+               break;
+       case AF_INET:
+               port = ntohs(((struct sockaddr_in *)&buf)->sin_port);
+       }
+out:
+       return port;
+}
+
+/**
+ * xs_set_port - reset the port number in the remote endpoint address
+ * @xprt: generic transport
+ * @port: new port number
+ *
+ */
+static void xs_set_port(struct rpc_xprt *xprt, unsigned short port)
+{
+       dprintk("RPC:       setting port for xprt %p to %u\n", xprt, port);
+
+       rpc_set_port(xs_addr(xprt), port);
+       xs_update_peer_port(xprt);
+}
+
+static void xs_set_srcport(struct sock_xprt *transport, struct socket *sock)
+{
+       if (transport->srcport == 0)
+               transport->srcport = xs_sock_getport(sock);
+}
+
+static unsigned short xs_get_srcport(struct sock_xprt *transport)
+{
+       unsigned short port = transport->srcport;
+
+       if (port == 0 && transport->xprt.resvport)
+               port = xs_get_random_port();
+       return port;
+}
+
+static unsigned short xs_next_srcport(struct sock_xprt *transport, unsigned short port)
+{
+       if (transport->srcport != 0)
+               transport->srcport = 0;
+       if (!transport->xprt.resvport)
+               return 0;
+       if (port <= xprt_min_resvport || port > xprt_max_resvport)
+               return xprt_max_resvport;
+       return --port;
+}
+static int xs_bind(struct sock_xprt *transport, struct socket *sock)
+{
+       struct sockaddr_storage myaddr;
+       int err, nloop = 0;
+       unsigned short port = xs_get_srcport(transport);
+       unsigned short last;
+
+       /*
+        * If we are asking for any ephemeral port (i.e. port == 0 &&
+        * transport->xprt.resvport == 0), don't bind.  Let the local
+        * port selection happen implicitly when the socket is used
+        * (for example at connect time).
+        *
+        * This ensures that we can continue to establish TCP
+        * connections even when all local ephemeral ports are already
+        * a part of some TCP connection.  This makes no difference
+        * for UDP sockets, but also doens't harm them.
+        *
+        * If we're asking for any reserved port (i.e. port == 0 &&
+        * transport->xprt.resvport == 1) xs_get_srcport above will
+        * ensure that port is non-zero and we will bind as needed.
+        */
+       if (port == 0)
+               return 0;
+
+       memcpy(&myaddr, &transport->srcaddr, transport->xprt.addrlen);
+       do {
+               rpc_set_port((struct sockaddr *)&myaddr, port);
+               err = kernel_bind(sock, (struct sockaddr *)&myaddr,
+                               transport->xprt.addrlen);
+               if (err == 0) {
+                       transport->srcport = port;
+                       break;
+               }
+               last = port;
+               port = xs_next_srcport(transport, port);
+               if (port > last)
+                       nloop++;
+       } while (err == -EADDRINUSE && nloop != 2);
+
+       if (myaddr.ss_family == AF_INET)
+               dprintk("RPC:       %s %pI4:%u: %s (%d)\n", __func__,
+                               &((struct sockaddr_in *)&myaddr)->sin_addr,
+                               port, err ? "failed" : "ok", err);
+       else
+               dprintk("RPC:       %s %pI6:%u: %s (%d)\n", __func__,
+                               &((struct sockaddr_in6 *)&myaddr)->sin6_addr,
+                               port, err ? "failed" : "ok", err);
+       return err;
+}
+
+/*
+ * We don't support autobind on AF_LOCAL sockets
+ */
+static void xs_local_rpcbind(struct rpc_task *task)
+{
+       rcu_read_lock();
+       xprt_set_bound(rcu_dereference(task->tk_client->cl_xprt));
+       rcu_read_unlock();
+}
+
+static void xs_local_set_port(struct rpc_xprt *xprt, unsigned short port)
+{
+}
+
+#ifdef CONFIG_DEBUG_LOCK_ALLOC
+static struct lock_class_key xs_key[2];
+static struct lock_class_key xs_slock_key[2];
+
+static inline void xs_reclassify_socketu(struct socket *sock)
+{
+       struct sock *sk = sock->sk;
+
+       sock_lock_init_class_and_name(sk, "slock-AF_LOCAL-RPC",
+               &xs_slock_key[1], "sk_lock-AF_LOCAL-RPC", &xs_key[1]);
+}
+
+static inline void xs_reclassify_socket4(struct socket *sock)
+{
+       struct sock *sk = sock->sk;
+
+       sock_lock_init_class_and_name(sk, "slock-AF_INET-RPC",
+               &xs_slock_key[0], "sk_lock-AF_INET-RPC", &xs_key[0]);
+}
+
+static inline void xs_reclassify_socket6(struct socket *sock)
+{
+       struct sock *sk = sock->sk;
+
+       sock_lock_init_class_and_name(sk, "slock-AF_INET6-RPC",
+               &xs_slock_key[1], "sk_lock-AF_INET6-RPC", &xs_key[1]);
+}
+
+static inline void xs_reclassify_socket(int family, struct socket *sock)
+{
+       WARN_ON_ONCE(sock_owned_by_user(sock->sk));
+       if (sock_owned_by_user(sock->sk))
+               return;
+
+       switch (family) {
+       case AF_LOCAL:
+               xs_reclassify_socketu(sock);
+               break;
+       case AF_INET:
+               xs_reclassify_socket4(sock);
+               break;
+       case AF_INET6:
+               xs_reclassify_socket6(sock);
+               break;
+       }
+}
+#else
+static inline void xs_reclassify_socketu(struct socket *sock)
+{
+}
+
+static inline void xs_reclassify_socket4(struct socket *sock)
+{
+}
+
+static inline void xs_reclassify_socket6(struct socket *sock)
+{
+}
+
+static inline void xs_reclassify_socket(int family, struct socket *sock)
+{
+}
+#endif
+
+static void xs_dummy_setup_socket(struct work_struct *work)
+{
+}
+
+static struct socket *xs_create_sock(struct rpc_xprt *xprt,
+               struct sock_xprt *transport, int family, int type,
+               int protocol, bool reuseport)
+{
+       struct socket *sock;
+       int err;
+
+       err = __sock_create(xprt->xprt_net, family, type, protocol, &sock, 1);
+       if (err < 0) {
+               dprintk("RPC:       can't create %d transport socket (%d).\n",
+                               protocol, -err);
+               goto out;
+       }
+       xs_reclassify_socket(family, sock);
+
+       if (reuseport)
+               xs_sock_set_reuseport(sock);
+
+       err = xs_bind(transport, sock);
+       if (err) {
+               sock_release(sock);
+               goto out;
+       }
+
+       return sock;
+out:
+       return ERR_PTR(err);
+}
+
+static int xs_local_finish_connecting(struct rpc_xprt *xprt,
+                                     struct socket *sock)
+{
+       struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
+                                                                       xprt);
+
+       if (!transport->inet) {
+               struct sock *sk = sock->sk;
+
+               write_lock_bh(&sk->sk_callback_lock);
+
+               xs_save_old_callbacks(transport, sk);
+
+               sk->sk_user_data = xprt;
+               sk->sk_data_ready = xs_local_data_ready;
+               sk->sk_write_space = xs_udp_write_space;
+               sk->sk_error_report = xs_error_report;
+               sk->sk_allocation = GFP_ATOMIC;
+
+               xprt_clear_connected(xprt);
+
+               /* Reset to new socket */
+               transport->sock = sock;
+               transport->inet = sk;
+
+               write_unlock_bh(&sk->sk_callback_lock);
+       }
+
+       /* Tell the socket layer to start connecting... */
+       xprt->stat.connect_count++;
+       xprt->stat.connect_start = jiffies;
+       return kernel_connect(sock, xs_addr(xprt), xprt->addrlen, 0);
+}
+
+/**
+ * xs_local_setup_socket - create AF_LOCAL socket, connect to a local endpoint
+ * @xprt: RPC transport to connect
+ * @transport: socket transport to connect
+ * @create_sock: function to create a socket of the correct type
+ */
+static int xs_local_setup_socket(struct sock_xprt *transport)
+{
+       struct rpc_xprt *xprt = &transport->xprt;
+       struct socket *sock;
+       int status = -EIO;
+
+       status = __sock_create(xprt->xprt_net, AF_LOCAL,
+                                       SOCK_STREAM, 0, &sock, 1);
+       if (status < 0) {
+               dprintk("RPC:       can't create AF_LOCAL "
+                       "transport socket (%d).\n", -status);
+               goto out;
+       }
+       xs_reclassify_socketu(sock);
+
+       dprintk("RPC:       worker connecting xprt %p via AF_LOCAL to %s\n",
+                       xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
+
+       status = xs_local_finish_connecting(xprt, sock);
+       trace_rpc_socket_connect(xprt, sock, status);
+       switch (status) {
+       case 0:
+               dprintk("RPC:       xprt %p connected to %s\n",
+                               xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
+               xprt_set_connected(xprt);
+       case -ENOBUFS:
+               break;
+       case -ENOENT:
+               dprintk("RPC:       xprt %p: socket %s does not exist\n",
+                               xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
+               break;
+       case -ECONNREFUSED:
+               dprintk("RPC:       xprt %p: connection refused for %s\n",
+                               xprt, xprt->address_strings[RPC_DISPLAY_ADDR]);
+               break;
+       default:
+               printk(KERN_ERR "%s: unhandled error (%d) connecting to %s\n",
+                               __func__, -status,
+                               xprt->address_strings[RPC_DISPLAY_ADDR]);
+       }
+
+out:
+       xprt_clear_connecting(xprt);
+       xprt_wake_pending_tasks(xprt, status);
+       return status;
+}
+
+static void xs_local_connect(struct rpc_xprt *xprt, struct rpc_task *task)
+{
+       struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
+       int ret;
+
+        if (RPC_IS_ASYNC(task)) {
+               /*
+                * We want the AF_LOCAL connect to be resolved in the
+                * filesystem namespace of the process making the rpc
+                * call.  Thus we connect synchronously.
+                *
+                * If we want to support asynchronous AF_LOCAL calls,
+                * we'll need to figure out how to pass a namespace to
+                * connect.
+                */
+               rpc_exit(task, -ENOTCONN);
+               return;
+       }
+       ret = xs_local_setup_socket(transport);
+       if (ret && !RPC_IS_SOFTCONN(task))
+               msleep_interruptible(15000);
+}
+
+#ifdef CONFIG_SUNRPC_SWAP
+static void xs_set_memalloc(struct rpc_xprt *xprt)
+{
+       struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
+                       xprt);
+
+       if (xprt->swapper)
+               sk_set_memalloc(transport->inet);
+}
+
+/**
+ * xs_swapper - Tag this transport as being used for swap.
+ * @xprt: transport to tag
+ * @enable: enable/disable
+ *
+ */
+int xs_swapper(struct rpc_xprt *xprt, int enable)
+{
+       struct sock_xprt *transport = container_of(xprt, struct sock_xprt,
+                       xprt);
+       int err = 0;
+
+       if (enable) {
+               xprt->swapper++;
+               xs_set_memalloc(xprt);
+       } else if (xprt->swapper) {
+               xprt->swapper--;
+               sk_clear_memalloc(transport->inet);
+       }
+
+       return err;
+}
+EXPORT_SYMBOL_GPL(xs_swapper);
+#else
+static void xs_set_memalloc(struct rpc_xprt *xprt)
+{
+}
+#endif
+
+static void xs_udp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
+{
+       struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
+
+       if (!transport->inet) {
+               struct sock *sk = sock->sk;
+
+               write_lock_bh(&sk->sk_callback_lock);
+
+               xs_save_old_callbacks(transport, sk);
+
+               sk->sk_user_data = xprt;
+               sk->sk_data_ready = xs_udp_data_ready;
+               sk->sk_write_space = xs_udp_write_space;
+               sk->sk_allocation = GFP_ATOMIC;
+
+               xprt_set_connected(xprt);
+
+               /* Reset to new socket */
+               transport->sock = sock;
+               transport->inet = sk;
+
+               xs_set_memalloc(xprt);
+
+               write_unlock_bh(&sk->sk_callback_lock);
+       }
+       xs_udp_do_set_buffer_size(xprt);
+}
+
+static void xs_udp_setup_socket(struct work_struct *work)
+{
+       struct sock_xprt *transport =
+               container_of(work, struct sock_xprt, connect_worker.work);
+       struct rpc_xprt *xprt = &transport->xprt;
+       struct socket *sock = transport->sock;
+       int status = -EIO;
+
+       sock = xs_create_sock(xprt, transport,
+                       xs_addr(xprt)->sa_family, SOCK_DGRAM,
+                       IPPROTO_UDP, false);
+       if (IS_ERR(sock))
+               goto out;
+
+       dprintk("RPC:       worker connecting xprt %p via %s to "
+                               "%s (port %s)\n", xprt,
+                       xprt->address_strings[RPC_DISPLAY_PROTO],
+                       xprt->address_strings[RPC_DISPLAY_ADDR],
+                       xprt->address_strings[RPC_DISPLAY_PORT]);
+
+       xs_udp_finish_connecting(xprt, sock);
+       trace_rpc_socket_connect(xprt, sock, 0);
+       status = 0;
+out:
+       xprt_unlock_connect(xprt, transport);
+       xprt_clear_connecting(xprt);
+       xprt_wake_pending_tasks(xprt, status);
+}
+
+static int xs_tcp_finish_connecting(struct rpc_xprt *xprt, struct socket *sock)
+{
+       struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
+       int ret = -ENOTCONN;
+
+       if (!transport->inet) {
+               struct sock *sk = sock->sk;
+               unsigned int keepidle = xprt->timeout->to_initval / HZ;
+               unsigned int keepcnt = xprt->timeout->to_retries + 1;
+               unsigned int opt_on = 1;
+
+               /* TCP Keepalive options */
+               kernel_setsockopt(sock, SOL_SOCKET, SO_KEEPALIVE,
+                               (char *)&opt_on, sizeof(opt_on));
+               kernel_setsockopt(sock, SOL_TCP, TCP_KEEPIDLE,
+                               (char *)&keepidle, sizeof(keepidle));
+               kernel_setsockopt(sock, SOL_TCP, TCP_KEEPINTVL,
+                               (char *)&keepidle, sizeof(keepidle));
+               kernel_setsockopt(sock, SOL_TCP, TCP_KEEPCNT,
+                               (char *)&keepcnt, sizeof(keepcnt));
+
+               write_lock_bh(&sk->sk_callback_lock);
+
+               xs_save_old_callbacks(transport, sk);
+
+               sk->sk_user_data = xprt;
+               sk->sk_data_ready = xs_tcp_data_ready;
+               sk->sk_state_change = xs_tcp_state_change;
+               sk->sk_write_space = xs_tcp_write_space;
+               sk->sk_error_report = xs_error_report;
+               sk->sk_allocation = GFP_ATOMIC;
+
+               /* socket options */
+               sock_reset_flag(sk, SOCK_LINGER);
+               tcp_sk(sk)->nonagle |= TCP_NAGLE_OFF;
+
+               xprt_clear_connected(xprt);
+
+               /* Reset to new socket */
+               transport->sock = sock;
+               transport->inet = sk;
+
+               write_unlock_bh(&sk->sk_callback_lock);
+       }
+
+       if (!xprt_bound(xprt))
+               goto out;
+
+       xs_set_memalloc(xprt);
+
+       /* Tell the socket layer to start connecting... */
+       xprt->stat.connect_count++;
+       xprt->stat.connect_start = jiffies;
+       ret = kernel_connect(sock, xs_addr(xprt), xprt->addrlen, O_NONBLOCK);
+       switch (ret) {
+       case 0:
+               xs_set_srcport(transport, sock);
+       case -EINPROGRESS:
+               /* SYN_SENT! */
+               if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
+                       xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
+       }
+out:
+       return ret;
+}
+
+/**
+ * xs_tcp_setup_socket - create a TCP socket and connect to a remote endpoint
+ * @xprt: RPC transport to connect
+ * @transport: socket transport to connect
+ * @create_sock: function to create a socket of the correct type
+ *
+ * Invoked by a work queue tasklet.
+ */
+static void xs_tcp_setup_socket(struct work_struct *work)
+{
+       struct sock_xprt *transport =
+               container_of(work, struct sock_xprt, connect_worker.work);
+       struct socket *sock = transport->sock;
+       struct rpc_xprt *xprt = &transport->xprt;
+       int status = -EIO;
+
+       if (!sock) {
+               sock = xs_create_sock(xprt, transport,
+                               xs_addr(xprt)->sa_family, SOCK_STREAM,
+                               IPPROTO_TCP, true);
+               if (IS_ERR(sock)) {
+                       status = PTR_ERR(sock);
+                       goto out;
+               }
+       }
+
+       dprintk("RPC:       worker connecting xprt %p via %s to "
+                               "%s (port %s)\n", xprt,
+                       xprt->address_strings[RPC_DISPLAY_PROTO],
+                       xprt->address_strings[RPC_DISPLAY_ADDR],
+                       xprt->address_strings[RPC_DISPLAY_PORT]);
+
+       status = xs_tcp_finish_connecting(xprt, sock);
+       trace_rpc_socket_connect(xprt, sock, status);
+       dprintk("RPC:       %p connect status %d connected %d sock state %d\n",
+                       xprt, -status, xprt_connected(xprt),
+                       sock->sk->sk_state);
+       switch (status) {
+       default:
+               printk("%s: connect returned unhandled error %d\n",
+                       __func__, status);
+       case -EADDRNOTAVAIL:
+               /* We're probably in TIME_WAIT. Get rid of existing socket,
+                * and retry
+                */
+               xs_tcp_force_close(xprt);
+               break;
+       case 0:
+       case -EINPROGRESS:
+       case -EALREADY:
+               xprt_unlock_connect(xprt, transport);
+               xprt_clear_connecting(xprt);
+               return;
+       case -EINVAL:
+               /* Happens, for instance, if the user specified a link
+                * local IPv6 address without a scope-id.
+                */
+       case -ECONNREFUSED:
+       case -ECONNRESET:
+       case -ENETUNREACH:
+       case -EADDRINUSE:
+       case -ENOBUFS:
+               /* retry with existing socket, after a delay */
+               xs_tcp_force_close(xprt);
+               goto out;
+       }
+       status = -EAGAIN;
+out:
+       xprt_unlock_connect(xprt, transport);
+       xprt_clear_connecting(xprt);
+       xprt_wake_pending_tasks(xprt, status);
+}
+
+/**
+ * xs_connect - connect a socket to a remote endpoint
+ * @xprt: pointer to transport structure
+ * @task: address of RPC task that manages state of connect request
+ *
+ * TCP: If the remote end dropped the connection, delay reconnecting.
+ *
+ * UDP socket connects are synchronous, but we use a work queue anyway
+ * to guarantee that even unprivileged user processes can set up a
+ * socket on a privileged port.
+ *
+ * If a UDP socket connect fails, the delay behavior here prevents
+ * retry floods (hard mounts).
+ */
+static void xs_connect(struct rpc_xprt *xprt, struct rpc_task *task)
+{
+       struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
+
+       WARN_ON_ONCE(!xprt_lock_connect(xprt, task, transport));
+
+       /* Start by resetting any existing state */
+       xs_reset_transport(transport);
+
+       if (transport->sock != NULL && !RPC_IS_SOFTCONN(task)) {
+               dprintk("RPC:       xs_connect delayed xprt %p for %lu "
+                               "seconds\n",
+                               xprt, xprt->reestablish_timeout / HZ);
+               queue_delayed_work(rpciod_workqueue,
+                                  &transport->connect_worker,
+                                  xprt->reestablish_timeout);
+               xprt->reestablish_timeout <<= 1;
+               if (xprt->reestablish_timeout < XS_TCP_INIT_REEST_TO)
+                       xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
+               if (xprt->reestablish_timeout > XS_TCP_MAX_REEST_TO)
+                       xprt->reestablish_timeout = XS_TCP_MAX_REEST_TO;
+       } else {
+               dprintk("RPC:       xs_connect scheduled xprt %p\n", xprt);
+               queue_delayed_work(rpciod_workqueue,
+                                  &transport->connect_worker, 0);
+       }
+}
+
+/**
+ * xs_local_print_stats - display AF_LOCAL socket-specifc stats
+ * @xprt: rpc_xprt struct containing statistics
+ * @seq: output file
+ *
+ */
+static void xs_local_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
+{
+       long idle_time = 0;
+
+       if (xprt_connected(xprt))
+               idle_time = (long)(jiffies - xprt->last_used) / HZ;
+
+       seq_printf(seq, "\txprt:\tlocal %lu %lu %lu %ld %lu %lu %lu "
+                       "%llu %llu %lu %llu %llu\n",
+                       xprt->stat.bind_count,
+                       xprt->stat.connect_count,
+                       xprt->stat.connect_time,
+                       idle_time,
+                       xprt->stat.sends,
+                       xprt->stat.recvs,
+                       xprt->stat.bad_xids,
+                       xprt->stat.req_u,
+                       xprt->stat.bklog_u,
+                       xprt->stat.max_slots,
+                       xprt->stat.sending_u,
+                       xprt->stat.pending_u);
+}
+
+/**
+ * xs_udp_print_stats - display UDP socket-specifc stats
+ * @xprt: rpc_xprt struct containing statistics
+ * @seq: output file
+ *
+ */
+static void xs_udp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
+{
+       struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
+
+       seq_printf(seq, "\txprt:\tudp %u %lu %lu %lu %lu %llu %llu "
+                       "%lu %llu %llu\n",
+                       transport->srcport,
+                       xprt->stat.bind_count,
+                       xprt->stat.sends,
+                       xprt->stat.recvs,
+                       xprt->stat.bad_xids,
+                       xprt->stat.req_u,
+                       xprt->stat.bklog_u,
+                       xprt->stat.max_slots,
+                       xprt->stat.sending_u,
+                       xprt->stat.pending_u);
+}
+
+/**
+ * xs_tcp_print_stats - display TCP socket-specifc stats
+ * @xprt: rpc_xprt struct containing statistics
+ * @seq: output file
+ *
+ */
+static void xs_tcp_print_stats(struct rpc_xprt *xprt, struct seq_file *seq)
+{
+       struct sock_xprt *transport = container_of(xprt, struct sock_xprt, xprt);
+       long idle_time = 0;
+
+       if (xprt_connected(xprt))
+               idle_time = (long)(jiffies - xprt->last_used) / HZ;
+
+       seq_printf(seq, "\txprt:\ttcp %u %lu %lu %lu %ld %lu %lu %lu "
+                       "%llu %llu %lu %llu %llu\n",
+                       transport->srcport,
+                       xprt->stat.bind_count,
+                       xprt->stat.connect_count,
+                       xprt->stat.connect_time,
+                       idle_time,
+                       xprt->stat.sends,
+                       xprt->stat.recvs,
+                       xprt->stat.bad_xids,
+                       xprt->stat.req_u,
+                       xprt->stat.bklog_u,
+                       xprt->stat.max_slots,
+                       xprt->stat.sending_u,
+                       xprt->stat.pending_u);
+}
+
+/*
+ * Allocate a bunch of pages for a scratch buffer for the rpc code. The reason
+ * we allocate pages instead doing a kmalloc like rpc_malloc is because we want
+ * to use the server side send routines.
+ */
+static void *bc_malloc(struct rpc_task *task, size_t size)
+{
+       struct page *page;
+       struct rpc_buffer *buf;
+
+       WARN_ON_ONCE(size > PAGE_SIZE - sizeof(struct rpc_buffer));
+       if (size > PAGE_SIZE - sizeof(struct rpc_buffer))
+               return NULL;
+
+       page = alloc_page(GFP_KERNEL);
+       if (!page)
+               return NULL;
+
+       buf = page_address(page);
+       buf->len = PAGE_SIZE;
+
+       return buf->data;
+}
+
+/*
+ * Free the space allocated in the bc_alloc routine
+ */
+static void bc_free(void *buffer)
+{
+       struct rpc_buffer *buf;
+
+       if (!buffer)
+               return;
+
+       buf = container_of(buffer, struct rpc_buffer, data);
+       free_page((unsigned long)buf);
+}
+
+/*
+ * Use the svc_sock to send the callback. Must be called with svsk->sk_mutex
+ * held. Borrows heavily from svc_tcp_sendto and xs_tcp_send_request.
+ */
+static int bc_sendto(struct rpc_rqst *req)
+{
+       int len;
+       struct xdr_buf *xbufp = &req->rq_snd_buf;
+       struct rpc_xprt *xprt = req->rq_xprt;
+       struct sock_xprt *transport =
+                               container_of(xprt, struct sock_xprt, xprt);
+       struct socket *sock = transport->sock;
+       unsigned long headoff;
+       unsigned long tailoff;
+
+       xs_encode_stream_record_marker(xbufp);
+
+       tailoff = (unsigned long)xbufp->tail[0].iov_base & ~PAGE_MASK;
+       headoff = (unsigned long)xbufp->head[0].iov_base & ~PAGE_MASK;
+       len = svc_send_common(sock, xbufp,
+                             virt_to_page(xbufp->head[0].iov_base), headoff,
+                             xbufp->tail[0].iov_base, tailoff);
+
+       if (len != xbufp->len) {
+               printk(KERN_NOTICE "Error sending entire callback!\n");
+               len = -EAGAIN;
+       }
+
+       return len;
+}
+
+/*
+ * The send routine. Borrows from svc_send
+ */
+static int bc_send_request(struct rpc_task *task)
+{
+       struct rpc_rqst *req = task->tk_rqstp;
+       struct svc_xprt *xprt;
+       u32                     len;
+
+       dprintk("sending request with xid: %08x\n", ntohl(req->rq_xid));
+       /*
+        * Get the server socket associated with this callback xprt
+        */
+       xprt = req->rq_xprt->bc_xprt;
+
+       /*
+        * Grab the mutex to serialize data as the connection is shared
+        * with the fore channel
+        */
+       if (!mutex_trylock(&xprt->xpt_mutex)) {
+               rpc_sleep_on(&xprt->xpt_bc_pending, task, NULL);
+               if (!mutex_trylock(&xprt->xpt_mutex))
+                       return -EAGAIN;
+               rpc_wake_up_queued_task(&xprt->xpt_bc_pending, task);
+       }
+       if (test_bit(XPT_DEAD, &xprt->xpt_flags))
+               len = -ENOTCONN;
+       else
+               len = bc_sendto(req);
+       mutex_unlock(&xprt->xpt_mutex);
+
+       if (len > 0)
+               len = 0;
+
+       return len;
+}
+
+/*
+ * The close routine. Since this is client initiated, we do nothing
+ */
+
+static void bc_close(struct rpc_xprt *xprt)
+{
+}
+
+/*
+ * The xprt destroy routine. Again, because this connection is client
+ * initiated, we do nothing
+ */
+
+static void bc_destroy(struct rpc_xprt *xprt)
+{
+       dprintk("RPC:       bc_destroy xprt %p\n", xprt);
+
+       xs_xprt_free(xprt);
+       module_put(THIS_MODULE);
+}
+
+static struct rpc_xprt_ops xs_local_ops = {
+       .reserve_xprt           = xprt_reserve_xprt,
+       .release_xprt           = xs_tcp_release_xprt,
+       .alloc_slot             = xprt_alloc_slot,
+       .rpcbind                = xs_local_rpcbind,
+       .set_port               = xs_local_set_port,
+       .connect                = xs_local_connect,
+       .buf_alloc              = rpc_malloc,
+       .buf_free               = rpc_free,
+       .send_request           = xs_local_send_request,
+       .set_retrans_timeout    = xprt_set_retrans_timeout_def,
+       .close                  = xs_close,
+       .destroy                = xs_destroy,
+       .print_stats            = xs_local_print_stats,
+};
+
+static struct rpc_xprt_ops xs_udp_ops = {
+       .set_buffer_size        = xs_udp_set_buffer_size,
+       .reserve_xprt           = xprt_reserve_xprt_cong,
+       .release_xprt           = xprt_release_xprt_cong,
+       .alloc_slot             = xprt_alloc_slot,
+       .rpcbind                = rpcb_getport_async,
+       .set_port               = xs_set_port,
+       .connect                = xs_connect,
+       .buf_alloc              = rpc_malloc,
+       .buf_free               = rpc_free,
+       .send_request           = xs_udp_send_request,
+       .set_retrans_timeout    = xprt_set_retrans_timeout_rtt,
+       .timer                  = xs_udp_timer,
+       .release_request        = xprt_release_rqst_cong,
+       .close                  = xs_close,
+       .destroy                = xs_destroy,
+       .print_stats            = xs_udp_print_stats,
+};
+
+static struct rpc_xprt_ops xs_tcp_ops = {
+       .reserve_xprt           = xprt_reserve_xprt,
+       .release_xprt           = xs_tcp_release_xprt,
+       .alloc_slot             = xprt_lock_and_alloc_slot,
+       .rpcbind                = rpcb_getport_async,
+       .set_port               = xs_set_port,
+       .connect                = xs_connect,
+       .buf_alloc              = rpc_malloc,
+       .buf_free               = rpc_free,
+       .send_request           = xs_tcp_send_request,
+       .set_retrans_timeout    = xprt_set_retrans_timeout_def,
+       .close                  = xs_tcp_shutdown,
+       .destroy                = xs_destroy,
+       .print_stats            = xs_tcp_print_stats,
+};
+
+/*
+ * The rpc_xprt_ops for the server backchannel
+ */
+
+static struct rpc_xprt_ops bc_tcp_ops = {
+       .reserve_xprt           = xprt_reserve_xprt,
+       .release_xprt           = xprt_release_xprt,
+       .alloc_slot             = xprt_alloc_slot,
+       .buf_alloc              = bc_malloc,
+       .buf_free               = bc_free,
+       .send_request           = bc_send_request,
+       .set_retrans_timeout    = xprt_set_retrans_timeout_def,
+       .close                  = bc_close,
+       .destroy                = bc_destroy,
+       .print_stats            = xs_tcp_print_stats,
+};
+
+static int xs_init_anyaddr(const int family, struct sockaddr *sap)
+{
+       static const struct sockaddr_in sin = {
+               .sin_family             = AF_INET,
+               .sin_addr.s_addr        = htonl(INADDR_ANY),
+       };
+       static const struct sockaddr_in6 sin6 = {
+               .sin6_family            = AF_INET6,
+               .sin6_addr              = IN6ADDR_ANY_INIT,
+       };
+
+       switch (family) {
+       case AF_LOCAL:
+               break;
+       case AF_INET:
+               memcpy(sap, &sin, sizeof(sin));
+               break;
+       case AF_INET6:
+               memcpy(sap, &sin6, sizeof(sin6));
+               break;
+       default:
+               dprintk("RPC:       %s: Bad address family\n", __func__);
+               return -EAFNOSUPPORT;
+       }
+       return 0;
+}
+
+static struct rpc_xprt *xs_setup_xprt(struct xprt_create *args,
+                                     unsigned int slot_table_size,
+                                     unsigned int max_slot_table_size)
+{
+       struct rpc_xprt *xprt;
+       struct sock_xprt *new;
+
+       if (args->addrlen > sizeof(xprt->addr)) {
+               dprintk("RPC:       xs_setup_xprt: address too large\n");
+               return ERR_PTR(-EBADF);
+       }
+
+       xprt = xprt_alloc(args->net, sizeof(*new), slot_table_size,
+                       max_slot_table_size);
+       if (xprt == NULL) {
+               dprintk("RPC:       xs_setup_xprt: couldn't allocate "
+                               "rpc_xprt\n");
+               return ERR_PTR(-ENOMEM);
+       }
+
+       new = container_of(xprt, struct sock_xprt, xprt);
+       memcpy(&xprt->addr, args->dstaddr, args->addrlen);
+       xprt->addrlen = args->addrlen;
+       if (args->srcaddr)
+               memcpy(&new->srcaddr, args->srcaddr, args->addrlen);
+       else {
+               int err;
+               err = xs_init_anyaddr(args->dstaddr->sa_family,
+                                       (struct sockaddr *)&new->srcaddr);
+               if (err != 0) {
+                       xprt_free(xprt);
+                       return ERR_PTR(err);
+               }
+       }
+
+       return xprt;
+}
+
+static const struct rpc_timeout xs_local_default_timeout = {
+       .to_initval = 10 * HZ,
+       .to_maxval = 10 * HZ,
+       .to_retries = 2,
+};
+
+/**
+ * xs_setup_local - Set up transport to use an AF_LOCAL socket
+ * @args: rpc transport creation arguments
+ *
+ * AF_LOCAL is a "tpi_cots_ord" transport, just like TCP
+ */
+static struct rpc_xprt *xs_setup_local(struct xprt_create *args)
+{
+       struct sockaddr_un *sun = (struct sockaddr_un *)args->dstaddr;
+       struct sock_xprt *transport;
+       struct rpc_xprt *xprt;
+       struct rpc_xprt *ret;
+
+       xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
+                       xprt_max_tcp_slot_table_entries);
+       if (IS_ERR(xprt))
+               return xprt;
+       transport = container_of(xprt, struct sock_xprt, xprt);
+
+       xprt->prot = 0;
+       xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
+       xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
+
+       xprt->bind_timeout = XS_BIND_TO;
+       xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
+       xprt->idle_timeout = XS_IDLE_DISC_TO;
+
+       xprt->ops = &xs_local_ops;
+       xprt->timeout = &xs_local_default_timeout;
+
+       INIT_DELAYED_WORK(&transport->connect_worker,
+                       xs_dummy_setup_socket);
+
+       switch (sun->sun_family) {
+       case AF_LOCAL:
+               if (sun->sun_path[0] != '/') {
+                       dprintk("RPC:       bad AF_LOCAL address: %s\n",
+                                       sun->sun_path);
+                       ret = ERR_PTR(-EINVAL);
+                       goto out_err;
+               }
+               xprt_set_bound(xprt);
+               xs_format_peer_addresses(xprt, "local", RPCBIND_NETID_LOCAL);
+               ret = ERR_PTR(xs_local_setup_socket(transport));
+               if (ret)
+                       goto out_err;
+               break;
+       default:
+               ret = ERR_PTR(-EAFNOSUPPORT);
+               goto out_err;
+       }
+
+       dprintk("RPC:       set up xprt to %s via AF_LOCAL\n",
+                       xprt->address_strings[RPC_DISPLAY_ADDR]);
+
+       if (try_module_get(THIS_MODULE))
+               return xprt;
+       ret = ERR_PTR(-EINVAL);
+out_err:
+       xs_xprt_free(xprt);
+       return ret;
+}
+
+static const struct rpc_timeout xs_udp_default_timeout = {
+       .to_initval = 5 * HZ,
+       .to_maxval = 30 * HZ,
+       .to_increment = 5 * HZ,
+       .to_retries = 5,
+};
+
+/**
+ * xs_setup_udp - Set up transport to use a UDP socket
+ * @args: rpc transport creation arguments
+ *
+ */
+static struct rpc_xprt *xs_setup_udp(struct xprt_create *args)
+{
+       struct sockaddr *addr = args->dstaddr;
+       struct rpc_xprt *xprt;
+       struct sock_xprt *transport;
+       struct rpc_xprt *ret;
+
+       xprt = xs_setup_xprt(args, xprt_udp_slot_table_entries,
+                       xprt_udp_slot_table_entries);
+       if (IS_ERR(xprt))
+               return xprt;
+       transport = container_of(xprt, struct sock_xprt, xprt);
+
+       xprt->prot = IPPROTO_UDP;
+       xprt->tsh_size = 0;
+       /* XXX: header size can vary due to auth type, IPv6, etc. */
+       xprt->max_payload = (1U << 16) - (MAX_HEADER << 3);
+
+       xprt->bind_timeout = XS_BIND_TO;
+       xprt->reestablish_timeout = XS_UDP_REEST_TO;
+       xprt->idle_timeout = XS_IDLE_DISC_TO;
+
+       xprt->ops = &xs_udp_ops;
+
+       xprt->timeout = &xs_udp_default_timeout;
+
+       switch (addr->sa_family) {
+       case AF_INET:
+               if (((struct sockaddr_in *)addr)->sin_port != htons(0))
+                       xprt_set_bound(xprt);
+
+               INIT_DELAYED_WORK(&transport->connect_worker,
+                                       xs_udp_setup_socket);
+               xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP);
+               break;
+       case AF_INET6:
+               if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
+                       xprt_set_bound(xprt);
+
+               INIT_DELAYED_WORK(&transport->connect_worker,
+                                       xs_udp_setup_socket);
+               xs_format_peer_addresses(xprt, "udp", RPCBIND_NETID_UDP6);
+               break;
+       default:
+               ret = ERR_PTR(-EAFNOSUPPORT);
+               goto out_err;
+       }
+
+       if (xprt_bound(xprt))
+               dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
+                               xprt->address_strings[RPC_DISPLAY_ADDR],
+                               xprt->address_strings[RPC_DISPLAY_PORT],
+                               xprt->address_strings[RPC_DISPLAY_PROTO]);
+       else
+               dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
+                               xprt->address_strings[RPC_DISPLAY_ADDR],
+                               xprt->address_strings[RPC_DISPLAY_PROTO]);
+
+       if (try_module_get(THIS_MODULE))
+               return xprt;
+       ret = ERR_PTR(-EINVAL);
+out_err:
+       xs_xprt_free(xprt);
+       return ret;
+}
+
+static const struct rpc_timeout xs_tcp_default_timeout = {
+       .to_initval = 60 * HZ,
+       .to_maxval = 60 * HZ,
+       .to_retries = 2,
+};
+
+/**
+ * xs_setup_tcp - Set up transport to use a TCP socket
+ * @args: rpc transport creation arguments
+ *
+ */
+static struct rpc_xprt *xs_setup_tcp(struct xprt_create *args)
+{
+       struct sockaddr *addr = args->dstaddr;
+       struct rpc_xprt *xprt;
+       struct sock_xprt *transport;
+       struct rpc_xprt *ret;
+       unsigned int max_slot_table_size = xprt_max_tcp_slot_table_entries;
+
+       if (args->flags & XPRT_CREATE_INFINITE_SLOTS)
+               max_slot_table_size = RPC_MAX_SLOT_TABLE_LIMIT;
+
+       xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
+                       max_slot_table_size);
+       if (IS_ERR(xprt))
+               return xprt;
+       transport = container_of(xprt, struct sock_xprt, xprt);
+
+       xprt->prot = IPPROTO_TCP;
+       xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
+       xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
+
+       xprt->bind_timeout = XS_BIND_TO;
+       xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
+       xprt->idle_timeout = XS_IDLE_DISC_TO;
+
+       xprt->ops = &xs_tcp_ops;
+       xprt->timeout = &xs_tcp_default_timeout;
+
+       switch (addr->sa_family) {
+       case AF_INET:
+               if (((struct sockaddr_in *)addr)->sin_port != htons(0))
+                       xprt_set_bound(xprt);
+
+               INIT_DELAYED_WORK(&transport->connect_worker,
+                                       xs_tcp_setup_socket);
+               xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP);
+               break;
+       case AF_INET6:
+               if (((struct sockaddr_in6 *)addr)->sin6_port != htons(0))
+                       xprt_set_bound(xprt);
+
+               INIT_DELAYED_WORK(&transport->connect_worker,
+                                       xs_tcp_setup_socket);
+               xs_format_peer_addresses(xprt, "tcp", RPCBIND_NETID_TCP6);
+               break;
+       default:
+               ret = ERR_PTR(-EAFNOSUPPORT);
+               goto out_err;
+       }
+
+       if (xprt_bound(xprt))
+               dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
+                               xprt->address_strings[RPC_DISPLAY_ADDR],
+                               xprt->address_strings[RPC_DISPLAY_PORT],
+                               xprt->address_strings[RPC_DISPLAY_PROTO]);
+       else
+               dprintk("RPC:       set up xprt to %s (autobind) via %s\n",
+                               xprt->address_strings[RPC_DISPLAY_ADDR],
+                               xprt->address_strings[RPC_DISPLAY_PROTO]);
+
+       if (try_module_get(THIS_MODULE))
+               return xprt;
+       ret = ERR_PTR(-EINVAL);
+out_err:
+       xs_xprt_free(xprt);
+       return ret;
+}
+
+/**
+ * xs_setup_bc_tcp - Set up transport to use a TCP backchannel socket
+ * @args: rpc transport creation arguments
+ *
+ */
+static struct rpc_xprt *xs_setup_bc_tcp(struct xprt_create *args)
+{
+       struct sockaddr *addr = args->dstaddr;
+       struct rpc_xprt *xprt;
+       struct sock_xprt *transport;
+       struct svc_sock *bc_sock;
+       struct rpc_xprt *ret;
+
+       xprt = xs_setup_xprt(args, xprt_tcp_slot_table_entries,
+                       xprt_tcp_slot_table_entries);
+       if (IS_ERR(xprt))
+               return xprt;
+       transport = container_of(xprt, struct sock_xprt, xprt);
+
+       xprt->prot = IPPROTO_TCP;
+       xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
+       xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
+       xprt->timeout = &xs_tcp_default_timeout;
+
+       /* backchannel */
+       xprt_set_bound(xprt);
+       xprt->bind_timeout = 0;
+       xprt->reestablish_timeout = 0;
+       xprt->idle_timeout = 0;
+
+       xprt->ops = &bc_tcp_ops;
+
+       switch (addr->sa_family) {
+       case AF_INET:
+               xs_format_peer_addresses(xprt, "tcp",
+                                        RPCBIND_NETID_TCP);
+               break;
+       case AF_INET6:
+               xs_format_peer_addresses(xprt, "tcp",
+                                  RPCBIND_NETID_TCP6);
+               break;
+       default:
+               ret = ERR_PTR(-EAFNOSUPPORT);
+               goto out_err;
+       }
+
+       dprintk("RPC:       set up xprt to %s (port %s) via %s\n",
+                       xprt->address_strings[RPC_DISPLAY_ADDR],
+                       xprt->address_strings[RPC_DISPLAY_PORT],
+                       xprt->address_strings[RPC_DISPLAY_PROTO]);
+
+       /*
+        * Once we've associated a backchannel xprt with a connection,
+        * we want to keep it around as long as the connection lasts,
+        * in case we need to start using it for a backchannel again;
+        * this reference won't be dropped until bc_xprt is destroyed.
+        */
+       xprt_get(xprt);
+       args->bc_xprt->xpt_bc_xprt = xprt;
+       xprt->bc_xprt = args->bc_xprt;
+       bc_sock = container_of(args->bc_xprt, struct svc_sock, sk_xprt);
+       transport->sock = bc_sock->sk_sock;
+       transport->inet = bc_sock->sk_sk;
+
+       /*
+        * Since we don't want connections for the backchannel, we set
+        * the xprt status to connected
+        */
+       xprt_set_connected(xprt);
+
+       if (try_module_get(THIS_MODULE))
+               return xprt;
+
+       args->bc_xprt->xpt_bc_xprt = NULL;
+       xprt_put(xprt);
+       ret = ERR_PTR(-EINVAL);
+out_err:
+       xs_xprt_free(xprt);
+       return ret;
+}
+
+static struct xprt_class       xs_local_transport = {
+       .list           = LIST_HEAD_INIT(xs_local_transport.list),
+       .name           = "named UNIX socket",
+       .owner          = THIS_MODULE,
+       .ident          = XPRT_TRANSPORT_LOCAL,
+       .setup          = xs_setup_local,
+};
+
+static struct xprt_class       xs_udp_transport = {
+       .list           = LIST_HEAD_INIT(xs_udp_transport.list),
+       .name           = "udp",
+       .owner          = THIS_MODULE,
+       .ident          = XPRT_TRANSPORT_UDP,
+       .setup          = xs_setup_udp,
+};
+
+static struct xprt_class       xs_tcp_transport = {
+       .list           = LIST_HEAD_INIT(xs_tcp_transport.list),
+       .name           = "tcp",
+       .owner          = THIS_MODULE,
+       .ident          = XPRT_TRANSPORT_TCP,
+       .setup          = xs_setup_tcp,
+};
+
+static struct xprt_class       xs_bc_tcp_transport = {
+       .list           = LIST_HEAD_INIT(xs_bc_tcp_transport.list),
+       .name           = "tcp NFSv4.1 backchannel",
+       .owner          = THIS_MODULE,
+       .ident          = XPRT_TRANSPORT_BC_TCP,
+       .setup          = xs_setup_bc_tcp,
+};
+
+/**
+ * init_socket_xprt - set up xprtsock's sysctls, register with RPC client
+ *
+ */
+int init_socket_xprt(void)
+{
+#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
+       if (!sunrpc_table_header)
+               sunrpc_table_header = register_sysctl_table(sunrpc_table);
+#endif
+
+       xprt_register_transport(&xs_local_transport);
+       xprt_register_transport(&xs_udp_transport);
+       xprt_register_transport(&xs_tcp_transport);
+       xprt_register_transport(&xs_bc_tcp_transport);
+
+       return 0;
+}
+
+/**
+ * cleanup_socket_xprt - remove xprtsock's sysctls, unregister
+ *
+ */
+void cleanup_socket_xprt(void)
+{
+#if IS_ENABLED(CONFIG_SUNRPC_DEBUG)
+       if (sunrpc_table_header) {
+               unregister_sysctl_table(sunrpc_table_header);
+               sunrpc_table_header = NULL;
+       }
+#endif
+
+       xprt_unregister_transport(&xs_local_transport);
+       xprt_unregister_transport(&xs_udp_transport);
+       xprt_unregister_transport(&xs_tcp_transport);
+       xprt_unregister_transport(&xs_bc_tcp_transport);
+}
+
+static int param_set_uint_minmax(const char *val,
+               const struct kernel_param *kp,
+               unsigned int min, unsigned int max)
+{
+       unsigned int num;
+       int ret;
+
+       if (!val)
+               return -EINVAL;
+       ret = kstrtouint(val, 0, &num);
+       if (ret == -EINVAL || num < min || num > max)
+               return -EINVAL;
+       *((unsigned int *)kp->arg) = num;
+       return 0;
+}
+
+static int param_set_portnr(const char *val, const struct kernel_param *kp)
+{
+       return param_set_uint_minmax(val, kp,
+                       RPC_MIN_RESVPORT,
+                       RPC_MAX_RESVPORT);
+}
+
+static struct kernel_param_ops param_ops_portnr = {
+       .set = param_set_portnr,
+       .get = param_get_uint,
+};
+
+#define param_check_portnr(name, p) \
+       __param_check(name, p, unsigned int);
+
+module_param_named(min_resvport, xprt_min_resvport, portnr, 0644);
+module_param_named(max_resvport, xprt_max_resvport, portnr, 0644);
+
+static int param_set_slot_table_size(const char *val,
+                                    const struct kernel_param *kp)
+{
+       return param_set_uint_minmax(val, kp,
+                       RPC_MIN_SLOT_TABLE,
+                       RPC_MAX_SLOT_TABLE);
+}
+
+static struct kernel_param_ops param_ops_slot_table_size = {
+       .set = param_set_slot_table_size,
+       .get = param_get_uint,
+};
+
+#define param_check_slot_table_size(name, p) \
+       __param_check(name, p, unsigned int);
+
+static int param_set_max_slot_table_size(const char *val,
+                                    const struct kernel_param *kp)
+{
+       return param_set_uint_minmax(val, kp,
+                       RPC_MIN_SLOT_TABLE,
+                       RPC_MAX_SLOT_TABLE_LIMIT);
+}
+
+static struct kernel_param_ops param_ops_max_slot_table_size = {
+       .set = param_set_max_slot_table_size,
+       .get = param_get_uint,
+};
+
+#define param_check_max_slot_table_size(name, p) \
+       __param_check(name, p, unsigned int);
+
+module_param_named(tcp_slot_table_entries, xprt_tcp_slot_table_entries,
+                  slot_table_size, 0644);
+module_param_named(tcp_max_slot_table_entries, xprt_max_tcp_slot_table_entries,
+                  max_slot_table_size, 0644);
+module_param_named(udp_slot_table_entries, xprt_udp_slot_table_entries,
+                  slot_table_size, 0644);
+