1 // SPDX-License-Identifier: GPL-2.0 2 /* 3 * Shared Memory Communications over RDMA (SMC-R) and RoCE 4 * 5 * Manage RMBE 6 * copy new RMBE data into user space 7 * 8 * Copyright IBM Corp. 2016 9 * 10 * Author(s): Ursula Braun <ubraun@linux.vnet.ibm.com> 11 */ 12 13 #include <linux/net.h> 14 #include <linux/rcupdate.h> 15 #include <linux/sched/signal.h> 16 #include <linux/splice.h> 17 18 #include <net/sock.h> 19 #include <trace/events/sock.h> 20 21 #include "smc.h" 22 #include "smc_core.h" 23 #include "smc_cdc.h" 24 #include "smc_tx.h" /* smc_tx_consumer_update() */ 25 #include "smc_rx.h" 26 #include "smc_stats.h" 27 #include "smc_tracepoint.h" 28 29 /* callback implementation to wakeup consumers blocked with smc_rx_wait(). 30 * indirectly called by smc_cdc_msg_recv_action(). 31 */ 32 static void smc_rx_wake_up(struct sock *sk) 33 { 34 struct socket_wq *wq; 35 36 trace_sk_data_ready(sk); 37 38 /* derived from sock_def_readable() */ 39 /* called already in smc_listen_work() */ 40 rcu_read_lock(); 41 wq = rcu_dereference(sk->sk_wq); 42 if (skwq_has_sleeper(wq)) 43 wake_up_interruptible_sync_poll(&wq->wait, EPOLLIN | EPOLLPRI | 44 EPOLLRDNORM | EPOLLRDBAND); 45 sk_wake_async_rcu(sk, SOCK_WAKE_WAITD, POLL_IN); 46 if ((sk->sk_shutdown == SHUTDOWN_MASK) || 47 (sk->sk_state == SMC_CLOSED)) 48 sk_wake_async_rcu(sk, SOCK_WAKE_WAITD, POLL_HUP); 49 rcu_read_unlock(); 50 } 51 52 /* Update consumer cursor 53 * @conn connection to update 54 * @cons consumer cursor 55 * @len number of Bytes consumed 56 * Returns: 57 * 1 if we should end our receive, 0 otherwise 58 */ 59 static int smc_rx_update_consumer(struct smc_sock *smc, 60 union smc_host_cursor cons, size_t len) 61 { 62 struct smc_connection *conn = &smc->conn; 63 struct sock *sk = &smc->sk; 64 bool force = false; 65 int diff, rc = 0; 66 67 smc_curs_add(conn->rmb_desc->len, &cons, len); 68 69 /* did we process urgent data? */ 70 if (conn->urg_state == SMC_URG_VALID || conn->urg_rx_skip_pend) { 71 diff = smc_curs_comp(conn->rmb_desc->len, &cons, 72 &conn->urg_curs); 73 if (sock_flag(sk, SOCK_URGINLINE)) { 74 if (diff == 0) { 75 force = true; 76 rc = 1; 77 conn->urg_state = SMC_URG_READ; 78 } 79 } else { 80 if (diff == 1) { 81 /* skip urgent byte */ 82 force = true; 83 smc_curs_add(conn->rmb_desc->len, &cons, 1); 84 conn->urg_rx_skip_pend = false; 85 } else if (diff < -1) 86 /* we read past urgent byte */ 87 conn->urg_state = SMC_URG_READ; 88 } 89 } 90 91 smc_curs_copy(&conn->local_tx_ctrl.cons, &cons, conn); 92 93 /* send consumer cursor update if required */ 94 /* similar to advertising new TCP rcv_wnd if required */ 95 smc_tx_consumer_update(conn, force); 96 97 return rc; 98 } 99 100 static void smc_rx_update_cons(struct smc_sock *smc, size_t len) 101 { 102 struct smc_connection *conn = &smc->conn; 103 union smc_host_cursor cons; 104 105 smc_curs_copy(&cons, &conn->local_tx_ctrl.cons, conn); 106 smc_rx_update_consumer(smc, cons, len); 107 } 108 109 struct smc_spd_priv { 110 struct smc_sock *smc; 111 size_t len; 112 }; 113 114 static void smc_rx_pipe_buf_release(struct pipe_inode_info *pipe, 115 struct pipe_buffer *buf) 116 { 117 struct smc_spd_priv *priv = (struct smc_spd_priv *)buf->private; 118 struct smc_sock *smc = priv->smc; 119 struct smc_connection *conn; 120 struct sock *sk = &smc->sk; 121 122 if (sk->sk_state == SMC_CLOSED || 123 sk->sk_state == SMC_PEERFINCLOSEWAIT || 124 sk->sk_state == SMC_APPFINCLOSEWAIT) 125 goto out; 126 conn = &smc->conn; 127 lock_sock(sk); 128 smc_rx_update_cons(smc, priv->len); 129 release_sock(sk); 130 if (atomic_sub_and_test(priv->len, &conn->splice_pending)) 131 smc_rx_wake_up(sk); 132 out: 133 kfree(priv); 134 put_page(buf->page); 135 sock_put(sk); 136 } 137 138 static const struct pipe_buf_operations smc_pipe_ops = { 139 .release = smc_rx_pipe_buf_release, 140 .get = generic_pipe_buf_get 141 }; 142 143 static void smc_rx_spd_release(struct splice_pipe_desc *spd, 144 unsigned int i) 145 { 146 put_page(spd->pages[i]); 147 } 148 149 static int smc_rx_splice(struct pipe_inode_info *pipe, char *src, size_t len, 150 struct smc_sock *smc) 151 { 152 struct smc_link_group *lgr = smc->conn.lgr; 153 int offset = offset_in_page(src); 154 struct partial_page *partial; 155 struct splice_pipe_desc spd; 156 struct smc_spd_priv **priv; 157 struct page **pages; 158 int bytes, nr_pages; 159 int i; 160 161 nr_pages = !lgr->is_smcd && smc->conn.rmb_desc->is_vm ? 162 PAGE_ALIGN(len + offset) / PAGE_SIZE : 1; 163 164 pages = kcalloc(nr_pages, sizeof(*pages), GFP_KERNEL); 165 if (!pages) 166 goto out; 167 partial = kcalloc(nr_pages, sizeof(*partial), GFP_KERNEL); 168 if (!partial) 169 goto out_page; 170 priv = kcalloc(nr_pages, sizeof(*priv), GFP_KERNEL); 171 if (!priv) 172 goto out_part; 173 for (i = 0; i < nr_pages; i++) { 174 priv[i] = kzalloc(sizeof(**priv), GFP_KERNEL); 175 if (!priv[i]) 176 goto out_priv; 177 } 178 179 if (lgr->is_smcd || 180 (!lgr->is_smcd && !smc->conn.rmb_desc->is_vm)) { 181 /* smcd or smcr that uses physically contiguous RMBs */ 182 priv[0]->len = len; 183 priv[0]->smc = smc; 184 partial[0].offset = src - (char *)smc->conn.rmb_desc->cpu_addr; 185 partial[0].len = len; 186 partial[0].private = (unsigned long)priv[0]; 187 pages[0] = smc->conn.rmb_desc->pages; 188 } else { 189 int size, left = len; 190 void *buf = src; 191 /* smcr that uses virtually contiguous RMBs*/ 192 for (i = 0; i < nr_pages; i++) { 193 size = min_t(int, PAGE_SIZE - offset, left); 194 priv[i]->len = size; 195 priv[i]->smc = smc; 196 pages[i] = vmalloc_to_page(buf); 197 partial[i].offset = offset; 198 partial[i].len = size; 199 partial[i].private = (unsigned long)priv[i]; 200 buf += size / sizeof(*buf); 201 left -= size; 202 offset = 0; 203 } 204 } 205 spd.nr_pages_max = nr_pages; 206 spd.nr_pages = nr_pages; 207 spd.pages = pages; 208 spd.partial = partial; 209 spd.ops = &smc_pipe_ops; 210 spd.spd_release = smc_rx_spd_release; 211 212 bytes = splice_to_pipe(pipe, &spd); 213 if (bytes > 0) { 214 sock_hold(&smc->sk); 215 if (!lgr->is_smcd && smc->conn.rmb_desc->is_vm) { 216 for (i = 0; i < PAGE_ALIGN(bytes + offset) / PAGE_SIZE; i++) 217 get_page(pages[i]); 218 } else { 219 get_page(smc->conn.rmb_desc->pages); 220 } 221 atomic_add(bytes, &smc->conn.splice_pending); 222 } 223 kfree(priv); 224 kfree(partial); 225 kfree(pages); 226 227 return bytes; 228 229 out_priv: 230 for (i = (i - 1); i >= 0; i--) 231 kfree(priv[i]); 232 kfree(priv); 233 out_part: 234 kfree(partial); 235 out_page: 236 kfree(pages); 237 out: 238 return -ENOMEM; 239 } 240 241 static int smc_rx_data_available_and_no_splice_pend(struct smc_connection *conn) 242 { 243 return atomic_read(&conn->bytes_to_rcv) && 244 !atomic_read(&conn->splice_pending); 245 } 246 247 /* blocks rcvbuf consumer until >=len bytes available or timeout or interrupted 248 * @smc smc socket 249 * @timeo pointer to max seconds to wait, pointer to value 0 for no timeout 250 * @fcrit add'l criterion to evaluate as function pointer 251 * Returns: 252 * 1 if at least 1 byte available in rcvbuf or if socket error/shutdown. 253 * 0 otherwise (nothing in rcvbuf nor timeout, e.g. interrupted). 254 */ 255 int smc_rx_wait(struct smc_sock *smc, long *timeo, 256 int (*fcrit)(struct smc_connection *conn)) 257 { 258 DEFINE_WAIT_FUNC(wait, woken_wake_function); 259 struct smc_connection *conn = &smc->conn; 260 struct smc_cdc_conn_state_flags *cflags = 261 &conn->local_tx_ctrl.conn_state_flags; 262 struct sock *sk = &smc->sk; 263 int rc; 264 265 if (fcrit(conn)) 266 return 1; 267 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); 268 add_wait_queue(sk_sleep(sk), &wait); 269 rc = sk_wait_event(sk, timeo, 270 READ_ONCE(sk->sk_err) || 271 cflags->peer_conn_abort || 272 READ_ONCE(sk->sk_shutdown) & RCV_SHUTDOWN || 273 conn->killed || 274 fcrit(conn), 275 &wait); 276 remove_wait_queue(sk_sleep(sk), &wait); 277 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); 278 return rc; 279 } 280 281 static int smc_rx_recv_urg(struct smc_sock *smc, struct msghdr *msg, int len, 282 int flags) 283 { 284 struct smc_connection *conn = &smc->conn; 285 union smc_host_cursor cons; 286 struct sock *sk = &smc->sk; 287 int rc = 0; 288 289 if (sock_flag(sk, SOCK_URGINLINE) || 290 !(conn->urg_state == SMC_URG_VALID) || 291 conn->urg_state == SMC_URG_READ) 292 return -EINVAL; 293 294 SMC_STAT_INC(smc, urg_data_cnt); 295 if (conn->urg_state == SMC_URG_VALID) { 296 if (!(flags & MSG_PEEK)) 297 smc->conn.urg_state = SMC_URG_READ; 298 msg->msg_flags |= MSG_OOB; 299 if (len > 0) { 300 if (!(flags & MSG_TRUNC)) 301 rc = memcpy_to_msg(msg, &conn->urg_rx_byte, 1); 302 len = 1; 303 smc_curs_copy(&cons, &conn->local_tx_ctrl.cons, conn); 304 if (smc_curs_diff(conn->rmb_desc->len, &cons, 305 &conn->urg_curs) > 1) 306 conn->urg_rx_skip_pend = true; 307 /* Urgent Byte was already accounted for, but trigger 308 * skipping the urgent byte in non-inline case 309 */ 310 if (!(flags & MSG_PEEK)) 311 smc_rx_update_consumer(smc, cons, 0); 312 } else { 313 msg->msg_flags |= MSG_TRUNC; 314 } 315 316 return rc ? -EFAULT : len; 317 } 318 319 if (sk->sk_state == SMC_CLOSED || sk->sk_shutdown & RCV_SHUTDOWN) 320 return 0; 321 322 return -EAGAIN; 323 } 324 325 static bool smc_rx_recvmsg_data_available(struct smc_sock *smc) 326 { 327 struct smc_connection *conn = &smc->conn; 328 329 if (smc_rx_data_available(conn)) 330 return true; 331 else if (conn->urg_state == SMC_URG_VALID) 332 /* we received a single urgent Byte - skip */ 333 smc_rx_update_cons(smc, 0); 334 return false; 335 } 336 337 /* smc_rx_recvmsg - receive data from RMBE 338 * @msg: copy data to receive buffer 339 * @pipe: copy data to pipe if set - indicates splice() call 340 * 341 * rcvbuf consumer: main API called by socket layer. 342 * Called under sk lock. 343 */ 344 int smc_rx_recvmsg(struct smc_sock *smc, struct msghdr *msg, 345 struct pipe_inode_info *pipe, size_t len, int flags) 346 { 347 size_t copylen, read_done = 0, read_remaining = len; 348 size_t chunk_len, chunk_off, chunk_len_sum; 349 struct smc_connection *conn = &smc->conn; 350 int (*func)(struct smc_connection *conn); 351 union smc_host_cursor cons; 352 int readable, chunk; 353 char *rcvbuf_base; 354 struct sock *sk; 355 int splbytes; 356 long timeo; 357 int target; /* Read at least these many bytes */ 358 int rc; 359 360 if (unlikely(flags & MSG_ERRQUEUE)) 361 return -EINVAL; /* future work for sk.sk_family == AF_SMC */ 362 363 sk = &smc->sk; 364 if (sk->sk_state == SMC_LISTEN) 365 return -ENOTCONN; 366 if (flags & MSG_OOB) 367 return smc_rx_recv_urg(smc, msg, len, flags); 368 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); 369 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); 370 371 readable = atomic_read(&conn->bytes_to_rcv); 372 if (readable >= conn->rmb_desc->len) 373 SMC_STAT_RMB_RX_FULL(smc, !conn->lnk); 374 375 if (len < readable) 376 SMC_STAT_RMB_RX_SIZE_SMALL(smc, !conn->lnk); 377 /* we currently use 1 RMBE per RMB, so RMBE == RMB base addr */ 378 rcvbuf_base = conn->rx_off + conn->rmb_desc->cpu_addr; 379 380 do { /* while (read_remaining) */ 381 if (read_done >= target || (pipe && read_done)) 382 break; 383 384 if (conn->killed) 385 break; 386 387 if (smc_rx_recvmsg_data_available(smc)) 388 goto copy; 389 390 if (sk->sk_shutdown & RCV_SHUTDOWN) { 391 /* smc_cdc_msg_recv_action() could have run after 392 * above smc_rx_recvmsg_data_available() 393 */ 394 if (smc_rx_recvmsg_data_available(smc)) 395 goto copy; 396 break; 397 } 398 399 if (read_done) { 400 if (sk->sk_err || 401 sk->sk_state == SMC_CLOSED || 402 !timeo || 403 signal_pending(current)) 404 break; 405 } else { 406 if (sk->sk_err) { 407 read_done = sock_error(sk); 408 break; 409 } 410 if (sk->sk_state == SMC_CLOSED) { 411 if (!sock_flag(sk, SOCK_DONE)) { 412 /* This occurs when user tries to read 413 * from never connected socket. 414 */ 415 read_done = -ENOTCONN; 416 break; 417 } 418 break; 419 } 420 if (!timeo) 421 return -EAGAIN; 422 if (signal_pending(current)) { 423 read_done = sock_intr_errno(timeo); 424 break; 425 } 426 } 427 428 if (!smc_rx_data_available(conn)) { 429 smc_rx_wait(smc, &timeo, smc_rx_data_available); 430 continue; 431 } 432 433 copy: 434 /* initialize variables for 1st iteration of subsequent loop */ 435 /* could be just 1 byte, even after waiting on data above */ 436 readable = atomic_read(&conn->bytes_to_rcv); 437 splbytes = atomic_read(&conn->splice_pending); 438 if (!readable || (msg && splbytes)) { 439 if (splbytes) 440 func = smc_rx_data_available_and_no_splice_pend; 441 else 442 func = smc_rx_data_available; 443 smc_rx_wait(smc, &timeo, func); 444 continue; 445 } 446 447 smc_curs_copy(&cons, &conn->local_tx_ctrl.cons, conn); 448 /* subsequent splice() calls pick up where previous left */ 449 if (splbytes) 450 smc_curs_add(conn->rmb_desc->len, &cons, splbytes); 451 if (conn->urg_state == SMC_URG_VALID && 452 sock_flag(&smc->sk, SOCK_URGINLINE) && 453 readable > 1) 454 readable--; /* always stop at urgent Byte */ 455 /* not more than what user space asked for */ 456 copylen = min_t(size_t, read_remaining, readable); 457 /* determine chunks where to read from rcvbuf */ 458 /* either unwrapped case, or 1st chunk of wrapped case */ 459 chunk_len = min_t(size_t, copylen, conn->rmb_desc->len - 460 cons.count); 461 chunk_len_sum = chunk_len; 462 chunk_off = cons.count; 463 smc_rmb_sync_sg_for_cpu(conn); 464 for (chunk = 0; chunk < 2; chunk++) { 465 if (!(flags & MSG_TRUNC)) { 466 if (msg) { 467 rc = memcpy_to_msg(msg, rcvbuf_base + 468 chunk_off, 469 chunk_len); 470 } else { 471 rc = smc_rx_splice(pipe, rcvbuf_base + 472 chunk_off, chunk_len, 473 smc); 474 } 475 if (rc < 0) { 476 if (!read_done) 477 read_done = -EFAULT; 478 goto out; 479 } 480 } 481 read_remaining -= chunk_len; 482 read_done += chunk_len; 483 484 if (chunk_len_sum == copylen) 485 break; /* either on 1st or 2nd iteration */ 486 /* prepare next (== 2nd) iteration */ 487 chunk_len = copylen - chunk_len; /* remainder */ 488 chunk_len_sum += chunk_len; 489 chunk_off = 0; /* modulo offset in recv ring buffer */ 490 } 491 492 /* update cursors */ 493 if (!(flags & MSG_PEEK)) { 494 /* increased in recv tasklet smc_cdc_msg_rcv() */ 495 smp_mb__before_atomic(); 496 atomic_sub(copylen, &conn->bytes_to_rcv); 497 /* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */ 498 smp_mb__after_atomic(); 499 if (msg && smc_rx_update_consumer(smc, cons, copylen)) 500 goto out; 501 } 502 503 trace_smc_rx_recvmsg(smc, copylen); 504 } while (read_remaining); 505 out: 506 return read_done; 507 } 508 509 /* Initialize receive properties on connection establishment. NB: not __init! */ 510 void smc_rx_init(struct smc_sock *smc) 511 { 512 smc->sk.sk_data_ready = smc_rx_wake_up; 513 atomic_set(&smc->conn.splice_pending, 0); 514 smc->conn.urg_state = SMC_URG_READ; 515 } 516