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