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