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 bool smc_rx_pipe_buf_get(struct pipe_inode_info *pipe, 139 struct pipe_buffer *buf) 140 { 141 /* smc_spd_priv in buf->private is not shareable; disallow cloning. */ 142 return false; 143 } 144 145 static const struct pipe_buf_operations smc_pipe_ops = { 146 .release = smc_rx_pipe_buf_release, 147 .get = smc_rx_pipe_buf_get, 148 }; 149 150 static void smc_rx_spd_release(struct splice_pipe_desc *spd, 151 unsigned int i) 152 { 153 put_page(spd->pages[i]); 154 } 155 156 static int smc_rx_splice(struct pipe_inode_info *pipe, char *src, size_t len, 157 struct smc_sock *smc) 158 { 159 struct smc_link_group *lgr = smc->conn.lgr; 160 int offset = offset_in_page(src); 161 struct partial_page *partial; 162 struct splice_pipe_desc spd; 163 struct smc_spd_priv **priv; 164 struct page **pages; 165 int bytes, nr_pages; 166 int i; 167 168 nr_pages = !lgr->is_smcd && smc->conn.rmb_desc->is_vm ? 169 PAGE_ALIGN(len + offset) / PAGE_SIZE : 1; 170 171 pages = kzalloc_objs(*pages, nr_pages); 172 if (!pages) 173 goto out; 174 partial = kzalloc_objs(*partial, nr_pages); 175 if (!partial) 176 goto out_page; 177 priv = kzalloc_objs(*priv, nr_pages); 178 if (!priv) 179 goto out_part; 180 for (i = 0; i < nr_pages; i++) { 181 priv[i] = kzalloc_obj(**priv); 182 if (!priv[i]) 183 goto out_priv; 184 } 185 186 if (lgr->is_smcd || 187 (!lgr->is_smcd && !smc->conn.rmb_desc->is_vm)) { 188 /* smcd or smcr that uses physically contiguous RMBs */ 189 priv[0]->len = len; 190 priv[0]->smc = smc; 191 partial[0].offset = src - (char *)smc->conn.rmb_desc->cpu_addr; 192 partial[0].len = len; 193 partial[0].private = (unsigned long)priv[0]; 194 pages[0] = smc->conn.rmb_desc->pages; 195 } else { 196 int size, left = len; 197 void *buf = src; 198 /* smcr that uses virtually contiguous RMBs*/ 199 for (i = 0; i < nr_pages; i++) { 200 size = min_t(int, PAGE_SIZE - offset, left); 201 priv[i]->len = size; 202 priv[i]->smc = smc; 203 pages[i] = vmalloc_to_page(buf); 204 partial[i].offset = offset; 205 partial[i].len = size; 206 partial[i].private = (unsigned long)priv[i]; 207 buf += size; 208 left -= size; 209 offset = 0; 210 } 211 } 212 spd.nr_pages_max = nr_pages; 213 spd.nr_pages = nr_pages; 214 spd.pages = pages; 215 spd.partial = partial; 216 spd.ops = &smc_pipe_ops; 217 spd.spd_release = smc_rx_spd_release; 218 219 bytes = splice_to_pipe(pipe, &spd); 220 if (bytes > 0) { 221 sock_hold(&smc->sk); 222 if (!lgr->is_smcd && smc->conn.rmb_desc->is_vm) { 223 for (i = 0; i < PAGE_ALIGN(bytes + offset) / PAGE_SIZE; i++) 224 get_page(pages[i]); 225 } else { 226 get_page(smc->conn.rmb_desc->pages); 227 } 228 atomic_add(bytes, &smc->conn.splice_pending); 229 } 230 kfree(priv); 231 kfree(partial); 232 kfree(pages); 233 234 return bytes; 235 236 out_priv: 237 for (i = (i - 1); i >= 0; i--) 238 kfree(priv[i]); 239 kfree(priv); 240 out_part: 241 kfree(partial); 242 out_page: 243 kfree(pages); 244 out: 245 return -ENOMEM; 246 } 247 248 static int smc_rx_data_available_and_no_splice_pend(struct smc_connection *conn, size_t peeked) 249 { 250 return smc_rx_data_available(conn, peeked) && 251 !atomic_read(&conn->splice_pending); 252 } 253 254 /* blocks rcvbuf consumer until >=len bytes available or timeout or interrupted 255 * @smc smc socket 256 * @timeo pointer to max seconds to wait, pointer to value 0 for no timeout 257 * @peeked number of bytes already peeked 258 * @fcrit add'l criterion to evaluate as function pointer 259 * Returns: 260 * 1 if at least 1 byte available in rcvbuf or if socket error/shutdown. 261 * 0 otherwise (nothing in rcvbuf nor timeout, e.g. interrupted). 262 */ 263 int smc_rx_wait(struct smc_sock *smc, long *timeo, size_t peeked, 264 int (*fcrit)(struct smc_connection *conn, size_t baseline)) 265 { 266 DEFINE_WAIT_FUNC(wait, woken_wake_function); 267 struct smc_connection *conn = &smc->conn; 268 struct smc_cdc_conn_state_flags *cflags = 269 &conn->local_tx_ctrl.conn_state_flags; 270 struct sock *sk = &smc->sk; 271 int rc; 272 273 if (fcrit(conn, peeked)) 274 return 1; 275 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); 276 add_wait_queue(sk_sleep(sk), &wait); 277 rc = sk_wait_event(sk, timeo, 278 READ_ONCE(sk->sk_err) || 279 cflags->peer_conn_abort || 280 READ_ONCE(sk->sk_shutdown) & RCV_SHUTDOWN || 281 conn->killed || 282 fcrit(conn, peeked), 283 &wait); 284 remove_wait_queue(sk_sleep(sk), &wait); 285 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); 286 return rc; 287 } 288 289 static int smc_rx_recv_urg(struct smc_sock *smc, struct msghdr *msg, int len, 290 int flags) 291 { 292 struct smc_connection *conn = &smc->conn; 293 union smc_host_cursor cons; 294 struct sock *sk = &smc->sk; 295 int rc = 0; 296 297 if (sock_flag(sk, SOCK_URGINLINE) || 298 !(conn->urg_state == SMC_URG_VALID) || 299 conn->urg_state == SMC_URG_READ) 300 return -EINVAL; 301 302 SMC_STAT_INC(smc, urg_data_cnt); 303 if (conn->urg_state == SMC_URG_VALID) { 304 if (!(flags & MSG_PEEK)) 305 smc->conn.urg_state = SMC_URG_READ; 306 msg->msg_flags |= MSG_OOB; 307 if (len > 0) { 308 if (!(flags & MSG_TRUNC)) 309 rc = memcpy_to_msg(msg, &conn->urg_rx_byte, 1); 310 len = 1; 311 smc_curs_copy(&cons, &conn->local_tx_ctrl.cons, conn); 312 if (smc_curs_diff(conn->rmb_desc->len, &cons, 313 &conn->urg_curs) > 1) 314 conn->urg_rx_skip_pend = true; 315 /* Urgent Byte was already accounted for, but trigger 316 * skipping the urgent byte in non-inline case 317 */ 318 if (!(flags & MSG_PEEK)) 319 smc_rx_update_consumer(smc, cons, 0); 320 } else { 321 msg->msg_flags |= MSG_TRUNC; 322 } 323 324 return rc ? -EFAULT : len; 325 } 326 327 if (sk->sk_state == SMC_CLOSED || sk->sk_shutdown & RCV_SHUTDOWN) 328 return 0; 329 330 return -EAGAIN; 331 } 332 333 static bool smc_rx_recvmsg_data_available(struct smc_sock *smc, size_t peeked) 334 { 335 struct smc_connection *conn = &smc->conn; 336 337 if (smc_rx_data_available(conn, peeked)) 338 return true; 339 else if (conn->urg_state == SMC_URG_VALID) 340 /* we received a single urgent Byte - skip */ 341 smc_rx_update_cons(smc, 0); 342 return false; 343 } 344 345 /* smc_rx_recvmsg - receive data from RMBE 346 * @msg: copy data to receive buffer 347 * @pipe: copy data to pipe if set - indicates splice() call 348 * 349 * rcvbuf consumer: main API called by socket layer. 350 * Called under sk lock. 351 */ 352 int smc_rx_recvmsg(struct smc_sock *smc, struct msghdr *msg, 353 struct pipe_inode_info *pipe, size_t len, int flags) 354 { 355 size_t copylen, read_done = 0, read_remaining = len, peeked_bytes = 0; 356 size_t chunk_len, chunk_off, chunk_len_sum; 357 struct smc_connection *conn = &smc->conn; 358 int (*func)(struct smc_connection *conn, size_t baseline); 359 union smc_host_cursor cons; 360 int readable, chunk; 361 char *rcvbuf_base; 362 struct sock *sk; 363 int splbytes; 364 long timeo; 365 int target; /* Read at least these many bytes */ 366 int rc; 367 368 if (unlikely(flags & MSG_ERRQUEUE)) 369 return -EINVAL; /* future work for sk.sk_family == AF_SMC */ 370 371 sk = &smc->sk; 372 if (sk->sk_state == SMC_LISTEN) 373 return -ENOTCONN; 374 if (flags & MSG_OOB) 375 return smc_rx_recv_urg(smc, msg, len, flags); 376 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); 377 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); 378 379 readable = atomic_read(&conn->bytes_to_rcv); 380 if (readable >= conn->rmb_desc->len) 381 SMC_STAT_RMB_RX_FULL(smc, !conn->lnk); 382 383 if (len < readable) 384 SMC_STAT_RMB_RX_SIZE_SMALL(smc, !conn->lnk); 385 /* we currently use 1 RMBE per RMB, so RMBE == RMB base addr */ 386 rcvbuf_base = conn->rx_off + conn->rmb_desc->cpu_addr; 387 388 do { /* while (read_remaining) */ 389 if (read_done >= target || (pipe && read_done)) 390 break; 391 392 if (conn->killed) 393 break; 394 395 if (smc_rx_recvmsg_data_available(smc, peeked_bytes)) 396 goto copy; 397 398 if (sk->sk_shutdown & RCV_SHUTDOWN) { 399 /* smc_cdc_msg_recv_action() could have run after 400 * above smc_rx_recvmsg_data_available() 401 */ 402 if (smc_rx_recvmsg_data_available(smc, peeked_bytes)) 403 goto copy; 404 break; 405 } 406 407 if (read_done) { 408 if (sk->sk_err || 409 sk->sk_state == SMC_CLOSED || 410 !timeo || 411 signal_pending(current)) 412 break; 413 } else { 414 if (sk->sk_err) { 415 read_done = sock_error(sk); 416 break; 417 } 418 if (sk->sk_state == SMC_CLOSED) { 419 if (!sock_flag(sk, SOCK_DONE)) { 420 /* This occurs when user tries to read 421 * from never connected socket. 422 */ 423 read_done = -ENOTCONN; 424 break; 425 } 426 break; 427 } 428 if (!timeo) 429 return -EAGAIN; 430 if (signal_pending(current)) { 431 read_done = sock_intr_errno(timeo); 432 break; 433 } 434 } 435 436 if (!smc_rx_data_available(conn, peeked_bytes)) { 437 smc_rx_wait(smc, &timeo, peeked_bytes, smc_rx_data_available); 438 continue; 439 } 440 441 copy: 442 /* initialize variables for 1st iteration of subsequent loop */ 443 /* could be just 1 byte, even after waiting on data above */ 444 readable = smc_rx_data_available(conn, peeked_bytes); 445 splbytes = atomic_read(&conn->splice_pending); 446 if (!readable || (msg && splbytes)) { 447 if (splbytes) 448 func = smc_rx_data_available_and_no_splice_pend; 449 else 450 func = smc_rx_data_available; 451 smc_rx_wait(smc, &timeo, peeked_bytes, func); 452 continue; 453 } 454 455 smc_curs_copy(&cons, &conn->local_tx_ctrl.cons, conn); 456 if ((flags & MSG_PEEK) && peeked_bytes) 457 smc_curs_add(conn->rmb_desc->len, &cons, peeked_bytes); 458 /* subsequent splice() calls pick up where previous left */ 459 if (splbytes) 460 smc_curs_add(conn->rmb_desc->len, &cons, splbytes); 461 if (conn->urg_state == SMC_URG_VALID && 462 sock_flag(&smc->sk, SOCK_URGINLINE) && 463 readable > 1) 464 readable--; /* always stop at urgent Byte */ 465 /* not more than what user space asked for */ 466 copylen = min_t(size_t, read_remaining, readable); 467 /* determine chunks where to read from rcvbuf */ 468 /* either unwrapped case, or 1st chunk of wrapped case */ 469 chunk_len = min_t(size_t, copylen, conn->rmb_desc->len - 470 cons.count); 471 chunk_len_sum = chunk_len; 472 chunk_off = cons.count; 473 smc_rmb_sync_sg_for_cpu(conn); 474 for (chunk = 0; chunk < 2; chunk++) { 475 if (!(flags & MSG_TRUNC)) { 476 if (msg) { 477 rc = memcpy_to_msg(msg, rcvbuf_base + 478 chunk_off, 479 chunk_len); 480 } else { 481 rc = smc_rx_splice(pipe, rcvbuf_base + 482 chunk_off, chunk_len, 483 smc); 484 } 485 if (rc < 0) { 486 if (!read_done) 487 read_done = -EFAULT; 488 goto out; 489 } 490 } 491 read_remaining -= chunk_len; 492 read_done += chunk_len; 493 if (flags & MSG_PEEK) 494 peeked_bytes += chunk_len; 495 496 if (chunk_len_sum == copylen) 497 break; /* either on 1st or 2nd iteration */ 498 /* prepare next (== 2nd) iteration */ 499 chunk_len = copylen - chunk_len; /* remainder */ 500 chunk_len_sum += chunk_len; 501 chunk_off = 0; /* modulo offset in recv ring buffer */ 502 } 503 504 /* update cursors */ 505 if (!(flags & MSG_PEEK)) { 506 /* increased in recv tasklet smc_cdc_msg_rcv() */ 507 smp_mb__before_atomic(); 508 atomic_sub(copylen, &conn->bytes_to_rcv); 509 /* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */ 510 smp_mb__after_atomic(); 511 if (msg && smc_rx_update_consumer(smc, cons, copylen)) 512 goto out; 513 } 514 515 trace_smc_rx_recvmsg(smc, copylen); 516 } while (read_remaining); 517 out: 518 return read_done; 519 } 520 521 /* Initialize receive properties on connection establishment. NB: not __init! */ 522 void smc_rx_init(struct smc_sock *smc) 523 { 524 smc->sk.sk_data_ready = smc_rx_wake_up; 525 atomic_set(&smc->conn.splice_pending, 0); 526 smc->conn.urg_state = SMC_URG_READ; 527 } 528