net/rxrpc/ar-output.c

   1 /* RxRPC packet transmission
   2  *
   3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  *
   6  * This program is free software; you can redistribute it and/or
   7  * modify it under the terms of the GNU General Public License
   8  * as published by the Free Software Foundation; either version
   9  * 2 of the License, or (at your option) any later version.
  10  */
  11
  12 #include <linux/net.h>
  13 #include <linux/skbuff.h>
  14 #include <linux/circ_buf.h>
  15 #include <net/sock.h>
  16 #include <net/af_rxrpc.h>
  17 #include "ar-internal.h"
  18
  19 int rxrpc_resend_timeout = 4;
  20
  21 static int rxrpc_send_data(struct kiocb *iocb,
  22                            struct rxrpc_sock *rx,
  23                            struct rxrpc_call *call,
  24                            struct msghdr *msg, size_t len);
  25
  26 /*
  27  * extract control messages from the sendmsg() control buffer
  28  */
  29 static int rxrpc_sendmsg_cmsg(struct rxrpc_sock *rx, struct msghdr *msg,
  30                               unsigned long *user_call_ID,
  31                               enum rxrpc_command *command,
  32                               u32 *abort_code,
  33                               bool server)
  34 {
  35         struct cmsghdr *cmsg;
  36         int len;
  37
  38         *command = RXRPC_CMD_SEND_DATA;
  39
  40         if (msg->msg_controllen == 0)
  41                 return -EINVAL;
  42
  43         for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
  44                 if (!CMSG_OK(msg, cmsg))
  45                         return -EINVAL;
  46
  47                 len = cmsg->cmsg_len - CMSG_ALIGN(sizeof(struct cmsghdr));
  48                 _debug("CMSG %d, %d, %d",
  49                        cmsg->cmsg_level, cmsg->cmsg_type, len);
  50
  51                 if (cmsg->cmsg_level != SOL_RXRPC)
  52                         continue;
  53
  54                 switch (cmsg->cmsg_type) {
  55                 case RXRPC_USER_CALL_ID:
  56                         if (msg->msg_flags & MSG_CMSG_COMPAT) {
  57                                 if (len != sizeof(u32))
  58                                         return -EINVAL;
  59                                 *user_call_ID = *(u32 *) CMSG_DATA(cmsg);
  60                         } else {
  61                                 if (len != sizeof(unsigned long))
  62                                         return -EINVAL;
  63                                 *user_call_ID = *(unsigned long *)
  64                                         CMSG_DATA(cmsg);
  65                         }
  66                         _debug("User Call ID %lx", *user_call_ID);
  67                         break;
  68
  69                 case RXRPC_ABORT:
  70                         if (*command != RXRPC_CMD_SEND_DATA)
  71                                 return -EINVAL;
  72                         *command = RXRPC_CMD_SEND_ABORT;
  73                         if (len != sizeof(*abort_code))
  74                                 return -EINVAL;
  75                         *abort_code = *(unsigned int *) CMSG_DATA(cmsg);
  76                         _debug("Abort %x", *abort_code);
  77                         if (*abort_code == 0)
  78                                 return -EINVAL;
  79                         break;
  80
  81                 case RXRPC_ACCEPT:
  82                         if (*command != RXRPC_CMD_SEND_DATA)
  83                                 return -EINVAL;
  84                         *command = RXRPC_CMD_ACCEPT;
  85                         if (len != 0)
  86                                 return -EINVAL;
  87                         if (!server)
  88                                 return -EISCONN;
  89                         break;
  90
  91                 default:
  92                         return -EINVAL;
  93                 }
  94         }
  95
  96         _leave(" = 0");
  97         return 0;
  98 }
  99
 100 /*
 101  * abort a call, sending an ABORT packet to the peer
 102  */
 103 static void rxrpc_send_abort(struct rxrpc_call *call, u32 abort_code)
 104 {
 105         write_lock_bh(&call->state_lock);
 106
 107         if (call->state <= RXRPC_CALL_COMPLETE) {
 108                 call->state = RXRPC_CALL_LOCALLY_ABORTED;
 109                 call->abort_code = abort_code;
 110                 set_bit(RXRPC_CALL_ABORT, &call->events);
 111                 del_timer_sync(&call->resend_timer);
 112                 del_timer_sync(&call->ack_timer);
 113                 clear_bit(RXRPC_CALL_RESEND_TIMER, &call->events);
 114                 clear_bit(RXRPC_CALL_ACK, &call->events);
 115                 clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 116                 schedule_work(&call->processor);
 117         }
 118
 119         write_unlock_bh(&call->state_lock);
 120 }
 121
 122 /*
 123  * send a message forming part of a client call through an RxRPC socket
 124  * - caller holds the socket locked
 125  * - the socket may be either a client socket or a server socket
 126  */
 127 int rxrpc_client_sendmsg(struct kiocb *iocb, struct rxrpc_sock *rx,
 128                          struct rxrpc_transport *trans, struct msghdr *msg,
 129                          size_t len)
 130 {
 131         struct rxrpc_conn_bundle *bundle;
 132         enum rxrpc_command cmd;
 133         struct rxrpc_call *call;
 134         unsigned long user_call_ID = 0;
 135         struct key *key;
 136         __be16 service_id;
 137         u32 abort_code = 0;
 138         int ret;
 139
 140         _enter("");
 141
 142         ASSERT(trans != NULL);
 143
 144         ret = rxrpc_sendmsg_cmsg(rx, msg, &user_call_ID, &cmd, &abort_code,
 145                                  false);
 146         if (ret < 0)
 147                 return ret;
 148
 149         bundle = NULL;
 150         if (trans) {
 151                 service_id = rx->service_id;
 152                 if (msg->msg_name) {
 153                         struct sockaddr_rxrpc *srx =
 154                                 (struct sockaddr_rxrpc *) msg->msg_name;
 155                         service_id = htons(srx->srx_service);
 156                 }
 157                 key = rx->key;
 158                 if (key && !rx->key->payload.data)
 159                         key = NULL;
 160                 bundle = rxrpc_get_bundle(rx, trans, key, service_id,
 161                                           GFP_KERNEL);
 162                 if (IS_ERR(bundle))
 163                         return PTR_ERR(bundle);
 164         }
 165
 166         call = rxrpc_get_client_call(rx, trans, bundle, user_call_ID,
 167                                      abort_code == 0, GFP_KERNEL);
 168         if (trans)
 169                 rxrpc_put_bundle(trans, bundle);
 170         if (IS_ERR(call)) {
 171                 _leave(" = %ld", PTR_ERR(call));
 172                 return PTR_ERR(call);
 173         }
 174
 175         _debug("CALL %d USR %lx ST %d on CONN %p",
 176                call->debug_id, call->user_call_ID, call->state, call->conn);
 177
 178         if (call->state >= RXRPC_CALL_COMPLETE) {
 179                 /* it's too late for this call */
 180                 ret = -ESHUTDOWN;
 181         } else if (cmd == RXRPC_CMD_SEND_ABORT) {
 182                 rxrpc_send_abort(call, abort_code);
 183         } else if (cmd != RXRPC_CMD_SEND_DATA) {
 184                 ret = -EINVAL;
 185         } else if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST) {
 186                 /* request phase complete for this client call */
 187                 ret = -EPROTO;
 188         } else {
 189                 ret = rxrpc_send_data(iocb, rx, call, msg, len);
 190         }
 191
 192         rxrpc_put_call(call);
 193         _leave(" = %d", ret);
 194         return ret;
 195 }
 196
 197 /*
 198  * send a message through a server socket
 199  * - caller holds the socket locked
 200  */
 201 int rxrpc_server_sendmsg(struct kiocb *iocb, struct rxrpc_sock *rx,
 202                          struct msghdr *msg, size_t len)
 203 {
 204         enum rxrpc_command cmd;
 205         struct rxrpc_call *call;
 206         unsigned long user_call_ID = 0;
 207         u32 abort_code = 0;
 208         int ret;
 209
 210         _enter("");
 211
 212         ret = rxrpc_sendmsg_cmsg(rx, msg, &user_call_ID, &cmd, &abort_code,
 213                                  true);
 214         if (ret < 0)
 215                 return ret;
 216
 217         if (cmd == RXRPC_CMD_ACCEPT)
 218                 return rxrpc_accept_call(rx, user_call_ID);
 219
 220         call = rxrpc_find_server_call(rx, user_call_ID);
 221         if (!call)
 222                 return -EBADSLT;
 223         if (call->state >= RXRPC_CALL_COMPLETE) {
 224                 ret = -ESHUTDOWN;
 225                 goto out;
 226         }
 227
 228         switch (cmd) {
 229         case RXRPC_CMD_SEND_DATA:
 230                 if (call->state != RXRPC_CALL_CLIENT_SEND_REQUEST &&
 231                     call->state != RXRPC_CALL_SERVER_ACK_REQUEST &&
 232                     call->state != RXRPC_CALL_SERVER_SEND_REPLY) {
 233                         /* Tx phase not yet begun for this call */
 234                         ret = -EPROTO;
 235                         break;
 236                 }
 237
 238                 ret = rxrpc_send_data(iocb, rx, call, msg, len);
 239                 break;
 240
 241         case RXRPC_CMD_SEND_ABORT:
 242                 rxrpc_send_abort(call, abort_code);
 243                 break;
 244         default:
 245                 BUG();
 246         }
 247
 248         out:
 249         rxrpc_put_call(call);
 250         _leave(" = %d", ret);
 251         return ret;
 252 }
 253
 254 /*
 255  * send a packet through the transport endpoint
 256  */
 257 int rxrpc_send_packet(struct rxrpc_transport *trans, struct sk_buff *skb)
 258 {
 259         struct kvec iov[1];
 260         struct msghdr msg;
 261         int ret, opt;
 262
 263         _enter(",{%d}", skb->len);
 264
 265         iov[0].iov_base = skb->head;
 266         iov[0].iov_len = skb->len;
 267
 268         msg.msg_name = &trans->peer->srx.transport.sin;
 269         msg.msg_namelen = sizeof(trans->peer->srx.transport.sin);
 270         msg.msg_control = NULL;
 271         msg.msg_controllen = 0;
 272         msg.msg_flags = 0;
 273
 274         /* send the packet with the don't fragment bit set if we currently
 275          * think it's small enough */
 276         if (skb->len - sizeof(struct rxrpc_header) < trans->peer->maxdata) {
 277                 down_read(&trans->local->defrag_sem);
 278                 /* send the packet by UDP
 279                  * - returns -EMSGSIZE if UDP would have to fragment the packet
 280                  *   to go out of the interface
 281                  *   - in which case, we'll have processed the ICMP error
 282                  *     message and update the peer record
 283                  */
 284                 ret = kernel_sendmsg(trans->local->socket, &msg, iov, 1,
 285                                      iov[0].iov_len);
 286
 287                 up_read(&trans->local->defrag_sem);
 288                 if (ret == -EMSGSIZE)
 289                         goto send_fragmentable;
 290
 291                 _leave(" = %d [%u]", ret, trans->peer->maxdata);
 292                 return ret;
 293         }
 294
 295 send_fragmentable:
 296         /* attempt to send this message with fragmentation enabled */
 297         _debug("send fragment");
 298
 299         down_write(&trans->local->defrag_sem);
 300         opt = IP_PMTUDISC_DONT;
 301         ret = kernel_setsockopt(trans->local->socket, SOL_IP, IP_MTU_DISCOVER,
 302                                 (char *) &opt, sizeof(opt));
 303         if (ret == 0) {
 304                 ret = kernel_sendmsg(trans->local->socket, &msg, iov, 1,
 305                                      iov[0].iov_len);
 306
 307                 opt = IP_PMTUDISC_DO;
 308                 kernel_setsockopt(trans->local->socket, SOL_IP,
 309                                   IP_MTU_DISCOVER, (char *) &opt, sizeof(opt));
 310         }
 311
 312         up_write(&trans->local->defrag_sem);
 313         _leave(" = %d [frag %u]", ret, trans->peer->maxdata);
 314         return ret;
 315 }
 316
 317 /*
 318  * wait for space to appear in the transmit/ACK window
 319  * - caller holds the socket locked
 320  */
 321 static int rxrpc_wait_for_tx_window(struct rxrpc_sock *rx,
 322                                     struct rxrpc_call *call,
 323                                     long *timeo)
 324 {
 325         DECLARE_WAITQUEUE(myself, current);
 326         int ret;
 327
 328         _enter(",{%d},%ld",
 329                CIRC_SPACE(call->acks_head, call->acks_tail, call->acks_winsz),
 330                *timeo);
 331
 332         add_wait_queue(&call->tx_waitq, &myself);
 333
 334         for (;;) {
 335                 set_current_state(TASK_INTERRUPTIBLE);
 336                 ret = 0;
 337                 if (CIRC_SPACE(call->acks_head, call->acks_tail,
 338                                call->acks_winsz) > 0)
 339                         break;
 340                 if (signal_pending(current)) {
 341                         ret = sock_intr_errno(*timeo);
 342                         break;
 343                 }
 344
 345                 release_sock(&rx->sk);
 346                 *timeo = schedule_timeout(*timeo);
 347                 lock_sock(&rx->sk);
 348         }
 349
 350         remove_wait_queue(&call->tx_waitq, &myself);
 351         set_current_state(TASK_RUNNING);
 352         _leave(" = %d", ret);
 353         return ret;
 354 }
 355
 356 /*
 357  * attempt to schedule an instant Tx resend
 358  */
 359 static inline void rxrpc_instant_resend(struct rxrpc_call *call)
 360 {
 361         read_lock_bh(&call->state_lock);
 362         if (try_to_del_timer_sync(&call->resend_timer) >= 0) {
 363                 clear_bit(RXRPC_CALL_RUN_RTIMER, &call->flags);
 364                 if (call->state < RXRPC_CALL_COMPLETE &&
 365                     !test_and_set_bit(RXRPC_CALL_RESEND_TIMER, &call->events))
 366                         schedule_work(&call->processor);
 367         }
 368         read_unlock_bh(&call->state_lock);
 369 }
 370
 371 /*
 372  * queue a packet for transmission, set the resend timer and attempt
 373  * to send the packet immediately
 374  */
 375 static void rxrpc_queue_packet(struct rxrpc_call *call, struct sk_buff *skb,
 376                                bool last)
 377 {
 378         struct rxrpc_skb_priv *sp = rxrpc_skb(skb);
 379         int ret;
 380
 381         _net("queue skb %p [%d]", skb, call->acks_head);
 382
 383         ASSERT(call->acks_window != NULL);
 384         call->acks_window[call->acks_head] = (unsigned long) skb;
 385         smp_wmb();
 386         call->acks_head = (call->acks_head + 1) & (call->acks_winsz - 1);
 387
 388         if (last || call->state == RXRPC_CALL_SERVER_ACK_REQUEST) {
 389                 _debug("________awaiting reply/ACK__________");
 390                 write_lock_bh(&call->state_lock);
 391                 switch (call->state) {
 392                 case RXRPC_CALL_CLIENT_SEND_REQUEST:
 393                         call->state = RXRPC_CALL_CLIENT_AWAIT_REPLY;
 394                         break;
 395                 case RXRPC_CALL_SERVER_ACK_REQUEST:
 396                         call->state = RXRPC_CALL_SERVER_SEND_REPLY;
 397                         if (!last)
 398                                 break;
 399                 case RXRPC_CALL_SERVER_SEND_REPLY:
 400                         call->state = RXRPC_CALL_SERVER_AWAIT_ACK;
 401                         break;
 402                 default:
 403                         break;
 404                 }
 405                 write_unlock_bh(&call->state_lock);
 406         }
 407
 408         _proto("Tx DATA %%%u { #%u }",
 409                ntohl(sp->hdr.serial), ntohl(sp->hdr.seq));
 410
 411         sp->need_resend = 0;
 412         sp->resend_at = jiffies + rxrpc_resend_timeout * HZ;
 413         if (!test_and_set_bit(RXRPC_CALL_RUN_RTIMER, &call->flags)) {
 414                 _debug("run timer");
 415                 call->resend_timer.expires = sp->resend_at;
 416                 add_timer(&call->resend_timer);
 417         }
 418
 419         /* attempt to cancel the rx-ACK timer, deferring reply transmission if
 420          * we're ACK'ing the request phase of an incoming call */
 421         ret = -EAGAIN;
 422         if (try_to_del_timer_sync(&call->ack_timer) >= 0) {
 423                 /* the packet may be freed by rxrpc_process_call() before this
 424                  * returns */
 425                 ret = rxrpc_send_packet(call->conn->trans, skb);
 426                 _net("sent skb %p", skb);
 427         } else {
 428                 _debug("failed to delete ACK timer");
 429         }
 430
 431         if (ret < 0) {
 432                 _debug("need instant resend %d", ret);
 433                 sp->need_resend = 1;
 434                 rxrpc_instant_resend(call);
 435         }
 436
 437         _leave("");
 438 }
 439
 440 /*
 441  * send data through a socket
 442  * - must be called in process context
 443  * - caller holds the socket locked
 444  */
 445 static int rxrpc_send_data(struct kiocb *iocb,
 446                            struct rxrpc_sock *rx,
 447                            struct rxrpc_call *call,
 448                            struct msghdr *msg, size_t len)
 449 {
 450         struct rxrpc_skb_priv *sp;
 451         unsigned char __user *from;
 452         struct sk_buff *skb;
 453         struct iovec *iov;
 454         struct sock *sk = &rx->sk;
 455         long timeo;
 456         bool more;
 457         int ret, ioc, segment, copied;
 458
 459         _enter(",,,{%zu},%zu", msg->msg_iovlen, len);
 460
 461         timeo = sock_sndtimeo(sk, msg->msg_flags & MSG_DONTWAIT);
 462
 463         /* this should be in poll */
 464         clear_bit(SOCK_ASYNC_NOSPACE, &sk->sk_socket->flags);
 465
 466         if (sk->sk_err || (sk->sk_shutdown & SEND_SHUTDOWN))
 467                 return -EPIPE;
 468
 469         iov = msg->msg_iov;
 470         ioc = msg->msg_iovlen - 1;
 471         from = iov->iov_base;
 472         segment = iov->iov_len;
 473         iov++;
 474         more = msg->msg_flags & MSG_MORE;
 475
 476         skb = call->tx_pending;
 477         call->tx_pending = NULL;
 478
 479         copied = 0;
 480         do {
 481                 int copy;
 482
 483                 if (segment > len)
 484                         segment = len;
 485
 486                 _debug("SEGMENT %d @%p", segment, from);
 487
 488                 if (!skb) {
 489                         size_t size, chunk, max, space;
 490
 491                         _debug("alloc");
 492
 493                         if (CIRC_SPACE(call->acks_head, call->acks_tail,
 494                                        call->acks_winsz) <= 0) {
 495                                 ret = -EAGAIN;
 496                                 if (msg->msg_flags & MSG_DONTWAIT)
 497                                         goto maybe_error;
 498                                 ret = rxrpc_wait_for_tx_window(rx, call,
 499                                                                &timeo);
 500                                 if (ret < 0)
 501                                         goto maybe_error;
 502                         }
 503
 504                         max = call->conn->trans->peer->maxdata;
 505                         max -= call->conn->security_size;
 506                         max &= ~(call->conn->size_align - 1UL);
 507
 508                         chunk = max;
 509                         if (chunk > len)
 510                                 chunk = len;
 511
 512                         space = chunk + call->conn->size_align;
 513                         space &= ~(call->conn->size_align - 1UL);
 514
 515                         size = space + call->conn->header_size;
 516
 517                         _debug("SIZE: %zu/%zu/%zu", chunk, space, size);
 518
 519                         /* create a buffer that we can retain until it's ACK'd */
 520                         skb = sock_alloc_send_skb(
 521                                 sk, size, msg->msg_flags & MSG_DONTWAIT, &ret);
 522                         if (!skb)
 523                                 goto maybe_error;
 524
 525                         rxrpc_new_skb(skb);
 526
 527                         _debug("ALLOC SEND %p", skb);
 528
 529                         ASSERTCMP(skb->mark, ==, 0);
 530
 531                         _debug("HS: %u", call->conn->header_size);
 532                         skb_reserve(skb, call->conn->header_size);
 533                         skb->len += call->conn->header_size;
 534
 535                         sp = rxrpc_skb(skb);
 536                         sp->remain = chunk;
 537                         if (sp->remain > skb_tailroom(skb))
 538                                 sp->remain = skb_tailroom(skb);
 539
 540                         _net("skb: hr %d, tr %d, hl %d, rm %d",
 541                                skb_headroom(skb),
 542                                skb_tailroom(skb),
 543                                skb_headlen(skb),
 544                                sp->remain);
 545
 546                         skb->ip_summed = CHECKSUM_UNNECESSARY;
 547                 }
 548
 549                 _debug("append");
 550                 sp = rxrpc_skb(skb);
 551
 552                 /* append next segment of data to the current buffer */
 553                 copy = skb_tailroom(skb);
 554                 ASSERTCMP(copy, >, 0);
 555                 if (copy > segment)
 556                         copy = segment;
 557                 if (copy > sp->remain)
 558                         copy = sp->remain;
 559
 560                 _debug("add");
 561                 ret = skb_add_data(skb, from, copy);
 562                 _debug("added");
 563                 if (ret < 0)
 564                         goto efault;
 565                 sp->remain -= copy;
 566                 skb->mark += copy;
 567
 568                 len -= copy;
 569                 segment -= copy;
 570                 from += copy;
 571                 while (segment == 0 && ioc > 0) {
 572                         from = iov->iov_base;
 573                         segment = iov->iov_len;
 574                         iov++;
 575                         ioc--;
 576                 }
 577                 if (len == 0) {
 578                         segment = 0;
 579                         ioc = 0;
 580                 }
 581
 582                 /* check for the far side aborting the call or a network error
 583                  * occurring */
 584                 if (call->state > RXRPC_CALL_COMPLETE)
 585                         goto call_aborted;
 586
 587                 /* add the packet to the send queue if it's now full */
 588                 if (sp->remain <= 0 || (segment == 0 && !more)) {
 589                         struct rxrpc_connection *conn = call->conn;
 590                         size_t pad;
 591
 592                         /* pad out if we're using security */
 593                         if (conn->security) {
 594                                 pad = conn->security_size + skb->mark;
 595                                 pad = conn->size_align - pad;
 596                                 pad &= conn->size_align - 1;
 597                                 _debug("pad %zu", pad);
 598                                 if (pad)
 599                                         memset(skb_put(skb, pad), 0, pad);
 600                         }
 601
 602                         sp->hdr.epoch = conn->epoch;
 603                         sp->hdr.cid = call->cid;
 604                         sp->hdr.callNumber = call->call_id;
 605                         sp->hdr.seq =
 606                                 htonl(atomic_inc_return(&call->sequence));
 607                         sp->hdr.serial =
 608                                 htonl(atomic_inc_return(&conn->serial));
 609                         sp->hdr.type = RXRPC_PACKET_TYPE_DATA;
 610                         sp->hdr.userStatus = 0;
 611                         sp->hdr.securityIndex = conn->security_ix;
 612                         sp->hdr._rsvd = 0;
 613                         sp->hdr.serviceId = conn->service_id;
 614
 615                         sp->hdr.flags = conn->out_clientflag;
 616                         if (len == 0 && !more)
 617                                 sp->hdr.flags |= RXRPC_LAST_PACKET;
 618                         else if (CIRC_SPACE(call->acks_head, call->acks_tail,
 619                                             call->acks_winsz) > 1)
 620                                 sp->hdr.flags |= RXRPC_MORE_PACKETS;
 621
 622                         ret = rxrpc_secure_packet(
 623                                 call, skb, skb->mark,
 624                                 skb->head + sizeof(struct rxrpc_header));
 625                         if (ret < 0)
 626                                 goto out;
 627
 628                         memcpy(skb->head, &sp->hdr,
 629                                sizeof(struct rxrpc_header));
 630                         rxrpc_queue_packet(call, skb, segment == 0 && !more);
 631                         skb = NULL;
 632                 }
 633
 634         } while (segment > 0);
 635
 636 out:
 637         call->tx_pending = skb;
 638         _leave(" = %d", ret);
 639         return ret;
 640
 641 call_aborted:
 642         rxrpc_free_skb(skb);
 643         if (call->state == RXRPC_CALL_NETWORK_ERROR)
 644                 ret = call->conn->trans->peer->net_error;
 645         else
 646                 ret = -ECONNABORTED;
 647         _leave(" = %d", ret);
 648         return ret;
 649
 650 maybe_error:
 651         if (copied)
 652                 ret = copied;
 653         goto out;
 654
 655 efault:
 656         ret = -EFAULT;
 657         goto out;
 658 }