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