net/sunrpc/xprt.c

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