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   1 /*
   2  *  linux/net/sunrpc/xprt.c
   3  *
   4  *  This is a generic RPC call interface supporting congestion avoidance,
   5  *  and asynchronous calls.
   6  *
   7  *  The interface works like this:
   8  *
   9  *  -   When a process places a call, it allocates a request slot if
  10  *      one is available. Otherwise, it sleeps on the backlog queue
  11  *      (xprt_reserve).
  12  *  -   Next, the caller puts together the RPC message, stuffs it into
  13  *      the request struct, and calls xprt_call().
  14  *  -   xprt_call transmits the message and installs the caller on the
  15  *      socket's wait list. At the same time, it installs a timer that
  16  *      is run after the packet's timeout has expired.
  17  *  -   When a packet arrives, the data_ready handler walks the list of
  18  *      pending requests for that socket. If a matching XID is found, the
  19  *      caller is woken up, and the timer removed.
  20  *  -   When no reply arrives within the timeout interval, the timer is
  21  *      fired by the kernel and runs xprt_timer(). It either adjusts the
  22  *      timeout values (minor timeout) or wakes up the caller with a status
  23  *      of -ETIMEDOUT.
  24  *  -   When the caller receives a notification from RPC that a reply arrived,
  25  *      it should release the RPC slot, and process the reply.
  26  *      If the call timed out, it may choose to retry the operation by
  27  *      adjusting the initial timeout value, and simply calling rpc_call
  28  *      again.
  29  *
  30  *  Support for async RPC is done through a set of RPC-specific scheduling
  31  *  primitives that `transparently' work for processes as well as async
  32  *  tasks that rely on callbacks.
  33  *
  34  *  Copyright (C) 1995-1997, Olaf Kirch <okir@monad.swb.de>
  35  *
  36  *  TCP callback races fixes (C) 1998 Red Hat Software <alan@redhat.com>
  37  *  TCP send fixes (C) 1998 Red Hat Software <alan@redhat.com>
  38  *  TCP NFS related read + write fixes
  39  *   (C) 1999 Dave Airlie, University of Limerick, Ireland <airlied@linux.ie>
  40  *
  41  *  Rewrite of larges part of the code in order to stabilize TCP stuff.
  42  *  Fix behaviour when socket buffer is full.
  43  *   (C) 1999 Trond Myklebust <trond.myklebust@fys.uio.no>
  44  */
  45
  46 #include <linux/types.h>
  47 #include <linux/slab.h>
  48 #include <linux/capability.h>
  49 #include <linux/sched.h>
  50 #include <linux/errno.h>
  51 #include <linux/socket.h>
  52 #include <linux/in.h>
  53 #include <linux/net.h>
  54 #include <linux/mm.h>
  55 #include <linux/udp.h>
  56 #include <linux/tcp.h>
  57 #include <linux/sunrpc/clnt.h>
  58 #include <linux/file.h>
  59 #include <linux/workqueue.h>
  60 #include <linux/random.h>
  61
  62 #include <net/sock.h>
  63 #include <net/checksum.h>
  64 #include <net/udp.h>
  65 #include <net/tcp.h>
  66
  67 /*
  68  * Local variables
  69  */
  70
  71 #ifdef RPC_DEBUG
  72 # undef  RPC_DEBUG_DATA
  73 # define RPCDBG_FACILITY        RPCDBG_XPRT
  74 #endif
  75
  76 #define XPRT_MAX_BACKOFF        (8)
  77 #define XPRT_IDLE_TIMEOUT       (5*60*HZ)
  78 #define XPRT_MAX_RESVPORT       (800)
  79
  80 /*
  81  * Local functions
  82  */
  83 static void     xprt_request_init(struct rpc_task *, struct rpc_xprt *);
  84 static inline void      do_xprt_reserve(struct rpc_task *);
  85 static void     xprt_disconnect(struct rpc_xprt *);
  86 static void     xprt_connect_status(struct rpc_task *task);
  87 static struct rpc_xprt * xprt_setup(int proto, struct sockaddr_in *ap,
  88                                                 struct rpc_timeout *to);
  89 static struct socket *xprt_create_socket(struct rpc_xprt *, int, int);
  90 static void     xprt_bind_socket(struct rpc_xprt *, struct socket *);
  91 static int      __xprt_get_cong(struct rpc_xprt *, struct rpc_task *);
  92
  93 static int      xprt_clear_backlog(struct rpc_xprt *xprt);
  94
  95 #ifdef RPC_DEBUG_DATA
  96 /*
  97  * Print the buffer contents (first 128 bytes only--just enough for
  98  * diropres return).
  99  */
 100 static void
 101 xprt_pktdump(char *msg, u32 *packet, unsigned int count)
 102 {
 103         u8      *buf = (u8 *) packet;
 104         int     j;
 105
 106         dprintk("RPC:      %s\n", msg);
 107         for (j = 0; j < count && j < 128; j += 4) {
 108                 if (!(j & 31)) {
 109                         if (j)
 110                                 dprintk("\n");
 111                         dprintk("0x%04x ", j);
 112                 }
 113                 dprintk("%02x%02x%02x%02x ",
 114                         buf[j], buf[j+1], buf[j+2], buf[j+3]);
 115         }
 116         dprintk("\n");
 117 }
 118 #else
 119 static inline void
 120 xprt_pktdump(char *msg, u32 *packet, unsigned int count)
 121 {
 122         /* NOP */
 123 }
 124 #endif
 125
 126 /*
 127  * Look up RPC transport given an INET socket
 128  */
 129 static inline struct rpc_xprt *
 130 xprt_from_sock(struct sock *sk)
 131 {
 132         return (struct rpc_xprt *) sk->sk_user_data;
 133 }
 134
 135 /*
 136  * Serialize write access to sockets, in order to prevent different
 137  * requests from interfering with each other.
 138  * Also prevents TCP socket connects from colliding with writes.
 139  */
 140 static int
 141 __xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task)
 142 {
 143         struct rpc_rqst *req = task->tk_rqstp;
 144
 145         if (test_and_set_bit(XPRT_LOCKED, &xprt->sockstate)) {
 146                 if (task == xprt->snd_task)
 147                         return 1;
 148                 if (task == NULL)
 149                         return 0;
 150                 goto out_sleep;
 151         }
 152         if (xprt->nocong || __xprt_get_cong(xprt, task)) {
 153                 xprt->snd_task = task;
 154                 if (req) {
 155                         req->rq_bytes_sent = 0;
 156                         req->rq_ntrans++;
 157                 }
 158                 return 1;
 159         }
 160         smp_mb__before_clear_bit();
 161         clear_bit(XPRT_LOCKED, &xprt->sockstate);
 162         smp_mb__after_clear_bit();
 163 out_sleep:
 164         dprintk("RPC: %4d failed to lock socket %p\n", task->tk_pid, xprt);
 165         task->tk_timeout = 0;
 166         task->tk_status = -EAGAIN;
 167         if (req && req->rq_ntrans)
 168                 rpc_sleep_on(&xprt->resend, task, NULL, NULL);
 169         else
 170                 rpc_sleep_on(&xprt->sending, task, NULL, NULL);
 171         return 0;
 172 }
 173
 174 static inline int
 175 xprt_lock_write(struct rpc_xprt *xprt, struct rpc_task *task)
 176 {
 177         int retval;
 178
 179         spin_lock_bh(&xprt->sock_lock);
 180         retval = __xprt_lock_write(xprt, task);
 181         spin_unlock_bh(&xprt->sock_lock);
 182         return retval;
 183 }
 184
 185
 186 static void
 187 __xprt_lock_write_next(struct rpc_xprt *xprt)
 188 {
 189         struct rpc_task *task;
 190
 191         if (test_and_set_bit(XPRT_LOCKED, &xprt->sockstate))
 192                 return;
 193         if (!xprt->nocong && RPCXPRT_CONGESTED(xprt))
 194                 goto out_unlock;
 195         task = rpc_wake_up_next(&xprt->resend);
 196         if (!task) {
 197                 task = rpc_wake_up_next(&xprt->sending);
 198                 if (!task)
 199                         goto out_unlock;
 200         }
 201         if (xprt->nocong || __xprt_get_cong(xprt, task)) {
 202                 struct rpc_rqst *req = task->tk_rqstp;
 203                 xprt->snd_task = task;
 204                 if (req) {
 205                         req->rq_bytes_sent = 0;
 206                         req->rq_ntrans++;
 207                 }
 208                 return;
 209         }
 210 out_unlock:
 211         smp_mb__before_clear_bit();
 212         clear_bit(XPRT_LOCKED, &xprt->sockstate);
 213         smp_mb__after_clear_bit();
 214 }
 215
 216 /*
 217  * Releases the socket for use by other requests.
 218  */
 219 static void
 220 __xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task)
 221 {
 222         if (xprt->snd_task == task) {
 223                 xprt->snd_task = NULL;
 224                 smp_mb__before_clear_bit();
 225                 clear_bit(XPRT_LOCKED, &xprt->sockstate);
 226                 smp_mb__after_clear_bit();
 227                 __xprt_lock_write_next(xprt);
 228         }
 229 }
 230
 231 static inline void
 232 xprt_release_write(struct rpc_xprt *xprt, struct rpc_task *task)
 233 {
 234         spin_lock_bh(&xprt->sock_lock);
 235         __xprt_release_write(xprt, task);
 236         spin_unlock_bh(&xprt->sock_lock);
 237 }
 238
 239 /*
 240  * Write data to socket.
 241  */
 242 static inline int
 243 xprt_sendmsg(struct rpc_xprt *xprt, struct rpc_rqst *req)
 244 {
 245         struct socket   *sock = xprt->sock;
 246         struct xdr_buf  *xdr = &req->rq_snd_buf;
 247         struct sockaddr *addr = NULL;
 248         int addrlen = 0;
 249         unsigned int    skip;
 250         int             result;
 251
 252         if (!sock)
 253                 return -ENOTCONN;
 254
 255         xprt_pktdump("packet data:",
 256                                 req->rq_svec->iov_base,
 257                                 req->rq_svec->iov_len);
 258
 259         /* For UDP, we need to provide an address */
 260         if (!xprt->stream) {
 261                 addr = (struct sockaddr *) &xprt->addr;
 262                 addrlen = sizeof(xprt->addr);
 263         }
 264         /* Dont repeat bytes */
 265         skip = req->rq_bytes_sent;
 266
 267         clear_bit(SOCK_ASYNC_NOSPACE, &sock->flags);
 268         result = xdr_sendpages(sock, addr, addrlen, xdr, skip, MSG_DONTWAIT);
 269
 270         dprintk("RPC:      xprt_sendmsg(%d) = %d\n", xdr->len - skip, result);
 271
 272         if (result >= 0)
 273                 return result;
 274
 275         switch (result) {
 276         case -ECONNREFUSED:
 277                 /* When the server has died, an ICMP port unreachable message
 278                  * prompts ECONNREFUSED.
 279                  */
 280         case -EAGAIN:
 281                 break;
 282         case -ECONNRESET:
 283         case -ENOTCONN:
 284         case -EPIPE:
 285                 /* connection broken */
 286                 if (xprt->stream)
 287                         result = -ENOTCONN;
 288                 break;
 289         default:
 290                 printk(KERN_NOTICE "RPC: sendmsg returned error %d\n", -result);
 291         }
 292         return result;
 293 }
 294
 295 /*
 296  * Van Jacobson congestion avoidance. Check if the congestion window
 297  * overflowed. Put the task to sleep if this is the case.
 298  */
 299 static int
 300 __xprt_get_cong(struct rpc_xprt *xprt, struct rpc_task *task)
 301 {
 302         struct rpc_rqst *req = task->tk_rqstp;
 303
 304         if (req->rq_cong)
 305                 return 1;
 306         dprintk("RPC: %4d xprt_cwnd_limited cong = %ld cwnd = %ld\n",
 307                         task->tk_pid, xprt->cong, xprt->cwnd);
 308         if (RPCXPRT_CONGESTED(xprt))
 309                 return 0;
 310         req->rq_cong = 1;
 311         xprt->cong += RPC_CWNDSCALE;
 312         return 1;
 313 }
 314
 315 /*
 316  * Adjust the congestion window, and wake up the next task
 317  * that has been sleeping due to congestion
 318  */
 319 static void
 320 __xprt_put_cong(struct rpc_xprt *xprt, struct rpc_rqst *req)
 321 {
 322         if (!req->rq_cong)
 323                 return;
 324         req->rq_cong = 0;
 325         xprt->cong -= RPC_CWNDSCALE;
 326         __xprt_lock_write_next(xprt);
 327 }
 328
 329 /*
 330  * Adjust RPC congestion window
 331  * We use a time-smoothed congestion estimator to avoid heavy oscillation.
 332  */
 333 static void
 334 xprt_adjust_cwnd(struct rpc_xprt *xprt, int result)
 335 {
 336         unsigned long   cwnd;
 337
 338         cwnd = xprt->cwnd;
 339         if (result >= 0 && cwnd <= xprt->cong) {
 340                 /* The (cwnd >> 1) term makes sure
 341                  * the result gets rounded properly. */
 342                 cwnd += (RPC_CWNDSCALE * RPC_CWNDSCALE + (cwnd >> 1)) / cwnd;
 343                 if (cwnd > RPC_MAXCWND(xprt))
 344                         cwnd = RPC_MAXCWND(xprt);
 345                 __xprt_lock_write_next(xprt);
 346         } else if (result == -ETIMEDOUT) {
 347                 cwnd >>= 1;
 348                 if (cwnd < RPC_CWNDSCALE)
 349                         cwnd = RPC_CWNDSCALE;
 350         }
 351         dprintk("RPC:      cong %ld, cwnd was %ld, now %ld\n",
 352                         xprt->cong, xprt->cwnd, cwnd);
 353         xprt->cwnd = cwnd;
 354 }
 355
 356 /*
 357  * Reset the major timeout value
 358  */
 359 static void xprt_reset_majortimeo(struct rpc_rqst *req)
 360 {
 361         struct rpc_timeout *to = &req->rq_xprt->timeout;
 362
 363         req->rq_majortimeo = req->rq_timeout;
 364         if (to->to_exponential)
 365                 req->rq_majortimeo <<= to->to_retries;
 366         else
 367                 req->rq_majortimeo += to->to_increment * to->to_retries;
 368         if (req->rq_majortimeo > to->to_maxval || req->rq_majortimeo == 0)
 369                 req->rq_majortimeo = to->to_maxval;
 370         req->rq_majortimeo += jiffies;
 371 }
 372
 373 /*
 374  * Adjust timeout values etc for next retransmit
 375  */
 376 int xprt_adjust_timeout(struct rpc_rqst *req)
 377 {
 378         struct rpc_xprt *xprt = req->rq_xprt;
 379         struct rpc_timeout *to = &xprt->timeout;
 380         int status = 0;
 381
 382         if (time_before(jiffies, req->rq_majortimeo)) {
 383                 if (to->to_exponential)
 384                         req->rq_timeout <<= 1;
 385                 else
 386                         req->rq_timeout += to->to_increment;
 387                 if (to->to_maxval && req->rq_timeout >= to->to_maxval)
 388                         req->rq_timeout = to->to_maxval;
 389                 req->rq_retries++;
 390                 pprintk("RPC: %lu retrans\n", jiffies);
 391         } else {
 392                 req->rq_timeout = to->to_initval;
 393                 req->rq_retries = 0;
 394                 xprt_reset_majortimeo(req);
 395                 /* Reset the RTT counters == "slow start" */
 396                 spin_lock_bh(&xprt->sock_lock);
 397                 rpc_init_rtt(req->rq_task->tk_client->cl_rtt, to->to_initval);
 398                 spin_unlock_bh(&xprt->sock_lock);
 399                 pprintk("RPC: %lu timeout\n", jiffies);
 400                 status = -ETIMEDOUT;
 401         }
 402
 403         if (req->rq_timeout == 0) {
 404                 printk(KERN_WARNING "xprt_adjust_timeout: rq_timeout = 0!\n");
 405                 req->rq_timeout = 5 * HZ;
 406         }
 407         return status;
 408 }
 409
 410 /*
 411  * Close down a transport socket
 412  */
 413 static void
 414 xprt_close(struct rpc_xprt *xprt)
 415 {
 416         struct socket   *sock = xprt->sock;
 417         struct sock     *sk = xprt->inet;
 418
 419         if (!sk)
 420                 return;
 421
 422         write_lock_bh(&sk->sk_callback_lock);
 423         xprt->inet = NULL;
 424         xprt->sock = NULL;
 425
 426         sk->sk_user_data    = NULL;
 427         sk->sk_data_ready   = xprt->old_data_ready;
 428         sk->sk_state_change = xprt->old_state_change;
 429         sk->sk_write_space  = xprt->old_write_space;
 430         write_unlock_bh(&sk->sk_callback_lock);
 431
 432         sk->sk_no_check  = 0;
 433
 434         sock_release(sock);
 435 }
 436
 437 static void
 438 xprt_socket_autoclose(void *args)
 439 {
 440         struct rpc_xprt *xprt = (struct rpc_xprt *)args;
 441
 442         xprt_disconnect(xprt);
 443         xprt_close(xprt);
 444         xprt_release_write(xprt, NULL);
 445 }
 446
 447 /*
 448  * Mark a transport as disconnected
 449  */
 450 static void
 451 xprt_disconnect(struct rpc_xprt *xprt)
 452 {
 453         dprintk("RPC:      disconnected transport %p\n", xprt);
 454         spin_lock_bh(&xprt->sock_lock);
 455         xprt_clear_connected(xprt);
 456         rpc_wake_up_status(&xprt->pending, -ENOTCONN);
 457         spin_unlock_bh(&xprt->sock_lock);
 458 }
 459
 460 /*
 461  * Used to allow disconnection when we've been idle
 462  */
 463 static void
 464 xprt_init_autodisconnect(unsigned long data)
 465 {
 466         struct rpc_xprt *xprt = (struct rpc_xprt *)data;
 467
 468         spin_lock(&xprt->sock_lock);
 469         if (!list_empty(&xprt->recv) || xprt->shutdown)
 470                 goto out_abort;
 471         if (test_and_set_bit(XPRT_LOCKED, &xprt->sockstate))
 472                 goto out_abort;
 473         spin_unlock(&xprt->sock_lock);
 474         /* Let keventd close the socket */
 475         if (test_bit(XPRT_CONNECTING, &xprt->sockstate) != 0)
 476                 xprt_release_write(xprt, NULL);
 477         else
 478                 schedule_work(&xprt->task_cleanup);
 479         return;
 480 out_abort:
 481         spin_unlock(&xprt->sock_lock);
 482 }
 483
 484 static void xprt_socket_connect(void *args)
 485 {
 486         struct rpc_xprt *xprt = (struct rpc_xprt *)args;
 487         struct socket *sock = xprt->sock;
 488         int status = -EIO;
 489
 490         if (xprt->shutdown || xprt->addr.sin_port == 0)
 491                 goto out;
 492
 493         /*
 494          * Start by resetting any existing state
 495          */
 496         xprt_close(xprt);
 497         sock = xprt_create_socket(xprt, xprt->prot, xprt->resvport);
 498         if (sock == NULL) {
 499                 /* couldn't create socket or bind to reserved port;
 500                  * this is likely a permanent error, so cause an abort */
 501                 goto out;
 502         }
 503         xprt_bind_socket(xprt, sock);
 504         xprt_sock_setbufsize(xprt);
 505
 506         status = 0;
 507         if (!xprt->stream)
 508                 goto out;
 509
 510         /*
 511          * Tell the socket layer to start connecting...
 512          */
 513         status = sock->ops->connect(sock, (struct sockaddr *) &xprt->addr,
 514                         sizeof(xprt->addr), O_NONBLOCK);
 515         dprintk("RPC: %p  connect status %d connected %d sock state %d\n",
 516                         xprt, -status, xprt_connected(xprt), sock->sk->sk_state);
 517         if (status < 0) {
 518                 switch (status) {
 519                         case -EINPROGRESS:
 520                         case -EALREADY:
 521                                 goto out_clear;
 522                 }
 523         }
 524 out:
 525         if (status < 0)
 526                 rpc_wake_up_status(&xprt->pending, status);
 527         else
 528                 rpc_wake_up(&xprt->pending);
 529 out_clear:
 530         smp_mb__before_clear_bit();
 531         clear_bit(XPRT_CONNECTING, &xprt->sockstate);
 532         smp_mb__after_clear_bit();
 533 }
 534
 535 /*
 536  * Attempt to connect a TCP socket.
 537  *
 538  */
 539 void xprt_connect(struct rpc_task *task)
 540 {
 541         struct rpc_xprt *xprt = task->tk_xprt;
 542
 543         dprintk("RPC: %4d xprt_connect xprt %p %s connected\n", task->tk_pid,
 544                         xprt, (xprt_connected(xprt) ? "is" : "is not"));
 545
 546         if (xprt->shutdown) {
 547                 task->tk_status = -EIO;
 548                 return;
 549         }
 550         if (!xprt->addr.sin_port) {
 551                 task->tk_status = -EIO;
 552                 return;
 553         }
 554         if (!xprt_lock_write(xprt, task))
 555                 return;
 556         if (xprt_connected(xprt))
 557                 goto out_write;
 558
 559         if (task->tk_rqstp)
 560                 task->tk_rqstp->rq_bytes_sent = 0;
 561
 562         task->tk_timeout = RPC_CONNECT_TIMEOUT;
 563         rpc_sleep_on(&xprt->pending, task, xprt_connect_status, NULL);
 564         if (!test_and_set_bit(XPRT_CONNECTING, &xprt->sockstate)) {
 565                 /* Note: if we are here due to a dropped connection
 566                  *       we delay reconnecting by RPC_REESTABLISH_TIMEOUT/HZ
 567                  *       seconds
 568                  */
 569                 if (xprt->sock != NULL)
 570                         schedule_delayed_work(&xprt->sock_connect,
 571                                         RPC_REESTABLISH_TIMEOUT);
 572                 else
 573                         schedule_work(&xprt->sock_connect);
 574         }
 575         return;
 576  out_write:
 577         xprt_release_write(xprt, task);
 578 }
 579
 580 /*
 581  * We arrive here when awoken from waiting on connection establishment.
 582  */
 583 static void
 584 xprt_connect_status(struct rpc_task *task)
 585 {
 586         struct rpc_xprt *xprt = task->tk_xprt;
 587
 588         if (task->tk_status >= 0) {
 589                 dprintk("RPC: %4d xprt_connect_status: connection established\n",
 590                                 task->tk_pid);
 591                 return;
 592         }
 593
 594         /* if soft mounted, just cause this RPC to fail */
 595         if (RPC_IS_SOFT(task))
 596                 task->tk_status = -EIO;
 597
 598         switch (task->tk_status) {
 599         case -ECONNREFUSED:
 600         case -ECONNRESET:
 601         case -ENOTCONN:
 602                 return;
 603         case -ETIMEDOUT:
 604                 dprintk("RPC: %4d xprt_connect_status: timed out\n",
 605                                 task->tk_pid);
 606                 break;
 607         default:
 608                 printk(KERN_ERR "RPC: error %d connecting to server %s\n",
 609                                 -task->tk_status, task->tk_client->cl_server);
 610         }
 611         xprt_release_write(xprt, task);
 612 }
 613
 614 /*
 615  * Look up the RPC request corresponding to a reply, and then lock it.
 616  */
 617 static inline struct rpc_rqst *
 618 xprt_lookup_rqst(struct rpc_xprt *xprt, u32 xid)
 619 {
 620         struct list_head *pos;
 621         struct rpc_rqst *req = NULL;
 622
 623         list_for_each(pos, &xprt->recv) {
 624                 struct rpc_rqst *entry = list_entry(pos, struct rpc_rqst, rq_list);
 625                 if (entry->rq_xid == xid) {
 626                         req = entry;
 627                         break;
 628                 }
 629         }
 630         return req;
 631 }
 632
 633 /*
 634  * Complete reply received.
 635  * The TCP code relies on us to remove the request from xprt->pending.
 636  */
 637 static void
 638 xprt_complete_rqst(struct rpc_xprt *xprt, struct rpc_rqst *req, int copied)
 639 {
 640         struct rpc_task *task = req->rq_task;
 641         struct rpc_clnt *clnt = task->tk_client;
 642
 643         /* Adjust congestion window */
 644         if (!xprt->nocong) {
 645                 unsigned timer = task->tk_msg.rpc_proc->p_timer;
 646                 xprt_adjust_cwnd(xprt, copied);
 647                 __xprt_put_cong(xprt, req);
 648                 if (timer) {
 649                         if (req->rq_ntrans == 1)
 650                                 rpc_update_rtt(clnt->cl_rtt, timer,
 651                                                 (long)jiffies - req->rq_xtime);
 652                         rpc_set_timeo(clnt->cl_rtt, timer, req->rq_ntrans - 1);
 653                 }
 654         }
 655
 656 #ifdef RPC_PROFILE
 657         /* Profile only reads for now */
 658         if (copied > 1024) {
 659                 static unsigned long    nextstat;
 660                 static unsigned long    pkt_rtt, pkt_len, pkt_cnt;
 661
 662                 pkt_cnt++;
 663                 pkt_len += req->rq_slen + copied;
 664                 pkt_rtt += jiffies - req->rq_xtime;
 665                 if (time_before(nextstat, jiffies)) {
 666                         printk("RPC: %lu %ld cwnd\n", jiffies, xprt->cwnd);
 667                         printk("RPC: %ld %ld %ld %ld stat\n",
 668                                         jiffies, pkt_cnt, pkt_len, pkt_rtt);
 669                         pkt_rtt = pkt_len = pkt_cnt = 0;
 670                         nextstat = jiffies + 5 * HZ;
 671                 }
 672         }
 673 #endif
 674
 675         dprintk("RPC: %4d has input (%d bytes)\n", task->tk_pid, copied);
 676         list_del_init(&req->rq_list);
 677         req->rq_received = req->rq_private_buf.len = copied;
 678
 679         /* ... and wake up the process. */
 680         rpc_wake_up_task(task);
 681         return;
 682 }
 683
 684 static size_t
 685 skb_read_bits(skb_reader_t *desc, void *to, size_t len)
 686 {
 687         if (len > desc->count)
 688                 len = desc->count;
 689         if (skb_copy_bits(desc->skb, desc->offset, to, len))
 690                 return 0;
 691         desc->count -= len;
 692         desc->offset += len;
 693         return len;
 694 }
 695
 696 static size_t
 697 skb_read_and_csum_bits(skb_reader_t *desc, void *to, size_t len)
 698 {
 699         unsigned int csum2, pos;
 700
 701         if (len > desc->count)
 702                 len = desc->count;
 703         pos = desc->offset;
 704         csum2 = skb_copy_and_csum_bits(desc->skb, pos, to, len, 0);
 705         desc->csum = csum_block_add(desc->csum, csum2, pos);
 706         desc->count -= len;
 707         desc->offset += len;
 708         return len;
 709 }
 710
 711 /*
 712  * We have set things up such that we perform the checksum of the UDP
 713  * packet in parallel with the copies into the RPC client iovec.  -DaveM
 714  */
 715 int
 716 csum_partial_copy_to_xdr(struct xdr_buf *xdr, struct sk_buff *skb)
 717 {
 718         skb_reader_t desc;
 719
 720         desc.skb = skb;
 721         desc.offset = sizeof(struct udphdr);
 722         desc.count = skb->len - desc.offset;
 723
 724         if (skb->ip_summed == CHECKSUM_UNNECESSARY)
 725                 goto no_checksum;
 726
 727         desc.csum = csum_partial(skb->data, desc.offset, skb->csum);
 728         if (xdr_partial_copy_from_skb(xdr, 0, &desc, skb_read_and_csum_bits) < 0)
 729                 return -1;
 730         if (desc.offset != skb->len) {
 731                 unsigned int csum2;
 732                 csum2 = skb_checksum(skb, desc.offset, skb->len - desc.offset, 0);
 733                 desc.csum = csum_block_add(desc.csum, csum2, desc.offset);
 734         }
 735         if (desc.count)
 736                 return -1;
 737         if ((unsigned short)csum_fold(desc.csum))
 738                 return -1;
 739         return 0;
 740 no_checksum:
 741         if (xdr_partial_copy_from_skb(xdr, 0, &desc, skb_read_bits) < 0)
 742                 return -1;
 743         if (desc.count)
 744                 return -1;
 745         return 0;
 746 }
 747
 748 /*
 749  * Input handler for RPC replies. Called from a bottom half and hence
 750  * atomic.
 751  */
 752 static void
 753 udp_data_ready(struct sock *sk, int len)
 754 {
 755         struct rpc_task *task;
 756         struct rpc_xprt *xprt;
 757         struct rpc_rqst *rovr;
 758         struct sk_buff  *skb;
 759         int err, repsize, copied;
 760         u32 _xid, *xp;
 761
 762         read_lock(&sk->sk_callback_lock);
 763         dprintk("RPC:      udp_data_ready...\n");
 764         if (!(xprt = xprt_from_sock(sk))) {
 765                 printk("RPC:      udp_data_ready request not found!\n");
 766                 goto out;
 767         }
 768
 769         dprintk("RPC:      udp_data_ready client %p\n", xprt);
 770
 771         if ((skb = skb_recv_datagram(sk, 0, 1, &err)) == NULL)
 772                 goto out;
 773
 774         if (xprt->shutdown)
 775                 goto dropit;
 776
 777         repsize = skb->len - sizeof(struct udphdr);
 778         if (repsize < 4) {
 779                 printk("RPC: impossible RPC reply size %d!\n", repsize);
 780                 goto dropit;
 781         }
 782
 783         /* Copy the XID from the skb... */
 784         xp = skb_header_pointer(skb, sizeof(struct udphdr),
 785                                 sizeof(_xid), &_xid);
 786         if (xp == NULL)
 787                 goto dropit;
 788
 789         /* Look up and lock the request corresponding to the given XID */
 790         spin_lock(&xprt->sock_lock);
 791         rovr = xprt_lookup_rqst(xprt, *xp);
 792         if (!rovr)
 793                 goto out_unlock;
 794         task = rovr->rq_task;
 795
 796         dprintk("RPC: %4d received reply\n", task->tk_pid);
 797
 798         if ((copied = rovr->rq_private_buf.buflen) > repsize)
 799                 copied = repsize;
 800
 801         /* Suck it into the iovec, verify checksum if not done by hw. */
 802         if (csum_partial_copy_to_xdr(&rovr->rq_private_buf, skb))
 803                 goto out_unlock;
 804
 805         /* Something worked... */
 806         dst_confirm(skb->dst);
 807
 808         xprt_complete_rqst(xprt, rovr, copied);
 809
 810  out_unlock:
 811         spin_unlock(&xprt->sock_lock);
 812  dropit:
 813         skb_free_datagram(sk, skb);
 814  out:
 815         read_unlock(&sk->sk_callback_lock);
 816 }
 817
 818 /*
 819  * Copy from an skb into memory and shrink the skb.
 820  */
 821 static inline size_t
 822 tcp_copy_data(skb_reader_t *desc, void *p, size_t len)
 823 {
 824         if (len > desc->count)
 825                 len = desc->count;
 826         if (skb_copy_bits(desc->skb, desc->offset, p, len)) {
 827                 dprintk("RPC:      failed to copy %zu bytes from skb. %zu bytes remain\n",
 828                                 len, desc->count);
 829                 return 0;
 830         }
 831         desc->offset += len;
 832         desc->count -= len;
 833         dprintk("RPC:      copied %zu bytes from skb. %zu bytes remain\n",
 834                         len, desc->count);
 835         return len;
 836 }
 837
 838 /*
 839  * TCP read fragment marker
 840  */
 841 static inline void
 842 tcp_read_fraghdr(struct rpc_xprt *xprt, skb_reader_t *desc)
 843 {
 844         size_t len, used;
 845         char *p;
 846
 847         p = ((char *) &xprt->tcp_recm) + xprt->tcp_offset;
 848         len = sizeof(xprt->tcp_recm) - xprt->tcp_offset;
 849         used = tcp_copy_data(desc, p, len);
 850         xprt->tcp_offset += used;
 851         if (used != len)
 852                 return;
 853         xprt->tcp_reclen = ntohl(xprt->tcp_recm);
 854         if (xprt->tcp_reclen & 0x80000000)
 855                 xprt->tcp_flags |= XPRT_LAST_FRAG;
 856         else
 857                 xprt->tcp_flags &= ~XPRT_LAST_FRAG;
 858         xprt->tcp_reclen &= 0x7fffffff;
 859         xprt->tcp_flags &= ~XPRT_COPY_RECM;
 860         xprt->tcp_offset = 0;
 861         /* Sanity check of the record length */
 862         if (xprt->tcp_reclen < 4) {
 863                 printk(KERN_ERR "RPC: Invalid TCP record fragment length\n");
 864                 xprt_disconnect(xprt);
 865         }
 866         dprintk("RPC:      reading TCP record fragment of length %d\n",
 867                         xprt->tcp_reclen);
 868 }
 869
 870 static void
 871 tcp_check_recm(struct rpc_xprt *xprt)
 872 {
 873         dprintk("RPC:      xprt = %p, tcp_copied = %lu, tcp_offset = %u, tcp_reclen = %u, tcp_flags = %lx\n",
 874                         xprt, xprt->tcp_copied, xprt->tcp_offset, xprt->tcp_reclen, xprt->tcp_flags);
 875         if (xprt->tcp_offset == xprt->tcp_reclen) {
 876                 xprt->tcp_flags |= XPRT_COPY_RECM;
 877                 xprt->tcp_offset = 0;
 878                 if (xprt->tcp_flags & XPRT_LAST_FRAG) {
 879                         xprt->tcp_flags &= ~XPRT_COPY_DATA;
 880                         xprt->tcp_flags |= XPRT_COPY_XID;
 881                         xprt->tcp_copied = 0;
 882                 }
 883         }
 884 }
 885
 886 /*
 887  * TCP read xid
 888  */
 889 static inline void
 890 tcp_read_xid(struct rpc_xprt *xprt, skb_reader_t *desc)
 891 {
 892         size_t len, used;
 893         char *p;
 894
 895         len = sizeof(xprt->tcp_xid) - xprt->tcp_offset;
 896         dprintk("RPC:      reading XID (%Zu bytes)\n", len);
 897         p = ((char *) &xprt->tcp_xid) + xprt->tcp_offset;
 898         used = tcp_copy_data(desc, p, len);
 899         xprt->tcp_offset += used;
 900         if (used != len)
 901                 return;
 902         xprt->tcp_flags &= ~XPRT_COPY_XID;
 903         xprt->tcp_flags |= XPRT_COPY_DATA;
 904         xprt->tcp_copied = 4;
 905         dprintk("RPC:      reading reply for XID %08x\n",
 906                                                 ntohl(xprt->tcp_xid));
 907         tcp_check_recm(xprt);
 908 }
 909
 910 /*
 911  * TCP read and complete request
 912  */
 913 static inline void
 914 tcp_read_request(struct rpc_xprt *xprt, skb_reader_t *desc)
 915 {
 916         struct rpc_rqst *req;
 917         struct xdr_buf *rcvbuf;
 918         size_t len;
 919         ssize_t r;
 920
 921         /* Find and lock the request corresponding to this xid */
 922         spin_lock(&xprt->sock_lock);
 923         req = xprt_lookup_rqst(xprt, xprt->tcp_xid);
 924         if (!req) {
 925                 xprt->tcp_flags &= ~XPRT_COPY_DATA;
 926                 dprintk("RPC:      XID %08x request not found!\n",
 927                                 ntohl(xprt->tcp_xid));
 928                 spin_unlock(&xprt->sock_lock);
 929                 return;
 930         }
 931
 932         rcvbuf = &req->rq_private_buf;
 933         len = desc->count;
 934         if (len > xprt->tcp_reclen - xprt->tcp_offset) {
 935                 skb_reader_t my_desc;
 936
 937                 len = xprt->tcp_reclen - xprt->tcp_offset;
 938                 memcpy(&my_desc, desc, sizeof(my_desc));
 939                 my_desc.count = len;
 940                 r = xdr_partial_copy_from_skb(rcvbuf, xprt->tcp_copied,
 941                                           &my_desc, tcp_copy_data);
 942                 desc->count -= r;
 943                 desc->offset += r;
 944         } else
 945                 r = xdr_partial_copy_from_skb(rcvbuf, xprt->tcp_copied,
 946                                           desc, tcp_copy_data);
 947
 948         if (r > 0) {
 949                 xprt->tcp_copied += r;
 950                 xprt->tcp_offset += r;
 951         }
 952         if (r != len) {
 953                 /* Error when copying to the receive buffer,
 954                  * usually because we weren't able to allocate
 955                  * additional buffer pages. All we can do now
 956                  * is turn off XPRT_COPY_DATA, so the request
 957                  * will not receive any additional updates,
 958                  * and time out.
 959                  * Any remaining data from this record will
 960                  * be discarded.
 961                  */
 962                 xprt->tcp_flags &= ~XPRT_COPY_DATA;
 963                 dprintk("RPC:      XID %08x truncated request\n",
 964                                 ntohl(xprt->tcp_xid));
 965                 dprintk("RPC:      xprt = %p, tcp_copied = %lu, tcp_offset = %u, tcp_reclen = %u\n",
 966                                 xprt, xprt->tcp_copied, xprt->tcp_offset, xprt->tcp_reclen);
 967                 goto out;
 968         }
 969
 970         dprintk("RPC:      XID %08x read %u bytes\n",
 971                         ntohl(xprt->tcp_xid), r);
 972         dprintk("RPC:      xprt = %p, tcp_copied = %lu, tcp_offset = %u, tcp_reclen = %u\n",
 973                         xprt, xprt->tcp_copied, xprt->tcp_offset, xprt->tcp_reclen);
 974
 975         if (xprt->tcp_copied == req->rq_private_buf.buflen)
 976                 xprt->tcp_flags &= ~XPRT_COPY_DATA;
 977         else if (xprt->tcp_offset == xprt->tcp_reclen) {
 978                 if (xprt->tcp_flags & XPRT_LAST_FRAG)
 979                         xprt->tcp_flags &= ~XPRT_COPY_DATA;
 980         }
 981
 982 out:
 983         if (!(xprt->tcp_flags & XPRT_COPY_DATA)) {
 984                 dprintk("RPC: %4d received reply complete\n",
 985                                 req->rq_task->tk_pid);
 986                 xprt_complete_rqst(xprt, req, xprt->tcp_copied);
 987         }
 988         spin_unlock(&xprt->sock_lock);
 989         tcp_check_recm(xprt);
 990 }
 991
 992 /*
 993  * TCP discard extra bytes from a short read
 994  */
 995 static inline void
 996 tcp_read_discard(struct rpc_xprt *xprt, skb_reader_t *desc)
 997 {
 998         size_t len;
 999
1000         len = xprt->tcp_reclen - xprt->tcp_offset;
1001         if (len > desc->count)
1002                 len = desc->count;
1003         desc->count -= len;
1004         desc->offset += len;
1005         xprt->tcp_offset += len;
1006         dprintk("RPC:      discarded %u bytes\n", len);
1007         tcp_check_recm(xprt);
1008 }
1009
1010 /*
1011  * TCP record receive routine
1012  * We first have to grab the record marker, then the XID, then the data.
1013  */
1014 static int
1015 tcp_data_recv(read_descriptor_t *rd_desc, struct sk_buff *skb,
1016                 unsigned int offset, size_t len)
1017 {
1018         struct rpc_xprt *xprt = rd_desc->arg.data;
1019         skb_reader_t desc = {
1020                 .skb    = skb,
1021                 .offset = offset,
1022                 .count  = len,
1023                 .csum   = 0
1024         };
1025
1026         dprintk("RPC:      tcp_data_recv\n");
1027         do {
1028                 /* Read in a new fragment marker if necessary */
1029                 /* Can we ever really expect to get completely empty fragments? */
1030                 if (xprt->tcp_flags & XPRT_COPY_RECM) {
1031                         tcp_read_fraghdr(xprt, &desc);
1032                         continue;
1033                 }
1034                 /* Read in the xid if necessary */
1035                 if (xprt->tcp_flags & XPRT_COPY_XID) {
1036                         tcp_read_xid(xprt, &desc);
1037                         continue;
1038                 }
1039                 /* Read in the request data */
1040                 if (xprt->tcp_flags & XPRT_COPY_DATA) {
1041                         tcp_read_request(xprt, &desc);
1042                         continue;
1043                 }
1044                 /* Skip over any trailing bytes on short reads */
1045                 tcp_read_discard(xprt, &desc);
1046         } while (desc.count);
1047         dprintk("RPC:      tcp_data_recv done\n");
1048         return len - desc.count;
1049 }
1050
1051 static void tcp_data_ready(struct sock *sk, int bytes)
1052 {
1053         struct rpc_xprt *xprt;
1054         read_descriptor_t rd_desc;
1055
1056         read_lock(&sk->sk_callback_lock);
1057         dprintk("RPC:      tcp_data_ready...\n");
1058         if (!(xprt = xprt_from_sock(sk))) {
1059                 printk("RPC:      tcp_data_ready socket info not found!\n");
1060                 goto out;
1061         }
1062         if (xprt->shutdown)
1063                 goto out;
1064
1065         /* We use rd_desc to pass struct xprt to tcp_data_recv */
1066         rd_desc.arg.data = xprt;
1067         rd_desc.count = 65536;
1068         tcp_read_sock(sk, &rd_desc, tcp_data_recv);
1069 out:
1070         read_unlock(&sk->sk_callback_lock);
1071 }
1072
1073 static void
1074 tcp_state_change(struct sock *sk)
1075 {
1076         struct rpc_xprt *xprt;
1077
1078         read_lock(&sk->sk_callback_lock);
1079         if (!(xprt = xprt_from_sock(sk)))
1080                 goto out;
1081         dprintk("RPC:      tcp_state_change client %p...\n", xprt);
1082         dprintk("RPC:      state %x conn %d dead %d zapped %d\n",
1083                                 sk->sk_state, xprt_connected(xprt),
1084                                 sock_flag(sk, SOCK_DEAD),
1085                                 sock_flag(sk, SOCK_ZAPPED));
1086
1087         switch (sk->sk_state) {
1088         case TCP_ESTABLISHED:
1089                 spin_lock_bh(&xprt->sock_lock);
1090                 if (!xprt_test_and_set_connected(xprt)) {
1091                         /* Reset TCP record info */
1092                         xprt->tcp_offset = 0;
1093                         xprt->tcp_reclen = 0;
1094                         xprt->tcp_copied = 0;
1095                         xprt->tcp_flags = XPRT_COPY_RECM | XPRT_COPY_XID;
1096                         rpc_wake_up(&xprt->pending);
1097                 }
1098                 spin_unlock_bh(&xprt->sock_lock);
1099                 break;
1100         case TCP_SYN_SENT:
1101         case TCP_SYN_RECV:
1102                 break;
1103         default:
1104                 xprt_disconnect(xprt);
1105                 break;
1106         }
1107  out:
1108         read_unlock(&sk->sk_callback_lock);
1109 }
1110
1111 /*
1112  * Called when more output buffer space is available for this socket.
1113  * We try not to wake our writers until they can make "significant"
1114  * progress, otherwise we'll waste resources thrashing sock_sendmsg
1115  * with a bunch of small requests.
1116  */
1117 static void
1118 xprt_write_space(struct sock *sk)
1119 {
1120         struct rpc_xprt *xprt;
1121         struct socket   *sock;
1122
1123         read_lock(&sk->sk_callback_lock);
1124         if (!(xprt = xprt_from_sock(sk)) || !(sock = sk->sk_socket))
1125                 goto out;
1126         if (xprt->shutdown)
1127                 goto out;
1128
1129         /* Wait until we have enough socket memory */
1130         if (xprt->stream) {
1131                 /* from net/core/stream.c:sk_stream_write_space */
1132                 if (sk_stream_wspace(sk) < sk_stream_min_wspace(sk))
1133                         goto out;
1134         } else {
1135                 /* from net/core/sock.c:sock_def_write_space */
1136                 if (!sock_writeable(sk))
1137                         goto out;
1138         }
1139
1140         if (!test_and_clear_bit(SOCK_NOSPACE, &sock->flags))
1141                 goto out;
1142
1143         spin_lock_bh(&xprt->sock_lock);
1144         if (xprt->snd_task)
1145                 rpc_wake_up_task(xprt->snd_task);
1146         spin_unlock_bh(&xprt->sock_lock);
1147 out:
1148         read_unlock(&sk->sk_callback_lock);
1149 }
1150
1151 /*
1152  * RPC receive timeout handler.
1153  */
1154 static void
1155 xprt_timer(struct rpc_task *task)
1156 {
1157         struct rpc_rqst *req = task->tk_rqstp;
1158         struct rpc_xprt *xprt = req->rq_xprt;
1159
1160         spin_lock(&xprt->sock_lock);
1161         if (req->rq_received)
1162                 goto out;
1163
1164         xprt_adjust_cwnd(req->rq_xprt, -ETIMEDOUT);
1165         __xprt_put_cong(xprt, req);
1166
1167         dprintk("RPC: %4d xprt_timer (%s request)\n",
1168                 task->tk_pid, req ? "pending" : "backlogged");
1169
1170         task->tk_status  = -ETIMEDOUT;
1171 out:
1172         task->tk_timeout = 0;
1173         rpc_wake_up_task(task);
1174         spin_unlock(&xprt->sock_lock);
1175 }
1176
1177 /*
1178  * Place the actual RPC call.
1179  * We have to copy the iovec because sendmsg fiddles with its contents.
1180  */
1181 int
1182 xprt_prepare_transmit(struct rpc_task *task)
1183 {
1184         struct rpc_rqst *req = task->tk_rqstp;
1185         struct rpc_xprt *xprt = req->rq_xprt;
1186         int err = 0;
1187
1188         dprintk("RPC: %4d xprt_prepare_transmit\n", task->tk_pid);
1189
1190         if (xprt->shutdown)
1191                 return -EIO;
1192
1193         spin_lock_bh(&xprt->sock_lock);
1194         if (req->rq_received && !req->rq_bytes_sent) {
1195                 err = req->rq_received;
1196                 goto out_unlock;
1197         }
1198         if (!__xprt_lock_write(xprt, task)) {
1199                 err = -EAGAIN;
1200                 goto out_unlock;
1201         }
1202
1203         if (!xprt_connected(xprt)) {
1204                 err = -ENOTCONN;
1205                 goto out_unlock;
1206         }
1207 out_unlock:
1208         spin_unlock_bh(&xprt->sock_lock);
1209         return err;
1210 }
1211
1212 void
1213 xprt_transmit(struct rpc_task *task)
1214 {
1215         struct rpc_clnt *clnt = task->tk_client;
1216         struct rpc_rqst *req = task->tk_rqstp;
1217         struct rpc_xprt *xprt = req->rq_xprt;
1218         int status, retry = 0;
1219
1220
1221         dprintk("RPC: %4d xprt_transmit(%u)\n", task->tk_pid, req->rq_slen);
1222
1223         /* set up everything as needed. */
1224         /* Write the record marker */
1225         if (xprt->stream) {
1226                 u32     *marker = req->rq_svec[0].iov_base;
1227
1228                 *marker = htonl(0x80000000|(req->rq_slen-sizeof(*marker)));
1229         }
1230
1231         smp_rmb();
1232         if (!req->rq_received) {
1233                 if (list_empty(&req->rq_list)) {
1234                         spin_lock_bh(&xprt->sock_lock);
1235                         /* Update the softirq receive buffer */
1236                         memcpy(&req->rq_private_buf, &req->rq_rcv_buf,
1237                                         sizeof(req->rq_private_buf));
1238                         /* Add request to the receive list */
1239                         list_add_tail(&req->rq_list, &xprt->recv);
1240                         spin_unlock_bh(&xprt->sock_lock);
1241                         xprt_reset_majortimeo(req);
1242                         /* Turn off autodisconnect */
1243                         del_singleshot_timer_sync(&xprt->timer);
1244                 }
1245         } else if (!req->rq_bytes_sent)
1246                 return;
1247
1248         /* Continue transmitting the packet/record. We must be careful
1249          * to cope with writespace callbacks arriving _after_ we have
1250          * called xprt_sendmsg().
1251          */
1252         while (1) {
1253                 req->rq_xtime = jiffies;
1254                 status = xprt_sendmsg(xprt, req);
1255
1256                 if (status < 0)
1257                         break;
1258
1259                 if (xprt->stream) {
1260                         req->rq_bytes_sent += status;
1261
1262                         /* If we've sent the entire packet, immediately
1263                          * reset the count of bytes sent. */
1264                         if (req->rq_bytes_sent >= req->rq_slen) {
1265                                 req->rq_bytes_sent = 0;
1266                                 goto out_receive;
1267                         }
1268                 } else {
1269                         if (status >= req->rq_slen)
1270                                 goto out_receive;
1271                         status = -EAGAIN;
1272                         break;
1273                 }
1274
1275                 dprintk("RPC: %4d xmit incomplete (%d left of %d)\n",
1276                                 task->tk_pid, req->rq_slen - req->rq_bytes_sent,
1277                                 req->rq_slen);
1278
1279                 status = -EAGAIN;
1280                 if (retry++ > 50)
1281                         break;
1282         }
1283
1284         /* Note: at this point, task->tk_sleeping has not yet been set,
1285          *       hence there is no danger of the waking up task being put on
1286          *       schedq, and being picked up by a parallel run of rpciod().
1287          */
1288         task->tk_status = status;
1289
1290         switch (status) {
1291         case -EAGAIN:
1292                 if (test_bit(SOCK_ASYNC_NOSPACE, &xprt->sock->flags)) {
1293                         /* Protect against races with xprt_write_space */
1294                         spin_lock_bh(&xprt->sock_lock);
1295                         /* Don't race with disconnect */
1296                         if (!xprt_connected(xprt))
1297                                 task->tk_status = -ENOTCONN;
1298                         else if (test_bit(SOCK_NOSPACE, &xprt->sock->flags)) {
1299                                 task->tk_timeout = req->rq_timeout;
1300                                 rpc_sleep_on(&xprt->pending, task, NULL, NULL);
1301                         }
1302                         spin_unlock_bh(&xprt->sock_lock);
1303                         return;
1304                 }
1305                 /* Keep holding the socket if it is blocked */
1306                 rpc_delay(task, HZ>>4);
1307                 return;
1308         case -ECONNREFUSED:
1309                 task->tk_timeout = RPC_REESTABLISH_TIMEOUT;
1310                 rpc_sleep_on(&xprt->sending, task, NULL, NULL);
1311         case -ENOTCONN:
1312                 return;
1313         default:
1314                 if (xprt->stream)
1315                         xprt_disconnect(xprt);
1316         }
1317         xprt_release_write(xprt, task);
1318         return;
1319  out_receive:
1320         dprintk("RPC: %4d xmit complete\n", task->tk_pid);
1321         /* Set the task's receive timeout value */
1322         spin_lock_bh(&xprt->sock_lock);
1323         if (!xprt->nocong) {
1324                 int timer = task->tk_msg.rpc_proc->p_timer;
1325                 task->tk_timeout = rpc_calc_rto(clnt->cl_rtt, timer);
1326                 task->tk_timeout <<= rpc_ntimeo(clnt->cl_rtt, timer) + req->rq_retries;
1327                 if (task->tk_timeout > xprt->timeout.to_maxval || task->tk_timeout == 0)
1328                         task->tk_timeout = xprt->timeout.to_maxval;
1329         } else
1330                 task->tk_timeout = req->rq_timeout;
1331         /* Don't race with disconnect */
1332         if (!xprt_connected(xprt))
1333                 task->tk_status = -ENOTCONN;
1334         else if (!req->rq_received)
1335                 rpc_sleep_on(&xprt->pending, task, NULL, xprt_timer);
1336         __xprt_release_write(xprt, task);
1337         spin_unlock_bh(&xprt->sock_lock);
1338 }
1339
1340 /*
1341  * Reserve an RPC call slot.
1342  */
1343 static inline void
1344 do_xprt_reserve(struct rpc_task *task)
1345 {
1346         struct rpc_xprt *xprt = task->tk_xprt;
1347
1348         task->tk_status = 0;
1349         if (task->tk_rqstp)
1350                 return;
1351         if (!list_empty(&xprt->free)) {
1352                 struct rpc_rqst *req = list_entry(xprt->free.next, struct rpc_rqst, rq_list);
1353                 list_del_init(&req->rq_list);
1354                 task->tk_rqstp = req;
1355                 xprt_request_init(task, xprt);
1356                 return;
1357         }
1358         dprintk("RPC:      waiting for request slot\n");
1359         task->tk_status = -EAGAIN;
1360         task->tk_timeout = 0;
1361         rpc_sleep_on(&xprt->backlog, task, NULL, NULL);
1362 }
1363
1364 void
1365 xprt_reserve(struct rpc_task *task)
1366 {
1367         struct rpc_xprt *xprt = task->tk_xprt;
1368
1369         task->tk_status = -EIO;
1370         if (!xprt->shutdown) {
1371                 spin_lock(&xprt->xprt_lock);
1372                 do_xprt_reserve(task);
1373                 spin_unlock(&xprt->xprt_lock);
1374         }
1375 }
1376
1377 /*
1378  * Allocate a 'unique' XID
1379  */
1380 static inline u32 xprt_alloc_xid(struct rpc_xprt *xprt)
1381 {
1382         return xprt->xid++;
1383 }
1384
1385 static inline void xprt_init_xid(struct rpc_xprt *xprt)
1386 {
1387         get_random_bytes(&xprt->xid, sizeof(xprt->xid));
1388 }
1389
1390 /*
1391  * Initialize RPC request
1392  */
1393 static void
1394 xprt_request_init(struct rpc_task *task, struct rpc_xprt *xprt)
1395 {
1396         struct rpc_rqst *req = task->tk_rqstp;
1397
1398         req->rq_timeout = xprt->timeout.to_initval;
1399         req->rq_task    = task;
1400         req->rq_xprt    = xprt;
1401         req->rq_xid     = xprt_alloc_xid(xprt);
1402         dprintk("RPC: %4d reserved req %p xid %08x\n", task->tk_pid,
1403                         req, ntohl(req->rq_xid));
1404 }
1405
1406 /*
1407  * Release an RPC call slot
1408  */
1409 void
1410 xprt_release(struct rpc_task *task)
1411 {
1412         struct rpc_xprt *xprt = task->tk_xprt;
1413         struct rpc_rqst *req;
1414
1415         if (!(req = task->tk_rqstp))
1416                 return;
1417         spin_lock_bh(&xprt->sock_lock);
1418         __xprt_release_write(xprt, task);
1419         __xprt_put_cong(xprt, req);
1420         if (!list_empty(&req->rq_list))
1421                 list_del(&req->rq_list);
1422         xprt->last_used = jiffies;
1423         if (list_empty(&xprt->recv) && !xprt->shutdown)
1424                 mod_timer(&xprt->timer, xprt->last_used + XPRT_IDLE_TIMEOUT);
1425         spin_unlock_bh(&xprt->sock_lock);
1426         task->tk_rqstp = NULL;
1427         memset(req, 0, sizeof(*req));   /* mark unused */
1428
1429         dprintk("RPC: %4d release request %p\n", task->tk_pid, req);
1430
1431         spin_lock(&xprt->xprt_lock);
1432         list_add(&req->rq_list, &xprt->free);
1433         xprt_clear_backlog(xprt);
1434         spin_unlock(&xprt->xprt_lock);
1435 }
1436
1437 /*
1438  * Set default timeout parameters
1439  */
1440 static void
1441 xprt_default_timeout(struct rpc_timeout *to, int proto)
1442 {
1443         if (proto == IPPROTO_UDP)
1444                 xprt_set_timeout(to, 5,  5 * HZ);
1445         else
1446                 xprt_set_timeout(to, 5, 60 * HZ);
1447 }
1448
1449 /*
1450  * Set constant timeout
1451  */
1452 void
1453 xprt_set_timeout(struct rpc_timeout *to, unsigned int retr, unsigned long incr)
1454 {
1455         to->to_initval   =
1456         to->to_increment = incr;
1457         to->to_maxval    = incr * retr;
1458         to->to_retries   = retr;
1459         to->to_exponential = 0;
1460 }
1461
1462 unsigned int xprt_udp_slot_table_entries = RPC_DEF_SLOT_TABLE;
1463 unsigned int xprt_tcp_slot_table_entries = RPC_DEF_SLOT_TABLE;
1464
1465 /*
1466  * Initialize an RPC client
1467  */
1468 static struct rpc_xprt *
1469 xprt_setup(int proto, struct sockaddr_in *ap, struct rpc_timeout *to)
1470 {
1471         struct rpc_xprt *xprt;
1472         unsigned int entries;
1473         size_t slot_table_size;
1474         struct rpc_rqst *req;
1475
1476         dprintk("RPC:      setting up %s transport...\n",
1477                                 proto == IPPROTO_UDP? "UDP" : "TCP");
1478
1479         entries = (proto == IPPROTO_TCP)?
1480                 xprt_tcp_slot_table_entries : xprt_udp_slot_table_entries;
1481
1482         if ((xprt = kmalloc(sizeof(struct rpc_xprt), GFP_KERNEL)) == NULL)
1483                 return ERR_PTR(-ENOMEM);
1484         memset(xprt, 0, sizeof(*xprt)); /* Nnnngh! */
1485         xprt->max_reqs = entries;
1486         slot_table_size = entries * sizeof(xprt->slot[0]);
1487         xprt->slot = kmalloc(slot_table_size, GFP_KERNEL);
1488         if (xprt->slot == NULL) {
1489                 kfree(xprt);
1490                 return ERR_PTR(-ENOMEM);
1491         }
1492         memset(xprt->slot, 0, slot_table_size);
1493
1494         xprt->addr = *ap;
1495         xprt->prot = proto;
1496         xprt->stream = (proto == IPPROTO_TCP)? 1 : 0;
1497         if (xprt->stream) {
1498                 xprt->cwnd = RPC_MAXCWND(xprt);
1499                 xprt->nocong = 1;
1500                 xprt->max_payload = (1U << 31) - 1;
1501         } else {
1502                 xprt->cwnd = RPC_INITCWND;
1503                 xprt->max_payload = (1U << 16) - (MAX_HEADER << 3);
1504         }
1505         spin_lock_init(&xprt->sock_lock);
1506         spin_lock_init(&xprt->xprt_lock);
1507         init_waitqueue_head(&xprt->cong_wait);
1508
1509         INIT_LIST_HEAD(&xprt->free);
1510         INIT_LIST_HEAD(&xprt->recv);
1511         INIT_WORK(&xprt->sock_connect, xprt_socket_connect, xprt);
1512         INIT_WORK(&xprt->task_cleanup, xprt_socket_autoclose, xprt);
1513         init_timer(&xprt->timer);
1514         xprt->timer.function = xprt_init_autodisconnect;
1515         xprt->timer.data = (unsigned long) xprt;
1516         xprt->last_used = jiffies;
1517         xprt->port = XPRT_MAX_RESVPORT;
1518
1519         /* Set timeout parameters */
1520         if (to) {
1521                 xprt->timeout = *to;
1522         } else
1523                 xprt_default_timeout(&xprt->timeout, xprt->prot);
1524
1525         rpc_init_wait_queue(&xprt->pending, "xprt_pending");
1526         rpc_init_wait_queue(&xprt->sending, "xprt_sending");
1527         rpc_init_wait_queue(&xprt->resend, "xprt_resend");
1528         rpc_init_priority_wait_queue(&xprt->backlog, "xprt_backlog");
1529
1530         /* initialize free list */
1531         for (req = &xprt->slot[entries-1]; req >= &xprt->slot[0]; req--)
1532                 list_add(&req->rq_list, &xprt->free);
1533
1534         xprt_init_xid(xprt);
1535
1536         /* Check whether we want to use a reserved port */
1537         xprt->resvport = capable(CAP_NET_BIND_SERVICE) ? 1 : 0;
1538
1539         dprintk("RPC:      created transport %p with %u slots\n", xprt,
1540                         xprt->max_reqs);
1541
1542         return xprt;
1543 }
1544
1545 /*
1546  * Bind to a reserved port
1547  */
1548 static inline int xprt_bindresvport(struct rpc_xprt *xprt, struct socket *sock)
1549 {
1550         struct sockaddr_in myaddr = {
1551                 .sin_family = AF_INET,
1552         };
1553         int             err, port;
1554
1555         /* Were we already bound to a given port? Try to reuse it */
1556         port = xprt->port;
1557         do {
1558                 myaddr.sin_port = htons(port);
1559                 err = sock->ops->bind(sock, (struct sockaddr *) &myaddr,
1560                                                 sizeof(myaddr));
1561                 if (err == 0) {
1562                         xprt->port = port;
1563                         return 0;
1564                 }
1565                 if (--port == 0)
1566                         port = XPRT_MAX_RESVPORT;
1567         } while (err == -EADDRINUSE && port != xprt->port);
1568
1569         printk("RPC: Can't bind to reserved port (%d).\n", -err);
1570         return err;
1571 }
1572
1573 static void
1574 xprt_bind_socket(struct rpc_xprt *xprt, struct socket *sock)
1575 {
1576         struct sock     *sk = sock->sk;
1577
1578         if (xprt->inet)
1579                 return;
1580
1581         write_lock_bh(&sk->sk_callback_lock);
1582         sk->sk_user_data = xprt;
1583         xprt->old_data_ready = sk->sk_data_ready;
1584         xprt->old_state_change = sk->sk_state_change;
1585         xprt->old_write_space = sk->sk_write_space;
1586         if (xprt->prot == IPPROTO_UDP) {
1587                 sk->sk_data_ready = udp_data_ready;
1588                 sk->sk_no_check = UDP_CSUM_NORCV;
1589                 xprt_set_connected(xprt);
1590         } else {
1591                 tcp_sk(sk)->nonagle = 1;        /* disable Nagle's algorithm */
1592                 sk->sk_data_ready = tcp_data_ready;
1593                 sk->sk_state_change = tcp_state_change;
1594                 xprt_clear_connected(xprt);
1595         }
1596         sk->sk_write_space = xprt_write_space;
1597
1598         /* Reset to new socket */
1599         xprt->sock = sock;
1600         xprt->inet = sk;
1601         write_unlock_bh(&sk->sk_callback_lock);
1602
1603         return;
1604 }
1605
1606 /*
1607  * Set socket buffer length
1608  */
1609 void
1610 xprt_sock_setbufsize(struct rpc_xprt *xprt)
1611 {
1612         struct sock *sk = xprt->inet;
1613
1614         if (xprt->stream)
1615                 return;
1616         if (xprt->rcvsize) {
1617                 sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
1618                 sk->sk_rcvbuf = xprt->rcvsize * xprt->max_reqs *  2;
1619         }
1620         if (xprt->sndsize) {
1621                 sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
1622                 sk->sk_sndbuf = xprt->sndsize * xprt->max_reqs * 2;
1623                 sk->sk_write_space(sk);
1624         }
1625 }
1626
1627 /*
1628  * Datastream sockets are created here, but xprt_connect will create
1629  * and connect stream sockets.
1630  */
1631 static struct socket * xprt_create_socket(struct rpc_xprt *xprt, int proto, int resvport)
1632 {
1633         struct socket   *sock;
1634         int             type, err;
1635
1636         dprintk("RPC:      xprt_create_socket(%s %d)\n",
1637                            (proto == IPPROTO_UDP)? "udp" : "tcp", proto);
1638
1639         type = (proto == IPPROTO_UDP)? SOCK_DGRAM : SOCK_STREAM;
1640
1641         if ((err = sock_create_kern(PF_INET, type, proto, &sock)) < 0) {
1642                 printk("RPC: can't create socket (%d).\n", -err);
1643                 return NULL;
1644         }
1645
1646         /* If the caller has the capability, bind to a reserved port */
1647         if (resvport && xprt_bindresvport(xprt, sock) < 0) {
1648                 printk("RPC: can't bind to reserved port.\n");
1649                 goto failed;
1650         }
1651
1652         return sock;
1653
1654 failed:
1655         sock_release(sock);
1656         return NULL;
1657 }
1658
1659 /*
1660  * Create an RPC client transport given the protocol and peer address.
1661  */
1662 struct rpc_xprt *
1663 xprt_create_proto(int proto, struct sockaddr_in *sap, struct rpc_timeout *to)
1664 {
1665         struct rpc_xprt *xprt;
1666
1667         xprt = xprt_setup(proto, sap, to);
1668         if (IS_ERR(xprt))
1669                 dprintk("RPC:      xprt_create_proto failed\n");
1670         else
1671                 dprintk("RPC:      xprt_create_proto created xprt %p\n", xprt);
1672         return xprt;
1673 }
1674
1675 /*
1676  * Prepare for transport shutdown.
1677  */
1678 static void
1679 xprt_shutdown(struct rpc_xprt *xprt)
1680 {
1681         xprt->shutdown = 1;
1682         rpc_wake_up(&xprt->sending);
1683         rpc_wake_up(&xprt->resend);
1684         rpc_wake_up(&xprt->pending);
1685         rpc_wake_up(&xprt->backlog);
1686         wake_up(&xprt->cong_wait);
1687         del_timer_sync(&xprt->timer);
1688 }
1689
1690 /*
1691  * Clear the xprt backlog queue
1692  */
1693 static int
1694 xprt_clear_backlog(struct rpc_xprt *xprt) {
1695         rpc_wake_up_next(&xprt->backlog);
1696         wake_up(&xprt->cong_wait);
1697         return 1;
1698 }
1699
1700 /*
1701  * Destroy an RPC transport, killing off all requests.
1702  */
1703 int
1704 xprt_destroy(struct rpc_xprt *xprt)
1705 {
1706         dprintk("RPC:      destroying transport %p\n", xprt);
1707         xprt_shutdown(xprt);
1708         xprt_disconnect(xprt);
1709         xprt_close(xprt);
1710         kfree(xprt->slot);
1711         kfree(xprt);
1712
1713         return 0;
1714 }