Merge tag 'cramfs_fixes' of git://git.linaro.org/people/nicolas.pitre/linux
[linux-2.6-block.git] / net / rds / recv.c
1 /*
2  * Copyright (c) 2006, 2018 Oracle and/or its affiliates. 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                  struct in6_addr *saddr)
45 {
46         refcount_set(&inc->i_refcount, 1);
47         INIT_LIST_HEAD(&inc->i_item);
48         inc->i_conn = conn;
49         inc->i_saddr = *saddr;
50         inc->i_rdma_cookie = 0;
51         inc->i_rx_tstamp = ktime_set(0, 0);
52
53         memset(inc->i_rx_lat_trace, 0, sizeof(inc->i_rx_lat_trace));
54 }
55 EXPORT_SYMBOL_GPL(rds_inc_init);
56
57 void rds_inc_path_init(struct rds_incoming *inc, struct rds_conn_path *cp,
58                        struct in6_addr  *saddr)
59 {
60         refcount_set(&inc->i_refcount, 1);
61         INIT_LIST_HEAD(&inc->i_item);
62         inc->i_conn = cp->cp_conn;
63         inc->i_conn_path = cp;
64         inc->i_saddr = *saddr;
65         inc->i_rdma_cookie = 0;
66         inc->i_rx_tstamp = ktime_set(0, 0);
67 }
68 EXPORT_SYMBOL_GPL(rds_inc_path_init);
69
70 static void rds_inc_addref(struct rds_incoming *inc)
71 {
72         rdsdebug("addref inc %p ref %d\n", inc, refcount_read(&inc->i_refcount));
73         refcount_inc(&inc->i_refcount);
74 }
75
76 void rds_inc_put(struct rds_incoming *inc)
77 {
78         rdsdebug("put inc %p ref %d\n", inc, refcount_read(&inc->i_refcount));
79         if (refcount_dec_and_test(&inc->i_refcount)) {
80                 BUG_ON(!list_empty(&inc->i_item));
81
82                 inc->i_conn->c_trans->inc_free(inc);
83         }
84 }
85 EXPORT_SYMBOL_GPL(rds_inc_put);
86
87 static void rds_recv_rcvbuf_delta(struct rds_sock *rs, struct sock *sk,
88                                   struct rds_cong_map *map,
89                                   int delta, __be16 port)
90 {
91         int now_congested;
92
93         if (delta == 0)
94                 return;
95
96         rs->rs_rcv_bytes += delta;
97         if (delta > 0)
98                 rds_stats_add(s_recv_bytes_added_to_socket, delta);
99         else
100                 rds_stats_add(s_recv_bytes_removed_from_socket, -delta);
101
102         /* loop transport doesn't send/recv congestion updates */
103         if (rs->rs_transport->t_type == RDS_TRANS_LOOP)
104                 return;
105
106         now_congested = rs->rs_rcv_bytes > rds_sk_rcvbuf(rs);
107
108         rdsdebug("rs %p (%pI6c:%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                                                be16_to_cpu(buffer.rds_npaths));
219                         break;
220                 case RDS_EXTHDR_GEN_NUM:
221                         new_peer_gen_num = be32_to_cpu(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         conn->c_ping_triggered = 0;
231         rds_conn_peer_gen_update(conn, new_peer_gen_num);
232 }
233
234 /* rds_start_mprds() will synchronously start multiple paths when appropriate.
235  * The scheme is based on the following rules:
236  *
237  * 1. rds_sendmsg on first connect attempt sends the probe ping, with the
238  *    sender's npaths (s_npaths)
239  * 2. rcvr of probe-ping knows the mprds_paths = min(s_npaths, r_npaths). It
240  *    sends back a probe-pong with r_npaths. After that, if rcvr is the
241  *    smaller ip addr, it starts rds_conn_path_connect_if_down on all
242  *    mprds_paths.
243  * 3. sender gets woken up, and can move to rds_conn_path_connect_if_down.
244  *    If it is the smaller ipaddr, rds_conn_path_connect_if_down can be
245  *    called after reception of the probe-pong on all mprds_paths.
246  *    Otherwise (sender of probe-ping is not the smaller ip addr): just call
247  *    rds_conn_path_connect_if_down on the hashed path. (see rule 4)
248  * 4. rds_connect_worker must only trigger 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 &&
258             rds_addr_cmp(&conn->c_laddr, &conn->c_faddr) < 0) {
259                 for (i = 0; i < conn->c_npaths; i++) {
260                         cp = &conn->c_path[i];
261                         rds_conn_path_connect_if_down(cp);
262                 }
263         }
264 }
265
266 /*
267  * The transport must make sure that this is serialized against other
268  * rx and conn reset on this specific conn.
269  *
270  * We currently assert that only one fragmented message will be sent
271  * down a connection at a time.  This lets us reassemble in the conn
272  * instead of per-flow which means that we don't have to go digging through
273  * flows to tear down partial reassembly progress on conn failure and
274  * we save flow lookup and locking for each frag arrival.  It does mean
275  * that small messages will wait behind large ones.  Fragmenting at all
276  * is only to reduce the memory consumption of pre-posted buffers.
277  *
278  * The caller passes in saddr and daddr instead of us getting it from the
279  * conn.  This lets loopback, who only has one conn for both directions,
280  * tell us which roles the addrs in the conn are playing for this message.
281  */
282 void rds_recv_incoming(struct rds_connection *conn, struct in6_addr *saddr,
283                        struct in6_addr *daddr,
284                        struct rds_incoming *inc, gfp_t gfp)
285 {
286         struct rds_sock *rs = NULL;
287         struct sock *sk;
288         unsigned long flags;
289         struct rds_conn_path *cp;
290
291         inc->i_conn = conn;
292         inc->i_rx_jiffies = jiffies;
293         if (conn->c_trans->t_mp_capable)
294                 cp = inc->i_conn_path;
295         else
296                 cp = &conn->c_path[0];
297
298         rdsdebug("conn %p next %llu inc %p seq %llu len %u sport %u dport %u "
299                  "flags 0x%x rx_jiffies %lu\n", conn,
300                  (unsigned long long)cp->cp_next_rx_seq,
301                  inc,
302                  (unsigned long long)be64_to_cpu(inc->i_hdr.h_sequence),
303                  be32_to_cpu(inc->i_hdr.h_len),
304                  be16_to_cpu(inc->i_hdr.h_sport),
305                  be16_to_cpu(inc->i_hdr.h_dport),
306                  inc->i_hdr.h_flags,
307                  inc->i_rx_jiffies);
308
309         /*
310          * Sequence numbers should only increase.  Messages get their
311          * sequence number as they're queued in a sending conn.  They
312          * can be dropped, though, if the sending socket is closed before
313          * they hit the wire.  So sequence numbers can skip forward
314          * under normal operation.  They can also drop back in the conn
315          * failover case as previously sent messages are resent down the
316          * new instance of a conn.  We drop those, otherwise we have
317          * to assume that the next valid seq does not come after a
318          * hole in the fragment stream.
319          *
320          * The headers don't give us a way to realize if fragments of
321          * a message have been dropped.  We assume that frags that arrive
322          * to a flow are part of the current message on the flow that is
323          * being reassembled.  This means that senders can't drop messages
324          * from the sending conn until all their frags are sent.
325          *
326          * XXX we could spend more on the wire to get more robust failure
327          * detection, arguably worth it to avoid data corruption.
328          */
329         if (be64_to_cpu(inc->i_hdr.h_sequence) < cp->cp_next_rx_seq &&
330             (inc->i_hdr.h_flags & RDS_FLAG_RETRANSMITTED)) {
331                 rds_stats_inc(s_recv_drop_old_seq);
332                 goto out;
333         }
334         cp->cp_next_rx_seq = be64_to_cpu(inc->i_hdr.h_sequence) + 1;
335
336         if (rds_sysctl_ping_enable && inc->i_hdr.h_dport == 0) {
337                 if (inc->i_hdr.h_sport == 0) {
338                         rdsdebug("ignore ping with 0 sport from %pI6c\n",
339                                  saddr);
340                         goto out;
341                 }
342                 rds_stats_inc(s_recv_ping);
343                 rds_send_pong(cp, inc->i_hdr.h_sport);
344                 /* if this is a handshake ping, start multipath if necessary */
345                 if (RDS_HS_PROBE(be16_to_cpu(inc->i_hdr.h_sport),
346                                  be16_to_cpu(inc->i_hdr.h_dport))) {
347                         rds_recv_hs_exthdrs(&inc->i_hdr, cp->cp_conn);
348                         rds_start_mprds(cp->cp_conn);
349                 }
350                 goto out;
351         }
352
353         if (be16_to_cpu(inc->i_hdr.h_dport) ==  RDS_FLAG_PROBE_PORT &&
354             inc->i_hdr.h_sport == 0) {
355                 rds_recv_hs_exthdrs(&inc->i_hdr, cp->cp_conn);
356                 /* if this is a handshake pong, start multipath if necessary */
357                 rds_start_mprds(cp->cp_conn);
358                 wake_up(&cp->cp_conn->c_hs_waitq);
359                 goto out;
360         }
361
362         rs = rds_find_bound(daddr, inc->i_hdr.h_dport, conn->c_bound_if);
363         if (!rs) {
364                 rds_stats_inc(s_recv_drop_no_sock);
365                 goto out;
366         }
367
368         /* Process extension headers */
369         rds_recv_incoming_exthdrs(inc, rs);
370
371         /* We can be racing with rds_release() which marks the socket dead. */
372         sk = rds_rs_to_sk(rs);
373
374         /* serialize with rds_release -> sock_orphan */
375         write_lock_irqsave(&rs->rs_recv_lock, flags);
376         if (!sock_flag(sk, SOCK_DEAD)) {
377                 rdsdebug("adding inc %p to rs %p's recv queue\n", inc, rs);
378                 rds_stats_inc(s_recv_queued);
379                 rds_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
380                                       be32_to_cpu(inc->i_hdr.h_len),
381                                       inc->i_hdr.h_dport);
382                 if (sock_flag(sk, SOCK_RCVTSTAMP))
383                         inc->i_rx_tstamp = ktime_get_real();
384                 rds_inc_addref(inc);
385                 inc->i_rx_lat_trace[RDS_MSG_RX_END] = local_clock();
386                 list_add_tail(&inc->i_item, &rs->rs_recv_queue);
387                 __rds_wake_sk_sleep(sk);
388         } else {
389                 rds_stats_inc(s_recv_drop_dead_sock);
390         }
391         write_unlock_irqrestore(&rs->rs_recv_lock, flags);
392
393 out:
394         if (rs)
395                 rds_sock_put(rs);
396 }
397 EXPORT_SYMBOL_GPL(rds_recv_incoming);
398
399 /*
400  * be very careful here.  This is being called as the condition in
401  * wait_event_*() needs to cope with being called many times.
402  */
403 static int rds_next_incoming(struct rds_sock *rs, struct rds_incoming **inc)
404 {
405         unsigned long flags;
406
407         if (!*inc) {
408                 read_lock_irqsave(&rs->rs_recv_lock, flags);
409                 if (!list_empty(&rs->rs_recv_queue)) {
410                         *inc = list_entry(rs->rs_recv_queue.next,
411                                           struct rds_incoming,
412                                           i_item);
413                         rds_inc_addref(*inc);
414                 }
415                 read_unlock_irqrestore(&rs->rs_recv_lock, flags);
416         }
417
418         return *inc != NULL;
419 }
420
421 static int rds_still_queued(struct rds_sock *rs, struct rds_incoming *inc,
422                             int drop)
423 {
424         struct sock *sk = rds_rs_to_sk(rs);
425         int ret = 0;
426         unsigned long flags;
427
428         write_lock_irqsave(&rs->rs_recv_lock, flags);
429         if (!list_empty(&inc->i_item)) {
430                 ret = 1;
431                 if (drop) {
432                         /* XXX make sure this i_conn is reliable */
433                         rds_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
434                                               -be32_to_cpu(inc->i_hdr.h_len),
435                                               inc->i_hdr.h_dport);
436                         list_del_init(&inc->i_item);
437                         rds_inc_put(inc);
438                 }
439         }
440         write_unlock_irqrestore(&rs->rs_recv_lock, flags);
441
442         rdsdebug("inc %p rs %p still %d dropped %d\n", inc, rs, ret, drop);
443         return ret;
444 }
445
446 /*
447  * Pull errors off the error queue.
448  * If msghdr is NULL, we will just purge the error queue.
449  */
450 int rds_notify_queue_get(struct rds_sock *rs, struct msghdr *msghdr)
451 {
452         struct rds_notifier *notifier;
453         struct rds_rdma_notify cmsg = { 0 }; /* fill holes with zero */
454         unsigned int count = 0, max_messages = ~0U;
455         unsigned long flags;
456         LIST_HEAD(copy);
457         int err = 0;
458
459
460         /* put_cmsg copies to user space and thus may sleep. We can't do this
461          * with rs_lock held, so first grab as many notifications as we can stuff
462          * in the user provided cmsg buffer. We don't try to copy more, to avoid
463          * losing notifications - except when the buffer is so small that it wouldn't
464          * even hold a single notification. Then we give him as much of this single
465          * msg as we can squeeze in, and set MSG_CTRUNC.
466          */
467         if (msghdr) {
468                 max_messages = msghdr->msg_controllen / CMSG_SPACE(sizeof(cmsg));
469                 if (!max_messages)
470                         max_messages = 1;
471         }
472
473         spin_lock_irqsave(&rs->rs_lock, flags);
474         while (!list_empty(&rs->rs_notify_queue) && count < max_messages) {
475                 notifier = list_entry(rs->rs_notify_queue.next,
476                                 struct rds_notifier, n_list);
477                 list_move(&notifier->n_list, &copy);
478                 count++;
479         }
480         spin_unlock_irqrestore(&rs->rs_lock, flags);
481
482         if (!count)
483                 return 0;
484
485         while (!list_empty(&copy)) {
486                 notifier = list_entry(copy.next, struct rds_notifier, n_list);
487
488                 if (msghdr) {
489                         cmsg.user_token = notifier->n_user_token;
490                         cmsg.status = notifier->n_status;
491
492                         err = put_cmsg(msghdr, SOL_RDS, RDS_CMSG_RDMA_STATUS,
493                                        sizeof(cmsg), &cmsg);
494                         if (err)
495                                 break;
496                 }
497
498                 list_del_init(&notifier->n_list);
499                 kfree(notifier);
500         }
501
502         /* If we bailed out because of an error in put_cmsg,
503          * we may be left with one or more notifications that we
504          * didn't process. Return them to the head of the list. */
505         if (!list_empty(&copy)) {
506                 spin_lock_irqsave(&rs->rs_lock, flags);
507                 list_splice(&copy, &rs->rs_notify_queue);
508                 spin_unlock_irqrestore(&rs->rs_lock, flags);
509         }
510
511         return err;
512 }
513
514 /*
515  * Queue a congestion notification
516  */
517 static int rds_notify_cong(struct rds_sock *rs, struct msghdr *msghdr)
518 {
519         uint64_t notify = rs->rs_cong_notify;
520         unsigned long flags;
521         int err;
522
523         err = put_cmsg(msghdr, SOL_RDS, RDS_CMSG_CONG_UPDATE,
524                         sizeof(notify), &notify);
525         if (err)
526                 return err;
527
528         spin_lock_irqsave(&rs->rs_lock, flags);
529         rs->rs_cong_notify &= ~notify;
530         spin_unlock_irqrestore(&rs->rs_lock, flags);
531
532         return 0;
533 }
534
535 /*
536  * Receive any control messages.
537  */
538 static int rds_cmsg_recv(struct rds_incoming *inc, struct msghdr *msg,
539                          struct rds_sock *rs)
540 {
541         int ret = 0;
542
543         if (inc->i_rdma_cookie) {
544                 ret = put_cmsg(msg, SOL_RDS, RDS_CMSG_RDMA_DEST,
545                                 sizeof(inc->i_rdma_cookie), &inc->i_rdma_cookie);
546                 if (ret)
547                         goto out;
548         }
549
550         if ((inc->i_rx_tstamp != 0) &&
551             sock_flag(rds_rs_to_sk(rs), SOCK_RCVTSTAMP)) {
552                 struct timeval tv = ktime_to_timeval(inc->i_rx_tstamp);
553                 ret = put_cmsg(msg, SOL_SOCKET, SCM_TIMESTAMP,
554                                sizeof(tv), &tv);
555                 if (ret)
556                         goto out;
557         }
558
559         if (rs->rs_rx_traces) {
560                 struct rds_cmsg_rx_trace t;
561                 int i, j;
562
563                 memset(&t, 0, sizeof(t));
564                 inc->i_rx_lat_trace[RDS_MSG_RX_CMSG] = local_clock();
565                 t.rx_traces =  rs->rs_rx_traces;
566                 for (i = 0; i < rs->rs_rx_traces; i++) {
567                         j = rs->rs_rx_trace[i];
568                         t.rx_trace_pos[i] = j;
569                         t.rx_trace[i] = inc->i_rx_lat_trace[j + 1] -
570                                           inc->i_rx_lat_trace[j];
571                 }
572
573                 ret = put_cmsg(msg, SOL_RDS, RDS_CMSG_RXPATH_LATENCY,
574                                sizeof(t), &t);
575                 if (ret)
576                         goto out;
577         }
578
579 out:
580         return ret;
581 }
582
583 static bool rds_recvmsg_zcookie(struct rds_sock *rs, struct msghdr *msg)
584 {
585         struct rds_msg_zcopy_queue *q = &rs->rs_zcookie_queue;
586         struct rds_msg_zcopy_info *info = NULL;
587         struct rds_zcopy_cookies *done;
588         unsigned long flags;
589
590         if (!msg->msg_control)
591                 return false;
592
593         if (!sock_flag(rds_rs_to_sk(rs), SOCK_ZEROCOPY) ||
594             msg->msg_controllen < CMSG_SPACE(sizeof(*done)))
595                 return false;
596
597         spin_lock_irqsave(&q->lock, flags);
598         if (!list_empty(&q->zcookie_head)) {
599                 info = list_entry(q->zcookie_head.next,
600                                   struct rds_msg_zcopy_info, rs_zcookie_next);
601                 list_del(&info->rs_zcookie_next);
602         }
603         spin_unlock_irqrestore(&q->lock, flags);
604         if (!info)
605                 return false;
606         done = &info->zcookies;
607         if (put_cmsg(msg, SOL_RDS, RDS_CMSG_ZCOPY_COMPLETION, sizeof(*done),
608                      done)) {
609                 spin_lock_irqsave(&q->lock, flags);
610                 list_add(&info->rs_zcookie_next, &q->zcookie_head);
611                 spin_unlock_irqrestore(&q->lock, flags);
612                 return false;
613         }
614         kfree(info);
615         return true;
616 }
617
618 int rds_recvmsg(struct socket *sock, struct msghdr *msg, size_t size,
619                 int msg_flags)
620 {
621         struct sock *sk = sock->sk;
622         struct rds_sock *rs = rds_sk_to_rs(sk);
623         long timeo;
624         int ret = 0, nonblock = msg_flags & MSG_DONTWAIT;
625         DECLARE_SOCKADDR(struct sockaddr_in6 *, sin6, msg->msg_name);
626         DECLARE_SOCKADDR(struct sockaddr_in *, sin, msg->msg_name);
627         struct rds_incoming *inc = NULL;
628
629         /* udp_recvmsg()->sock_recvtimeo() gets away without locking too.. */
630         timeo = sock_rcvtimeo(sk, nonblock);
631
632         rdsdebug("size %zu flags 0x%x timeo %ld\n", size, msg_flags, timeo);
633
634         if (msg_flags & MSG_OOB)
635                 goto out;
636         if (msg_flags & MSG_ERRQUEUE)
637                 return sock_recv_errqueue(sk, msg, size, SOL_IP, IP_RECVERR);
638
639         while (1) {
640                 /* If there are pending notifications, do those - and nothing else */
641                 if (!list_empty(&rs->rs_notify_queue)) {
642                         ret = rds_notify_queue_get(rs, msg);
643                         break;
644                 }
645
646                 if (rs->rs_cong_notify) {
647                         ret = rds_notify_cong(rs, msg);
648                         break;
649                 }
650
651                 if (!rds_next_incoming(rs, &inc)) {
652                         if (nonblock) {
653                                 bool reaped = rds_recvmsg_zcookie(rs, msg);
654
655                                 ret = reaped ?  0 : -EAGAIN;
656                                 break;
657                         }
658
659                         timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
660                                         (!list_empty(&rs->rs_notify_queue) ||
661                                          rs->rs_cong_notify ||
662                                          rds_next_incoming(rs, &inc)), timeo);
663                         rdsdebug("recvmsg woke inc %p timeo %ld\n", inc,
664                                  timeo);
665                         if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
666                                 continue;
667
668                         ret = timeo;
669                         if (ret == 0)
670                                 ret = -ETIMEDOUT;
671                         break;
672                 }
673
674                 rdsdebug("copying inc %p from %pI6c:%u to user\n", inc,
675                          &inc->i_conn->c_faddr,
676                          ntohs(inc->i_hdr.h_sport));
677                 ret = inc->i_conn->c_trans->inc_copy_to_user(inc, &msg->msg_iter);
678                 if (ret < 0)
679                         break;
680
681                 /*
682                  * if the message we just copied isn't at the head of the
683                  * recv queue then someone else raced us to return it, try
684                  * to get the next message.
685                  */
686                 if (!rds_still_queued(rs, inc, !(msg_flags & MSG_PEEK))) {
687                         rds_inc_put(inc);
688                         inc = NULL;
689                         rds_stats_inc(s_recv_deliver_raced);
690                         iov_iter_revert(&msg->msg_iter, ret);
691                         continue;
692                 }
693
694                 if (ret < be32_to_cpu(inc->i_hdr.h_len)) {
695                         if (msg_flags & MSG_TRUNC)
696                                 ret = be32_to_cpu(inc->i_hdr.h_len);
697                         msg->msg_flags |= MSG_TRUNC;
698                 }
699
700                 if (rds_cmsg_recv(inc, msg, rs)) {
701                         ret = -EFAULT;
702                         goto out;
703                 }
704                 rds_recvmsg_zcookie(rs, msg);
705
706                 rds_stats_inc(s_recv_delivered);
707
708                 if (msg->msg_name) {
709                         if (ipv6_addr_v4mapped(&inc->i_saddr)) {
710                                 sin = (struct sockaddr_in *)msg->msg_name;
711
712                                 sin->sin_family = AF_INET;
713                                 sin->sin_port = inc->i_hdr.h_sport;
714                                 sin->sin_addr.s_addr =
715                                     inc->i_saddr.s6_addr32[3];
716                                 memset(sin->sin_zero, 0, sizeof(sin->sin_zero));
717                                 msg->msg_namelen = sizeof(*sin);
718                         } else {
719                                 sin6 = (struct sockaddr_in6 *)msg->msg_name;
720
721                                 sin6->sin6_family = AF_INET6;
722                                 sin6->sin6_port = inc->i_hdr.h_sport;
723                                 sin6->sin6_addr = inc->i_saddr;
724                                 sin6->sin6_flowinfo = 0;
725                                 sin6->sin6_scope_id = rs->rs_bound_scope_id;
726                                 msg->msg_namelen = sizeof(*sin6);
727                         }
728                 }
729                 break;
730         }
731
732         if (inc)
733                 rds_inc_put(inc);
734
735 out:
736         return ret;
737 }
738
739 /*
740  * The socket is being shut down and we're asked to drop messages that were
741  * queued for recvmsg.  The caller has unbound the socket so the receive path
742  * won't queue any more incoming fragments or messages on the socket.
743  */
744 void rds_clear_recv_queue(struct rds_sock *rs)
745 {
746         struct sock *sk = rds_rs_to_sk(rs);
747         struct rds_incoming *inc, *tmp;
748         unsigned long flags;
749
750         write_lock_irqsave(&rs->rs_recv_lock, flags);
751         list_for_each_entry_safe(inc, tmp, &rs->rs_recv_queue, i_item) {
752                 rds_recv_rcvbuf_delta(rs, sk, inc->i_conn->c_lcong,
753                                       -be32_to_cpu(inc->i_hdr.h_len),
754                                       inc->i_hdr.h_dport);
755                 list_del_init(&inc->i_item);
756                 rds_inc_put(inc);
757         }
758         write_unlock_irqrestore(&rs->rs_recv_lock, flags);
759 }
760
761 /*
762  * inc->i_saddr isn't used here because it is only set in the receive
763  * path.
764  */
765 void rds_inc_info_copy(struct rds_incoming *inc,
766                        struct rds_info_iterator *iter,
767                        __be32 saddr, __be32 daddr, int flip)
768 {
769         struct rds_info_message minfo;
770
771         minfo.seq = be64_to_cpu(inc->i_hdr.h_sequence);
772         minfo.len = be32_to_cpu(inc->i_hdr.h_len);
773
774         if (flip) {
775                 minfo.laddr = daddr;
776                 minfo.faddr = saddr;
777                 minfo.lport = inc->i_hdr.h_dport;
778                 minfo.fport = inc->i_hdr.h_sport;
779         } else {
780                 minfo.laddr = saddr;
781                 minfo.faddr = daddr;
782                 minfo.lport = inc->i_hdr.h_sport;
783                 minfo.fport = inc->i_hdr.h_dport;
784         }
785
786         minfo.flags = 0;
787
788         rds_info_copy(iter, &minfo, sizeof(minfo));
789 }
790
791 #if IS_ENABLED(CONFIG_IPV6)
792 void rds6_inc_info_copy(struct rds_incoming *inc,
793                         struct rds_info_iterator *iter,
794                         struct in6_addr *saddr, struct in6_addr *daddr,
795                         int flip)
796 {
797         struct rds6_info_message minfo6;
798
799         minfo6.seq = be64_to_cpu(inc->i_hdr.h_sequence);
800         minfo6.len = be32_to_cpu(inc->i_hdr.h_len);
801
802         if (flip) {
803                 minfo6.laddr = *daddr;
804                 minfo6.faddr = *saddr;
805                 minfo6.lport = inc->i_hdr.h_dport;
806                 minfo6.fport = inc->i_hdr.h_sport;
807         } else {
808                 minfo6.laddr = *saddr;
809                 minfo6.faddr = *daddr;
810                 minfo6.lport = inc->i_hdr.h_sport;
811                 minfo6.fport = inc->i_hdr.h_dport;
812         }
813
814         rds_info_copy(iter, &minfo6, sizeof(minfo6));
815 }
816 #endif