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 sock *sk = &smc->sk; 205 int rc; 206 207 if (fcrit(conn)) 208 return 1; 209 sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk); 210 add_wait_queue(sk_sleep(sk), &wait); 211 rc = sk_wait_event(sk, timeo, 212 sk->sk_err || 213 sk->sk_shutdown & RCV_SHUTDOWN || 214 fcrit(conn), 215 &wait); 216 remove_wait_queue(sk_sleep(sk), &wait); 217 sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk); 218 return rc; 219 } 220 221 static int smc_rx_recv_urg(struct smc_sock *smc, struct msghdr *msg, int len, 222 int flags) 223 { 224 struct smc_connection *conn = &smc->conn; 225 union smc_host_cursor cons; 226 struct sock *sk = &smc->sk; 227 int rc = 0; 228 229 if (sock_flag(sk, SOCK_URGINLINE) || 230 !(conn->urg_state == SMC_URG_VALID) || 231 conn->urg_state == SMC_URG_READ) 232 return -EINVAL; 233 234 if (conn->urg_state == SMC_URG_VALID) { 235 if (!(flags & MSG_PEEK)) 236 smc->conn.urg_state = SMC_URG_READ; 237 msg->msg_flags |= MSG_OOB; 238 if (len > 0) { 239 if (!(flags & MSG_TRUNC)) 240 rc = memcpy_to_msg(msg, &conn->urg_rx_byte, 1); 241 len = 1; 242 smc_curs_copy(&cons, &conn->local_tx_ctrl.cons, conn); 243 if (smc_curs_diff(conn->rmb_desc->len, &cons, 244 &conn->urg_curs) > 1) 245 conn->urg_rx_skip_pend = true; 246 /* Urgent Byte was already accounted for, but trigger 247 * skipping the urgent byte in non-inline case 248 */ 249 if (!(flags & MSG_PEEK)) 250 smc_rx_update_consumer(smc, cons, 0); 251 } else { 252 msg->msg_flags |= MSG_TRUNC; 253 } 254 255 return rc ? -EFAULT : len; 256 } 257 258 if (sk->sk_state == SMC_CLOSED || sk->sk_shutdown & RCV_SHUTDOWN) 259 return 0; 260 261 return -EAGAIN; 262 } 263 264 static bool smc_rx_recvmsg_data_available(struct smc_sock *smc) 265 { 266 struct smc_connection *conn = &smc->conn; 267 268 if (smc_rx_data_available(conn)) 269 return true; 270 else if (conn->urg_state == SMC_URG_VALID) 271 /* we received a single urgent Byte - skip */ 272 smc_rx_update_cons(smc, 0); 273 return false; 274 } 275 276 /* smc_rx_recvmsg - receive data from RMBE 277 * @msg: copy data to receive buffer 278 * @pipe: copy data to pipe if set - indicates splice() call 279 * 280 * rcvbuf consumer: main API called by socket layer. 281 * Called under sk lock. 282 */ 283 int smc_rx_recvmsg(struct smc_sock *smc, struct msghdr *msg, 284 struct pipe_inode_info *pipe, size_t len, int flags) 285 { 286 size_t copylen, read_done = 0, read_remaining = len; 287 size_t chunk_len, chunk_off, chunk_len_sum; 288 struct smc_connection *conn = &smc->conn; 289 int (*func)(struct smc_connection *conn); 290 union smc_host_cursor cons; 291 int readable, chunk; 292 char *rcvbuf_base; 293 struct sock *sk; 294 int splbytes; 295 long timeo; 296 int target; /* Read at least these many bytes */ 297 int rc; 298 299 if (unlikely(flags & MSG_ERRQUEUE)) 300 return -EINVAL; /* future work for sk.sk_family == AF_SMC */ 301 302 sk = &smc->sk; 303 if (sk->sk_state == SMC_LISTEN) 304 return -ENOTCONN; 305 if (flags & MSG_OOB) 306 return smc_rx_recv_urg(smc, msg, len, flags); 307 timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT); 308 target = sock_rcvlowat(sk, flags & MSG_WAITALL, len); 309 310 /* we currently use 1 RMBE per RMB, so RMBE == RMB base addr */ 311 rcvbuf_base = conn->rx_off + conn->rmb_desc->cpu_addr; 312 313 do { /* while (read_remaining) */ 314 if (read_done >= target || (pipe && read_done)) 315 break; 316 317 if (smc_rx_recvmsg_data_available(smc)) 318 goto copy; 319 320 if (sk->sk_shutdown & RCV_SHUTDOWN || 321 conn->local_tx_ctrl.conn_state_flags.peer_conn_abort) { 322 /* smc_cdc_msg_recv_action() could have run after 323 * above smc_rx_recvmsg_data_available() 324 */ 325 if (smc_rx_recvmsg_data_available(smc)) 326 goto copy; 327 break; 328 } 329 330 if (read_done) { 331 if (sk->sk_err || 332 sk->sk_state == SMC_CLOSED || 333 !timeo || 334 signal_pending(current)) 335 break; 336 } else { 337 if (sk->sk_err) { 338 read_done = sock_error(sk); 339 break; 340 } 341 if (sk->sk_state == SMC_CLOSED) { 342 if (!sock_flag(sk, SOCK_DONE)) { 343 /* This occurs when user tries to read 344 * from never connected socket. 345 */ 346 read_done = -ENOTCONN; 347 break; 348 } 349 break; 350 } 351 if (signal_pending(current)) { 352 read_done = sock_intr_errno(timeo); 353 break; 354 } 355 if (!timeo) 356 return -EAGAIN; 357 } 358 359 if (!smc_rx_data_available(conn)) { 360 smc_rx_wait(smc, &timeo, smc_rx_data_available); 361 continue; 362 } 363 364 copy: 365 /* initialize variables for 1st iteration of subsequent loop */ 366 /* could be just 1 byte, even after waiting on data above */ 367 readable = atomic_read(&conn->bytes_to_rcv); 368 splbytes = atomic_read(&conn->splice_pending); 369 if (!readable || (msg && splbytes)) { 370 if (splbytes) 371 func = smc_rx_data_available_and_no_splice_pend; 372 else 373 func = smc_rx_data_available; 374 smc_rx_wait(smc, &timeo, func); 375 continue; 376 } 377 378 smc_curs_copy(&cons, &conn->local_tx_ctrl.cons, conn); 379 /* subsequent splice() calls pick up where previous left */ 380 if (splbytes) 381 smc_curs_add(conn->rmb_desc->len, &cons, splbytes); 382 if (conn->urg_state == SMC_URG_VALID && 383 sock_flag(&smc->sk, SOCK_URGINLINE) && 384 readable > 1) 385 readable--; /* always stop at urgent Byte */ 386 /* not more than what user space asked for */ 387 copylen = min_t(size_t, read_remaining, readable); 388 /* determine chunks where to read from rcvbuf */ 389 /* either unwrapped case, or 1st chunk of wrapped case */ 390 chunk_len = min_t(size_t, copylen, conn->rmb_desc->len - 391 cons.count); 392 chunk_len_sum = chunk_len; 393 chunk_off = cons.count; 394 smc_rmb_sync_sg_for_cpu(conn); 395 for (chunk = 0; chunk < 2; chunk++) { 396 if (!(flags & MSG_TRUNC)) { 397 if (msg) { 398 rc = memcpy_to_msg(msg, rcvbuf_base + 399 chunk_off, 400 chunk_len); 401 } else { 402 rc = smc_rx_splice(pipe, rcvbuf_base + 403 chunk_off, chunk_len, 404 smc); 405 } 406 if (rc < 0) { 407 if (!read_done) 408 read_done = -EFAULT; 409 smc_rmb_sync_sg_for_device(conn); 410 goto out; 411 } 412 } 413 read_remaining -= chunk_len; 414 read_done += chunk_len; 415 416 if (chunk_len_sum == copylen) 417 break; /* either on 1st or 2nd iteration */ 418 /* prepare next (== 2nd) iteration */ 419 chunk_len = copylen - chunk_len; /* remainder */ 420 chunk_len_sum += chunk_len; 421 chunk_off = 0; /* modulo offset in recv ring buffer */ 422 } 423 smc_rmb_sync_sg_for_device(conn); 424 425 /* update cursors */ 426 if (!(flags & MSG_PEEK)) { 427 /* increased in recv tasklet smc_cdc_msg_rcv() */ 428 smp_mb__before_atomic(); 429 atomic_sub(copylen, &conn->bytes_to_rcv); 430 /* guarantee 0 <= bytes_to_rcv <= rmb_desc->len */ 431 smp_mb__after_atomic(); 432 if (msg && smc_rx_update_consumer(smc, cons, copylen)) 433 goto out; 434 } 435 } while (read_remaining); 436 out: 437 return read_done; 438 } 439 440 /* Initialize receive properties on connection establishment. NB: not __init! */ 441 void smc_rx_init(struct smc_sock *smc) 442 { 443 smc->sk.sk_data_ready = smc_rx_wake_up; 444 atomic_set(&smc->conn.splice_pending, 0); 445 smc->conn.urg_state = SMC_URG_READ; 446 } 447