Merge branch 'linus' of git://git.kernel.org/pub/scm/linux/kernel/git/herbert/crypto-2.6
[linux-2.6-microblaze.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 /* handler for send/transmission completion of a CDC msg */
25 static void smc_cdc_tx_handler(struct smc_wr_tx_pend_priv *pnd_snd,
26                                struct smc_link *link,
27                                enum ib_wc_status wc_status)
28 {
29         struct smc_cdc_tx_pend *cdcpend = (struct smc_cdc_tx_pend *)pnd_snd;
30         struct smc_connection *conn = cdcpend->conn;
31         struct smc_sock *smc;
32         int diff;
33
34         if (!conn)
35                 /* already dismissed */
36                 return;
37
38         smc = container_of(conn, struct smc_sock, conn);
39         bh_lock_sock(&smc->sk);
40         if (!wc_status) {
41                 diff = smc_curs_diff(cdcpend->conn->sndbuf_desc->len,
42                                      &cdcpend->conn->tx_curs_fin,
43                                      &cdcpend->cursor);
44                 /* sndbuf_space is decreased in smc_sendmsg */
45                 smp_mb__before_atomic();
46                 atomic_add(diff, &cdcpend->conn->sndbuf_space);
47                 /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
48                 smp_mb__after_atomic();
49                 smc_curs_copy(&conn->tx_curs_fin, &cdcpend->cursor, conn);
50         }
51         smc_tx_sndbuf_nonfull(smc);
52         bh_unlock_sock(&smc->sk);
53 }
54
55 int smc_cdc_get_free_slot(struct smc_connection *conn,
56                           struct smc_wr_buf **wr_buf,
57                           struct smc_rdma_wr **wr_rdma_buf,
58                           struct smc_cdc_tx_pend **pend)
59 {
60         struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
61         int rc;
62
63         rc = smc_wr_tx_get_free_slot(link, smc_cdc_tx_handler, wr_buf,
64                                      wr_rdma_buf,
65                                      (struct smc_wr_tx_pend_priv **)pend);
66         if (conn->killed)
67                 /* abnormal termination */
68                 rc = -EPIPE;
69         return rc;
70 }
71
72 static inline void smc_cdc_add_pending_send(struct smc_connection *conn,
73                                             struct smc_cdc_tx_pend *pend)
74 {
75         BUILD_BUG_ON_MSG(
76                 sizeof(struct smc_cdc_msg) > SMC_WR_BUF_SIZE,
77                 "must increase SMC_WR_BUF_SIZE to at least sizeof(struct smc_cdc_msg)");
78         BUILD_BUG_ON_MSG(
79                 offsetofend(struct smc_cdc_msg, reserved) > SMC_WR_TX_SIZE,
80                 "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()");
81         BUILD_BUG_ON_MSG(
82                 sizeof(struct smc_cdc_tx_pend) > SMC_WR_TX_PEND_PRIV_SIZE,
83                 "must increase SMC_WR_TX_PEND_PRIV_SIZE to at least sizeof(struct smc_cdc_tx_pend)");
84         pend->conn = conn;
85         pend->cursor = conn->tx_curs_sent;
86         pend->p_cursor = conn->local_tx_ctrl.prod;
87         pend->ctrl_seq = conn->tx_cdc_seq;
88 }
89
90 int smc_cdc_msg_send(struct smc_connection *conn,
91                      struct smc_wr_buf *wr_buf,
92                      struct smc_cdc_tx_pend *pend)
93 {
94         union smc_host_cursor cfed;
95         struct smc_link *link;
96         int rc;
97
98         link = &conn->lgr->lnk[SMC_SINGLE_LINK];
99
100         smc_cdc_add_pending_send(conn, pend);
101
102         conn->tx_cdc_seq++;
103         conn->local_tx_ctrl.seqno = conn->tx_cdc_seq;
104         smc_host_msg_to_cdc((struct smc_cdc_msg *)wr_buf, conn, &cfed);
105         rc = smc_wr_tx_send(link, (struct smc_wr_tx_pend_priv *)pend);
106         if (!rc) {
107                 smc_curs_copy(&conn->rx_curs_confirmed, &cfed, conn);
108                 conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0;
109         }
110
111         return rc;
112 }
113
114 static int smcr_cdc_get_slot_and_msg_send(struct smc_connection *conn)
115 {
116         struct smc_cdc_tx_pend *pend;
117         struct smc_wr_buf *wr_buf;
118         int rc;
119
120         rc = smc_cdc_get_free_slot(conn, &wr_buf, NULL, &pend);
121         if (rc)
122                 return rc;
123
124         spin_lock_bh(&conn->send_lock);
125         rc = smc_cdc_msg_send(conn, wr_buf, pend);
126         spin_unlock_bh(&conn->send_lock);
127         return rc;
128 }
129
130 int smc_cdc_get_slot_and_msg_send(struct smc_connection *conn)
131 {
132         int rc;
133
134         if (!conn->lgr || (conn->lgr->is_smcd && conn->lgr->peer_shutdown))
135                 return -EPIPE;
136
137         if (conn->lgr->is_smcd) {
138                 spin_lock_bh(&conn->send_lock);
139                 rc = smcd_cdc_msg_send(conn);
140                 spin_unlock_bh(&conn->send_lock);
141         } else {
142                 rc = smcr_cdc_get_slot_and_msg_send(conn);
143         }
144
145         return rc;
146 }
147
148 static bool smc_cdc_tx_filter(struct smc_wr_tx_pend_priv *tx_pend,
149                               unsigned long data)
150 {
151         struct smc_connection *conn = (struct smc_connection *)data;
152         struct smc_cdc_tx_pend *cdc_pend =
153                 (struct smc_cdc_tx_pend *)tx_pend;
154
155         return cdc_pend->conn == conn;
156 }
157
158 static void smc_cdc_tx_dismisser(struct smc_wr_tx_pend_priv *tx_pend)
159 {
160         struct smc_cdc_tx_pend *cdc_pend =
161                 (struct smc_cdc_tx_pend *)tx_pend;
162
163         cdc_pend->conn = NULL;
164 }
165
166 void smc_cdc_tx_dismiss_slots(struct smc_connection *conn)
167 {
168         struct smc_link *link = &conn->lgr->lnk[SMC_SINGLE_LINK];
169
170         smc_wr_tx_dismiss_slots(link, SMC_CDC_MSG_TYPE,
171                                 smc_cdc_tx_filter, smc_cdc_tx_dismisser,
172                                 (unsigned long)conn);
173 }
174
175 /* Send a SMC-D CDC header.
176  * This increments the free space available in our send buffer.
177  * Also update the confirmed receive buffer with what was sent to the peer.
178  */
179 int smcd_cdc_msg_send(struct smc_connection *conn)
180 {
181         struct smc_sock *smc = container_of(conn, struct smc_sock, conn);
182         union smc_host_cursor curs;
183         struct smcd_cdc_msg cdc;
184         int rc, diff;
185
186         memset(&cdc, 0, sizeof(cdc));
187         cdc.common.type = SMC_CDC_MSG_TYPE;
188         curs.acurs.counter = atomic64_read(&conn->local_tx_ctrl.prod.acurs);
189         cdc.prod.wrap = curs.wrap;
190         cdc.prod.count = curs.count;
191         curs.acurs.counter = atomic64_read(&conn->local_tx_ctrl.cons.acurs);
192         cdc.cons.wrap = curs.wrap;
193         cdc.cons.count = curs.count;
194         cdc.cons.prod_flags = conn->local_tx_ctrl.prod_flags;
195         cdc.cons.conn_state_flags = conn->local_tx_ctrl.conn_state_flags;
196         rc = smcd_tx_ism_write(conn, &cdc, sizeof(cdc), 0, 1);
197         if (rc)
198                 return rc;
199         smc_curs_copy(&conn->rx_curs_confirmed, &curs, conn);
200         conn->local_rx_ctrl.prod_flags.cons_curs_upd_req = 0;
201         /* Calculate transmitted data and increment free send buffer space */
202         diff = smc_curs_diff(conn->sndbuf_desc->len, &conn->tx_curs_fin,
203                              &conn->tx_curs_sent);
204         /* increased by confirmed number of bytes */
205         smp_mb__before_atomic();
206         atomic_add(diff, &conn->sndbuf_space);
207         /* guarantee 0 <= sndbuf_space <= sndbuf_desc->len */
208         smp_mb__after_atomic();
209         smc_curs_copy(&conn->tx_curs_fin, &conn->tx_curs_sent, conn);
210
211         smc_tx_sndbuf_nonfull(smc);
212         return rc;
213 }
214
215 /********************************* receive ***********************************/
216
217 static inline bool smc_cdc_before(u16 seq1, u16 seq2)
218 {
219         return (s16)(seq1 - seq2) < 0;
220 }
221
222 static void smc_cdc_handle_urg_data_arrival(struct smc_sock *smc,
223                                             int *diff_prod)
224 {
225         struct smc_connection *conn = &smc->conn;
226         char *base;
227
228         /* new data included urgent business */
229         smc_curs_copy(&conn->urg_curs, &conn->local_rx_ctrl.prod, conn);
230         conn->urg_state = SMC_URG_VALID;
231         if (!sock_flag(&smc->sk, SOCK_URGINLINE))
232                 /* we'll skip the urgent byte, so don't account for it */
233                 (*diff_prod)--;
234         base = (char *)conn->rmb_desc->cpu_addr + conn->rx_off;
235         if (conn->urg_curs.count)
236                 conn->urg_rx_byte = *(base + conn->urg_curs.count - 1);
237         else
238                 conn->urg_rx_byte = *(base + conn->rmb_desc->len - 1);
239         sk_send_sigurg(&smc->sk);
240 }
241
242 static void smc_cdc_msg_recv_action(struct smc_sock *smc,
243                                     struct smc_cdc_msg *cdc)
244 {
245         union smc_host_cursor cons_old, prod_old;
246         struct smc_connection *conn = &smc->conn;
247         int diff_cons, diff_prod;
248
249         smc_curs_copy(&prod_old, &conn->local_rx_ctrl.prod, conn);
250         smc_curs_copy(&cons_old, &conn->local_rx_ctrl.cons, conn);
251         smc_cdc_msg_to_host(&conn->local_rx_ctrl, cdc, conn);
252
253         diff_cons = smc_curs_diff(conn->peer_rmbe_size, &cons_old,
254                                   &conn->local_rx_ctrl.cons);
255         if (diff_cons) {
256                 /* peer_rmbe_space is decreased during data transfer with RDMA
257                  * write
258                  */
259                 smp_mb__before_atomic();
260                 atomic_add(diff_cons, &conn->peer_rmbe_space);
261                 /* guarantee 0 <= peer_rmbe_space <= peer_rmbe_size */
262                 smp_mb__after_atomic();
263         }
264
265         diff_prod = smc_curs_diff(conn->rmb_desc->len, &prod_old,
266                                   &conn->local_rx_ctrl.prod);
267         if (diff_prod) {
268                 if (conn->local_rx_ctrl.prod_flags.urg_data_present)
269                         smc_cdc_handle_urg_data_arrival(smc, &diff_prod);
270                 /* bytes_to_rcv is decreased in smc_recvmsg */
271                 smp_mb__before_atomic();
272                 atomic_add(diff_prod, &conn->bytes_to_rcv);
273                 /* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */
274                 smp_mb__after_atomic();
275                 smc->sk.sk_data_ready(&smc->sk);
276         } else {
277                 if (conn->local_rx_ctrl.prod_flags.write_blocked)
278                         smc->sk.sk_data_ready(&smc->sk);
279                 if (conn->local_rx_ctrl.prod_flags.urg_data_pending)
280                         conn->urg_state = SMC_URG_NOTYET;
281         }
282
283         /* trigger sndbuf consumer: RDMA write into peer RMBE and CDC */
284         if ((diff_cons && smc_tx_prepared_sends(conn)) ||
285             conn->local_rx_ctrl.prod_flags.cons_curs_upd_req ||
286             conn->local_rx_ctrl.prod_flags.urg_data_pending)
287                 smc_tx_sndbuf_nonempty(conn);
288
289         if (diff_cons && conn->urg_tx_pend &&
290             atomic_read(&conn->peer_rmbe_space) == conn->peer_rmbe_size) {
291                 /* urg data confirmed by peer, indicate we're ready for more */
292                 conn->urg_tx_pend = false;
293                 smc->sk.sk_write_space(&smc->sk);
294         }
295
296         if (conn->local_rx_ctrl.conn_state_flags.peer_conn_abort) {
297                 smc->sk.sk_err = ECONNRESET;
298                 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort = 1;
299         }
300         if (smc_cdc_rxed_any_close_or_senddone(conn)) {
301                 smc->sk.sk_shutdown |= RCV_SHUTDOWN;
302                 if (smc->clcsock && smc->clcsock->sk)
303                         smc->clcsock->sk->sk_shutdown |= RCV_SHUTDOWN;
304                 sock_set_flag(&smc->sk, SOCK_DONE);
305                 sock_hold(&smc->sk); /* sock_put in close_work */
306                 if (!schedule_work(&conn->close_work))
307                         sock_put(&smc->sk);
308         }
309 }
310
311 /* called under tasklet context */
312 static void smc_cdc_msg_recv(struct smc_sock *smc, struct smc_cdc_msg *cdc)
313 {
314         sock_hold(&smc->sk);
315         bh_lock_sock(&smc->sk);
316         smc_cdc_msg_recv_action(smc, cdc);
317         bh_unlock_sock(&smc->sk);
318         sock_put(&smc->sk); /* no free sk in softirq-context */
319 }
320
321 /* Schedule a tasklet for this connection. Triggered from the ISM device IRQ
322  * handler to indicate update in the DMBE.
323  *
324  * Context:
325  * - tasklet context
326  */
327 static void smcd_cdc_rx_tsklet(unsigned long data)
328 {
329         struct smc_connection *conn = (struct smc_connection *)data;
330         struct smcd_cdc_msg *data_cdc;
331         struct smcd_cdc_msg cdc;
332         struct smc_sock *smc;
333
334         if (!conn || conn->killed)
335                 return;
336
337         data_cdc = (struct smcd_cdc_msg *)conn->rmb_desc->cpu_addr;
338         smcd_curs_copy(&cdc.prod, &data_cdc->prod, conn);
339         smcd_curs_copy(&cdc.cons, &data_cdc->cons, conn);
340         smc = container_of(conn, struct smc_sock, conn);
341         smc_cdc_msg_recv(smc, (struct smc_cdc_msg *)&cdc);
342 }
343
344 /* Initialize receive tasklet. Called from ISM device IRQ handler to start
345  * receiver side.
346  */
347 void smcd_cdc_rx_init(struct smc_connection *conn)
348 {
349         tasklet_init(&conn->rx_tsklet, smcd_cdc_rx_tsklet, (unsigned long)conn);
350 }
351
352 /***************************** init, exit, misc ******************************/
353
354 static void smc_cdc_rx_handler(struct ib_wc *wc, void *buf)
355 {
356         struct smc_link *link = (struct smc_link *)wc->qp->qp_context;
357         struct smc_cdc_msg *cdc = buf;
358         struct smc_connection *conn;
359         struct smc_link_group *lgr;
360         struct smc_sock *smc;
361
362         if (wc->byte_len < offsetof(struct smc_cdc_msg, reserved))
363                 return; /* short message */
364         if (cdc->len != SMC_WR_TX_SIZE)
365                 return; /* invalid message */
366
367         /* lookup connection */
368         lgr = smc_get_lgr(link);
369         read_lock_bh(&lgr->conns_lock);
370         conn = smc_lgr_find_conn(ntohl(cdc->token), lgr);
371         read_unlock_bh(&lgr->conns_lock);
372         if (!conn)
373                 return;
374         smc = container_of(conn, struct smc_sock, conn);
375
376         if (!cdc->prod_flags.failover_validation) {
377                 if (smc_cdc_before(ntohs(cdc->seqno),
378                                    conn->local_rx_ctrl.seqno))
379                         /* received seqno is old */
380                         return;
381         }
382         smc_cdc_msg_recv(smc, cdc);
383 }
384
385 static struct smc_wr_rx_handler smc_cdc_rx_handlers[] = {
386         {
387                 .handler        = smc_cdc_rx_handler,
388                 .type           = SMC_CDC_MSG_TYPE
389         },
390         {
391                 .handler        = NULL,
392         }
393 };
394
395 int __init smc_cdc_init(void)
396 {
397         struct smc_wr_rx_handler *handler;
398         int rc = 0;
399
400         for (handler = smc_cdc_rx_handlers; handler->handler; handler++) {
401                 INIT_HLIST_NODE(&handler->list);
402                 rc = smc_wr_rx_register_handler(handler);
403                 if (rc)
404                         break;
405         }
406         return rc;
407 }