ed5dcf03fe0b6ded9d363c1e5891be76f86fd49c
[sfrench/cifs-2.6.git] / net / smc / smc_cdc.c
1 // SPDX-License-Identifier: GPL-2.0
2 /*
3  * Shared Memory Communications over RDMA (SMC-R) and RoCE
4  *
5  * Connection Data Control (CDC)
6  * handles flow control
7  *
8  * Copyright IBM Corp. 2016
9  *
10  * Author(s):  Ursula Braun <ubraun@linux.vnet.ibm.com>
11  */
12
13 #include <linux/spinlock.h>
14
15 #include "smc.h"
16 #include "smc_wr.h"
17 #include "smc_cdc.h"
18 #include "smc_tx.h"
19 #include "smc_rx.h"
20 #include "smc_close.h"
21
22 /********************************** send *************************************/
23
24 struct smc_cdc_tx_pend {
25         struct smc_connection   *conn;          /* socket connection */
26         union smc_host_cursor   cursor; /* tx sndbuf cursor sent */
27         union smc_host_cursor   p_cursor;       /* rx RMBE cursor produced */
28         u16                     ctrl_seq;       /* conn. tx sequence # */
29 };
30
31 /* handler for send/transmission completion of a CDC msg */
32 static void smc_cdc_tx_handler(struct smc_wr_tx_pend_priv *pnd_snd,
33                                struct smc_link *link,
34                                enum ib_wc_status wc_status)
35 {
36         struct smc_cdc_tx_pend *cdcpend = (struct smc_cdc_tx_pend *)pnd_snd;
37         struct smc_connection *conn = cdcpend->conn;
38         struct smc_sock *smc;
39         int diff;
40
41         if (!conn)
42                 /* already dismissed */
43                 return;
44
45         smc = container_of(conn, struct smc_sock, conn);
46         bh_lock_sock(&smc->sk);
47         if (!wc_status) {
48                 diff = smc_curs_diff(cdcpend->conn->sndbuf_desc->len,
49                                      &cdcpend->conn->tx_curs_fin,
50                                      &cdcpend->cursor);
51                 /* sndbuf_space is decreased in smc_sendmsg */
52                 smp_mb__before_atomic();
53                 atomic_add(diff, &cdcpend->conn->sndbuf_space);
54                 /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
55                 smp_mb__after_atomic();
56                 smc_curs_copy(&conn->tx_curs_fin, &cdcpend->cursor, conn);
57         }
58         smc_tx_sndbuf_nonfull(smc);
59         bh_unlock_sock(&smc->sk);
60 }
61
62 int smc_cdc_get_free_slot(struct smc_connection *conn,
63                           struct smc_wr_buf **wr_buf,
64                           struct smc_cdc_tx_pend **pend)
65 {
66         struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
67         int rc;
68
69         rc = smc_wr_tx_get_free_slot(link, smc_cdc_tx_handler, wr_buf,
70                                      (struct smc_wr_tx_pend_priv **)pend);
71         if (!conn->alert_token_local)
72                 /* abnormal termination */
73                 rc = -EPIPE;
74         return rc;
75 }
76
77 static inline void smc_cdc_add_pending_send(struct smc_connection *conn,
78                                             struct smc_cdc_tx_pend *pend)
79 {
80         BUILD_BUG_ON_MSG(
81                 sizeof(struct smc_cdc_msg) > SMC_WR_BUF_SIZE,
82                 "must increase SMC_WR_BUF_SIZE to at least sizeof(struct smc_cdc_msg)");
83         BUILD_BUG_ON_MSG(
84                 sizeof(struct smc_cdc_msg) != SMC_WR_TX_SIZE,
85                 "must adapt SMC_WR_TX_SIZE to sizeof(struct smc_cdc_msg); if not all smc_wr upper layer protocols use the same message size any more, must start to set link->wr_tx_sges[i].length on each individual smc_wr_tx_send()");
86         BUILD_BUG_ON_MSG(
87                 sizeof(struct smc_cdc_tx_pend) > SMC_WR_TX_PEND_PRIV_SIZE,
88                 "must increase SMC_WR_TX_PEND_PRIV_SIZE to at least sizeof(struct smc_cdc_tx_pend)");
89         pend->conn = conn;
90         pend->cursor = conn->tx_curs_sent;
91         pend->p_cursor = conn->local_tx_ctrl.prod;
92         pend->ctrl_seq = conn->tx_cdc_seq;
93 }
94
95 int smc_cdc_msg_send(struct smc_connection *conn,
96                      struct smc_wr_buf *wr_buf,
97                      struct smc_cdc_tx_pend *pend)
98 {
99         struct smc_link *link;
100         int rc;
101
102         link = &conn->lgr->lnk[SMC_SINGLE_LINK];
103
104         smc_cdc_add_pending_send(conn, pend);
105
106         conn->tx_cdc_seq++;
107         conn->local_tx_ctrl.seqno = conn->tx_cdc_seq;
108         smc_host_msg_to_cdc((struct smc_cdc_msg *)wr_buf,
109                             &conn->local_tx_ctrl, conn);
110         rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend);
111         if (!rc)
112                 smc_curs_copy(&conn->rx_curs_confirmed,
113                               &conn->local_tx_ctrl.cons, conn);
114
115         return rc;
116 }
117
118 static int smcr_cdc_get_slot_and_msg_send(struct smc_connection *conn)
119 {
120         struct smc_cdc_tx_pend *pend;
121         struct smc_wr_buf *wr_buf;
122         int rc;
123
124         rc = smc_cdc_get_free_slot(conn, &wr_buf, &pend);
125         if (rc)
126                 return rc;
127
128         return smc_cdc_msg_send(conn, wr_buf, pend);
129 }
130
131 int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn)
132 {
133         int rc;
134
135         if (conn->lgr->is_smcd) {
136                 spin_lock_bh(&conn->send_lock);
137                 rc = smcd_cdc_msg_send(conn);
138                 spin_unlock_bh(&conn->send_lock);
139         } else {
140                 rc = smcr_cdc_get_slot_and_msg_send(conn);
141         }
142
143         return rc;
144 }
145
146 static bool smc_cdc_tx_filter(struct smc_wr_tx_pend_priv *tx_pend,
147                               unsigned long data)
148 {
149         struct smc_connection *conn = (struct smc_connection *)data;
150         struct smc_cdc_tx_pend *cdc_pend =
151                 (struct smc_cdc_tx_pend *)tx_pend;
152
153         return cdc_pend->conn == conn;
154 }
155
156 static void smc_cdc_tx_dismisser(struct smc_wr_tx_pend_priv *tx_pend)
157 {
158         struct smc_cdc_tx_pend *cdc_pend =
159                 (struct smc_cdc_tx_pend *)tx_pend;
160
161         cdc_pend->conn = NULL;
162 }
163
164 void smc_cdc_tx_dismiss_slots(struct smc_connection *conn)
165 {
166         struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
167
168         smc_wr_tx_dismiss_slots(link, SMC_CDC_MSG_TYPE,
169                                 smc_cdc_tx_filter, smc_cdc_tx_dismisser,
170                                 (unsigned long)conn);
171 }
172
173 /* Send a SMC-D CDC header.
174  * This increments the free space available in our send buffer.
175  * Also update the confirmed receive buffer with what was sent to the peer.
176  */
177 int smcd_cdc_msg_send(struct smc_connection *conn)
178 {
179         struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
180         struct smcd_cdc_msg cdc;
181         int rc, diff;
182
183         memset(&cdc, 0, sizeof(cdc));
184         cdc.common.type = SMC_CDC_MSG_TYPE;
185         cdc.prod_wrap = conn->local_tx_ctrl.prod.wrap;
186         cdc.prod_count = conn->local_tx_ctrl.prod.count;
187
188         cdc.cons_wrap = conn->local_tx_ctrl.cons.wrap;
189         cdc.cons_count = conn->local_tx_ctrl.cons.count;
190         cdc.prod_flags = conn->local_tx_ctrl.prod_flags;
191         cdc.conn_state_flags = conn->local_tx_ctrl.conn_state_flags;
192         rc = smcd_tx_ism_write(conn, &cdc, sizeof(cdc), 0, 1);
193         if (rc)
194                 return rc;
195         smc_curs_copy(&conn->rx_curs_confirmed, &conn->local_tx_ctrl.cons,
196                       conn);
197         /* Calculate transmitted data and increment free send buffer space */
198         diff = smc_curs_diff(conn->sndbuf_desc->len, &conn->tx_curs_fin,
199                              &conn->tx_curs_sent);
200         /* increased by confirmed number of bytes */
201         smp_mb__before_atomic();
202         atomic_add(diff, &conn->sndbuf_space);
203         /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
204         smp_mb__after_atomic();
205         smc_curs_copy(&conn->tx_curs_fin, &conn->tx_curs_sent, conn);
206
207         smc_tx_sndbuf_nonfull(smc);
208         return rc;
209 }
210
211 /********************************* receive ***********************************/
212
213 static inline bool smc_cdc_before(u16 seq1, u16 seq2)
214 {
215         return (s16)(seq1 - seq2) < 0;
216 }
217
218 static void smc_cdc_handle_urg_data_arrival(struct smc_sock *smc,
219                                             int *diff_prod)
220 {
221         struct smc_connection *conn = &smc->conn;
222         char *base;
223
224         /* new data included urgent business */
225         smc_curs_copy(&conn->urg_curs, &conn->local_rx_ctrl.prod, conn);
226         conn->urg_state = SMC_URG_VALID;
227         if (!sock_flag(&smc->sk, SOCK_URGINLINE))
228                 /* we'll skip the urgent byte, so don't account for it */
229                 (*diff_prod)--;
230         base = (char *)conn->rmb_desc->cpu_addr + conn->rx_off;
231         if (conn->urg_curs.count)
232                 conn->urg_rx_byte = *(base + conn->urg_curs.count - 1);
233         else
234                 conn->urg_rx_byte = *(base + conn->rmb_desc->len - 1);
235         sk_send_sigurg(&smc->sk);
236 }
237
238 static void smc_cdc_msg_recv_action(struct smc_sock *smc,
239                                     struct smc_cdc_msg *cdc)
240 {
241         union smc_host_cursor cons_old, prod_old;
242         struct smc_connection *conn = &smc->conn;
243         int diff_cons, diff_prod;
244
245         smc_curs_copy(&prod_old, &conn->local_rx_ctrl.prod, conn);
246         smc_curs_copy(&cons_old, &conn->local_rx_ctrl.cons, conn);
247         smc_cdc_msg_to_host(&conn->local_rx_ctrl, cdc, conn);
248
249         diff_cons = smc_curs_diff(conn->peer_rmbe_size, &cons_old,
250                                   &conn->local_rx_ctrl.cons);
251         if (diff_cons) {
252                 /* peer_rmbe_space is decreased during data transfer with RDMA
253                  * write
254                  */
255                 smp_mb__before_atomic();
256                 atomic_add(diff_cons, &conn->peer_rmbe_space);
257                 /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */
258                 smp_mb__after_atomic();
259         }
260
261         diff_prod = smc_curs_diff(conn->rmb_desc->len, &prod_old,
262                                   &conn->local_rx_ctrl.prod);
263         if (diff_prod) {
264                 if (conn->local_rx_ctrl.prod_flags.urg_data_present)
265                         smc_cdc_handle_urg_data_arrival(smc, &diff_prod);
266                 /* bytes_to_rcv is decreased in smc_recvmsg */
267                 smp_mb__before_atomic();
268                 atomic_add(diff_prod, &conn->bytes_to_rcv);
269                 /* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */
270                 smp_mb__after_atomic();
271                 smc->sk.sk_data_ready(&smc->sk);
272         } else {
273                 if (conn->local_rx_ctrl.prod_flags.write_blocked ||
274                     conn->local_rx_ctrl.prod_flags.cons_curs_upd_req ||
275                     conn->local_rx_ctrl.prod_flags.urg_data_pending) {
276                         if (conn->local_rx_ctrl.prod_flags.urg_data_pending)
277                                 conn->urg_state = SMC_URG_NOTYET;
278                         /* force immediate tx of current consumer cursor, but
279                          * under send_lock to guarantee arrival in seqno-order
280                          */
281                         if (smc->sk.sk_state != SMC_INIT)
282                                 smc_tx_sndbuf_nonempty(conn);
283                 }
284         }
285
286         /* piggy backed tx info */
287         /* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */
288         if (diff_cons && smc_tx_prepared_sends(conn)) {
289                 smc_tx_sndbuf_nonempty(conn);
290                 /* trigger socket release if connection closed */
291                 smc_close_wake_tx_prepared(smc);
292         }
293         if (diff_cons && conn->urg_tx_pend &&
294             atomic_read(&conn->peer_rmbe_space) == conn->peer_rmbe_size) {
295                 /* urg data confirmed by peer, indicate we're ready for more */
296                 conn->urg_tx_pend = false;
297                 smc->sk.sk_write_space(&smc->sk);
298         }
299
300         if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) {
301                 smc->sk.sk_err = ECONNRESET;
302                 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
303         }
304         if (smc_cdc_rxed_any_close_or_senddone(conn)) {
305                 smc->sk.sk_shutdown |= RCV_SHUTDOWN;
306                 if (smc->clcsock && smc->clcsock->sk)
307                         smc->clcsock->sk->sk_shutdown |= RCV_SHUTDOWN;
308                 sock_set_flag(&smc->sk, SOCK_DONE);
309                 sock_hold(&smc->sk); /* sock_put in close_work */
310                 if (!schedule_work(&conn->close_work))
311                         sock_put(&smc->sk);
312         }
313 }
314
315 /* called under tasklet context */
316 static void smc_cdc_msg_recv(struct smc_sock *smc, struct smc_cdc_msg *cdc)
317 {
318         sock_hold(&smc->sk);
319         bh_lock_sock(&smc->sk);
320         smc_cdc_msg_recv_action(smc, cdc);
321         bh_unlock_sock(&smc->sk);
322         sock_put(&smc->sk); /* no free sk in softirq-context */
323 }
324
325 /* Schedule a tasklet for this connection. Triggered from the ISM device IRQ
326  * handler to indicate update in the DMBE.
327  *
328  * Context:
329  * - tasklet context
330  */
331 static void smcd_cdc_rx_tsklet(unsigned long data)
332 {
333         struct smc_connection *conn = (struct smc_connection *)data;
334         struct smcd_cdc_msg cdc;
335         struct smc_sock *smc;
336
337         if (!conn)
338                 return;
339
340         memcpy(&cdc, conn->rmb_desc->cpu_addr, sizeof(cdc));
341         smc = container_of(conn, struct smc_sock, conn);
342         smc_cdc_msg_recv(smc, (struct smc_cdc_msg *)&cdc);
343 }
344
345 /* Initialize receive tasklet. Called from ISM device IRQ handler to start
346  * receiver side.
347  */
348 void smcd_cdc_rx_init(struct smc_connection *conn)
349 {
350         tasklet_init(&conn->rx_tsklet, smcd_cdc_rx_tsklet, (unsigned long)conn);
351 }
352
353 /***************************** init, exit, misc ******************************/
354
355 static void smc_cdc_rx_handler(struct ib_wc *wc, void *buf)
356 {
357         struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
358         struct smc_cdc_msg *cdc = buf;
359         struct smc_connection *conn;
360         struct smc_link_group *lgr;
361         struct smc_sock *smc;
362
363         if (wc->byte_len < offsetof(struct smc_cdc_msg, reserved))
364                 return; /* short message */
365         if (cdc->len != SMC_WR_TX_SIZE)
366                 return; /* invalid message */
367
368         /* lookup connection */
369         lgr = smc_get_lgr(link);
370         read_lock_bh(&lgr->conns_lock);
371         conn = smc_lgr_find_conn(ntohl(cdc->token), lgr);
372         read_unlock_bh(&lgr->conns_lock);
373         if (!conn)
374                 return;
375         smc = container_of(conn, struct smc_sock, conn);
376
377         if (!cdc->prod_flags.failover_validation) {
378                 if (smc_cdc_before(ntohs(cdc->seqno),
379                                    conn->local_rx_ctrl.seqno))
380                         /* received seqno is old */
381                         return;
382         }
383         smc_cdc_msg_recv(smc, cdc);
384 }
385
386 static struct smc_wr_rx_handler smc_cdc_rx_handlers[] = {
387         {
388                 .handler        = smc_cdc_rx_handler,
389                 .type           = SMC_CDC_MSG_TYPE
390         },
391         {
392                 .handler        = NULL,
393         }
394 };
395
396 int __init smc_cdc_init(void)
397 {
398         struct smc_wr_rx_handler *handler;
399         int rc = 0;
400
401         for (handler = smc_cdc_rx_handlers; handler->handler; handler++) {
402                 INIT_HLIST_NODE(&handler->list);
403                 rc = smc_wr_rx_register_handler(handler);
404                 if (rc)
405                         break;
406         }
407         return rc;
408 }