xref: /openbmc/linux/net/smc/smc_close.c (revision 0f613bfa)
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  *  Shared Memory Communications over RDMA (SMC-R) and RoCE
4  *
5  *  Socket Closing - normal and abnormal
6  *
7  *  Copyright IBM Corp. 2016
8  *
9  *  Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
10  */
11 
12 #include <linux/workqueue.h>
13 #include <linux/sched/signal.h>
14 
15 #include <net/sock.h>
16 #include <net/tcp.h>
17 
18 #include "smc.h"
19 #include "smc_tx.h"
20 #include "smc_cdc.h"
21 #include "smc_close.h"
22 
23 /* release the clcsock that is assigned to the smc_sock */
24 void smc_clcsock_release(struct smc_sock *smc)
25 {
26 	struct socket *tcp;
27 
28 	if (smc->listen_smc && current_work() != &smc->smc_listen_work)
29 		cancel_work_sync(&smc->smc_listen_work);
30 	mutex_lock(&smc->clcsock_release_lock);
31 	if (smc->clcsock) {
32 		tcp = smc->clcsock;
33 		smc->clcsock = NULL;
34 		sock_release(tcp);
35 	}
36 	mutex_unlock(&smc->clcsock_release_lock);
37 }
38 
39 static void smc_close_cleanup_listen(struct sock *parent)
40 {
41 	struct sock *sk;
42 
43 	/* Close non-accepted connections */
44 	while ((sk = smc_accept_dequeue(parent, NULL)))
45 		smc_close_non_accepted(sk);
46 }
47 
48 /* wait for sndbuf data being transmitted */
49 static void smc_close_stream_wait(struct smc_sock *smc, long timeout)
50 {
51 	DEFINE_WAIT_FUNC(wait, woken_wake_function);
52 	struct sock *sk = &smc->sk;
53 
54 	if (!timeout)
55 		return;
56 
57 	if (!smc_tx_prepared_sends(&smc->conn))
58 		return;
59 
60 	/* Send out corked data remaining in sndbuf */
61 	smc_tx_pending(&smc->conn);
62 
63 	smc->wait_close_tx_prepared = 1;
64 	add_wait_queue(sk_sleep(sk), &wait);
65 	while (!signal_pending(current) && timeout) {
66 		int rc;
67 
68 		rc = sk_wait_event(sk, &timeout,
69 				   !smc_tx_prepared_sends(&smc->conn) ||
70 				   READ_ONCE(sk->sk_err) == ECONNABORTED ||
71 				   READ_ONCE(sk->sk_err) == ECONNRESET ||
72 				   smc->conn.killed,
73 				   &wait);
74 		if (rc)
75 			break;
76 	}
77 	remove_wait_queue(sk_sleep(sk), &wait);
78 	smc->wait_close_tx_prepared = 0;
79 }
80 
81 void smc_close_wake_tx_prepared(struct smc_sock *smc)
82 {
83 	if (smc->wait_close_tx_prepared)
84 		/* wake up socket closing */
85 		smc->sk.sk_state_change(&smc->sk);
86 }
87 
88 static int smc_close_wr(struct smc_connection *conn)
89 {
90 	conn->local_tx_ctrl.conn_state_flags.peer_done_writing = 1;
91 
92 	return smc_cdc_get_slot_and_msg_send(conn);
93 }
94 
95 static int smc_close_final(struct smc_connection *conn)
96 {
97 	if (atomic_read(&conn->bytes_to_rcv))
98 		conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
99 	else
100 		conn->local_tx_ctrl.conn_state_flags.peer_conn_closed = 1;
101 	if (conn->killed)
102 		return -EPIPE;
103 
104 	return smc_cdc_get_slot_and_msg_send(conn);
105 }
106 
107 int smc_close_abort(struct smc_connection *conn)
108 {
109 	conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
110 
111 	return smc_cdc_get_slot_and_msg_send(conn);
112 }
113 
114 static void smc_close_cancel_work(struct smc_sock *smc)
115 {
116 	struct sock *sk = &smc->sk;
117 
118 	release_sock(sk);
119 	cancel_work_sync(&smc->conn.close_work);
120 	cancel_delayed_work_sync(&smc->conn.tx_work);
121 	lock_sock(sk);
122 }
123 
124 /* terminate smc socket abnormally - active abort
125  * link group is terminated, i.e. RDMA communication no longer possible
126  */
127 void smc_close_active_abort(struct smc_sock *smc)
128 {
129 	struct sock *sk = &smc->sk;
130 	bool release_clcsock = false;
131 
132 	if (sk->sk_state != SMC_INIT && smc->clcsock && smc->clcsock->sk) {
133 		sk->sk_err = ECONNABORTED;
134 		if (smc->clcsock && smc->clcsock->sk)
135 			tcp_abort(smc->clcsock->sk, ECONNABORTED);
136 	}
137 	switch (sk->sk_state) {
138 	case SMC_ACTIVE:
139 	case SMC_APPCLOSEWAIT1:
140 	case SMC_APPCLOSEWAIT2:
141 		sk->sk_state = SMC_PEERABORTWAIT;
142 		smc_close_cancel_work(smc);
143 		if (sk->sk_state != SMC_PEERABORTWAIT)
144 			break;
145 		sk->sk_state = SMC_CLOSED;
146 		sock_put(sk); /* (postponed) passive closing */
147 		break;
148 	case SMC_PEERCLOSEWAIT1:
149 	case SMC_PEERCLOSEWAIT2:
150 	case SMC_PEERFINCLOSEWAIT:
151 		sk->sk_state = SMC_PEERABORTWAIT;
152 		smc_close_cancel_work(smc);
153 		if (sk->sk_state != SMC_PEERABORTWAIT)
154 			break;
155 		sk->sk_state = SMC_CLOSED;
156 		smc_conn_free(&smc->conn);
157 		release_clcsock = true;
158 		sock_put(sk); /* passive closing */
159 		break;
160 	case SMC_PROCESSABORT:
161 	case SMC_APPFINCLOSEWAIT:
162 		sk->sk_state = SMC_PEERABORTWAIT;
163 		smc_close_cancel_work(smc);
164 		if (sk->sk_state != SMC_PEERABORTWAIT)
165 			break;
166 		sk->sk_state = SMC_CLOSED;
167 		smc_conn_free(&smc->conn);
168 		release_clcsock = true;
169 		break;
170 	case SMC_INIT:
171 	case SMC_PEERABORTWAIT:
172 	case SMC_CLOSED:
173 		break;
174 	}
175 
176 	sock_set_flag(sk, SOCK_DEAD);
177 	sk->sk_state_change(sk);
178 
179 	if (release_clcsock) {
180 		release_sock(sk);
181 		smc_clcsock_release(smc);
182 		lock_sock(sk);
183 	}
184 }
185 
186 static inline bool smc_close_sent_any_close(struct smc_connection *conn)
187 {
188 	return conn->local_tx_ctrl.conn_state_flags.peer_conn_abort ||
189 	       conn->local_tx_ctrl.conn_state_flags.peer_conn_closed;
190 }
191 
192 int smc_close_active(struct smc_sock *smc)
193 {
194 	struct smc_cdc_conn_state_flags *txflags =
195 		&smc->conn.local_tx_ctrl.conn_state_flags;
196 	struct smc_connection *conn = &smc->conn;
197 	struct sock *sk = &smc->sk;
198 	int old_state;
199 	long timeout;
200 	int rc = 0;
201 	int rc1 = 0;
202 
203 	timeout = current->flags & PF_EXITING ?
204 		  0 : sock_flag(sk, SOCK_LINGER) ?
205 		      sk->sk_lingertime : SMC_MAX_STREAM_WAIT_TIMEOUT;
206 
207 	old_state = sk->sk_state;
208 again:
209 	switch (sk->sk_state) {
210 	case SMC_INIT:
211 		sk->sk_state = SMC_CLOSED;
212 		break;
213 	case SMC_LISTEN:
214 		sk->sk_state = SMC_CLOSED;
215 		sk->sk_state_change(sk); /* wake up accept */
216 		if (smc->clcsock && smc->clcsock->sk) {
217 			write_lock_bh(&smc->clcsock->sk->sk_callback_lock);
218 			smc_clcsock_restore_cb(&smc->clcsock->sk->sk_data_ready,
219 					       &smc->clcsk_data_ready);
220 			smc->clcsock->sk->sk_user_data = NULL;
221 			write_unlock_bh(&smc->clcsock->sk->sk_callback_lock);
222 			rc = kernel_sock_shutdown(smc->clcsock, SHUT_RDWR);
223 		}
224 		smc_close_cleanup_listen(sk);
225 		release_sock(sk);
226 		flush_work(&smc->tcp_listen_work);
227 		lock_sock(sk);
228 		break;
229 	case SMC_ACTIVE:
230 		smc_close_stream_wait(smc, timeout);
231 		release_sock(sk);
232 		cancel_delayed_work_sync(&conn->tx_work);
233 		lock_sock(sk);
234 		if (sk->sk_state == SMC_ACTIVE) {
235 			/* send close request */
236 			rc = smc_close_final(conn);
237 			sk->sk_state = SMC_PEERCLOSEWAIT1;
238 
239 			/* actively shutdown clcsock before peer close it,
240 			 * prevent peer from entering TIME_WAIT state.
241 			 */
242 			if (smc->clcsock && smc->clcsock->sk) {
243 				rc1 = kernel_sock_shutdown(smc->clcsock,
244 							   SHUT_RDWR);
245 				rc = rc ? rc : rc1;
246 			}
247 		} else {
248 			/* peer event has changed the state */
249 			goto again;
250 		}
251 		break;
252 	case SMC_APPFINCLOSEWAIT:
253 		/* socket already shutdown wr or both (active close) */
254 		if (txflags->peer_done_writing &&
255 		    !smc_close_sent_any_close(conn)) {
256 			/* just shutdown wr done, send close request */
257 			rc = smc_close_final(conn);
258 		}
259 		sk->sk_state = SMC_CLOSED;
260 		break;
261 	case SMC_APPCLOSEWAIT1:
262 	case SMC_APPCLOSEWAIT2:
263 		if (!smc_cdc_rxed_any_close(conn))
264 			smc_close_stream_wait(smc, timeout);
265 		release_sock(sk);
266 		cancel_delayed_work_sync(&conn->tx_work);
267 		lock_sock(sk);
268 		if (sk->sk_state != SMC_APPCLOSEWAIT1 &&
269 		    sk->sk_state != SMC_APPCLOSEWAIT2)
270 			goto again;
271 		/* confirm close from peer */
272 		rc = smc_close_final(conn);
273 		if (smc_cdc_rxed_any_close(conn)) {
274 			/* peer has closed the socket already */
275 			sk->sk_state = SMC_CLOSED;
276 			sock_put(sk); /* postponed passive closing */
277 		} else {
278 			/* peer has just issued a shutdown write */
279 			sk->sk_state = SMC_PEERFINCLOSEWAIT;
280 		}
281 		break;
282 	case SMC_PEERCLOSEWAIT1:
283 	case SMC_PEERCLOSEWAIT2:
284 		if (txflags->peer_done_writing &&
285 		    !smc_close_sent_any_close(conn)) {
286 			/* just shutdown wr done, send close request */
287 			rc = smc_close_final(conn);
288 		}
289 		/* peer sending PeerConnectionClosed will cause transition */
290 		break;
291 	case SMC_PEERFINCLOSEWAIT:
292 		/* peer sending PeerConnectionClosed will cause transition */
293 		break;
294 	case SMC_PROCESSABORT:
295 		rc = smc_close_abort(conn);
296 		sk->sk_state = SMC_CLOSED;
297 		break;
298 	case SMC_PEERABORTWAIT:
299 		sk->sk_state = SMC_CLOSED;
300 		break;
301 	case SMC_CLOSED:
302 		/* nothing to do, add tracing in future patch */
303 		break;
304 	}
305 
306 	if (old_state != sk->sk_state)
307 		sk->sk_state_change(sk);
308 	return rc;
309 }
310 
311 static void smc_close_passive_abort_received(struct smc_sock *smc)
312 {
313 	struct smc_cdc_conn_state_flags *txflags =
314 		&smc->conn.local_tx_ctrl.conn_state_flags;
315 	struct sock *sk = &smc->sk;
316 
317 	switch (sk->sk_state) {
318 	case SMC_INIT:
319 	case SMC_ACTIVE:
320 	case SMC_APPCLOSEWAIT1:
321 		sk->sk_state = SMC_PROCESSABORT;
322 		sock_put(sk); /* passive closing */
323 		break;
324 	case SMC_APPFINCLOSEWAIT:
325 		sk->sk_state = SMC_PROCESSABORT;
326 		break;
327 	case SMC_PEERCLOSEWAIT1:
328 	case SMC_PEERCLOSEWAIT2:
329 		if (txflags->peer_done_writing &&
330 		    !smc_close_sent_any_close(&smc->conn))
331 			/* just shutdown, but not yet closed locally */
332 			sk->sk_state = SMC_PROCESSABORT;
333 		else
334 			sk->sk_state = SMC_CLOSED;
335 		sock_put(sk); /* passive closing */
336 		break;
337 	case SMC_APPCLOSEWAIT2:
338 	case SMC_PEERFINCLOSEWAIT:
339 		sk->sk_state = SMC_CLOSED;
340 		sock_put(sk); /* passive closing */
341 		break;
342 	case SMC_PEERABORTWAIT:
343 		sk->sk_state = SMC_CLOSED;
344 		break;
345 	case SMC_PROCESSABORT:
346 	/* nothing to do, add tracing in future patch */
347 		break;
348 	}
349 }
350 
351 /* Either some kind of closing has been received: peer_conn_closed,
352  * peer_conn_abort, or peer_done_writing
353  * or the link group of the connection terminates abnormally.
354  */
355 static void smc_close_passive_work(struct work_struct *work)
356 {
357 	struct smc_connection *conn = container_of(work,
358 						   struct smc_connection,
359 						   close_work);
360 	struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
361 	struct smc_cdc_conn_state_flags *rxflags;
362 	bool release_clcsock = false;
363 	struct sock *sk = &smc->sk;
364 	int old_state;
365 
366 	lock_sock(sk);
367 	old_state = sk->sk_state;
368 
369 	rxflags = &conn->local_rx_ctrl.conn_state_flags;
370 	if (rxflags->peer_conn_abort) {
371 		/* peer has not received all data */
372 		smc_close_passive_abort_received(smc);
373 		release_sock(sk);
374 		cancel_delayed_work_sync(&conn->tx_work);
375 		lock_sock(sk);
376 		goto wakeup;
377 	}
378 
379 	switch (sk->sk_state) {
380 	case SMC_INIT:
381 		sk->sk_state = SMC_APPCLOSEWAIT1;
382 		break;
383 	case SMC_ACTIVE:
384 		sk->sk_state = SMC_APPCLOSEWAIT1;
385 		/* postpone sock_put() for passive closing to cover
386 		 * received SEND_SHUTDOWN as well
387 		 */
388 		break;
389 	case SMC_PEERCLOSEWAIT1:
390 		if (rxflags->peer_done_writing)
391 			sk->sk_state = SMC_PEERCLOSEWAIT2;
392 		fallthrough;
393 		/* to check for closing */
394 	case SMC_PEERCLOSEWAIT2:
395 		if (!smc_cdc_rxed_any_close(conn))
396 			break;
397 		if (sock_flag(sk, SOCK_DEAD) &&
398 		    smc_close_sent_any_close(conn)) {
399 			/* smc_release has already been called locally */
400 			sk->sk_state = SMC_CLOSED;
401 		} else {
402 			/* just shutdown, but not yet closed locally */
403 			sk->sk_state = SMC_APPFINCLOSEWAIT;
404 		}
405 		sock_put(sk); /* passive closing */
406 		break;
407 	case SMC_PEERFINCLOSEWAIT:
408 		if (smc_cdc_rxed_any_close(conn)) {
409 			sk->sk_state = SMC_CLOSED;
410 			sock_put(sk); /* passive closing */
411 		}
412 		break;
413 	case SMC_APPCLOSEWAIT1:
414 	case SMC_APPCLOSEWAIT2:
415 		/* postpone sock_put() for passive closing to cover
416 		 * received SEND_SHUTDOWN as well
417 		 */
418 		break;
419 	case SMC_APPFINCLOSEWAIT:
420 	case SMC_PEERABORTWAIT:
421 	case SMC_PROCESSABORT:
422 	case SMC_CLOSED:
423 		/* nothing to do, add tracing in future patch */
424 		break;
425 	}
426 
427 wakeup:
428 	sk->sk_data_ready(sk); /* wakeup blocked rcvbuf consumers */
429 	sk->sk_write_space(sk); /* wakeup blocked sndbuf producers */
430 
431 	if (old_state != sk->sk_state) {
432 		sk->sk_state_change(sk);
433 		if ((sk->sk_state == SMC_CLOSED) &&
434 		    (sock_flag(sk, SOCK_DEAD) || !sk->sk_socket)) {
435 			smc_conn_free(conn);
436 			if (smc->clcsock)
437 				release_clcsock = true;
438 		}
439 	}
440 	release_sock(sk);
441 	if (release_clcsock)
442 		smc_clcsock_release(smc);
443 	sock_put(sk); /* sock_hold done by schedulers of close_work */
444 }
445 
446 int smc_close_shutdown_write(struct smc_sock *smc)
447 {
448 	struct smc_connection *conn = &smc->conn;
449 	struct sock *sk = &smc->sk;
450 	int old_state;
451 	long timeout;
452 	int rc = 0;
453 
454 	timeout = current->flags & PF_EXITING ?
455 		  0 : sock_flag(sk, SOCK_LINGER) ?
456 		      sk->sk_lingertime : SMC_MAX_STREAM_WAIT_TIMEOUT;
457 
458 	old_state = sk->sk_state;
459 again:
460 	switch (sk->sk_state) {
461 	case SMC_ACTIVE:
462 		smc_close_stream_wait(smc, timeout);
463 		release_sock(sk);
464 		cancel_delayed_work_sync(&conn->tx_work);
465 		lock_sock(sk);
466 		if (sk->sk_state != SMC_ACTIVE)
467 			goto again;
468 		/* send close wr request */
469 		rc = smc_close_wr(conn);
470 		sk->sk_state = SMC_PEERCLOSEWAIT1;
471 		break;
472 	case SMC_APPCLOSEWAIT1:
473 		/* passive close */
474 		if (!smc_cdc_rxed_any_close(conn))
475 			smc_close_stream_wait(smc, timeout);
476 		release_sock(sk);
477 		cancel_delayed_work_sync(&conn->tx_work);
478 		lock_sock(sk);
479 		if (sk->sk_state != SMC_APPCLOSEWAIT1)
480 			goto again;
481 		/* confirm close from peer */
482 		rc = smc_close_wr(conn);
483 		sk->sk_state = SMC_APPCLOSEWAIT2;
484 		break;
485 	case SMC_APPCLOSEWAIT2:
486 	case SMC_PEERFINCLOSEWAIT:
487 	case SMC_PEERCLOSEWAIT1:
488 	case SMC_PEERCLOSEWAIT2:
489 	case SMC_APPFINCLOSEWAIT:
490 	case SMC_PROCESSABORT:
491 	case SMC_PEERABORTWAIT:
492 		/* nothing to do, add tracing in future patch */
493 		break;
494 	}
495 
496 	if (old_state != sk->sk_state)
497 		sk->sk_state_change(sk);
498 	return rc;
499 }
500 
501 /* Initialize close properties on connection establishment. */
502 void smc_close_init(struct smc_sock *smc)
503 {
504 	INIT_WORK(&smc->conn.close_work, smc_close_passive_work);
505 }
506