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

Version: ~ [ linux-5.4-rc3 ] ~ [ linux-5.3.6 ] ~ [ linux-5.2.21 ] ~ [ linux-5.1.21 ] ~ [ linux-5.0.21 ] ~ [ linux-4.20.17 ] ~ [ linux-4.19.79 ] ~ [ linux-4.18.20 ] ~ [ linux-4.17.19 ] ~ [ linux-4.16.18 ] ~ [ linux-4.15.18 ] ~ [ linux-4.14.149 ] ~ [ linux-4.13.16 ] ~ [ linux-4.12.14 ] ~ [ linux-4.11.12 ] ~ [ linux-4.10.17 ] ~ [ linux-4.9.196 ] ~ [ linux-4.8.17 ] ~ [ linux-4.7.10 ] ~ [ linux-4.6.7 ] ~ [ linux-4.5.7 ] ~ [ linux-4.4.196 ] ~ [ linux-4.3.6 ] ~ [ linux-4.2.8 ] ~ [ linux-4.1.52 ] ~ [ linux-4.0.9 ] ~ [ linux-3.19.8 ] ~ [ linux-3.18.140 ] ~ [ linux-3.17.8 ] ~ [ linux-3.16.75 ] ~ [ linux-3.15.10 ] ~ [ linux-3.14.79 ] ~ [ linux-3.13.11 ] ~ [ linux-3.12.74 ] ~ [ linux-3.11.10 ] ~ [ linux-3.10.108 ] ~ [ linux-3.9.11 ] ~ [ linux-3.8.13 ] ~ [ linux-3.7.10 ] ~ [ linux-3.6.11 ] ~ [ linux-3.5.7 ] ~ [ linux-3.4.113 ] ~ [ linux-3.3.8 ] ~ [ linux-3.2.102 ] ~ [ linux-3.1.10 ] ~ [ linux-3.0.101 ] ~ [ 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 <linux/in.h>
 36 #include <linux/module.h>
 37 #include <net/tcp.h>
 38 #include <net/net_namespace.h>
 39 #include <net/netns/generic.h>
 40 
 41 #include "rds.h"
 42 #include "tcp.h"
 43 
 44 /* only for info exporting */
 45 static DEFINE_SPINLOCK(rds_tcp_tc_list_lock);
 46 static LIST_HEAD(rds_tcp_tc_list);
 47 static unsigned int rds_tcp_tc_count;
 48 
 49 /* Track rds_tcp_connection structs so they can be cleaned up */
 50 static DEFINE_SPINLOCK(rds_tcp_conn_lock);
 51 static LIST_HEAD(rds_tcp_conn_list);
 52 
 53 static struct kmem_cache *rds_tcp_conn_slab;
 54 
 55 static int rds_tcp_skbuf_handler(struct ctl_table *ctl, int write,
 56                                  void __user *buffer, size_t *lenp,
 57                                  loff_t *fpos);
 58 
 59 static int rds_tcp_min_sndbuf = SOCK_MIN_SNDBUF;
 60 static int rds_tcp_min_rcvbuf = SOCK_MIN_RCVBUF;
 61 
 62 static struct ctl_table rds_tcp_sysctl_table[] = {
 63 #define RDS_TCP_SNDBUF  0
 64         {
 65                 .procname       = "rds_tcp_sndbuf",
 66                 /* data is per-net pointer */
 67                 .maxlen         = sizeof(int),
 68                 .mode           = 0644,
 69                 .proc_handler   = rds_tcp_skbuf_handler,
 70                 .extra1         = &rds_tcp_min_sndbuf,
 71         },
 72 #define RDS_TCP_RCVBUF  1
 73         {
 74                 .procname       = "rds_tcp_rcvbuf",
 75                 /* data is per-net pointer */
 76                 .maxlen         = sizeof(int),
 77                 .mode           = 0644,
 78                 .proc_handler   = rds_tcp_skbuf_handler,
 79                 .extra1         = &rds_tcp_min_rcvbuf,
 80         },
 81         { }
 82 };
 83 
 84 /* doing it this way avoids calling tcp_sk() */
 85 void rds_tcp_nonagle(struct socket *sock)
 86 {
 87         int val = 1;
 88 
 89         kernel_setsockopt(sock, SOL_TCP, TCP_NODELAY, (void *)&val,
 90                               sizeof(val));
 91 }
 92 
 93 u32 rds_tcp_snd_nxt(struct rds_tcp_connection *tc)
 94 {
 95         return tcp_sk(tc->t_sock->sk)->snd_nxt;
 96 }
 97 
 98 u32 rds_tcp_snd_una(struct rds_tcp_connection *tc)
 99 {
100         return tcp_sk(tc->t_sock->sk)->snd_una;
101 }
102 
103 void rds_tcp_restore_callbacks(struct socket *sock,
104                                struct rds_tcp_connection *tc)
105 {
106         rdsdebug("restoring sock %p callbacks from tc %p\n", sock, tc);
107         write_lock_bh(&sock->sk->sk_callback_lock);
108 
109         /* done under the callback_lock to serialize with write_space */
110         spin_lock(&rds_tcp_tc_list_lock);
111         list_del_init(&tc->t_list_item);
112         rds_tcp_tc_count--;
113         spin_unlock(&rds_tcp_tc_list_lock);
114 
115         tc->t_sock = NULL;
116 
117         sock->sk->sk_write_space = tc->t_orig_write_space;
118         sock->sk->sk_data_ready = tc->t_orig_data_ready;
119         sock->sk->sk_state_change = tc->t_orig_state_change;
120         sock->sk->sk_user_data = NULL;
121 
122         write_unlock_bh(&sock->sk->sk_callback_lock);
123 }
124 
125 /*
126  * rds_tcp_reset_callbacks() switches the to the new sock and
127  * returns the existing tc->t_sock.
128  *
129  * The only functions that set tc->t_sock are rds_tcp_set_callbacks
130  * and rds_tcp_reset_callbacks.  Send and receive trust that
131  * it is set.  The absence of RDS_CONN_UP bit protects those paths
132  * from being called while it isn't set.
133  */
134 void rds_tcp_reset_callbacks(struct socket *sock,
135                              struct rds_conn_path *cp)
136 {
137         struct rds_tcp_connection *tc = cp->cp_transport_data;
138         struct socket *osock = tc->t_sock;
139 
140         if (!osock)
141                 goto newsock;
142 
143         /* Need to resolve a duelling SYN between peers.
144          * We have an outstanding SYN to this peer, which may
145          * potentially have transitioned to the RDS_CONN_UP state,
146          * so we must quiesce any send threads before resetting
147          * cp_transport_data. We quiesce these threads by setting
148          * cp_state to something other than RDS_CONN_UP, and then
149          * waiting for any existing threads in rds_send_xmit to
150          * complete release_in_xmit(). (Subsequent threads entering
151          * rds_send_xmit() will bail on !rds_conn_up().
152          *
153          * However an incoming syn-ack at this point would end up
154          * marking the conn as RDS_CONN_UP, and would again permit
155          * rds_send_xmi() threads through, so ideally we would
156          * synchronize on RDS_CONN_UP after lock_sock(), but cannot
157          * do that: waiting on !RDS_IN_XMIT after lock_sock() may
158          * end up deadlocking with tcp_sendmsg(), and the RDS_IN_XMIT
159          * would not get set. As a result, we set c_state to
160          * RDS_CONN_RESETTTING, to ensure that rds_tcp_state_change
161          * cannot mark rds_conn_path_up() in the window before lock_sock()
162          */
163         atomic_set(&cp->cp_state, RDS_CONN_RESETTING);
164         wait_event(cp->cp_waitq, !test_bit(RDS_IN_XMIT, &cp->cp_flags));
165         lock_sock(osock->sk);
166         /* reset receive side state for rds_tcp_data_recv() for osock  */
167         cancel_delayed_work_sync(&cp->cp_send_w);
168         cancel_delayed_work_sync(&cp->cp_recv_w);
169         if (tc->t_tinc) {
170                 rds_inc_put(&tc->t_tinc->ti_inc);
171                 tc->t_tinc = NULL;
172         }
173         tc->t_tinc_hdr_rem = sizeof(struct rds_header);
174         tc->t_tinc_data_rem = 0;
175         rds_tcp_restore_callbacks(osock, tc);
176         release_sock(osock->sk);
177         sock_release(osock);
178 newsock:
179         rds_send_path_reset(cp);
180         lock_sock(sock->sk);
181         rds_tcp_set_callbacks(sock, cp);
182         release_sock(sock->sk);
183 }
184 
185 /* Add tc to rds_tcp_tc_list and set tc->t_sock. See comments
186  * above rds_tcp_reset_callbacks for notes about synchronization
187  * with data path
188  */
189 void rds_tcp_set_callbacks(struct socket *sock, struct rds_conn_path *cp)
190 {
191         struct rds_tcp_connection *tc = cp->cp_transport_data;
192 
193         rdsdebug("setting sock %p callbacks to tc %p\n", sock, tc);
194         write_lock_bh(&sock->sk->sk_callback_lock);
195 
196         /* done under the callback_lock to serialize with write_space */
197         spin_lock(&rds_tcp_tc_list_lock);
198         list_add_tail(&tc->t_list_item, &rds_tcp_tc_list);
199         rds_tcp_tc_count++;
200         spin_unlock(&rds_tcp_tc_list_lock);
201 
202         /* accepted sockets need our listen data ready undone */
203         if (sock->sk->sk_data_ready == rds_tcp_listen_data_ready)
204                 sock->sk->sk_data_ready = sock->sk->sk_user_data;
205 
206         tc->t_sock = sock;
207         tc->t_cpath = cp;
208         tc->t_orig_data_ready = sock->sk->sk_data_ready;
209         tc->t_orig_write_space = sock->sk->sk_write_space;
210         tc->t_orig_state_change = sock->sk->sk_state_change;
211 
212         sock->sk->sk_user_data = cp;
213         sock->sk->sk_data_ready = rds_tcp_data_ready;
214         sock->sk->sk_write_space = rds_tcp_write_space;
215         sock->sk->sk_state_change = rds_tcp_state_change;
216 
217         write_unlock_bh(&sock->sk->sk_callback_lock);
218 }
219 
220 static void rds_tcp_tc_info(struct socket *rds_sock, unsigned int len,
221                             struct rds_info_iterator *iter,
222                             struct rds_info_lengths *lens)
223 {
224         struct rds_info_tcp_socket tsinfo;
225         struct rds_tcp_connection *tc;
226         unsigned long flags;
227         struct sockaddr_in sin;
228         int sinlen;
229         struct socket *sock;
230 
231         spin_lock_irqsave(&rds_tcp_tc_list_lock, flags);
232 
233         if (len / sizeof(tsinfo) < rds_tcp_tc_count)
234                 goto out;
235 
236         list_for_each_entry(tc, &rds_tcp_tc_list, t_list_item) {
237 
238                 sock = tc->t_sock;
239                 if (sock) {
240                         sock->ops->getname(sock, (struct sockaddr *)&sin,
241                                            &sinlen, 0);
242                         tsinfo.local_addr = sin.sin_addr.s_addr;
243                         tsinfo.local_port = sin.sin_port;
244                         sock->ops->getname(sock, (struct sockaddr *)&sin,
245                                            &sinlen, 1);
246                         tsinfo.peer_addr = sin.sin_addr.s_addr;
247                         tsinfo.peer_port = sin.sin_port;
248                 }
249 
250                 tsinfo.hdr_rem = tc->t_tinc_hdr_rem;
251                 tsinfo.data_rem = tc->t_tinc_data_rem;
252                 tsinfo.last_sent_nxt = tc->t_last_sent_nxt;
253                 tsinfo.last_expected_una = tc->t_last_expected_una;
254                 tsinfo.last_seen_una = tc->t_last_seen_una;
255 
256                 rds_info_copy(iter, &tsinfo, sizeof(tsinfo));
257         }
258 
259 out:
260         lens->nr = rds_tcp_tc_count;
261         lens->each = sizeof(tsinfo);
262 
263         spin_unlock_irqrestore(&rds_tcp_tc_list_lock, flags);
264 }
265 
266 static int rds_tcp_laddr_check(struct net *net, __be32 addr)
267 {
268         if (inet_addr_type(net, addr) == RTN_LOCAL)
269                 return 0;
270         return -EADDRNOTAVAIL;
271 }
272 
273 static int rds_tcp_conn_alloc(struct rds_connection *conn, gfp_t gfp)
274 {
275         struct rds_tcp_connection *tc;
276         int i;
277 
278         for (i = 0; i < RDS_MPATH_WORKERS; i++) {
279                 tc = kmem_cache_alloc(rds_tcp_conn_slab, gfp);
280                 if (!tc)
281                         return -ENOMEM;
282 
283                 mutex_init(&tc->t_conn_path_lock);
284                 tc->t_sock = NULL;
285                 tc->t_tinc = NULL;
286                 tc->t_tinc_hdr_rem = sizeof(struct rds_header);
287                 tc->t_tinc_data_rem = 0;
288 
289                 conn->c_path[i].cp_transport_data = tc;
290                 tc->t_cpath = &conn->c_path[i];
291 
292                 spin_lock_irq(&rds_tcp_conn_lock);
293                 list_add_tail(&tc->t_tcp_node, &rds_tcp_conn_list);
294                 spin_unlock_irq(&rds_tcp_conn_lock);
295                 rdsdebug("rds_conn_path [%d] tc %p\n", i,
296                          conn->c_path[i].cp_transport_data);
297         }
298 
299         return 0;
300 }
301 
302 static void rds_tcp_conn_free(void *arg)
303 {
304         struct rds_tcp_connection *tc = arg;
305         unsigned long flags;
306         rdsdebug("freeing tc %p\n", tc);
307 
308         spin_lock_irqsave(&rds_tcp_conn_lock, flags);
309         list_del(&tc->t_tcp_node);
310         spin_unlock_irqrestore(&rds_tcp_conn_lock, flags);
311 
312         kmem_cache_free(rds_tcp_conn_slab, tc);
313 }
314 
315 static bool list_has_conn(struct list_head *list, struct rds_connection *conn)
316 {
317         struct rds_tcp_connection *tc, *_tc;
318 
319         list_for_each_entry_safe(tc, _tc, list, t_tcp_node) {
320                 if (tc->t_cpath->cp_conn == conn)
321                         return true;
322         }
323         return false;
324 }
325 
326 static void rds_tcp_destroy_conns(void)
327 {
328         struct rds_tcp_connection *tc, *_tc;
329         LIST_HEAD(tmp_list);
330 
331         /* avoid calling conn_destroy with irqs off */
332         spin_lock_irq(&rds_tcp_conn_lock);
333         list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) {
334                 if (!list_has_conn(&tmp_list, tc->t_cpath->cp_conn))
335                         list_move_tail(&tc->t_tcp_node, &tmp_list);
336         }
337         spin_unlock_irq(&rds_tcp_conn_lock);
338 
339         list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node)
340                 rds_conn_destroy(tc->t_cpath->cp_conn);
341 }
342 
343 static void rds_tcp_exit(void);
344 
345 struct rds_transport rds_tcp_transport = {
346         .laddr_check            = rds_tcp_laddr_check,
347         .xmit_path_prepare      = rds_tcp_xmit_path_prepare,
348         .xmit_path_complete     = rds_tcp_xmit_path_complete,
349         .xmit                   = rds_tcp_xmit,
350         .recv_path              = rds_tcp_recv_path,
351         .conn_alloc             = rds_tcp_conn_alloc,
352         .conn_free              = rds_tcp_conn_free,
353         .conn_path_connect      = rds_tcp_conn_path_connect,
354         .conn_path_shutdown     = rds_tcp_conn_path_shutdown,
355         .inc_copy_to_user       = rds_tcp_inc_copy_to_user,
356         .inc_free               = rds_tcp_inc_free,
357         .stats_info_copy        = rds_tcp_stats_info_copy,
358         .exit                   = rds_tcp_exit,
359         .t_owner                = THIS_MODULE,
360         .t_name                 = "tcp",
361         .t_type                 = RDS_TRANS_TCP,
362         .t_prefer_loopback      = 1,
363         .t_mp_capable           = 1,
364 };
365 
366 static unsigned int rds_tcp_netid;
367 
368 /* per-network namespace private data for this module */
369 struct rds_tcp_net {
370         struct socket *rds_tcp_listen_sock;
371         struct work_struct rds_tcp_accept_w;
372         struct ctl_table_header *rds_tcp_sysctl;
373         struct ctl_table *ctl_table;
374         int sndbuf_size;
375         int rcvbuf_size;
376 };
377 
378 /* All module specific customizations to the RDS-TCP socket should be done in
379  * rds_tcp_tune() and applied after socket creation.
380  */
381 void rds_tcp_tune(struct socket *sock)
382 {
383         struct sock *sk = sock->sk;
384         struct net *net = sock_net(sk);
385         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
386 
387         rds_tcp_nonagle(sock);
388         lock_sock(sk);
389         if (rtn->sndbuf_size > 0) {
390                 sk->sk_sndbuf = rtn->sndbuf_size;
391                 sk->sk_userlocks |= SOCK_SNDBUF_LOCK;
392         }
393         if (rtn->rcvbuf_size > 0) {
394                 sk->sk_sndbuf = rtn->rcvbuf_size;
395                 sk->sk_userlocks |= SOCK_RCVBUF_LOCK;
396         }
397         release_sock(sk);
398 }
399 
400 static void rds_tcp_accept_worker(struct work_struct *work)
401 {
402         struct rds_tcp_net *rtn = container_of(work,
403                                                struct rds_tcp_net,
404                                                rds_tcp_accept_w);
405 
406         while (rds_tcp_accept_one(rtn->rds_tcp_listen_sock) == 0)
407                 cond_resched();
408 }
409 
410 void rds_tcp_accept_work(struct sock *sk)
411 {
412         struct net *net = sock_net(sk);
413         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
414 
415         queue_work(rds_wq, &rtn->rds_tcp_accept_w);
416 }
417 
418 static __net_init int rds_tcp_init_net(struct net *net)
419 {
420         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
421         struct ctl_table *tbl;
422         int err = 0;
423 
424         memset(rtn, 0, sizeof(*rtn));
425 
426         /* {snd, rcv}buf_size default to 0, which implies we let the
427          * stack pick the value, and permit auto-tuning of buffer size.
428          */
429         if (net == &init_net) {
430                 tbl = rds_tcp_sysctl_table;
431         } else {
432                 tbl = kmemdup(rds_tcp_sysctl_table,
433                               sizeof(rds_tcp_sysctl_table), GFP_KERNEL);
434                 if (!tbl) {
435                         pr_warn("could not set allocate syctl table\n");
436                         return -ENOMEM;
437                 }
438                 rtn->ctl_table = tbl;
439         }
440         tbl[RDS_TCP_SNDBUF].data = &rtn->sndbuf_size;
441         tbl[RDS_TCP_RCVBUF].data = &rtn->rcvbuf_size;
442         rtn->rds_tcp_sysctl = register_net_sysctl(net, "net/rds/tcp", tbl);
443         if (!rtn->rds_tcp_sysctl) {
444                 pr_warn("could not register sysctl\n");
445                 err = -ENOMEM;
446                 goto fail;
447         }
448         rtn->rds_tcp_listen_sock = rds_tcp_listen_init(net);
449         if (!rtn->rds_tcp_listen_sock) {
450                 pr_warn("could not set up listen sock\n");
451                 unregister_net_sysctl_table(rtn->rds_tcp_sysctl);
452                 rtn->rds_tcp_sysctl = NULL;
453                 err = -EAFNOSUPPORT;
454                 goto fail;
455         }
456         INIT_WORK(&rtn->rds_tcp_accept_w, rds_tcp_accept_worker);
457         return 0;
458 
459 fail:
460         if (net != &init_net)
461                 kfree(tbl);
462         return err;
463 }
464 
465 static void __net_exit rds_tcp_exit_net(struct net *net)
466 {
467         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
468 
469         if (rtn->rds_tcp_sysctl)
470                 unregister_net_sysctl_table(rtn->rds_tcp_sysctl);
471 
472         if (net != &init_net && rtn->ctl_table)
473                 kfree(rtn->ctl_table);
474 
475         /* If rds_tcp_exit_net() is called as a result of netns deletion,
476          * the rds_tcp_kill_sock() device notifier would already have cleaned
477          * up the listen socket, thus there is no work to do in this function.
478          *
479          * If rds_tcp_exit_net() is called as a result of module unload,
480          * i.e., due to rds_tcp_exit() -> unregister_pernet_subsys(), then
481          * we do need to clean up the listen socket here.
482          */
483         if (rtn->rds_tcp_listen_sock) {
484                 struct socket *lsock = rtn->rds_tcp_listen_sock;
485 
486                 rtn->rds_tcp_listen_sock = NULL;
487                 rds_tcp_listen_stop(lsock, &rtn->rds_tcp_accept_w);
488         }
489 }
490 
491 static struct pernet_operations rds_tcp_net_ops = {
492         .init = rds_tcp_init_net,
493         .exit = rds_tcp_exit_net,
494         .id = &rds_tcp_netid,
495         .size = sizeof(struct rds_tcp_net),
496 };
497 
498 /* explicitly send a RST on each socket, thereby releasing any socket refcnts
499  * that may otherwise hold up netns deletion.
500  */
501 static void rds_tcp_conn_paths_destroy(struct rds_connection *conn)
502 {
503         struct rds_conn_path *cp;
504         struct rds_tcp_connection *tc;
505         int i;
506         struct sock *sk;
507 
508         for (i = 0; i < RDS_MPATH_WORKERS; i++) {
509                 cp = &conn->c_path[i];
510                 tc = cp->cp_transport_data;
511                 if (!tc->t_sock)
512                         continue;
513                 sk = tc->t_sock->sk;
514                 sk->sk_prot->disconnect(sk, 0);
515                 tcp_done(sk);
516         }
517 }
518 
519 static void rds_tcp_kill_sock(struct net *net)
520 {
521         struct rds_tcp_connection *tc, *_tc;
522         LIST_HEAD(tmp_list);
523         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
524         struct socket *lsock = rtn->rds_tcp_listen_sock;
525 
526         rtn->rds_tcp_listen_sock = NULL;
527         rds_tcp_listen_stop(lsock, &rtn->rds_tcp_accept_w);
528         spin_lock_irq(&rds_tcp_conn_lock);
529         list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) {
530                 struct net *c_net = tc->t_cpath->cp_conn->c_net;
531 
532                 if (net != c_net || !tc->t_sock)
533                         continue;
534                 if (!list_has_conn(&tmp_list, tc->t_cpath->cp_conn))
535                         list_move_tail(&tc->t_tcp_node, &tmp_list);
536         }
537         spin_unlock_irq(&rds_tcp_conn_lock);
538         list_for_each_entry_safe(tc, _tc, &tmp_list, t_tcp_node) {
539                 rds_tcp_conn_paths_destroy(tc->t_cpath->cp_conn);
540                 rds_conn_destroy(tc->t_cpath->cp_conn);
541         }
542 }
543 
544 void *rds_tcp_listen_sock_def_readable(struct net *net)
545 {
546         struct rds_tcp_net *rtn = net_generic(net, rds_tcp_netid);
547         struct socket *lsock = rtn->rds_tcp_listen_sock;
548 
549         if (!lsock)
550                 return NULL;
551 
552         return lsock->sk->sk_user_data;
553 }
554 
555 static int rds_tcp_dev_event(struct notifier_block *this,
556                              unsigned long event, void *ptr)
557 {
558         struct net_device *dev = netdev_notifier_info_to_dev(ptr);
559 
560         /* rds-tcp registers as a pernet subys, so the ->exit will only
561          * get invoked after network acitivity has quiesced. We need to
562          * clean up all sockets  to quiesce network activity, and use
563          * the unregistration of the per-net loopback device as a trigger
564          * to start that cleanup.
565          */
566         if (event == NETDEV_UNREGISTER_FINAL &&
567             dev->ifindex == LOOPBACK_IFINDEX)
568                 rds_tcp_kill_sock(dev_net(dev));
569 
570         return NOTIFY_DONE;
571 }
572 
573 static struct notifier_block rds_tcp_dev_notifier = {
574         .notifier_call        = rds_tcp_dev_event,
575         .priority = -10, /* must be called after other network notifiers */
576 };
577 
578 /* when sysctl is used to modify some kernel socket parameters,this
579  * function  resets the RDS connections in that netns  so that we can
580  * restart with new parameters.  The assumption is that such reset
581  * events are few and far-between.
582  */
583 static void rds_tcp_sysctl_reset(struct net *net)
584 {
585         struct rds_tcp_connection *tc, *_tc;
586 
587         spin_lock_irq(&rds_tcp_conn_lock);
588         list_for_each_entry_safe(tc, _tc, &rds_tcp_conn_list, t_tcp_node) {
589                 struct net *c_net = tc->t_cpath->cp_conn->c_net;
590 
591                 if (net != c_net || !tc->t_sock)
592                         continue;
593 
594                 /* reconnect with new parameters */
595                 rds_conn_path_drop(tc->t_cpath);
596         }
597         spin_unlock_irq(&rds_tcp_conn_lock);
598 }
599 
600 static int rds_tcp_skbuf_handler(struct ctl_table *ctl, int write,
601                                  void __user *buffer, size_t *lenp,
602                                  loff_t *fpos)
603 {
604         struct net *net = current->nsproxy->net_ns;
605         int err;
606 
607         err = proc_dointvec_minmax(ctl, write, buffer, lenp, fpos);
608         if (err < 0) {
609                 pr_warn("Invalid input. Must be >= %d\n",
610                         *(int *)(ctl->extra1));
611                 return err;
612         }
613         if (write)
614                 rds_tcp_sysctl_reset(net);
615         return 0;
616 }
617 
618 static void rds_tcp_exit(void)
619 {
620         rds_info_deregister_func(RDS_INFO_TCP_SOCKETS, rds_tcp_tc_info);
621         unregister_pernet_subsys(&rds_tcp_net_ops);
622         if (unregister_netdevice_notifier(&rds_tcp_dev_notifier))
623                 pr_warn("could not unregister rds_tcp_dev_notifier\n");
624         rds_tcp_destroy_conns();
625         rds_trans_unregister(&rds_tcp_transport);
626         rds_tcp_recv_exit();
627         kmem_cache_destroy(rds_tcp_conn_slab);
628 }
629 module_exit(rds_tcp_exit);
630 
631 static int rds_tcp_init(void)
632 {
633         int ret;
634 
635         rds_tcp_conn_slab = kmem_cache_create("rds_tcp_connection",
636                                               sizeof(struct rds_tcp_connection),
637                                               0, 0, NULL);
638         if (!rds_tcp_conn_slab) {
639                 ret = -ENOMEM;
640                 goto out;
641         }
642 
643         ret = rds_tcp_recv_init();
644         if (ret)
645                 goto out_slab;
646 
647         ret = register_pernet_subsys(&rds_tcp_net_ops);
648         if (ret)
649                 goto out_recv;
650 
651         ret = register_netdevice_notifier(&rds_tcp_dev_notifier);
652         if (ret) {
653                 pr_warn("could not register rds_tcp_dev_notifier\n");
654                 goto out_pernet;
655         }
656 
657         rds_trans_register(&rds_tcp_transport);
658 
659         rds_info_register_func(RDS_INFO_TCP_SOCKETS, rds_tcp_tc_info);
660 
661         goto out;
662 
663 out_pernet:
664         unregister_pernet_subsys(&rds_tcp_net_ops);
665 out_recv:
666         rds_tcp_recv_exit();
667 out_slab:
668         kmem_cache_destroy(rds_tcp_conn_slab);
669 out:
670         return ret;
671 }
672 module_init(rds_tcp_init);
673 
674 MODULE_AUTHOR("Oracle Corporation <rds-devel@oss.oracle.com>");
675 MODULE_DESCRIPTION("RDS: TCP transport");
676 MODULE_LICENSE("Dual BSD/GPL");
677 
678 

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