net/sunrpc/xprtsock.c

   1 /*
   2  * linux/net/sunrpc/xprtsock.c
   3  *
   4  * Client-side transport implementation for sockets.
   5  *
   6  * TCP callback races fixes (C) 1998 Red Hat Software <alan@redhat.com>
   7  * TCP send fixes (C) 1998 Red Hat Software <alan@redhat.com>
   8  * TCP NFS related read + write fixes
   9  *  (C) 1999 Dave Airlie, University of Limerick, Ireland <airlied@linux.ie>
  10  *
  11  * Rewrite of larges part of the code in order to stabilize TCP stuff.
  12  * Fix behaviour when socket buffer is full.
  13  *  (C) 1999 Trond Myklebust <trond.myklebust@fys.uio.no>
  14  *
  15  * IP socket transport implementation, (C) 2005 Chuck Lever <cel@netapp.com>
  16  */
  17
  18 #include <linux/types.h>
  19 #include <linux/slab.h>
  20 #include <linux/capability.h>
  21 #include <linux/sched.h>
  22 #include <linux/pagemap.h>
  23 #include <linux/errno.h>
  24 #include <linux/socket.h>
  25 #include <linux/in.h>
  26 #include <linux/net.h>
  27 #include <linux/mm.h>
  28 #include <linux/udp.h>
  29 #include <linux/tcp.h>
  30 #include <linux/sunrpc/clnt.h>
  31 #include <linux/file.h>
  32
  33 #include <net/sock.h>
  34 #include <net/checksum.h>
  35 #include <net/udp.h>
  36 #include <net/tcp.h>
  37
  38 /*
  39  * xprtsock tunables
  40  */
  41 unsigned int xprt_udp_slot_table_entries = RPC_DEF_SLOT_TABLE;
  42 unsigned int xprt_tcp_slot_table_entries = RPC_DEF_SLOT_TABLE;
  43
  44 unsigned int xprt_min_resvport = RPC_DEF_MIN_RESVPORT;
  45 unsigned int xprt_max_resvport = RPC_DEF_MAX_RESVPORT;
  46
  47 /*
  48  * How many times to try sending a request on a socket before waiting
  49  * for the socket buffer to clear.
  50  */
  51 #define XS_SENDMSG_RETRY        (10U)
  52
  53 /*
  54  * Time out for an RPC UDP socket connect.  UDP socket connects are
  55  * synchronous, but we set a timeout anyway in case of resource
  56  * exhaustion on the local host.
  57  */
  58 #define XS_UDP_CONN_TO          (5U * HZ)
  59
  60 /*
  61  * Wait duration for an RPC TCP connection to be established.  Solaris
  62  * NFS over TCP uses 60 seconds, for example, which is in line with how
  63  * long a server takes to reboot.
  64  */
  65 #define XS_TCP_CONN_TO          (60U * HZ)
  66
  67 /*
  68  * Wait duration for a reply from the RPC portmapper.
  69  */
  70 #define XS_BIND_TO              (60U * HZ)
  71
  72 /*
  73  * Delay if a UDP socket connect error occurs.  This is most likely some
  74  * kind of resource problem on the local host.
  75  */
  76 #define XS_UDP_REEST_TO         (2U * HZ)
  77
  78 /*
  79  * The reestablish timeout allows clients to delay for a bit before attempting
  80  * to reconnect to a server that just dropped our connection.
  81  *
  82  * We implement an exponential backoff when trying to reestablish a TCP
  83  * transport connection with the server.  Some servers like to drop a TCP
  84  * connection when they are overworked, so we start with a short timeout and
  85  * increase over time if the server is down or not responding.
  86  */
  87 #define XS_TCP_INIT_REEST_TO    (3U * HZ)
  88 #define XS_TCP_MAX_REEST_TO     (5U * 60 * HZ)
  89
  90 /*
  91  * TCP idle timeout; client drops the transport socket if it is idle
  92  * for this long.  Note that we also timeout UDP sockets to prevent
  93  * holding port numbers when there is no RPC traffic.
  94  */
  95 #define XS_IDLE_DISC_TO         (5U * 60 * HZ)
  96
  97 #ifdef RPC_DEBUG
  98 # undef  RPC_DEBUG_DATA
  99 # define RPCDBG_FACILITY        RPCDBG_TRANS
 100 #endif
 101
 102 #ifdef RPC_DEBUG_DATA
 103 static void xs_pktdump(char *msg, u32 *packet, unsigned int count)
 104 {
 105         u8 *buf = (u8 *) packet;
 106         int j;
 107
 108         dprintk("RPC:      %s\n", msg);
 109         for (j = 0; j < count && j < 128; j += 4) {
 110                 if (!(j & 31)) {
 111                         if (j)
 112                                 dprintk("\n");
 113                         dprintk("0x%04x ", j);
 114                 }
 115                 dprintk("%02x%02x%02x%02x ",
 116                         buf[j], buf[j+1], buf[j+2], buf[j+3]);
 117         }
 118         dprintk("\n");
 119 }
 120 #else
 121 static inline void xs_pktdump(char *msg, u32 *packet, unsigned int count)
 122 {
 123         /* NOP */
 124 }
 125 #endif
 126
 127 #define XS_SENDMSG_FLAGS        (MSG_DONTWAIT | MSG_NOSIGNAL)
 128
 129 static inline int xs_send_head(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base, unsigned int len)
 130 {
 131         struct kvec iov = {
 132                 .iov_base       = xdr->head[0].iov_base + base,
 133                 .iov_len        = len - base,
 134         };
 135         struct msghdr msg = {
 136                 .msg_name       = addr,
 137                 .msg_namelen    = addrlen,
 138                 .msg_flags      = XS_SENDMSG_FLAGS,
 139         };
 140
 141         if (xdr->len > len)
 142                 msg.msg_flags |= MSG_MORE;
 143
 144         if (likely(iov.iov_len))
 145                 return kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len);
 146         return kernel_sendmsg(sock, &msg, NULL, 0, 0);
 147 }
 148
 149 static int xs_send_tail(struct socket *sock, struct xdr_buf *xdr, unsigned int base, unsigned int len)
 150 {
 151         struct kvec iov = {
 152                 .iov_base       = xdr->tail[0].iov_base + base,
 153                 .iov_len        = len - base,
 154         };
 155         struct msghdr msg = {
 156                 .msg_flags      = XS_SENDMSG_FLAGS,
 157         };
 158
 159         return kernel_sendmsg(sock, &msg, &iov, 1, iov.iov_len);
 160 }
 161
 162 /**
 163  * xs_sendpages - write pages directly to a socket
 164  * @sock: socket to send on
 165  * @addr: UDP only -- address of destination
 166  * @addrlen: UDP only -- length of destination address
 167  * @xdr: buffer containing this request
 168  * @base: starting position in the buffer
 169  *
 170  */
 171 static inline int xs_sendpages(struct socket *sock, struct sockaddr *addr, int addrlen, struct xdr_buf *xdr, unsigned int base)
 172 {
 173         struct page **ppage = xdr->pages;
 174         unsigned int len, pglen = xdr->page_len;
 175         int err, ret = 0;
 176         ssize_t (*sendpage)(struct socket *, struct page *, int, size_t, int);
 177
 178         if (unlikely(!sock))
 179                 return -ENOTCONN;
 180
 181         clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags);
 182
 183         len = xdr->head[0].iov_len;
 184         if (base < len || (addr != NULL && base == 0)) {
 185                 err = xs_send_head(sock, addr, addrlen, xdr, base, len);
 186                 if (ret == 0)
 187                         ret = err;
 188                 else if (err > 0)
 189                         ret += err;
 190                 if (err != (len - base))
 191                         goto out;
 192                 base = 0;
 193         } else
 194                 base -= len;
 195
 196         if (unlikely(pglen == 0))
 197                 goto copy_tail;
 198         if (unlikely(base >= pglen)) {
 199                 base -= pglen;
 200                 goto copy_tail;
 201         }
 202         if (base || xdr->page_base) {
 203                 pglen -= base;
 204                 base += xdr->page_base;
 205                 ppage += base >> PAGE_CACHE_SHIFT;
 206                 base &= ~PAGE_CACHE_MASK;
 207         }
 208
 209         sendpage = sock->ops->sendpage ? : sock_no_sendpage;
 210         do {
 211                 int flags = XS_SENDMSG_FLAGS;
 212
 213                 len = PAGE_CACHE_SIZE;
 214                 if (base)
 215                         len -= base;
 216                 if (pglen < len)
 217                         len = pglen;
 218
 219                 if (pglen != len || xdr->tail[0].iov_len != 0)
 220                         flags |= MSG_MORE;
 221
 222                 /* Hmm... We might be dealing with highmem pages */
 223                 if (PageHighMem(*ppage))
 224                         sendpage = sock_no_sendpage;
 225                 err = sendpage(sock, *ppage, base, len, flags);
 226                 if (ret == 0)
 227                         ret = err;
 228                 else if (err > 0)
 229                         ret += err;
 230                 if (err != len)
 231                         goto out;
 232                 base = 0;
 233                 ppage++;
 234         } while ((pglen -= len) != 0);
 235 copy_tail:
 236         len = xdr->tail[0].iov_len;
 237         if (base < len) {
 238                 err = xs_send_tail(sock, xdr, base, len);
 239                 if (ret == 0)
 240                         ret = err;
 241                 else if (err > 0)
 242                         ret += err;
 243         }
 244 out:
 245         return ret;
 246 }
 247
 248 /**
 249  * xs_nospace - place task on wait queue if transmit was incomplete
 250  * @task: task to put to sleep
 251  *
 252  */
 253 static void xs_nospace(struct rpc_task *task)
 254 {
 255         struct rpc_rqst *req = task->tk_rqstp;
 256         struct rpc_xprt *xprt = req->rq_xprt;
 257
 258         dprintk("RPC: %4d xmit incomplete (%u left of %u)\n",
 259                         task->tk_pid, req->rq_slen - req->rq_bytes_sent,
 260                         req->rq_slen);
 261
 262         if (test_bit(SOCK_ASYNC_NOSPACE, &xprt->sock->flags)) {
 263                 /* Protect against races with write_space */
 264                 spin_lock_bh(&xprt->transport_lock);
 265
 266                 /* Don't race with disconnect */
 267                 if (!xprt_connected(xprt))
 268                         task->tk_status = -ENOTCONN;
 269                 else if (test_bit(SOCK_NOSPACE, &xprt->sock->flags))
 270                         xprt_wait_for_buffer_space(task);
 271
 272                 spin_unlock_bh(&xprt->transport_lock);
 273         } else
 274                 /* Keep holding the socket if it is blocked */
 275                 rpc_delay(task, HZ>>4);
 276 }
 277
 278 /**
 279  * xs_udp_send_request - write an RPC request to a UDP socket
 280  * @task: address of RPC task that manages the state of an RPC request
 281  *
 282  * Return values:
 283  *        0:    The request has been sent
 284  *   EAGAIN:    The socket was blocked, please call again later to
 285  *              complete the request
 286  * ENOTCONN:    Caller needs to invoke connect logic then call again
 287  *    other:    Some other error occured, the request was not sent
 288  */
 289 static int xs_udp_send_request(struct rpc_task *task)
 290 {
 291         struct rpc_rqst *req = task->tk_rqstp;
 292         struct rpc_xprt *xprt = req->rq_xprt;
 293         struct xdr_buf *xdr = &req->rq_snd_buf;
 294         int status;
 295
 296         xs_pktdump("packet data:",
 297                                 req->rq_svec->iov_base,
 298                                 req->rq_svec->iov_len);
 299
 300         req->rq_xtime = jiffies;
 301         status = xs_sendpages(xprt->sock, (struct sockaddr *) &xprt->addr,
 302                                 sizeof(xprt->addr), xdr, req->rq_bytes_sent);
 303
 304         dprintk("RPC:      xs_udp_send_request(%u) = %d\n",
 305                         xdr->len - req->rq_bytes_sent, status);
 306
 307         if (likely(status >= (int) req->rq_slen))
 308                 return 0;
 309
 310         /* Still some bytes left; set up for a retry later. */
 311         if (status > 0)
 312                 status = -EAGAIN;
 313
 314         switch (status) {
 315         case -ENETUNREACH:
 316         case -EPIPE:
 317         case -ECONNREFUSED:
 318                 /* When the server has died, an ICMP port unreachable message
 319                  * prompts ECONNREFUSED. */
 320                 break;
 321         case -EAGAIN:
 322                 xs_nospace(task);
 323                 break;
 324         default:
 325                 dprintk("RPC:      sendmsg returned unrecognized error %d\n",
 326                         -status);
 327                 break;
 328         }
 329
 330         return status;
 331 }
 332
 333 static inline void xs_encode_tcp_record_marker(struct xdr_buf *buf)
 334 {
 335         u32 reclen = buf->len - sizeof(rpc_fraghdr);
 336         rpc_fraghdr *base = buf->head[0].iov_base;
 337         *base = htonl(RPC_LAST_STREAM_FRAGMENT | reclen);
 338 }
 339
 340 /**
 341  * xs_tcp_send_request - write an RPC request to a TCP socket
 342  * @task: address of RPC task that manages the state of an RPC request
 343  *
 344  * Return values:
 345  *        0:    The request has been sent
 346  *   EAGAIN:    The socket was blocked, please call again later to
 347  *              complete the request
 348  * ENOTCONN:    Caller needs to invoke connect logic then call again
 349  *    other:    Some other error occured, the request was not sent
 350  *
 351  * XXX: In the case of soft timeouts, should we eventually give up
 352  *      if sendmsg is not able to make progress?
 353  */
 354 static int xs_tcp_send_request(struct rpc_task *task)
 355 {
 356         struct rpc_rqst *req = task->tk_rqstp;
 357         struct rpc_xprt *xprt = req->rq_xprt;
 358         struct xdr_buf *xdr = &req->rq_snd_buf;
 359         int status, retry = 0;
 360
 361         xs_encode_tcp_record_marker(&req->rq_snd_buf);
 362
 363         xs_pktdump("packet data:",
 364                                 req->rq_svec->iov_base,
 365                                 req->rq_svec->iov_len);
 366
 367         /* Continue transmitting the packet/record. We must be careful
 368          * to cope with writespace callbacks arriving _after_ we have
 369          * called sendmsg(). */
 370         while (1) {
 371                 req->rq_xtime = jiffies;
 372                 status = xs_sendpages(xprt->sock, NULL, 0, xdr,
 373                                                 req->rq_bytes_sent);
 374
 375                 dprintk("RPC:      xs_tcp_send_request(%u) = %d\n",
 376                                 xdr->len - req->rq_bytes_sent, status);
 377
 378                 if (unlikely(status < 0))
 379                         break;
 380
 381                 /* If we've sent the entire packet, immediately
 382                  * reset the count of bytes sent. */
 383                 req->rq_bytes_sent += status;
 384                 if (likely(req->rq_bytes_sent >= req->rq_slen)) {
 385                         req->rq_bytes_sent = 0;
 386                         return 0;
 387                 }
 388
 389                 status = -EAGAIN;
 390                 if (retry++ > XS_SENDMSG_RETRY)
 391                         break;
 392         }
 393
 394         switch (status) {
 395         case -EAGAIN:
 396                 xs_nospace(task);
 397                 break;
 398         case -ECONNREFUSED:
 399         case -ECONNRESET:
 400         case -ENOTCONN:
 401         case -EPIPE:
 402                 status = -ENOTCONN;
 403                 break;
 404         default:
 405                 dprintk("RPC:      sendmsg returned unrecognized error %d\n",
 406                         -status);
 407                 xprt_disconnect(xprt);
 408                 break;
 409         }
 410
 411         return status;
 412 }
 413
 414 /**
 415  * xs_close - close a socket
 416  * @xprt: transport
 417  *
 418  * This is used when all requests are complete; ie, no DRC state remains
 419  * on the server we want to save.
 420  */
 421 static void xs_close(struct rpc_xprt *xprt)
 422 {
 423         struct socket *sock = xprt->sock;
 424         struct sock *sk = xprt->inet;
 425
 426         if (!sk)
 427                 return;
 428
 429         dprintk("RPC:      xs_close xprt %p\n", xprt);
 430
 431         write_lock_bh(&sk->sk_callback_lock);
 432         xprt->inet = NULL;
 433         xprt->sock = NULL;
 434
 435         sk->sk_user_data = NULL;
 436         sk->sk_data_ready = xprt->old_data_ready;
 437         sk->sk_state_change = xprt->old_state_change;
 438         sk->sk_write_space = xprt->old_write_space;
 439         write_unlock_bh(&sk->sk_callback_lock);
 440
 441         sk->sk_no_check = 0;
 442
 443         sock_release(sock);
 444 }
 445
 446 /**
 447  * xs_destroy - prepare to shutdown a transport
 448  * @xprt: doomed transport
 449  *
 450  */
 451 static void xs_destroy(struct rpc_xprt *xprt)
 452 {
 453         dprintk("RPC:      xs_destroy xprt %p\n", xprt);
 454
 455         cancel_delayed_work(&xprt->connect_worker);
 456         flush_scheduled_work();
 457
 458         xprt_disconnect(xprt);
 459         xs_close(xprt);
 460         kfree(xprt->slot);
 461 }
 462
 463 static inline struct rpc_xprt *xprt_from_sock(struct sock *sk)
 464 {
 465         return (struct rpc_xprt *) sk->sk_user_data;
 466 }
 467
 468 /**
 469  * xs_udp_data_ready - "data ready" callback for UDP sockets
 470  * @sk: socket with data to read
 471  * @len: how much data to read
 472  *
 473  */
 474 static void xs_udp_data_ready(struct sock *sk, int len)
 475 {
 476         struct rpc_task *task;
 477         struct rpc_xprt *xprt;
 478         struct rpc_rqst *rovr;
 479         struct sk_buff *skb;
 480         int err, repsize, copied;
 481         u32 _xid, *xp;
 482
 483         read_lock(&sk->sk_callback_lock);
 484         dprintk("RPC:      xs_udp_data_ready...\n");
 485         if (!(xprt = xprt_from_sock(sk)))
 486                 goto out;
 487
 488         if ((skb = skb_recv_datagram(sk, 0, 1, &err)) == NULL)
 489                 goto out;
 490
 491         if (xprt->shutdown)
 492                 goto dropit;
 493
 494         repsize = skb->len - sizeof(struct udphdr);
 495         if (repsize < 4) {
 496                 dprintk("RPC:      impossible RPC reply size %d!\n", repsize);
 497                 goto dropit;
 498         }
 499
 500         /* Copy the XID from the skb... */
 501         xp = skb_header_pointer(skb, sizeof(struct udphdr),
 502                                 sizeof(_xid), &_xid);
 503         if (xp == NULL)
 504                 goto dropit;
 505
 506         /* Look up and lock the request corresponding to the given XID */
 507         spin_lock(&xprt->transport_lock);
 508         rovr = xprt_lookup_rqst(xprt, *xp);
 509         if (!rovr)
 510                 goto out_unlock;
 511         task = rovr->rq_task;
 512
 513         if ((copied = rovr->rq_private_buf.buflen) > repsize)
 514                 copied = repsize;
 515
 516         /* Suck it into the iovec, verify checksum if not done by hw. */
 517         if (csum_partial_copy_to_xdr(&rovr->rq_private_buf, skb))
 518                 goto out_unlock;
 519
 520         /* Something worked... */
 521         dst_confirm(skb->dst);
 522
 523         xprt_adjust_cwnd(task, copied);
 524         xprt_update_rtt(task);
 525         xprt_complete_rqst(task, copied);
 526
 527  out_unlock:
 528         spin_unlock(&xprt->transport_lock);
 529  dropit:
 530         skb_free_datagram(sk, skb);
 531  out:
 532         read_unlock(&sk->sk_callback_lock);
 533 }
 534
 535 static inline size_t xs_tcp_copy_data(skb_reader_t *desc, void *p, size_t len)
 536 {
 537         if (len > desc->count)
 538                 len = desc->count;
 539         if (skb_copy_bits(desc->skb, desc->offset, p, len)) {
 540                 dprintk("RPC:      failed to copy %zu bytes from skb. %zu bytes remain\n",
 541                                 len, desc->count);
 542                 return 0;
 543         }
 544         desc->offset += len;
 545         desc->count -= len;
 546         dprintk("RPC:      copied %zu bytes from skb. %zu bytes remain\n",
 547                         len, desc->count);
 548         return len;
 549 }
 550
 551 static inline void xs_tcp_read_fraghdr(struct rpc_xprt *xprt, skb_reader_t *desc)
 552 {
 553         size_t len, used;
 554         char *p;
 555
 556         p = ((char *) &xprt->tcp_recm) + xprt->tcp_offset;
 557         len = sizeof(xprt->tcp_recm) - xprt->tcp_offset;
 558         used = xs_tcp_copy_data(desc, p, len);
 559         xprt->tcp_offset += used;
 560         if (used != len)
 561                 return;
 562
 563         xprt->tcp_reclen = ntohl(xprt->tcp_recm);
 564         if (xprt->tcp_reclen & RPC_LAST_STREAM_FRAGMENT)
 565                 xprt->tcp_flags |= XPRT_LAST_FRAG;
 566         else
 567                 xprt->tcp_flags &= ~XPRT_LAST_FRAG;
 568         xprt->tcp_reclen &= RPC_FRAGMENT_SIZE_MASK;
 569
 570         xprt->tcp_flags &= ~XPRT_COPY_RECM;
 571         xprt->tcp_offset = 0;
 572
 573         /* Sanity check of the record length */
 574         if (unlikely(xprt->tcp_reclen < 4)) {
 575                 dprintk("RPC:      invalid TCP record fragment length\n");
 576                 xprt_disconnect(xprt);
 577                 return;
 578         }
 579         dprintk("RPC:      reading TCP record fragment of length %d\n",
 580                         xprt->tcp_reclen);
 581 }
 582
 583 static void xs_tcp_check_recm(struct rpc_xprt *xprt)
 584 {
 585         dprintk("RPC:      xprt = %p, tcp_copied = %lu, tcp_offset = %u, tcp_reclen = %u, tcp_flags = %lx\n",
 586                         xprt, xprt->tcp_copied, xprt->tcp_offset, xprt->tcp_reclen, xprt->tcp_flags);
 587         if (xprt->tcp_offset == xprt->tcp_reclen) {
 588                 xprt->tcp_flags |= XPRT_COPY_RECM;
 589                 xprt->tcp_offset = 0;
 590                 if (xprt->tcp_flags & XPRT_LAST_FRAG) {
 591                         xprt->tcp_flags &= ~XPRT_COPY_DATA;
 592                         xprt->tcp_flags |= XPRT_COPY_XID;
 593                         xprt->tcp_copied = 0;
 594                 }
 595         }
 596 }
 597
 598 static inline void xs_tcp_read_xid(struct rpc_xprt *xprt, skb_reader_t *desc)
 599 {
 600         size_t len, used;
 601         char *p;
 602
 603         len = sizeof(xprt->tcp_xid) - xprt->tcp_offset;
 604         dprintk("RPC:      reading XID (%Zu bytes)\n", len);
 605         p = ((char *) &xprt->tcp_xid) + xprt->tcp_offset;
 606         used = xs_tcp_copy_data(desc, p, len);
 607         xprt->tcp_offset += used;
 608         if (used != len)
 609                 return;
 610         xprt->tcp_flags &= ~XPRT_COPY_XID;
 611         xprt->tcp_flags |= XPRT_COPY_DATA;
 612         xprt->tcp_copied = 4;
 613         dprintk("RPC:      reading reply for XID %08x\n",
 614                                                 ntohl(xprt->tcp_xid));
 615         xs_tcp_check_recm(xprt);
 616 }
 617
 618 static inline void xs_tcp_read_request(struct rpc_xprt *xprt, skb_reader_t *desc)
 619 {
 620         struct rpc_rqst *req;
 621         struct xdr_buf *rcvbuf;
 622         size_t len;
 623         ssize_t r;
 624
 625         /* Find and lock the request corresponding to this xid */
 626         spin_lock(&xprt->transport_lock);
 627         req = xprt_lookup_rqst(xprt, xprt->tcp_xid);
 628         if (!req) {
 629                 xprt->tcp_flags &= ~XPRT_COPY_DATA;
 630                 dprintk("RPC:      XID %08x request not found!\n",
 631                                 ntohl(xprt->tcp_xid));
 632                 spin_unlock(&xprt->transport_lock);
 633                 return;
 634         }
 635
 636         rcvbuf = &req->rq_private_buf;
 637         len = desc->count;
 638         if (len > xprt->tcp_reclen - xprt->tcp_offset) {
 639                 skb_reader_t my_desc;
 640
 641                 len = xprt->tcp_reclen - xprt->tcp_offset;
 642                 memcpy(&my_desc, desc, sizeof(my_desc));
 643                 my_desc.count = len;
 644                 r = xdr_partial_copy_from_skb(rcvbuf, xprt->tcp_copied,
 645                                           &my_desc, xs_tcp_copy_data);
 646                 desc->count -= r;
 647                 desc->offset += r;
 648         } else
 649                 r = xdr_partial_copy_from_skb(rcvbuf, xprt->tcp_copied,
 650                                           desc, xs_tcp_copy_data);
 651
 652         if (r > 0) {
 653                 xprt->tcp_copied += r;
 654                 xprt->tcp_offset += r;
 655         }
 656         if (r != len) {
 657                 /* Error when copying to the receive buffer,
 658                  * usually because we weren't able to allocate
 659                  * additional buffer pages. All we can do now
 660                  * is turn off XPRT_COPY_DATA, so the request
 661                  * will not receive any additional updates,
 662                  * and time out.
 663                  * Any remaining data from this record will
 664                  * be discarded.
 665                  */
 666                 xprt->tcp_flags &= ~XPRT_COPY_DATA;
 667                 dprintk("RPC:      XID %08x truncated request\n",
 668                                 ntohl(xprt->tcp_xid));
 669                 dprintk("RPC:      xprt = %p, tcp_copied = %lu, tcp_offset = %u, tcp_reclen = %u\n",
 670                                 xprt, xprt->tcp_copied, xprt->tcp_offset, xprt->tcp_reclen);
 671                 goto out;
 672         }
 673
 674         dprintk("RPC:      XID %08x read %Zd bytes\n",
 675                         ntohl(xprt->tcp_xid), r);
 676         dprintk("RPC:      xprt = %p, tcp_copied = %lu, tcp_offset = %u, tcp_reclen = %u\n",
 677                         xprt, xprt->tcp_copied, xprt->tcp_offset, xprt->tcp_reclen);
 678
 679         if (xprt->tcp_copied == req->rq_private_buf.buflen)
 680                 xprt->tcp_flags &= ~XPRT_COPY_DATA;
 681         else if (xprt->tcp_offset == xprt->tcp_reclen) {
 682                 if (xprt->tcp_flags & XPRT_LAST_FRAG)
 683                         xprt->tcp_flags &= ~XPRT_COPY_DATA;
 684         }
 685
 686 out:
 687         if (!(xprt->tcp_flags & XPRT_COPY_DATA))
 688                 xprt_complete_rqst(req->rq_task, xprt->tcp_copied);
 689         spin_unlock(&xprt->transport_lock);
 690         xs_tcp_check_recm(xprt);
 691 }
 692
 693 static inline void xs_tcp_read_discard(struct rpc_xprt *xprt, skb_reader_t *desc)
 694 {
 695         size_t len;
 696
 697         len = xprt->tcp_reclen - xprt->tcp_offset;
 698         if (len > desc->count)
 699                 len = desc->count;
 700         desc->count -= len;
 701         desc->offset += len;
 702         xprt->tcp_offset += len;
 703         dprintk("RPC:      discarded %Zu bytes\n", len);
 704         xs_tcp_check_recm(xprt);
 705 }
 706
 707 static int xs_tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb, unsigned int offset, size_t len)
 708 {
 709         struct rpc_xprt *xprt = rd_desc->arg.data;
 710         skb_reader_t desc = {
 711                 .skb    = skb,
 712                 .offset = offset,
 713                 .count  = len,
 714                 .csum   = 0
 715         };
 716
 717         dprintk("RPC:      xs_tcp_data_recv started\n");
 718         do {
 719                 /* Read in a new fragment marker if necessary */
 720                 /* Can we ever really expect to get completely empty fragments? */
 721                 if (xprt->tcp_flags & XPRT_COPY_RECM) {
 722                         xs_tcp_read_fraghdr(xprt, &desc);
 723                         continue;
 724                 }
 725                 /* Read in the xid if necessary */
 726                 if (xprt->tcp_flags & XPRT_COPY_XID) {
 727                         xs_tcp_read_xid(xprt, &desc);
 728                         continue;
 729                 }
 730                 /* Read in the request data */
 731                 if (xprt->tcp_flags & XPRT_COPY_DATA) {
 732                         xs_tcp_read_request(xprt, &desc);
 733                         continue;
 734                 }
 735                 /* Skip over any trailing bytes on short reads */
 736                 xs_tcp_read_discard(xprt, &desc);
 737         } while (desc.count);
 738         dprintk("RPC:      xs_tcp_data_recv done\n");
 739         return len - desc.count;
 740 }
 741
 742 /**
 743  * xs_tcp_data_ready - "data ready" callback for TCP sockets
 744  * @sk: socket with data to read
 745  * @bytes: how much data to read
 746  *
 747  */
 748 static void xs_tcp_data_ready(struct sock *sk, int bytes)
 749 {
 750         struct rpc_xprt *xprt;
 751         read_descriptor_t rd_desc;
 752
 753         read_lock(&sk->sk_callback_lock);
 754         dprintk("RPC:      xs_tcp_data_ready...\n");
 755         if (!(xprt = xprt_from_sock(sk)))
 756                 goto out;
 757         if (xprt->shutdown)
 758                 goto out;
 759
 760         /* We use rd_desc to pass struct xprt to xs_tcp_data_recv */
 761         rd_desc.arg.data = xprt;
 762         rd_desc.count = 65536;
 763         tcp_read_sock(sk, &rd_desc, xs_tcp_data_recv);
 764 out:
 765         read_unlock(&sk->sk_callback_lock);
 766 }
 767
 768 /**
 769  * xs_tcp_state_change - callback to handle TCP socket state changes
 770  * @sk: socket whose state has changed
 771  *
 772  */
 773 static void xs_tcp_state_change(struct sock *sk)
 774 {
 775         struct rpc_xprt *xprt;
 776
 777         read_lock(&sk->sk_callback_lock);
 778         if (!(xprt = xprt_from_sock(sk)))
 779                 goto out;
 780         dprintk("RPC:      xs_tcp_state_change client %p...\n", xprt);
 781         dprintk("RPC:      state %x conn %d dead %d zapped %d\n",
 782                                 sk->sk_state, xprt_connected(xprt),
 783                                 sock_flag(sk, SOCK_DEAD),
 784                                 sock_flag(sk, SOCK_ZAPPED));
 785
 786         switch (sk->sk_state) {
 787         case TCP_ESTABLISHED:
 788                 spin_lock_bh(&xprt->transport_lock);
 789                 if (!xprt_test_and_set_connected(xprt)) {
 790                         /* Reset TCP record info */
 791                         xprt->tcp_offset = 0;
 792                         xprt->tcp_reclen = 0;
 793                         xprt->tcp_copied = 0;
 794                         xprt->tcp_flags = XPRT_COPY_RECM | XPRT_COPY_XID;
 795                         xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
 796                         xprt_wake_pending_tasks(xprt, 0);
 797                 }
 798                 spin_unlock_bh(&xprt->transport_lock);
 799                 break;
 800         case TCP_SYN_SENT:
 801         case TCP_SYN_RECV:
 802                 break;
 803         default:
 804                 xprt_disconnect(xprt);
 805                 break;
 806         }
 807  out:
 808         read_unlock(&sk->sk_callback_lock);
 809 }
 810
 811 /**
 812  * xs_udp_write_space - callback invoked when socket buffer space
 813  *                             becomes available
 814  * @sk: socket whose state has changed
 815  *
 816  * Called when more output buffer space is available for this socket.
 817  * We try not to wake our writers until they can make "significant"
 818  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
 819  * with a bunch of small requests.
 820  */
 821 static void xs_udp_write_space(struct sock *sk)
 822 {
 823         read_lock(&sk->sk_callback_lock);
 824
 825         /* from net/core/sock.c:sock_def_write_space */
 826         if (sock_writeable(sk)) {
 827                 struct socket *sock;
 828                 struct rpc_xprt *xprt;
 829
 830                 if (unlikely(!(sock = sk->sk_socket)))
 831                         goto out;
 832                 if (unlikely(!(xprt = xprt_from_sock(sk))))
 833                         goto out;
 834                 if (unlikely(!test_and_clear_bit(SOCK_NOSPACE, &sock->flags)))
 835                         goto out;
 836
 837                 xprt_write_space(xprt);
 838         }
 839
 840  out:
 841         read_unlock(&sk->sk_callback_lock);
 842 }
 843
 844 /**
 845  * xs_tcp_write_space - callback invoked when socket buffer space
 846  *                             becomes available
 847  * @sk: socket whose state has changed
 848  *
 849  * Called when more output buffer space is available for this socket.
 850  * We try not to wake our writers until they can make "significant"
 851  * progress, otherwise we'll waste resources thrashing kernel_sendmsg
 852  * with a bunch of small requests.
 853  */
 854 static void xs_tcp_write_space(struct sock *sk)
 855 {
 856         read_lock(&sk->sk_callback_lock);
 857
 858         /* from net/core/stream.c:sk_stream_write_space */
 859         if (sk_stream_wspace(sk) >= sk_stream_min_wspace(sk)) {
 860                 struct socket *sock;
 861                 struct rpc_xprt *xprt;
 862
 863                 if (unlikely(!(sock = sk->sk_socket)))
 864                         goto out;
 865                 if (unlikely(!(xprt = xprt_from_sock(sk))))
 866                         goto out;
 867                 if (unlikely(!test_and_clear_bit(SOCK_NOSPACE, &sock->flags)))
 868                         goto out;
 869
 870                 xprt_write_space(xprt);
 871         }
 872
 873  out:
 874         read_unlock(&sk->sk_callback_lock);
 875 }
 876
 877 static void xs_udp_do_set_buffer_size(struct rpc_xprt *xprt)
 878 {
 879         struct sock *sk = xprt->inet;
 880
 881         if (xprt->rcvsize) {
 882                 sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
 883                 sk->sk_rcvbuf = xprt->rcvsize * xprt->max_reqs *  2;
 884         }
 885         if (xprt->sndsize) {
 886                 sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
 887                 sk->sk_sndbuf = xprt->sndsize * xprt->max_reqs * 2;
 888                 sk->sk_write_space(sk);
 889         }
 890 }
 891
 892 /**
 893  * xs_udp_set_buffer_size - set send and receive limits
 894  * @xprt: generic transport
 895  * @sndsize: requested size of send buffer, in bytes
 896  * @rcvsize: requested size of receive buffer, in bytes
 897  *
 898  * Set socket send and receive buffer size limits.
 899  */
 900 static void xs_udp_set_buffer_size(struct rpc_xprt *xprt, size_t sndsize, size_t rcvsize)
 901 {
 902         xprt->sndsize = 0;
 903         if (sndsize)
 904                 xprt->sndsize = sndsize + 1024;
 905         xprt->rcvsize = 0;
 906         if (rcvsize)
 907                 xprt->rcvsize = rcvsize + 1024;
 908
 909         xs_udp_do_set_buffer_size(xprt);
 910 }
 911
 912 /**
 913  * xs_udp_timer - called when a retransmit timeout occurs on a UDP transport
 914  * @task: task that timed out
 915  *
 916  * Adjust the congestion window after a retransmit timeout has occurred.
 917  */
 918 static void xs_udp_timer(struct rpc_task *task)
 919 {
 920         xprt_adjust_cwnd(task, -ETIMEDOUT);
 921 }
 922
 923 static int xs_bindresvport(struct rpc_xprt *xprt, struct socket *sock)
 924 {
 925         struct sockaddr_in myaddr = {
 926                 .sin_family = AF_INET,
 927         };
 928         int err;
 929         unsigned short port = xprt->port;
 930
 931         do {
 932                 myaddr.sin_port = htons(port);
 933                 err = sock->ops->bind(sock, (struct sockaddr *) &myaddr,
 934                                                 sizeof(myaddr));
 935                 if (err == 0) {
 936                         xprt->port = port;
 937                         dprintk("RPC:      xs_bindresvport bound to port %u\n",
 938                                         port);
 939                         return 0;
 940                 }
 941                 if (port <= xprt_min_resvport)
 942                         port = xprt_max_resvport;
 943                 else
 944                         port--;
 945         } while (err == -EADDRINUSE && port != xprt->port);
 946
 947         dprintk("RPC:      can't bind to reserved port (%d).\n", -err);
 948         return err;
 949 }
 950
 951 /**
 952  * xs_udp_connect_worker - set up a UDP socket
 953  * @args: RPC transport to connect
 954  *
 955  * Invoked by a work queue tasklet.
 956  */
 957 static void xs_udp_connect_worker(void *args)
 958 {
 959         struct rpc_xprt *xprt = (struct rpc_xprt *) args;
 960         struct socket *sock = xprt->sock;
 961         int err, status = -EIO;
 962
 963         if (xprt->shutdown || xprt->addr.sin_port == 0)
 964                 goto out;
 965
 966         dprintk("RPC:      xs_udp_connect_worker for xprt %p\n", xprt);
 967
 968         /* Start by resetting any existing state */
 969         xs_close(xprt);
 970
 971         if ((err = sock_create_kern(PF_INET, SOCK_DGRAM, IPPROTO_UDP, &sock)) < 0) {
 972                 dprintk("RPC:      can't create UDP transport socket (%d).\n", -err);
 973                 goto out;
 974         }
 975
 976         if (xprt->resvport && xs_bindresvport(xprt, sock) < 0) {
 977                 sock_release(sock);
 978                 goto out;
 979         }
 980
 981         if (!xprt->inet) {
 982                 struct sock *sk = sock->sk;
 983
 984                 write_lock_bh(&sk->sk_callback_lock);
 985
 986                 sk->sk_user_data = xprt;
 987                 xprt->old_data_ready = sk->sk_data_ready;
 988                 xprt->old_state_change = sk->sk_state_change;
 989                 xprt->old_write_space = sk->sk_write_space;
 990                 sk->sk_data_ready = xs_udp_data_ready;
 991                 sk->sk_write_space = xs_udp_write_space;
 992                 sk->sk_no_check = UDP_CSUM_NORCV;
 993
 994                 xprt_set_connected(xprt);
 995
 996                 /* Reset to new socket */
 997                 xprt->sock = sock;
 998                 xprt->inet = sk;
 999
1000                 write_unlock_bh(&sk->sk_callback_lock);
1001         }
1002         xs_udp_do_set_buffer_size(xprt);
1003         status = 0;
1004 out:
1005         xprt_wake_pending_tasks(xprt, status);
1006         xprt_clear_connecting(xprt);
1007 }
1008
1009 /*
1010  * We need to preserve the port number so the reply cache on the server can
1011  * find our cached RPC replies when we get around to reconnecting.
1012  */
1013 static void xs_tcp_reuse_connection(struct rpc_xprt *xprt)
1014 {
1015         int result;
1016         struct socket *sock = xprt->sock;
1017         struct sockaddr any;
1018
1019         dprintk("RPC:      disconnecting xprt %p to reuse port\n", xprt);
1020
1021         /*
1022          * Disconnect the transport socket by doing a connect operation
1023          * with AF_UNSPEC.  This should return immediately...
1024          */
1025         memset(&any, 0, sizeof(any));
1026         any.sa_family = AF_UNSPEC;
1027         result = sock->ops->connect(sock, &any, sizeof(any), 0);
1028         if (result)
1029                 dprintk("RPC:      AF_UNSPEC connect return code %d\n",
1030                                 result);
1031 }
1032
1033 /**
1034  * xs_tcp_connect_worker - connect a TCP socket to a remote endpoint
1035  * @args: RPC transport to connect
1036  *
1037  * Invoked by a work queue tasklet.
1038  */
1039 static void xs_tcp_connect_worker(void *args)
1040 {
1041         struct rpc_xprt *xprt = (struct rpc_xprt *)args;
1042         struct socket *sock = xprt->sock;
1043         int err, status = -EIO;
1044
1045         if (xprt->shutdown || xprt->addr.sin_port == 0)
1046                 goto out;
1047
1048         dprintk("RPC:      xs_tcp_connect_worker for xprt %p\n", xprt);
1049
1050         if (!xprt->sock) {
1051                 /* start from scratch */
1052                 if ((err = sock_create_kern(PF_INET, SOCK_STREAM, IPPROTO_TCP, &sock)) < 0) {
1053                         dprintk("RPC:      can't create TCP transport socket (%d).\n", -err);
1054                         goto out;
1055                 }
1056
1057                 if (xprt->resvport && xs_bindresvport(xprt, sock) < 0) {
1058                         sock_release(sock);
1059                         goto out;
1060                 }
1061         } else
1062                 /* "close" the socket, preserving the local port */
1063                 xs_tcp_reuse_connection(xprt);
1064
1065         if (!xprt->inet) {
1066                 struct sock *sk = sock->sk;
1067
1068                 write_lock_bh(&sk->sk_callback_lock);
1069
1070                 sk->sk_user_data = xprt;
1071                 xprt->old_data_ready = sk->sk_data_ready;
1072                 xprt->old_state_change = sk->sk_state_change;
1073                 xprt->old_write_space = sk->sk_write_space;
1074                 sk->sk_data_ready = xs_tcp_data_ready;
1075                 sk->sk_state_change = xs_tcp_state_change;
1076                 sk->sk_write_space = xs_tcp_write_space;
1077
1078                 /* socket options */
1079                 sk->sk_userlocks |= SOCK_BINDPORT_LOCK;
1080                 sock_reset_flag(sk, SOCK_LINGER);
1081                 tcp_sk(sk)->linger2 = 0;
1082                 tcp_sk(sk)->nonagle |= TCP_NAGLE_OFF;
1083
1084                 xprt_clear_connected(xprt);
1085
1086                 /* Reset to new socket */
1087                 xprt->sock = sock;
1088                 xprt->inet = sk;
1089
1090                 write_unlock_bh(&sk->sk_callback_lock);
1091         }
1092
1093         /* Tell the socket layer to start connecting... */
1094         status = sock->ops->connect(sock, (struct sockaddr *) &xprt->addr,
1095                         sizeof(xprt->addr), O_NONBLOCK);
1096         dprintk("RPC: %p  connect status %d connected %d sock state %d\n",
1097                         xprt, -status, xprt_connected(xprt), sock->sk->sk_state);
1098         if (status < 0) {
1099                 switch (status) {
1100                         case -EINPROGRESS:
1101                         case -EALREADY:
1102                                 goto out_clear;
1103                         case -ECONNREFUSED:
1104                         case -ECONNRESET:
1105                                 /* retry with existing socket, after a delay */
1106                                 break;
1107                         default:
1108                                 /* get rid of existing socket, and retry */
1109                                 xs_close(xprt);
1110                                 break;
1111                 }
1112         }
1113 out:
1114         xprt_wake_pending_tasks(xprt, status);
1115 out_clear:
1116         xprt_clear_connecting(xprt);
1117 }
1118
1119 /**
1120  * xs_connect - connect a socket to a remote endpoint
1121  * @task: address of RPC task that manages state of connect request
1122  *
1123  * TCP: If the remote end dropped the connection, delay reconnecting.
1124  *
1125  * UDP socket connects are synchronous, but we use a work queue anyway
1126  * to guarantee that even unprivileged user processes can set up a
1127  * socket on a privileged port.
1128  *
1129  * If a UDP socket connect fails, the delay behavior here prevents
1130  * retry floods (hard mounts).
1131  */
1132 static void xs_connect(struct rpc_task *task)
1133 {
1134         struct rpc_xprt *xprt = task->tk_xprt;
1135
1136         if (xprt_test_and_set_connecting(xprt))
1137                 return;
1138
1139         if (xprt->sock != NULL) {
1140                 dprintk("RPC:      xs_connect delayed xprt %p for %lu seconds\n",
1141                                 xprt, xprt->reestablish_timeout / HZ);
1142                 schedule_delayed_work(&xprt->connect_worker,
1143                                         xprt->reestablish_timeout);
1144                 xprt->reestablish_timeout <<= 1;
1145                 if (xprt->reestablish_timeout > XS_TCP_MAX_REEST_TO)
1146                         xprt->reestablish_timeout = XS_TCP_MAX_REEST_TO;
1147         } else {
1148                 dprintk("RPC:      xs_connect scheduled xprt %p\n", xprt);
1149                 schedule_work(&xprt->connect_worker);
1150
1151                 /* flush_scheduled_work can sleep... */
1152                 if (!RPC_IS_ASYNC(task))
1153                         flush_scheduled_work();
1154         }
1155 }
1156
1157 static struct rpc_xprt_ops xs_udp_ops = {
1158         .set_buffer_size        = xs_udp_set_buffer_size,
1159         .reserve_xprt           = xprt_reserve_xprt_cong,
1160         .release_xprt           = xprt_release_xprt_cong,
1161         .connect                = xs_connect,
1162         .send_request           = xs_udp_send_request,
1163         .set_retrans_timeout    = xprt_set_retrans_timeout_rtt,
1164         .timer                  = xs_udp_timer,
1165         .release_request        = xprt_release_rqst_cong,
1166         .close                  = xs_close,
1167         .destroy                = xs_destroy,
1168 };
1169
1170 static struct rpc_xprt_ops xs_tcp_ops = {
1171         .reserve_xprt           = xprt_reserve_xprt,
1172         .release_xprt           = xprt_release_xprt,
1173         .connect                = xs_connect,
1174         .send_request           = xs_tcp_send_request,
1175         .set_retrans_timeout    = xprt_set_retrans_timeout_def,
1176         .close                  = xs_close,
1177         .destroy                = xs_destroy,
1178 };
1179
1180 /**
1181  * xs_setup_udp - Set up transport to use a UDP socket
1182  * @xprt: transport to set up
1183  * @to:   timeout parameters
1184  *
1185  */
1186 int xs_setup_udp(struct rpc_xprt *xprt, struct rpc_timeout *to)
1187 {
1188         size_t slot_table_size;
1189
1190         dprintk("RPC:      setting up udp-ipv4 transport...\n");
1191
1192         xprt->max_reqs = xprt_udp_slot_table_entries;
1193         slot_table_size = xprt->max_reqs * sizeof(xprt->slot[0]);
1194         xprt->slot = kmalloc(slot_table_size, GFP_KERNEL);
1195         if (xprt->slot == NULL)
1196                 return -ENOMEM;
1197         memset(xprt->slot, 0, slot_table_size);
1198
1199         xprt->prot = IPPROTO_UDP;
1200         xprt->port = xprt_max_resvport;
1201         xprt->tsh_size = 0;
1202         xprt->resvport = capable(CAP_NET_BIND_SERVICE) ? 1 : 0;
1203         /* XXX: header size can vary due to auth type, IPv6, etc. */
1204         xprt->max_payload = (1U << 16) - (MAX_HEADER << 3);
1205
1206         INIT_WORK(&xprt->connect_worker, xs_udp_connect_worker, xprt);
1207         xprt->bind_timeout = XS_BIND_TO;
1208         xprt->connect_timeout = XS_UDP_CONN_TO;
1209         xprt->reestablish_timeout = XS_UDP_REEST_TO;
1210         xprt->idle_timeout = XS_IDLE_DISC_TO;
1211
1212         xprt->ops = &xs_udp_ops;
1213
1214         if (to)
1215                 xprt->timeout = *to;
1216         else
1217                 xprt_set_timeout(&xprt->timeout, 5, 5 * HZ);
1218
1219         return 0;
1220 }
1221
1222 /**
1223  * xs_setup_tcp - Set up transport to use a TCP socket
1224  * @xprt: transport to set up
1225  * @to: timeout parameters
1226  *
1227  */
1228 int xs_setup_tcp(struct rpc_xprt *xprt, struct rpc_timeout *to)
1229 {
1230         size_t slot_table_size;
1231
1232         dprintk("RPC:      setting up tcp-ipv4 transport...\n");
1233
1234         xprt->max_reqs = xprt_tcp_slot_table_entries;
1235         slot_table_size = xprt->max_reqs * sizeof(xprt->slot[0]);
1236         xprt->slot = kmalloc(slot_table_size, GFP_KERNEL);
1237         if (xprt->slot == NULL)
1238                 return -ENOMEM;
1239         memset(xprt->slot, 0, slot_table_size);
1240
1241         xprt->prot = IPPROTO_TCP;
1242         xprt->port = xprt_max_resvport;
1243         xprt->tsh_size = sizeof(rpc_fraghdr) / sizeof(u32);
1244         xprt->resvport = capable(CAP_NET_BIND_SERVICE) ? 1 : 0;
1245         xprt->max_payload = RPC_MAX_FRAGMENT_SIZE;
1246
1247         INIT_WORK(&xprt->connect_worker, xs_tcp_connect_worker, xprt);
1248         xprt->bind_timeout = XS_BIND_TO;
1249         xprt->connect_timeout = XS_TCP_CONN_TO;
1250         xprt->reestablish_timeout = XS_TCP_INIT_REEST_TO;
1251         xprt->idle_timeout = XS_IDLE_DISC_TO;
1252
1253         xprt->ops = &xs_tcp_ops;
1254
1255         if (to)
1256                 xprt->timeout = *to;
1257         else
1258                 xprt_set_timeout(&xprt->timeout, 2, 60 * HZ);
1259
1260         return 0;
1261 }