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