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TOMOYO Linux Cross Reference
Linux/net/rds/recv.c

Version: ~ [ linux-5.12-rc7 ] ~ [ linux-5.11.13 ] ~ [ linux-5.10.29 ] ~ [ linux-5.9.16 ] ~ [ linux-5.8.18 ] ~ [ linux-5.7.19 ] ~ [ linux-5.6.19 ] ~ [ linux-5.5.19 ] ~ [ linux-5.4.111 ] ~ [ linux-5.3.18 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.186 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.230 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.266 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.266 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.18.140 ] ~ [ linux-3.16.85 ] ~ [ linux-3.14.79 ] ~ [ linux-3.12.74 ] ~ [ linux-3.10.108 ] ~ [ linux-2.6.32.71 ] ~ [ linux-2.6.0 ] ~ [ linux-2.4.37.11 ] ~ [ unix-v6-master ] ~ [ ccs-tools-1.8.5 ] ~ [ policy-sample ] ~
Architecture: ~ [ i386 ] ~ [ alpha ] ~ [ m68k ] ~ [ mips ] ~ [ ppc ] ~ [ sparc ] ~ [ sparc64 ] ~

  1 /*
  2  * Copyright (c) 2006 Oracle.  All rights reserved.
  3  *
  4  * This software is available to you under a choice of one of two
  5  * licenses.  You may choose to be licensed under the terms of the GNU
  6  * General Public License (GPL) Version 2, available from the file
  7  * COPYING in the main directory of this source tree, or the
  8  * OpenIB.org BSD license below:
  9  *
 10  *     Redistribution and use in source and binary forms, with or
 11  *     without modification, are permitted provided that the following
 12  *     conditions are met:
 13  *
 14  *      - Redistributions of source code must retain the above
 15  *        copyright notice, this list of conditions and the following
 16  *        disclaimer.
 17  *
 18  *      - Redistributions in binary form must reproduce the above
 19  *        copyright notice, this list of conditions and the following
 20  *        disclaimer in the documentation and/or other materials
 21  *        provided with the distribution.
 22  *
 23  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 24  * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 25  * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 26  * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 27  * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 28  * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 29  * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 30  * SOFTWARE.
 31  *
 32  */
 33 #include <linux/kernel.h>
 34 #include <linux/slab.h>
 35 #include <net/sock.h>
 36 #include <linux/in.h>
 37 #include <linux/export.h>
 38 #include <linux/time.h>
 39 #include <linux/rds.h>
 40 
 41 #include "rds.h"
 42 
 43 void rds_inc_init(struct rds_incoming *inc, struct rds_connection *conn,
 44                   __be32 saddr)
 45 {
 46         int i;
 47 
 48         atomic_set(&inc->i_refcount, 1);
 49         INIT_LIST_HEAD(&inc->i_item);
 50         inc->i_conn = conn;
 51         inc->i_saddr = saddr;
 52         inc->i_rdma_cookie = 0;
 53         inc->i_rx_tstamp.tv_sec = 0;
 54         inc->i_rx_tstamp.tv_usec = 0;
 55 
 56         for (i = 0; i < RDS_RX_MAX_TRACES; i++)
 57                 inc->i_rx_lat_trace[i] = 0;
 58 }
 59 EXPORT_SYMBOL_GPL(rds_inc_init);
 60 
 61 void rds_inc_path_init(struct rds_incoming *inc, struct rds_conn_path *cp,
 62                        __be32 saddr)
 63 {
 64         atomic_set(&inc->i_refcount, 1);
 65         INIT_LIST_HEAD(&inc->i_item);
 66         inc->i_conn = cp->cp_conn;
 67         inc->i_conn_path = cp;
 68         inc->i_saddr = saddr;
 69         inc->i_rdma_cookie = 0;
 70         inc->i_rx_tstamp.tv_sec = 0;
 71         inc->i_rx_tstamp.tv_usec = 0;
 72 }
 73 EXPORT_SYMBOL_GPL(rds_inc_path_init);
 74 
 75 static void rds_inc_addref(struct rds_incoming *inc)
 76 {
 77         rdsdebug("addref inc %p ref %d\n", inc, atomic_read(&inc->i_refcount));
 78         atomic_inc(&inc->i_refcount);
 79 }
 80 
 81 void rds_inc_put(struct rds_incoming *inc)
 82 {
 83         rdsdebug("put inc %p ref %d\n", inc, atomic_read(&inc->i_refcount));
 84         if (atomic_dec_and_test(&inc->i_refcount)) {
 85                 BUG_ON(!list_empty(&inc->i_item));
 86 
 87                 inc->i_conn->c_trans->inc_free(inc);
 88         }
 89 }
 90 EXPORT_SYMBOL_GPL(rds_inc_put);
 91 
 92 static void rds_recv_rcvbuf_delta(struct rds_sock *rs, struct sock *sk,
 93                                   struct rds_cong_map *map,
 94                                   int delta, __be16 port)
 95 {
 96         int now_congested;
 97 
 98         if (delta == 0)
 99                 return;
100 
101         rs->rs_rcv_bytes += delta;
102         if (delta > 0)
103                 rds_stats_add(s_recv_bytes_added_to_socket, delta);
104         else
105                 rds_stats_add(s_recv_bytes_removed_from_socket, -delta);
106         now_congested = rs->rs_rcv_bytes > rds_sk_rcvbuf(rs);
107 
108         rdsdebug("rs %p (%pI4:%u) recv bytes %d buf %d "
109           "now_cong %d delta %d\n",
110           rs, &rs->rs_bound_addr,
111           ntohs(rs->rs_bound_port), rs->rs_rcv_bytes,
112           rds_sk_rcvbuf(rs), now_congested, delta);
113 
114         /* wasn't -> am congested */
115         if (!rs->rs_congested && now_congested) {
116                 rs->rs_congested = 1;
117                 rds_cong_set_bit(map, port);
118                 rds_cong_queue_updates(map);
119         }
120         /* was -> aren't congested */
121         /* Require more free space before reporting uncongested to prevent
122            bouncing cong/uncong state too often */
123         else if (rs->rs_congested && (rs->rs_rcv_bytes < (rds_sk_rcvbuf(rs)/2))) {
124                 rs->rs_congested = 0;
125                 rds_cong_clear_bit(map, port);
126                 rds_cong_queue_updates(map);
127         }
128 
129         /* do nothing if no change in cong state */
130 }
131 
132 static void rds_conn_peer_gen_update(struct rds_connection *conn,
133                                      u32 peer_gen_num)
134 {
135         int i;
136         struct rds_message *rm, *tmp;
137         unsigned long flags;
138 
139         WARN_ON(conn->c_trans->t_type != RDS_TRANS_TCP);
140         if (peer_gen_num != 0) {
141                 if (conn->c_peer_gen_num != 0 &&
142                     peer_gen_num != conn->c_peer_gen_num) {
143                         for (i = 0; i < RDS_MPATH_WORKERS; i++) {
144                                 struct rds_conn_path *cp;
145 
146                                 cp = &conn->c_path[i];
147                                 spin_lock_irqsave(&cp->cp_lock, flags);
148                                 cp->cp_next_tx_seq = 1;
149                                 cp->cp_next_rx_seq = 0;
150                                 list_for_each_entry_safe(rm, tmp,
151                                                          &cp->cp_retrans,
152                                                          m_conn_item) {
153                                         set_bit(RDS_MSG_FLUSH, &rm->m_flags);
154                                 }
155                                 spin_unlock_irqrestore(&cp->cp_lock, flags);
156                         }
157                 }
158                 conn->c_peer_gen_num = peer_gen_num;
159         }
160 }
161 
162 /*
163  * Process all extension headers that come with this message.
164  */
165 static void rds_recv_incoming_exthdrs(struct rds_incoming *inc, struct rds_sock *rs)
166 {
167         struct rds_header *hdr = &inc->i_hdr;
168         unsigned int pos = 0, type, len;
169         union {
170                 struct rds_ext_header_version version;
171                 struct rds_ext_header_rdma rdma;
172                 struct rds_ext_header_rdma_dest rdma_dest;
173         } buffer;
174 
175         while (1) {
176                 len = sizeof(buffer);
177                 type = rds_message_next_extension(hdr, &pos, &buffer, &len);
178                 if (type == RDS_EXTHDR_NONE)
179                         break;
180                 /* Process extension header here */
181                 switch (type) {
182                 case RDS_EXTHDR_RDMA:
183                         rds_rdma_unuse(rs, be32_to_cpu(buffer.rdma.h_rdma_rkey), 0);
184                         break;
185 
186                 case RDS_EXTHDR_RDMA_DEST:
187                         /* We ignore the size for now. We could stash it
188                          * somewhere and use it for error checking. */
189                         inc->i_rdma_cookie = rds_rdma_make_cookie(
190                                         be32_to_cpu(buffer.rdma_dest.h_rdma_rkey),
191                                         be32_to_cpu(buffer.rdma_dest.h_rdma_offset));
192 
193                         break;
194                 }
195         }
196 }
197 
198 static void rds_recv_hs_exthdrs(struct rds_header *hdr,
199                                 struct rds_connection *conn)
200 {
201         unsigned int pos = 0, type, len;
202         union {
203                 struct rds_ext_header_version version;
204                 u16 rds_npaths;
205                 u32 rds_gen_num;
206         } buffer;
207         u32 new_peer_gen_num = 0;
208 
209         while (1) {
210                 len = sizeof(buffer);
211                 type = rds_message_next_extension(hdr, &pos, &buffer, &len);
212                 if (type == RDS_EXTHDR_NONE)
213                         break;
214                 /* Process extension header here */
215                 switch (type) {
216                 case RDS_EXTHDR_NPATHS:
217                         conn->c_npaths = min_t(int, RDS_MPATH_WORKERS,
218                                                buffer.rds_npaths);
219                         break;
220                 case RDS_EXTHDR_GEN_NUM:
221                         new_peer_gen_num = buffer.rds_gen_num;
222                         break;
223                 default:
224                         pr_warn_ratelimited("ignoring unknown exthdr type "
225                                              "0x%x\n", type);
226                 }
227         }
228         /* if RDS_EXTHDR_NPATHS was not found, default to a single-path */
229         conn->c_npaths = max_t(int, conn->c_npaths, 1);
230         rds_conn_peer_gen_update(conn, new_peer_gen_num);
231 }
232 
233 /* rds_start_mprds() will synchronously start multiple paths when appropriate.
234  * The scheme is based on the following rules:
235  *
236  * 1. rds_sendmsg on first connect attempt sends the probe ping, with the
237  *    sender's npaths (s_npaths)
238  * 2. rcvr of probe-ping knows the mprds_paths = min(s_npaths, r_npaths). It
239  *    sends back a probe-pong with r_npaths. After that, if rcvr is the
240  *    smaller ip addr, it starts rds_conn_path_connect_if_down on all
241  *    mprds_paths.
242  * 3. sender gets woken up, and can move to rds_conn_path_connect_if_down.
243  *    If it is the smaller ipaddr, rds_conn_path_connect_if_down can be
244  *    called after reception of the probe-pong on all mprds_paths.
245  *    Otherwise (sender of probe-ping is not the smaller ip addr): just call
246  *    rds_conn_path_connect_if_down on the hashed path. (see rule 4)
247  * 4. when cp_index > 0, rds_connect_worker must only trigger
248  *    a connection if laddr < faddr.
249  * 5. sender may end up queuing the packet on the cp. will get sent out later.
250  *    when connection is completed.
251  */
252 static void rds_start_mprds(struct rds_connection *conn)
253 {
254         int i;
255         struct rds_conn_path *cp;
256 
257         if (conn->c_npaths > 1 && conn->c_laddr < conn->c_faddr) {
258                 for (i = 1; i < conn->c_npaths; i++) {
259                         cp = &conn->c_path[i];
260                         rds_conn_path_connect_if_down(cp);
261                 }
262         }
263 }
264 
265 /*
266  * The transport must make sure that this is serialized against other
267  * rx and conn reset on this specific conn.
268  *
269  * We currently assert that only one fragmented message will be sent
270  * down a connection at a time.  This lets us reassemble in the conn
271  * instead of per-flow which means that we don't have to go digging through
272  * flows to tear down partial reassembly progress on conn failure and
273  * we save flow lookup and locking for each frag arrival.  It does mean
274  * that small messages will wait behind large ones.  Fragmenting at all
275  * is only to reduce the memory consumption of pre-posted buffers.
276  *
277  * The caller passes in saddr and daddr instead of us getting it from the
278  * conn.  This lets loopback, who only has one conn for both directions,
279  * tell us which roles the addrs in the conn are playing for this message.
280  */
281 void rds_recv_incoming(struct rds_connection *conn, __be32 saddr, __be32 daddr,
282                        struct rds_incoming *inc, gfp_t gfp)
283 {
284         struct rds_sock *rs = NULL;
285         struct sock *sk;
286         unsigned long flags;
287         struct rds_conn_path *cp;
288 
289         inc->i_conn = conn;
290         inc->i_rx_jiffies = jiffies;
291         if (conn->c_trans->t_mp_capable)
292                 cp = inc->i_conn_path;
293         else
294                 cp = &conn->c_path[0];
295 
296         rdsdebug("conn %p next %llu inc %p seq %llu len %u sport %u dport %u "
297                  "flags 0x%x rx_jiffies %lu\n", conn,
298                  (unsigned long long)cp->cp_next_rx_seq,
299                  inc,
300                  (unsigned long long)be64_to_cpu(inc->i_hdr.h_sequence),
301                  be32_to_cpu(inc->i_hdr.h_len),
302                  be16_to_cpu(inc->i_hdr.h_sport),
303                  be16_to_cpu(inc->i_hdr.h_dport),
304                  inc->i_hdr.h_flags,
305                  inc->i_rx_jiffies);
306 
307         /*
308          * Sequence numbers should only increase.  Messages get their
309          * sequence number as they're queued in a sending conn.  They
310          * can be dropped, though, if the sending socket is closed before
311          * they hit the wire.  So sequence numbers can skip forward
312          * under normal operation.  They can also drop back in the conn
313          * failover case as previously sent messages are resent down the
314          * new instance of a conn.  We drop those, otherwise we have
315          * to assume that the next valid seq does not come after a
316          * hole in the fragment stream.
317          *
318          * The headers don't give us a way to realize if fragments of
319          * a message have been dropped.  We assume that frags that arrive
320          * to a flow are part of the current message on the flow that is
321          * being reassembled.  This means that senders can't drop messages
322          * from the sending conn until all their frags are sent.
323          *
324          * XXX we could spend more on the wire to get more robust failure
325          * detection, arguably worth it to avoid data corruption.
326          */
327         if (be64_to_cpu(inc->i_hdr.h_sequence) < cp->cp_next_rx_seq &&
328             (inc->i_hdr.h_flags & RDS_FLAG_RETRANSMITTED)) {
329                 rds_stats_inc(s_recv_drop_old_seq);
330                 goto out;
331         }
332         cp->cp_next_rx_seq = be64_to_cpu(inc->i_hdr.h_sequence) + 1;
333 
334         if (rds_sysctl_ping_enable && inc->i_hdr.h_dport == 0) {
335                 if (inc->i_hdr.h_sport == 0) {
336                         rdsdebug("ignore ping with 0 sport from 0x%x\n", saddr);
337                         goto out;
338                 }
339                 rds_stats_inc(s_recv_ping);
340                 rds_send_pong(cp, inc->i_hdr.h_sport);
341                 /* if this is a handshake ping, start multipath if necessary */
342                 if (RDS_HS_PROBE(inc->i_hdr.h_sport, inc->i_hdr.h_dport)) {
343                         rds_recv_hs_exthdrs(&inc->i_hdr, cp->cp_conn);
344                         rds_start_mprds(cp->cp_conn);
345                 }
346                 goto out;
347         }
348 
349         if (inc->i_hdr.h_dport ==  RDS_FLAG_PROBE_PORT &&
350             inc->i_hdr.h_sport == 0) {
351                 rds_recv_hs_exthdrs(&inc->i_hdr, cp->cp_conn);
352                 /* if this is a handshake pong, start multipath if necessary */
353                 rds_start_mprds(cp->cp_conn);
354                 wake_up(&cp->cp_conn->c_hs_waitq);
355                 goto out;
356         }
357 
358         rs = rds_find_bound(daddr, inc->i_hdr.h_dport);
359         if (!rs) {
360                 rds_stats_inc(s_recv_drop_no_sock);
361                 goto out;
362         }
363 
364         /* Process extension headers */
365         rds_recv_incoming_exthdrs(inc, rs);
366 
367         /* We can be racing with rds_release() which marks the socket dead. */
368         sk = rds_rs_to_sk(rs);
369 
370         /* serialize with rds_release -> sock_orphan */
371         write_lock_irqsave(&rs->rs_recv_lock, flags);
372         if (!sock_flag(sk, SOCK_DEAD)) {
373                 rdsdebug("adding inc %p to rs %p's recv queue\n", inc, rs);
374                 rds_stats_inc(s_recv_queued);
375                 rds_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
376                                       be32_to_cpu(inc->i_hdr.h_len),
377                                       inc->i_hdr.h_dport);
378                 if (sock_flag(sk, SOCK_RCVTSTAMP))
379                         do_gettimeofday(&inc->i_rx_tstamp);
380                 rds_inc_addref(inc);
381                 inc->i_rx_lat_trace[RDS_MSG_RX_END] = local_clock();
382                 list_add_tail(&inc->i_item, &rs->rs_recv_queue);
383                 __rds_wake_sk_sleep(sk);
384         } else {
385                 rds_stats_inc(s_recv_drop_dead_sock);
386         }
387         write_unlock_irqrestore(&rs->rs_recv_lock, flags);
388 
389 out:
390         if (rs)
391                 rds_sock_put(rs);
392 }
393 EXPORT_SYMBOL_GPL(rds_recv_incoming);
394 
395 /*
396  * be very careful here.  This is being called as the condition in
397  * wait_event_*() needs to cope with being called many times.
398  */
399 static int rds_next_incoming(struct rds_sock *rs, struct rds_incoming **inc)
400 {
401         unsigned long flags;
402 
403         if (!*inc) {
404                 read_lock_irqsave(&rs->rs_recv_lock, flags);
405                 if (!list_empty(&rs->rs_recv_queue)) {
406                         *inc = list_entry(rs->rs_recv_queue.next,
407                                           struct rds_incoming,
408                                           i_item);
409                         rds_inc_addref(*inc);
410                 }
411                 read_unlock_irqrestore(&rs->rs_recv_lock, flags);
412         }
413 
414         return *inc != NULL;
415 }
416 
417 static int rds_still_queued(struct rds_sock *rs, struct rds_incoming *inc,
418                             int drop)
419 {
420         struct sock *sk = rds_rs_to_sk(rs);
421         int ret = 0;
422         unsigned long flags;
423 
424         write_lock_irqsave(&rs->rs_recv_lock, flags);
425         if (!list_empty(&inc->i_item)) {
426                 ret = 1;
427                 if (drop) {
428                         /* XXX make sure this i_conn is reliable */
429                         rds_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
430                                               -be32_to_cpu(inc->i_hdr.h_len),
431                                               inc->i_hdr.h_dport);
432                         list_del_init(&inc->i_item);
433                         rds_inc_put(inc);
434                 }
435         }
436         write_unlock_irqrestore(&rs->rs_recv_lock, flags);
437 
438         rdsdebug("inc %p rs %p still %d dropped %d\n", inc, rs, ret, drop);
439         return ret;
440 }
441 
442 /*
443  * Pull errors off the error queue.
444  * If msghdr is NULL, we will just purge the error queue.
445  */
446 int rds_notify_queue_get(struct rds_sock *rs, struct msghdr *msghdr)
447 {
448         struct rds_notifier *notifier;
449         struct rds_rdma_notify cmsg = { 0 }; /* fill holes with zero */
450         unsigned int count = 0, max_messages = ~0U;
451         unsigned long flags;
452         LIST_HEAD(copy);
453         int err = 0;
454 
455 
456         /* put_cmsg copies to user space and thus may sleep. We can't do this
457          * with rs_lock held, so first grab as many notifications as we can stuff
458          * in the user provided cmsg buffer. We don't try to copy more, to avoid
459          * losing notifications - except when the buffer is so small that it wouldn't
460          * even hold a single notification. Then we give him as much of this single
461          * msg as we can squeeze in, and set MSG_CTRUNC.
462          */
463         if (msghdr) {
464                 max_messages = msghdr->msg_controllen / CMSG_SPACE(sizeof(cmsg));
465                 if (!max_messages)
466                         max_messages = 1;
467         }
468 
469         spin_lock_irqsave(&rs->rs_lock, flags);
470         while (!list_empty(&rs->rs_notify_queue) && count < max_messages) {
471                 notifier = list_entry(rs->rs_notify_queue.next,
472                                 struct rds_notifier, n_list);
473                 list_move(&notifier->n_list, &copy);
474                 count++;
475         }
476         spin_unlock_irqrestore(&rs->rs_lock, flags);
477 
478         if (!count)
479                 return 0;
480 
481         while (!list_empty(&copy)) {
482                 notifier = list_entry(copy.next, struct rds_notifier, n_list);
483 
484                 if (msghdr) {
485                         cmsg.user_token = notifier->n_user_token;
486                         cmsg.status = notifier->n_status;
487 
488                         err = put_cmsg(msghdr, SOL_RDS, RDS_CMSG_RDMA_STATUS,
489                                        sizeof(cmsg), &cmsg);
490                         if (err)
491                                 break;
492                 }
493 
494                 list_del_init(&notifier->n_list);
495                 kfree(notifier);
496         }
497 
498         /* If we bailed out because of an error in put_cmsg,
499          * we may be left with one or more notifications that we
500          * didn't process. Return them to the head of the list. */
501         if (!list_empty(&copy)) {
502                 spin_lock_irqsave(&rs->rs_lock, flags);
503                 list_splice(&copy, &rs->rs_notify_queue);
504                 spin_unlock_irqrestore(&rs->rs_lock, flags);
505         }
506 
507         return err;
508 }
509 
510 /*
511  * Queue a congestion notification
512  */
513 static int rds_notify_cong(struct rds_sock *rs, struct msghdr *msghdr)
514 {
515         uint64_t notify = rs->rs_cong_notify;
516         unsigned long flags;
517         int err;
518 
519         err = put_cmsg(msghdr, SOL_RDS, RDS_CMSG_CONG_UPDATE,
520                         sizeof(notify), &notify);
521         if (err)
522                 return err;
523 
524         spin_lock_irqsave(&rs->rs_lock, flags);
525         rs->rs_cong_notify &= ~notify;
526         spin_unlock_irqrestore(&rs->rs_lock, flags);
527 
528         return 0;
529 }
530 
531 /*
532  * Receive any control messages.
533  */
534 static int rds_cmsg_recv(struct rds_incoming *inc, struct msghdr *msg,
535                          struct rds_sock *rs)
536 {
537         int ret = 0;
538 
539         if (inc->i_rdma_cookie) {
540                 ret = put_cmsg(msg, SOL_RDS, RDS_CMSG_RDMA_DEST,
541                                 sizeof(inc->i_rdma_cookie), &inc->i_rdma_cookie);
542                 if (ret)
543                         goto out;
544         }
545 
546         if ((inc->i_rx_tstamp.tv_sec != 0) &&
547             sock_flag(rds_rs_to_sk(rs), SOCK_RCVTSTAMP)) {
548                 ret = put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMP,
549                                sizeof(struct timeval),
550                                &inc->i_rx_tstamp);
551                 if (ret)
552                         goto out;
553         }
554 
555         if (rs->rs_rx_traces) {
556                 struct rds_cmsg_rx_trace t;
557                 int i, j;
558 
559                 inc->i_rx_lat_trace[RDS_MSG_RX_CMSG] = local_clock();
560                 t.rx_traces =  rs->rs_rx_traces;
561                 for (i = 0; i < rs->rs_rx_traces; i++) {
562                         j = rs->rs_rx_trace[i];
563                         t.rx_trace_pos[i] = j;
564                         t.rx_trace[i] = inc->i_rx_lat_trace[j + 1] -
565                                           inc->i_rx_lat_trace[j];
566                 }
567 
568                 ret = put_cmsg(msg, SOL_RDS, RDS_CMSG_RXPATH_LATENCY,
569                                sizeof(t), &t);
570                 if (ret)
571                         goto out;
572         }
573 
574 out:
575         return ret;
576 }
577 
578 int rds_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
579                 int msg_flags)
580 {
581         struct sock *sk = sock->sk;
582         struct rds_sock *rs = rds_sk_to_rs(sk);
583         long timeo;
584         int ret = 0, nonblock = msg_flags & MSG_DONTWAIT;
585         DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
586         struct rds_incoming *inc = NULL;
587 
588         /* udp_recvmsg()->sock_recvtimeo() gets away without locking too.. */
589         timeo = sock_rcvtimeo(sk, nonblock);
590 
591         rdsdebug("size %zu flags 0x%x timeo %ld\n", size, msg_flags, timeo);
592 
593         if (msg_flags & MSG_OOB)
594                 goto out;
595 
596         while (1) {
597                 struct iov_iter save;
598                 /* If there are pending notifications, do those - and nothing else */
599                 if (!list_empty(&rs->rs_notify_queue)) {
600                         ret = rds_notify_queue_get(rs, msg);
601                         break;
602                 }
603 
604                 if (rs->rs_cong_notify) {
605                         ret = rds_notify_cong(rs, msg);
606                         break;
607                 }
608 
609                 if (!rds_next_incoming(rs, &inc)) {
610                         if (nonblock) {
611                                 ret = -EAGAIN;
612                                 break;
613                         }
614 
615                         timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
616                                         (!list_empty(&rs->rs_notify_queue) ||
617                                          rs->rs_cong_notify ||
618                                          rds_next_incoming(rs, &inc)), timeo);
619                         rdsdebug("recvmsg woke inc %p timeo %ld\n", inc,
620                                  timeo);
621                         if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
622                                 continue;
623 
624                         ret = timeo;
625                         if (ret == 0)
626                                 ret = -ETIMEDOUT;
627                         break;
628                 }
629 
630                 rdsdebug("copying inc %p from %pI4:%u to user\n", inc,
631                          &inc->i_conn->c_faddr,
632                          ntohs(inc->i_hdr.h_sport));
633                 save = msg->msg_iter;
634                 ret = inc->i_conn->c_trans->inc_copy_to_user(inc, &msg->msg_iter);
635                 if (ret < 0)
636                         break;
637 
638                 /*
639                  * if the message we just copied isn't at the head of the
640                  * recv queue then someone else raced us to return it, try
641                  * to get the next message.
642                  */
643                 if (!rds_still_queued(rs, inc, !(msg_flags & MSG_PEEK))) {
644                         rds_inc_put(inc);
645                         inc = NULL;
646                         rds_stats_inc(s_recv_deliver_raced);
647                         msg->msg_iter = save;
648                         continue;
649                 }
650 
651                 if (ret < be32_to_cpu(inc->i_hdr.h_len)) {
652                         if (msg_flags & MSG_TRUNC)
653                                 ret = be32_to_cpu(inc->i_hdr.h_len);
654                         msg->msg_flags |= MSG_TRUNC;
655                 }
656 
657                 if (rds_cmsg_recv(inc, msg, rs)) {
658                         ret = -EFAULT;
659                         goto out;
660                 }
661 
662                 rds_stats_inc(s_recv_delivered);
663 
664                 if (sin) {
665                         sin->sin_family = AF_INET;
666                         sin->sin_port = inc->i_hdr.h_sport;
667                         sin->sin_addr.s_addr = inc->i_saddr;
668                         memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
669                         msg->msg_namelen = sizeof(*sin);
670                 }
671                 break;
672         }
673 
674         if (inc)
675                 rds_inc_put(inc);
676 
677 out:
678         return ret;
679 }
680 
681 /*
682  * The socket is being shut down and we're asked to drop messages that were
683  * queued for recvmsg.  The caller has unbound the socket so the receive path
684  * won't queue any more incoming fragments or messages on the socket.
685  */
686 void rds_clear_recv_queue(struct rds_sock *rs)
687 {
688         struct sock *sk = rds_rs_to_sk(rs);
689         struct rds_incoming *inc, *tmp;
690         unsigned long flags;
691 
692         write_lock_irqsave(&rs->rs_recv_lock, flags);
693         list_for_each_entry_safe(inc, tmp, &rs->rs_recv_queue, i_item) {
694                 rds_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
695                                       -be32_to_cpu(inc->i_hdr.h_len),
696                                       inc->i_hdr.h_dport);
697                 list_del_init(&inc->i_item);
698                 rds_inc_put(inc);
699         }
700         write_unlock_irqrestore(&rs->rs_recv_lock, flags);
701 }
702 
703 /*
704  * inc->i_saddr isn't used here because it is only set in the receive
705  * path.
706  */
707 void rds_inc_info_copy(struct rds_incoming *inc,
708                        struct rds_info_iterator *iter,
709                        __be32 saddr, __be32 daddr, int flip)
710 {
711         struct rds_info_message minfo;
712 
713         minfo.seq = be64_to_cpu(inc->i_hdr.h_sequence);
714         minfo.len = be32_to_cpu(inc->i_hdr.h_len);
715 
716         if (flip) {
717                 minfo.laddr = daddr;
718                 minfo.faddr = saddr;
719                 minfo.lport = inc->i_hdr.h_dport;
720                 minfo.fport = inc->i_hdr.h_sport;
721         } else {
722                 minfo.laddr = saddr;
723                 minfo.faddr = daddr;
724                 minfo.lport = inc->i_hdr.h_sport;
725                 minfo.fport = inc->i_hdr.h_dport;
726         }
727 
728         minfo.flags = 0;
729 
730         rds_info_copy(iter, &minfo, sizeof(minfo));
731 }
732 

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