net/rxrpc/recvmsg.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /* RxRPC recvmsg() implementation
   3  *
   4  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   5  * Written by David Howells (dhowells@redhat.com)
   6  */
   7
   8 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
   9
  10 #include <linux/net.h>
  11 #include <linux/skbuff.h>
  12 #include <linux/export.h>
  13 #include <linux/sched/signal.h>
  14
  15 #include <net/sock.h>
  16 #include <net/af_rxrpc.h>
  17 #include "ar-internal.h"
  18
  19 /*
  20  * Post a call for attention by the socket or kernel service.  Further
  21  * notifications are suppressed by putting recvmsg_link on a dummy queue.
  22  */
  23 void rxrpc_notify_socket(struct rxrpc_call *call)
  24 {
  25         struct rxrpc_sock *rx;
  26         struct sock *sk;
  27
  28         _enter("%d", call->debug_id);
  29
  30         if (!list_empty(&call->recvmsg_link))
  31                 return;
  32
  33         rcu_read_lock();
  34
  35         rx = rcu_dereference(call->socket);
  36         sk = &rx->sk;
  37         if (rx && sk->sk_state < RXRPC_CLOSE) {
  38                 if (call->notify_rx) {
  39                         spin_lock(&call->notify_lock);
  40                         call->notify_rx(sk, call, call->user_call_ID);
  41                         spin_unlock(&call->notify_lock);
  42                 } else {
  43                         write_lock(&rx->recvmsg_lock);
  44                         if (list_empty(&call->recvmsg_link)) {
  45                                 rxrpc_get_call(call, rxrpc_call_get_notify_socket);
  46                                 list_add_tail(&call->recvmsg_link, &rx->recvmsg_q);
  47                         }
  48                         write_unlock(&rx->recvmsg_lock);
  49
  50                         if (!sock_flag(sk, SOCK_DEAD)) {
  51                                 _debug("call %ps", sk->sk_data_ready);
  52                                 sk->sk_data_ready(sk);
  53                         }
  54                 }
  55         }
  56
  57         rcu_read_unlock();
  58         _leave("");
  59 }
  60
  61 /*
  62  * Transition a call to the complete state.
  63  */
  64 bool __rxrpc_set_call_completion(struct rxrpc_call *call,
  65                                  enum rxrpc_call_completion compl,
  66                                  u32 abort_code,
  67                                  int error)
  68 {
  69         if (call->state < RXRPC_CALL_COMPLETE) {
  70                 call->abort_code = abort_code;
  71                 call->error = error;
  72                 call->completion = compl;
  73                 call->state = RXRPC_CALL_COMPLETE;
  74                 trace_rxrpc_call_complete(call);
  75                 wake_up(&call->waitq);
  76                 rxrpc_notify_socket(call);
  77                 return true;
  78         }
  79         return false;
  80 }
  81
  82 bool rxrpc_set_call_completion(struct rxrpc_call *call,
  83                                enum rxrpc_call_completion compl,
  84                                u32 abort_code,
  85                                int error)
  86 {
  87         bool ret = false;
  88
  89         if (call->state < RXRPC_CALL_COMPLETE) {
  90                 write_lock(&call->state_lock);
  91                 ret = __rxrpc_set_call_completion(call, compl, abort_code, error);
  92                 write_unlock(&call->state_lock);
  93         }
  94         return ret;
  95 }
  96
  97 /*
  98  * Record that a call successfully completed.
  99  */
 100 bool __rxrpc_call_completed(struct rxrpc_call *call)
 101 {
 102         return __rxrpc_set_call_completion(call, RXRPC_CALL_SUCCEEDED, 0, 0);
 103 }
 104
 105 bool rxrpc_call_completed(struct rxrpc_call *call)
 106 {
 107         bool ret = false;
 108
 109         if (call->state < RXRPC_CALL_COMPLETE) {
 110                 write_lock(&call->state_lock);
 111                 ret = __rxrpc_call_completed(call);
 112                 write_unlock(&call->state_lock);
 113         }
 114         return ret;
 115 }
 116
 117 /*
 118  * Record that a call is locally aborted.
 119  */
 120 bool __rxrpc_abort_call(const char *why, struct rxrpc_call *call,
 121                         rxrpc_seq_t seq, u32 abort_code, int error)
 122 {
 123         trace_rxrpc_abort(call->debug_id, why, call->cid, call->call_id, seq,
 124                           abort_code, error);
 125         return __rxrpc_set_call_completion(call, RXRPC_CALL_LOCALLY_ABORTED,
 126                                            abort_code, error);
 127 }
 128
 129 bool rxrpc_abort_call(const char *why, struct rxrpc_call *call,
 130                       rxrpc_seq_t seq, u32 abort_code, int error)
 131 {
 132         bool ret;
 133
 134         write_lock(&call->state_lock);
 135         ret = __rxrpc_abort_call(why, call, seq, abort_code, error);
 136         write_unlock(&call->state_lock);
 137         if (ret && test_bit(RXRPC_CALL_EXPOSED, &call->flags))
 138                 rxrpc_send_abort_packet(call);
 139         return ret;
 140 }
 141
 142 /*
 143  * Pass a call terminating message to userspace.
 144  */
 145 static int rxrpc_recvmsg_term(struct rxrpc_call *call, struct msghdr *msg)
 146 {
 147         u32 tmp = 0;
 148         int ret;
 149
 150         switch (call->completion) {
 151         case RXRPC_CALL_SUCCEEDED:
 152                 ret = 0;
 153                 if (rxrpc_is_service_call(call))
 154                         ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ACK, 0, &tmp);
 155                 break;
 156         case RXRPC_CALL_REMOTELY_ABORTED:
 157                 tmp = call->abort_code;
 158                 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &tmp);
 159                 break;
 160         case RXRPC_CALL_LOCALLY_ABORTED:
 161                 tmp = call->abort_code;
 162                 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_ABORT, 4, &tmp);
 163                 break;
 164         case RXRPC_CALL_NETWORK_ERROR:
 165                 tmp = -call->error;
 166                 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_NET_ERROR, 4, &tmp);
 167                 break;
 168         case RXRPC_CALL_LOCAL_ERROR:
 169                 tmp = -call->error;
 170                 ret = put_cmsg(msg, SOL_RXRPC, RXRPC_LOCAL_ERROR, 4, &tmp);
 171                 break;
 172         default:
 173                 pr_err("Invalid terminal call state %u\n", call->state);
 174                 BUG();
 175                 break;
 176         }
 177
 178         trace_rxrpc_recvdata(call, rxrpc_recvmsg_terminal,
 179                              lower_32_bits(atomic64_read(&call->ackr_window)) - 1,
 180                              call->rx_pkt_offset, call->rx_pkt_len, ret);
 181         return ret;
 182 }
 183
 184 /*
 185  * End the packet reception phase.
 186  */
 187 static void rxrpc_end_rx_phase(struct rxrpc_call *call, rxrpc_serial_t serial)
 188 {
 189         rxrpc_seq_t whigh = READ_ONCE(call->rx_highest_seq);
 190
 191         _enter("%d,%s", call->debug_id, rxrpc_call_states[call->state]);
 192
 193         trace_rxrpc_receive(call, rxrpc_receive_end, 0, whigh);
 194
 195         if (call->state == RXRPC_CALL_CLIENT_RECV_REPLY)
 196                 rxrpc_propose_delay_ACK(call, serial, rxrpc_propose_ack_terminal_ack);
 197
 198         write_lock(&call->state_lock);
 199
 200         switch (call->state) {
 201         case RXRPC_CALL_CLIENT_RECV_REPLY:
 202                 __rxrpc_call_completed(call);
 203                 write_unlock(&call->state_lock);
 204                 break;
 205
 206         case RXRPC_CALL_SERVER_RECV_REQUEST:
 207                 call->state = RXRPC_CALL_SERVER_ACK_REQUEST;
 208                 call->expect_req_by = jiffies + MAX_JIFFY_OFFSET;
 209                 write_unlock(&call->state_lock);
 210                 rxrpc_propose_delay_ACK(call, serial,
 211                                         rxrpc_propose_ack_processing_op);
 212                 break;
 213         default:
 214                 write_unlock(&call->state_lock);
 215                 break;
 216         }
 217 }
 218
 219 /*
 220  * Discard a packet we've used up and advance the Rx window by one.
 221  */
 222 static void rxrpc_rotate_rx_window(struct rxrpc_call *call)
 223 {
 224         struct rxrpc_skb_priv *sp;
 225         struct sk_buff *skb;
 226         rxrpc_serial_t serial;
 227         rxrpc_seq_t old_consumed = call->rx_consumed, tseq;
 228         bool last;
 229         int acked;
 230
 231         _enter("%d", call->debug_id);
 232
 233         skb = skb_dequeue(&call->recvmsg_queue);
 234         rxrpc_see_skb(skb, rxrpc_skb_see_rotate);
 235
 236         sp = rxrpc_skb(skb);
 237         tseq   = sp->hdr.seq;
 238         serial = sp->hdr.serial;
 239         last   = sp->hdr.flags & RXRPC_LAST_PACKET;
 240
 241         /* Barrier against rxrpc_input_data(). */
 242         if (after(tseq, call->rx_consumed))
 243                 smp_store_release(&call->rx_consumed, tseq);
 244
 245         rxrpc_free_skb(skb, rxrpc_skb_put_rotate);
 246
 247         trace_rxrpc_receive(call, last ? rxrpc_receive_rotate_last : rxrpc_receive_rotate,
 248                             serial, call->rx_consumed);
 249         if (last) {
 250                 rxrpc_end_rx_phase(call, serial);
 251                 return;
 252         }
 253
 254         /* Check to see if there's an ACK that needs sending. */
 255         acked = atomic_add_return(call->rx_consumed - old_consumed,
 256                                   &call->ackr_nr_consumed);
 257         if (acked > 2 &&
 258             !test_and_set_bit(RXRPC_CALL_RX_IS_IDLE, &call->flags))
 259                 rxrpc_poke_call(call, rxrpc_call_poke_idle);
 260 }
 261
 262 /*
 263  * Decrypt and verify a DATA packet.
 264  */
 265 static int rxrpc_verify_data(struct rxrpc_call *call, struct sk_buff *skb)
 266 {
 267         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 268
 269         if (sp->flags & RXRPC_RX_VERIFIED)
 270                 return 0;
 271         return call->security->verify_packet(call, skb);
 272 }
 273
 274 /*
 275  * Deliver messages to a call.  This keeps processing packets until the buffer
 276  * is filled and we find either more DATA (returns 0) or the end of the DATA
 277  * (returns 1).  If more packets are required, it returns -EAGAIN.
 278  */
 279 static int rxrpc_recvmsg_data(struct socket *sock, struct rxrpc_call *call,
 280                               struct msghdr *msg, struct iov_iter *iter,
 281                               size_t len, int flags, size_t *_offset)
 282 {
 283         struct rxrpc_skb_priv *sp;
 284         struct sk_buff *skb;
 285         rxrpc_seq_t seq = 0;
 286         size_t remain;
 287         unsigned int rx_pkt_offset, rx_pkt_len;
 288         int copy, ret = -EAGAIN, ret2;
 289
 290         rx_pkt_offset = call->rx_pkt_offset;
 291         rx_pkt_len = call->rx_pkt_len;
 292
 293         if (call->state >= RXRPC_CALL_SERVER_ACK_REQUEST) {
 294                 seq = lower_32_bits(atomic64_read(&call->ackr_window)) - 1;
 295                 ret = 1;
 296                 goto done;
 297         }
 298
 299         /* No one else can be removing stuff from the queue, so we shouldn't
 300          * need the Rx lock to walk it.
 301          */
 302         skb = skb_peek(&call->recvmsg_queue);
 303         while (skb) {
 304                 rxrpc_see_skb(skb, rxrpc_skb_see_recvmsg);
 305                 sp = rxrpc_skb(skb);
 306                 seq = sp->hdr.seq;
 307
 308                 if (!(flags & MSG_PEEK))
 309                         trace_rxrpc_receive(call, rxrpc_receive_front,
 310                                             sp->hdr.serial, seq);
 311
 312                 if (msg)
 313                         sock_recv_timestamp(msg, sock->sk, skb);
 314
 315                 if (rx_pkt_offset == 0) {
 316                         ret2 = rxrpc_verify_data(call, skb);
 317                         rx_pkt_offset = sp->offset;
 318                         rx_pkt_len = sp->len;
 319                         trace_rxrpc_recvdata(call, rxrpc_recvmsg_next, seq,
 320                                              rx_pkt_offset, rx_pkt_len, ret2);
 321                         if (ret2 < 0) {
 322                                 ret = ret2;
 323                                 goto out;
 324                         }
 325                 } else {
 326                         trace_rxrpc_recvdata(call, rxrpc_recvmsg_cont, seq,
 327                                              rx_pkt_offset, rx_pkt_len, 0);
 328                 }
 329
 330                 /* We have to handle short, empty and used-up DATA packets. */
 331                 remain = len - *_offset;
 332                 copy = rx_pkt_len;
 333                 if (copy > remain)
 334                         copy = remain;
 335                 if (copy > 0) {
 336                         ret2 = skb_copy_datagram_iter(skb, rx_pkt_offset, iter,
 337                                                       copy);
 338                         if (ret2 < 0) {
 339                                 ret = ret2;
 340                                 goto out;
 341                         }
 342
 343                         /* handle piecemeal consumption of data packets */
 344                         rx_pkt_offset += copy;
 345                         rx_pkt_len -= copy;
 346                         *_offset += copy;
 347                 }
 348
 349                 if (rx_pkt_len > 0) {
 350                         trace_rxrpc_recvdata(call, rxrpc_recvmsg_full, seq,
 351                                              rx_pkt_offset, rx_pkt_len, 0);
 352                         ASSERTCMP(*_offset, ==, len);
 353                         ret = 0;
 354                         break;
 355                 }
 356
 357                 /* The whole packet has been transferred. */
 358                 if (sp->hdr.flags & RXRPC_LAST_PACKET)
 359                         ret = 1;
 360                 rx_pkt_offset = 0;
 361                 rx_pkt_len = 0;
 362
 363                 skb = skb_peek_next(skb, &call->recvmsg_queue);
 364
 365                 if (!(flags & MSG_PEEK))
 366                         rxrpc_rotate_rx_window(call);
 367         }
 368
 369 out:
 370         if (!(flags & MSG_PEEK)) {
 371                 call->rx_pkt_offset = rx_pkt_offset;
 372                 call->rx_pkt_len = rx_pkt_len;
 373         }
 374 done:
 375         trace_rxrpc_recvdata(call, rxrpc_recvmsg_data_return, seq,
 376                              rx_pkt_offset, rx_pkt_len, ret);
 377         if (ret == -EAGAIN)
 378                 set_bit(RXRPC_CALL_RX_IS_IDLE, &call->flags);
 379         return ret;
 380 }
 381
 382 /*
 383  * Receive a message from an RxRPC socket
 384  * - we need to be careful about two or more threads calling recvmsg
 385  *   simultaneously
 386  */
 387 int rxrpc_recvmsg(struct socket *sock, struct msghdr *msg, size_t len,
 388                   int flags)
 389 {
 390         struct rxrpc_call *call;
 391         struct rxrpc_sock *rx = rxrpc_sk(sock->sk);
 392         struct list_head *l;
 393         unsigned int call_debug_id = 0;
 394         size_t copied = 0;
 395         long timeo;
 396         int ret;
 397
 398         DEFINE_WAIT(wait);
 399
 400         trace_rxrpc_recvmsg(0, rxrpc_recvmsg_enter, 0);
 401
 402         if (flags & (MSG_OOB | MSG_TRUNC))
 403                 return -EOPNOTSUPP;
 404
 405         timeo = sock_rcvtimeo(&rx->sk, flags & MSG_DONTWAIT);
 406
 407 try_again:
 408         lock_sock(&rx->sk);
 409
 410         /* Return immediately if a client socket has no outstanding calls */
 411         if (RB_EMPTY_ROOT(&rx->calls) &&
 412             list_empty(&rx->recvmsg_q) &&
 413             rx->sk.sk_state != RXRPC_SERVER_LISTENING) {
 414                 release_sock(&rx->sk);
 415                 return -EAGAIN;
 416         }
 417
 418         if (list_empty(&rx->recvmsg_q)) {
 419                 ret = -EWOULDBLOCK;
 420                 if (timeo == 0) {
 421                         call = NULL;
 422                         goto error_no_call;
 423                 }
 424
 425                 release_sock(&rx->sk);
 426
 427                 /* Wait for something to happen */
 428                 prepare_to_wait_exclusive(sk_sleep(&rx->sk), &wait,
 429                                           TASK_INTERRUPTIBLE);
 430                 ret = sock_error(&rx->sk);
 431                 if (ret)
 432                         goto wait_error;
 433
 434                 if (list_empty(&rx->recvmsg_q)) {
 435                         if (signal_pending(current))
 436                                 goto wait_interrupted;
 437                         trace_rxrpc_recvmsg(0, rxrpc_recvmsg_wait, 0);
 438                         timeo = schedule_timeout(timeo);
 439                 }
 440                 finish_wait(sk_sleep(&rx->sk), &wait);
 441                 goto try_again;
 442         }
 443
 444         /* Find the next call and dequeue it if we're not just peeking.  If we
 445          * do dequeue it, that comes with a ref that we will need to release.
 446          */
 447         write_lock(&rx->recvmsg_lock);
 448         l = rx->recvmsg_q.next;
 449         call = list_entry(l, struct rxrpc_call, recvmsg_link);
 450         if (!(flags & MSG_PEEK))
 451                 list_del_init(&call->recvmsg_link);
 452         else
 453                 rxrpc_get_call(call, rxrpc_call_get_recvmsg);
 454         write_unlock(&rx->recvmsg_lock);
 455
 456         call_debug_id = call->debug_id;
 457         trace_rxrpc_recvmsg(call_debug_id, rxrpc_recvmsg_dequeue, 0);
 458
 459         /* We're going to drop the socket lock, so we need to lock the call
 460          * against interference by sendmsg.
 461          */
 462         if (!mutex_trylock(&call->user_mutex)) {
 463                 ret = -EWOULDBLOCK;
 464                 if (flags & MSG_DONTWAIT)
 465                         goto error_requeue_call;
 466                 ret = -ERESTARTSYS;
 467                 if (mutex_lock_interruptible(&call->user_mutex) < 0)
 468                         goto error_requeue_call;
 469         }
 470
 471         release_sock(&rx->sk);
 472
 473         if (test_bit(RXRPC_CALL_RELEASED, &call->flags))
 474                 BUG();
 475
 476         if (test_bit(RXRPC_CALL_HAS_USERID, &call->flags)) {
 477                 if (flags & MSG_CMSG_COMPAT) {
 478                         unsigned int id32 = call->user_call_ID;
 479
 480                         ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
 481                                        sizeof(unsigned int), &id32);
 482                 } else {
 483                         unsigned long idl = call->user_call_ID;
 484
 485                         ret = put_cmsg(msg, SOL_RXRPC, RXRPC_USER_CALL_ID,
 486                                        sizeof(unsigned long), &idl);
 487                 }
 488                 if (ret < 0)
 489                         goto error_unlock_call;
 490         }
 491
 492         if (msg->msg_name && call->peer) {
 493                 size_t len = sizeof(call->dest_srx);
 494
 495                 memcpy(msg->msg_name, &call->dest_srx, len);
 496                 msg->msg_namelen = len;
 497         }
 498
 499         switch (READ_ONCE(call->state)) {
 500         case RXRPC_CALL_CLIENT_RECV_REPLY:
 501         case RXRPC_CALL_SERVER_RECV_REQUEST:
 502         case RXRPC_CALL_SERVER_ACK_REQUEST:
 503                 ret = rxrpc_recvmsg_data(sock, call, msg, &msg->msg_iter, len,
 504                                          flags, &copied);
 505                 if (ret == -EAGAIN)
 506                         ret = 0;
 507
 508                 if (!skb_queue_empty(&call->recvmsg_queue))
 509                         rxrpc_notify_socket(call);
 510                 break;
 511         default:
 512                 ret = 0;
 513                 break;
 514         }
 515
 516         if (ret < 0)
 517                 goto error_unlock_call;
 518
 519         if (call->state == RXRPC_CALL_COMPLETE) {
 520                 ret = rxrpc_recvmsg_term(call, msg);
 521                 if (ret < 0)
 522                         goto error_unlock_call;
 523                 if (!(flags & MSG_PEEK))
 524                         rxrpc_release_call(rx, call);
 525                 msg->msg_flags |= MSG_EOR;
 526                 ret = 1;
 527         }
 528
 529         if (ret == 0)
 530                 msg->msg_flags |= MSG_MORE;
 531         else
 532                 msg->msg_flags &= ~MSG_MORE;
 533         ret = copied;
 534
 535 error_unlock_call:
 536         mutex_unlock(&call->user_mutex);
 537         rxrpc_put_call(call, rxrpc_call_put_recvmsg);
 538         trace_rxrpc_recvmsg(call_debug_id, rxrpc_recvmsg_return, ret);
 539         return ret;
 540
 541 error_requeue_call:
 542         if (!(flags & MSG_PEEK)) {
 543                 write_lock(&rx->recvmsg_lock);
 544                 list_add(&call->recvmsg_link, &rx->recvmsg_q);
 545                 write_unlock(&rx->recvmsg_lock);
 546                 trace_rxrpc_recvmsg(call_debug_id, rxrpc_recvmsg_requeue, 0);
 547         } else {
 548                 rxrpc_put_call(call, rxrpc_call_put_recvmsg);
 549         }
 550 error_no_call:
 551         release_sock(&rx->sk);
 552 error_trace:
 553         trace_rxrpc_recvmsg(call_debug_id, rxrpc_recvmsg_return, ret);
 554         return ret;
 555
 556 wait_interrupted:
 557         ret = sock_intr_errno(timeo);
 558 wait_error:
 559         finish_wait(sk_sleep(&rx->sk), &wait);
 560         call = NULL;
 561         goto error_trace;
 562 }
 563
 564 /**
 565  * rxrpc_kernel_recv_data - Allow a kernel service to receive data/info
 566  * @sock: The socket that the call exists on
 567  * @call: The call to send data through
 568  * @iter: The buffer to receive into
 569  * @_len: The amount of data we want to receive (decreased on return)
 570  * @want_more: True if more data is expected to be read
 571  * @_abort: Where the abort code is stored if -ECONNABORTED is returned
 572  * @_service: Where to store the actual service ID (may be upgraded)
 573  *
 574  * Allow a kernel service to receive data and pick up information about the
 575  * state of a call.  Returns 0 if got what was asked for and there's more
 576  * available, 1 if we got what was asked for and we're at the end of the data
 577  * and -EAGAIN if we need more data.
 578  *
 579  * Note that we may return -EAGAIN to drain empty packets at the end of the
 580  * data, even if we've already copied over the requested data.
 581  *
 582  * *_abort should also be initialised to 0.
 583  */
 584 int rxrpc_kernel_recv_data(struct socket *sock, struct rxrpc_call *call,
 585                            struct iov_iter *iter, size_t *_len,
 586                            bool want_more, u32 *_abort, u16 *_service)
 587 {
 588         size_t offset = 0;
 589         int ret;
 590
 591         _enter("{%d,%s},%zu,%d",
 592                call->debug_id, rxrpc_call_states[call->state],
 593                *_len, want_more);
 594
 595         ASSERTCMP(call->state, !=, RXRPC_CALL_SERVER_SECURING);
 596
 597         mutex_lock(&call->user_mutex);
 598
 599         switch (READ_ONCE(call->state)) {
 600         case RXRPC_CALL_CLIENT_RECV_REPLY:
 601         case RXRPC_CALL_SERVER_RECV_REQUEST:
 602         case RXRPC_CALL_SERVER_ACK_REQUEST:
 603                 ret = rxrpc_recvmsg_data(sock, call, NULL, iter,
 604                                          *_len, 0, &offset);
 605                 *_len -= offset;
 606                 if (ret < 0)
 607                         goto out;
 608
 609                 /* We can only reach here with a partially full buffer if we
 610                  * have reached the end of the data.  We must otherwise have a
 611                  * full buffer or have been given -EAGAIN.
 612                  */
 613                 if (ret == 1) {
 614                         if (iov_iter_count(iter) > 0)
 615                                 goto short_data;
 616                         if (!want_more)
 617                                 goto read_phase_complete;
 618                         ret = 0;
 619                         goto out;
 620                 }
 621
 622                 if (!want_more)
 623                         goto excess_data;
 624                 goto out;
 625
 626         case RXRPC_CALL_COMPLETE:
 627                 goto call_complete;
 628
 629         default:
 630                 ret = -EINPROGRESS;
 631                 goto out;
 632         }
 633
 634 read_phase_complete:
 635         ret = 1;
 636 out:
 637         if (_service)
 638                 *_service = call->dest_srx.srx_service;
 639         mutex_unlock(&call->user_mutex);
 640         _leave(" = %d [%zu,%d]", ret, iov_iter_count(iter), *_abort);
 641         return ret;
 642
 643 short_data:
 644         trace_rxrpc_rx_eproto(call, 0, tracepoint_string("short_data"));
 645         ret = -EBADMSG;
 646         goto out;
 647 excess_data:
 648         trace_rxrpc_rx_eproto(call, 0, tracepoint_string("excess_data"));
 649         ret = -EMSGSIZE;
 650         goto out;
 651 call_complete:
 652         *_abort = call->abort_code;
 653         ret = call->error;
 654         if (call->completion == RXRPC_CALL_SUCCEEDED) {
 655                 ret = 1;
 656                 if (iov_iter_count(iter) > 0)
 657                         ret = -ECONNRESET;
 658         }
 659         goto out;
 660 }
 661 EXPORT_SYMBOL(rxrpc_kernel_recv_data);