send.c 30.2 KB
Newer Older
A
Andy Grover 已提交
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33
/*
 * Copyright (c) 2006 Oracle.  All rights reserved.
 *
 * This software is available to you under a choice of one of two
 * licenses.  You may choose to be licensed under the terms of the GNU
 * General Public License (GPL) Version 2, available from the file
 * COPYING in the main directory of this source tree, or the
 * OpenIB.org BSD license below:
 *
 *     Redistribution and use in source and binary forms, with or
 *     without modification, are permitted provided that the following
 *     conditions are met:
 *
 *      - Redistributions of source code must retain the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer.
 *
 *      - Redistributions in binary form must reproduce the above
 *        copyright notice, this list of conditions and the following
 *        disclaimer in the documentation and/or other materials
 *        provided with the distribution.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
 * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
 * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
 * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
 * SOFTWARE.
 *
 */
#include <linux/kernel.h>
34
#include <linux/gfp.h>
A
Andy Grover 已提交
35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70 71 72 73 74 75
#include <net/sock.h>
#include <linux/in.h>
#include <linux/list.h>

#include "rds.h"

/* When transmitting messages in rds_send_xmit, we need to emerge from
 * time to time and briefly release the CPU. Otherwise the softlock watchdog
 * will kick our shin.
 * Also, it seems fairer to not let one busy connection stall all the
 * others.
 *
 * send_batch_count is the number of times we'll loop in send_xmit. Setting
 * it to 0 will restore the old behavior (where we looped until we had
 * drained the queue).
 */
static int send_batch_count = 64;
module_param(send_batch_count, int, 0444);
MODULE_PARM_DESC(send_batch_count, " batch factor when working the send queue");

/*
 * Reset the send state. Caller must hold c_send_lock when calling here.
 */
void rds_send_reset(struct rds_connection *conn)
{
	struct rds_message *rm, *tmp;
	unsigned long flags;

	if (conn->c_xmit_rm) {
		/* Tell the user the RDMA op is no longer mapped by the
		 * transport. This isn't entirely true (it's flushed out
		 * independently) but as the connection is down, there's
		 * no ongoing RDMA to/from that memory */
		rds_message_unmapped(conn->c_xmit_rm);
		rds_message_put(conn->c_xmit_rm);
		conn->c_xmit_rm = NULL;
	}
	conn->c_xmit_sg = 0;
	conn->c_xmit_hdr_off = 0;
	conn->c_xmit_data_off = 0;
	conn->c_xmit_rdma_sent = 0;
A
Andy Grover 已提交
76
	conn->c_xmit_atomic_sent = 0;
A
Andy Grover 已提交
77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166

	conn->c_map_queued = 0;

	conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
	conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;

	/* Mark messages as retransmissions, and move them to the send q */
	spin_lock_irqsave(&conn->c_lock, flags);
	list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
		set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
		set_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags);
	}
	list_splice_init(&conn->c_retrans, &conn->c_send_queue);
	spin_unlock_irqrestore(&conn->c_lock, flags);
}

/*
 * We're making the concious trade-off here to only send one message
 * down the connection at a time.
 *   Pro:
 *      - tx queueing is a simple fifo list
 *   	- reassembly is optional and easily done by transports per conn
 *      - no per flow rx lookup at all, straight to the socket
 *   	- less per-frag memory and wire overhead
 *   Con:
 *      - queued acks can be delayed behind large messages
 *   Depends:
 *      - small message latency is higher behind queued large messages
 *      - large message latency isn't starved by intervening small sends
 */
int rds_send_xmit(struct rds_connection *conn)
{
	struct rds_message *rm;
	unsigned long flags;
	unsigned int tmp;
	unsigned int send_quota = send_batch_count;
	struct scatterlist *sg;
	int ret = 0;
	int was_empty = 0;
	LIST_HEAD(to_be_dropped);

	/*
	 * sendmsg calls here after having queued its message on the send
	 * queue.  We only have one task feeding the connection at a time.  If
	 * another thread is already feeding the queue then we back off.  This
	 * avoids blocking the caller and trading per-connection data between
	 * caches per message.
	 *
	 * The sem holder will issue a retry if they notice that someone queued
	 * a message after they stopped walking the send queue but before they
	 * dropped the sem.
	 */
	if (!mutex_trylock(&conn->c_send_lock)) {
		rds_stats_inc(s_send_sem_contention);
		ret = -ENOMEM;
		goto out;
	}

	if (conn->c_trans->xmit_prepare)
		conn->c_trans->xmit_prepare(conn);

	/*
	 * spin trying to push headers and data down the connection until
	 * the connection doens't make forward progress.
	 */
	while (--send_quota) {
		/*
		 * See if need to send a congestion map update if we're
		 * between sending messages.  The send_sem protects our sole
		 * use of c_map_offset and _bytes.
		 * Note this is used only by transports that define a special
		 * xmit_cong_map function. For all others, we create allocate
		 * a cong_map message and treat it just like any other send.
		 */
		if (conn->c_map_bytes) {
			ret = conn->c_trans->xmit_cong_map(conn, conn->c_lcong,
						conn->c_map_offset);
			if (ret <= 0)
				break;

			conn->c_map_offset += ret;
			conn->c_map_bytes -= ret;
			if (conn->c_map_bytes)
				continue;
		}

		/* If we're done sending the current message, clear the
		 * offset and S/G temporaries.
		 */
		rm = conn->c_xmit_rm;
167
		if (rm &&
A
Andy Grover 已提交
168
		    conn->c_xmit_hdr_off == sizeof(struct rds_header) &&
169
		    conn->c_xmit_sg == rm->data.m_nents) {
A
Andy Grover 已提交
170 171 172 173 174
			conn->c_xmit_rm = NULL;
			conn->c_xmit_sg = 0;
			conn->c_xmit_hdr_off = 0;
			conn->c_xmit_data_off = 0;
			conn->c_xmit_rdma_sent = 0;
A
Andy Grover 已提交
175
			conn->c_xmit_atomic_sent = 0;
A
Andy Grover 已提交
176 177 178 179 180 181 182 183

			/* Release the reference to the previous message. */
			rds_message_put(rm);
			rm = NULL;
		}

		/* If we're asked to send a cong map update, do so.
		 */
184 185
		if (!rm && test_and_clear_bit(0, &conn->c_map_queued)) {
			if (conn->c_trans->xmit_cong_map) {
A
Andy Grover 已提交
186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207
				conn->c_map_offset = 0;
				conn->c_map_bytes = sizeof(struct rds_header) +
					RDS_CONG_MAP_BYTES;
				continue;
			}

			rm = rds_cong_update_alloc(conn);
			if (IS_ERR(rm)) {
				ret = PTR_ERR(rm);
				break;
			}

			conn->c_xmit_rm = rm;
		}

		/*
		 * Grab the next message from the send queue, if there is one.
		 *
		 * c_xmit_rm holds a ref while we're sending this message down
		 * the connction.  We can use this ref while holding the
		 * send_sem.. rds_send_reset() is serialized with it.
		 */
208
		if (!rm) {
A
Andy Grover 已提交
209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227
			unsigned int len;

			spin_lock_irqsave(&conn->c_lock, flags);

			if (!list_empty(&conn->c_send_queue)) {
				rm = list_entry(conn->c_send_queue.next,
						struct rds_message,
						m_conn_item);
				rds_message_addref(rm);

				/*
				 * Move the message from the send queue to the retransmit
				 * list right away.
				 */
				list_move_tail(&rm->m_conn_item, &conn->c_retrans);
			}

			spin_unlock_irqrestore(&conn->c_lock, flags);

228
			if (!rm) {
A
Andy Grover 已提交
229 230 231 232 233 234 235 236 237 238 239
				was_empty = 1;
				break;
			}

			/* Unfortunately, the way Infiniband deals with
			 * RDMA to a bad MR key is by moving the entire
			 * queue pair to error state. We cold possibly
			 * recover from that, but right now we drop the
			 * connection.
			 * Therefore, we never retransmit messages with RDMA ops.
			 */
240
			if (rm->rdma.m_rdma_op.r_active &&
241
			    test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) {
A
Andy Grover 已提交
242 243 244 245 246 247 248 249 250 251
				spin_lock_irqsave(&conn->c_lock, flags);
				if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags))
					list_move(&rm->m_conn_item, &to_be_dropped);
				spin_unlock_irqrestore(&conn->c_lock, flags);
				rds_message_put(rm);
				continue;
			}

			/* Require an ACK every once in a while */
			len = ntohl(rm->m_inc.i_hdr.h_len);
252 253
			if (conn->c_unacked_packets == 0 ||
			    conn->c_unacked_bytes < len) {
A
Andy Grover 已提交
254 255 256 257 258 259 260 261 262 263 264 265 266
				__set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);

				conn->c_unacked_packets = rds_sysctl_max_unacked_packets;
				conn->c_unacked_bytes = rds_sysctl_max_unacked_bytes;
				rds_stats_inc(s_send_ack_required);
			} else {
				conn->c_unacked_bytes -= len;
				conn->c_unacked_packets--;
			}

			conn->c_xmit_rm = rm;
		}

A
Andy Grover 已提交
267 268 269 270 271 272 273 274 275 276 277

		if (rm->atomic.op_active && !conn->c_xmit_atomic_sent) {
			ret = conn->c_trans->xmit_atomic(conn, &rm->atomic);
			if (ret)
				break;
			conn->c_xmit_atomic_sent = 1;
			/* The transport owns the mapped memory for now.
			 * You can't unmap it while it's on the send queue */
			set_bit(RDS_MSG_MAPPED, &rm->m_flags);
		}

A
Andy Grover 已提交
278 279 280 281 282
		/*
		 * Try and send an rdma message.  Let's see if we can
		 * keep this simple and require that the transport either
		 * send the whole rdma or none of it.
		 */
283 284
		if (rm->rdma.m_rdma_op.r_active && !conn->c_xmit_rdma_sent) {
			ret = conn->c_trans->xmit_rdma(conn, &rm->rdma.m_rdma_op);
A
Andy Grover 已提交
285 286 287 288 289 290 291 292 293
			if (ret)
				break;
			conn->c_xmit_rdma_sent = 1;
			/* The transport owns the mapped memory for now.
			 * You can't unmap it while it's on the send queue */
			set_bit(RDS_MSG_MAPPED, &rm->m_flags);
		}

		if (conn->c_xmit_hdr_off < sizeof(struct rds_header) ||
294
		    conn->c_xmit_sg < rm->data.m_nents) {
A
Andy Grover 已提交
295 296 297 298 299 300 301 302 303 304 305 306 307 308 309
			ret = conn->c_trans->xmit(conn, rm,
						  conn->c_xmit_hdr_off,
						  conn->c_xmit_sg,
						  conn->c_xmit_data_off);
			if (ret <= 0)
				break;

			if (conn->c_xmit_hdr_off < sizeof(struct rds_header)) {
				tmp = min_t(int, ret,
					    sizeof(struct rds_header) -
					    conn->c_xmit_hdr_off);
				conn->c_xmit_hdr_off += tmp;
				ret -= tmp;
			}

310
			sg = &rm->data.m_sg[conn->c_xmit_sg];
A
Andy Grover 已提交
311 312 313 314 315 316 317 318 319 320
			while (ret) {
				tmp = min_t(int, ret, sg->length -
						      conn->c_xmit_data_off);
				conn->c_xmit_data_off += tmp;
				ret -= tmp;
				if (conn->c_xmit_data_off == sg->length) {
					conn->c_xmit_data_off = 0;
					sg++;
					conn->c_xmit_sg++;
					BUG_ON(ret != 0 &&
321
					       conn->c_xmit_sg == rm->data.m_nents);
A
Andy Grover 已提交
322 323 324 325 326 327 328 329 330 331 332 333 334 335 336 337 338 339 340 341 342 343 344 345 346 347 348 349 350 351 352 353 354 355 356 357 358 359 360 361 362 363 364 365 366 367 368 369 370 371 372 373 374 375 376 377 378 379 380 381 382 383 384 385 386 387 388 389 390 391 392 393 394 395 396 397 398 399 400 401 402 403 404 405 406 407 408 409 410 411 412 413 414 415 416 417 418 419 420 421 422 423 424 425 426 427 428 429
				}
			}
		}
	}

	/* Nuke any messages we decided not to retransmit. */
	if (!list_empty(&to_be_dropped))
		rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED);

	if (conn->c_trans->xmit_complete)
		conn->c_trans->xmit_complete(conn);

	/*
	 * We might be racing with another sender who queued a message but
	 * backed off on noticing that we held the c_send_lock.  If we check
	 * for queued messages after dropping the sem then either we'll
	 * see the queued message or the queuer will get the sem.  If we
	 * notice the queued message then we trigger an immediate retry.
	 *
	 * We need to be careful only to do this when we stopped processing
	 * the send queue because it was empty.  It's the only way we
	 * stop processing the loop when the transport hasn't taken
	 * responsibility for forward progress.
	 */
	mutex_unlock(&conn->c_send_lock);

	if (conn->c_map_bytes || (send_quota == 0 && !was_empty)) {
		/* We exhausted the send quota, but there's work left to
		 * do. Return and (re-)schedule the send worker.
		 */
		ret = -EAGAIN;
	}

	if (ret == 0 && was_empty) {
		/* A simple bit test would be way faster than taking the
		 * spin lock */
		spin_lock_irqsave(&conn->c_lock, flags);
		if (!list_empty(&conn->c_send_queue)) {
			rds_stats_inc(s_send_sem_queue_raced);
			ret = -EAGAIN;
		}
		spin_unlock_irqrestore(&conn->c_lock, flags);
	}
out:
	return ret;
}

static void rds_send_sndbuf_remove(struct rds_sock *rs, struct rds_message *rm)
{
	u32 len = be32_to_cpu(rm->m_inc.i_hdr.h_len);

	assert_spin_locked(&rs->rs_lock);

	BUG_ON(rs->rs_snd_bytes < len);
	rs->rs_snd_bytes -= len;

	if (rs->rs_snd_bytes == 0)
		rds_stats_inc(s_send_queue_empty);
}

static inline int rds_send_is_acked(struct rds_message *rm, u64 ack,
				    is_acked_func is_acked)
{
	if (is_acked)
		return is_acked(rm, ack);
	return be64_to_cpu(rm->m_inc.i_hdr.h_sequence) <= ack;
}

/*
 * Returns true if there are no messages on the send and retransmit queues
 * which have a sequence number greater than or equal to the given sequence
 * number.
 */
int rds_send_acked_before(struct rds_connection *conn, u64 seq)
{
	struct rds_message *rm, *tmp;
	int ret = 1;

	spin_lock(&conn->c_lock);

	list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
		if (be64_to_cpu(rm->m_inc.i_hdr.h_sequence) < seq)
			ret = 0;
		break;
	}

	list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
		if (be64_to_cpu(rm->m_inc.i_hdr.h_sequence) < seq)
			ret = 0;
		break;
	}

	spin_unlock(&conn->c_lock);

	return ret;
}

/*
 * This is pretty similar to what happens below in the ACK
 * handling code - except that we call here as soon as we get
 * the IB send completion on the RDMA op and the accompanying
 * message.
 */
void rds_rdma_send_complete(struct rds_message *rm, int status)
{
	struct rds_sock *rs = NULL;
	struct rds_rdma_op *ro;
	struct rds_notifier *notifier;
430
	unsigned long flags;
A
Andy Grover 已提交
431

432
	spin_lock_irqsave(&rm->m_rs_lock, flags);
A
Andy Grover 已提交
433

434
	ro = &rm->rdma.m_rdma_op;
435
	if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) &&
436
	    ro->r_active && ro->r_notify && ro->r_notifier) {
A
Andy Grover 已提交
437 438 439 440 441 442 443 444 445 446 447 448
		notifier = ro->r_notifier;
		rs = rm->m_rs;
		sock_hold(rds_rs_to_sk(rs));

		notifier->n_status = status;
		spin_lock(&rs->rs_lock);
		list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
		spin_unlock(&rs->rs_lock);

		ro->r_notifier = NULL;
	}

449
	spin_unlock_irqrestore(&rm->m_rs_lock, flags);
A
Andy Grover 已提交
450 451 452 453 454 455

	if (rs) {
		rds_wake_sk_sleep(rs);
		sock_put(rds_rs_to_sk(rs));
	}
}
A
Andy Grover 已提交
456
EXPORT_SYMBOL_GPL(rds_rdma_send_complete);
A
Andy Grover 已提交
457

A
Andy Grover 已提交
458 459 460 461 462 463 464 465 466 467 468 469 470 471 472 473 474 475 476 477 478 479 480 481 482 483 484 485 486 487 488 489 490 491 492
/*
 * Just like above, except looks at atomic op
 */
void rds_atomic_send_complete(struct rds_message *rm, int status)
{
	struct rds_sock *rs = NULL;
	struct rm_atomic_op *ao;
	struct rds_notifier *notifier;

	spin_lock(&rm->m_rs_lock);

	ao = &rm->atomic;
	if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags)
	    && ao->op_active && ao->op_notify && ao->op_notifier) {
		notifier = ao->op_notifier;
		rs = rm->m_rs;
		sock_hold(rds_rs_to_sk(rs));

		notifier->n_status = status;
		spin_lock(&rs->rs_lock);
		list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
		spin_unlock(&rs->rs_lock);

		ao->op_notifier = NULL;
	}

	spin_unlock(&rm->m_rs_lock);

	if (rs) {
		rds_wake_sk_sleep(rs);
		sock_put(rds_rs_to_sk(rs));
	}
}
EXPORT_SYMBOL_GPL(rds_atomic_send_complete);

A
Andy Grover 已提交
493 494 495 496 497 498 499 500 501 502
/*
 * This is the same as rds_rdma_send_complete except we
 * don't do any locking - we have all the ingredients (message,
 * socket, socket lock) and can just move the notifier.
 */
static inline void
__rds_rdma_send_complete(struct rds_sock *rs, struct rds_message *rm, int status)
{
	struct rds_rdma_op *ro;

503 504
	ro = &rm->rdma.m_rdma_op;
	if (ro->r_active && ro->r_notify && ro->r_notifier) {
A
Andy Grover 已提交
505 506 507 508 509 510 511 512 513 514 515 516 517 518 519 520 521 522 523 524 525 526
		ro->r_notifier->n_status = status;
		list_add_tail(&ro->r_notifier->n_list, &rs->rs_notify_queue);
		ro->r_notifier = NULL;
	}

	/* No need to wake the app - caller does this */
}

/*
 * This is called from the IB send completion when we detect
 * a RDMA operation that failed with remote access error.
 * So speed is not an issue here.
 */
struct rds_message *rds_send_get_message(struct rds_connection *conn,
					 struct rds_rdma_op *op)
{
	struct rds_message *rm, *tmp, *found = NULL;
	unsigned long flags;

	spin_lock_irqsave(&conn->c_lock, flags);

	list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
527
		if (&rm->rdma.m_rdma_op == op) {
A
Andy Grover 已提交
528 529 530 531 532 533 534
			atomic_inc(&rm->m_refcount);
			found = rm;
			goto out;
		}
	}

	list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
535
		if (&rm->rdma.m_rdma_op == op) {
A
Andy Grover 已提交
536 537 538 539 540 541 542 543 544 545 546
			atomic_inc(&rm->m_refcount);
			found = rm;
			break;
		}
	}

out:
	spin_unlock_irqrestore(&conn->c_lock, flags);

	return found;
}
A
Andy Grover 已提交
547
EXPORT_SYMBOL_GPL(rds_send_get_message);
A
Andy Grover 已提交
548 549 550 551 552 553 554 555 556 557 558

/*
 * This removes messages from the socket's list if they're on it.  The list
 * argument must be private to the caller, we must be able to modify it
 * without locks.  The messages must have a reference held for their
 * position on the list.  This function will drop that reference after
 * removing the messages from the 'messages' list regardless of if it found
 * the messages on the socket list or not.
 */
void rds_send_remove_from_sock(struct list_head *messages, int status)
{
559
	unsigned long flags;
A
Andy Grover 已提交
560 561 562 563
	struct rds_sock *rs = NULL;
	struct rds_message *rm;

	while (!list_empty(messages)) {
564 565
		int was_on_sock = 0;

A
Andy Grover 已提交
566 567 568 569 570 571 572 573 574 575 576 577 578 579
		rm = list_entry(messages->next, struct rds_message,
				m_conn_item);
		list_del_init(&rm->m_conn_item);

		/*
		 * If we see this flag cleared then we're *sure* that someone
		 * else beat us to removing it from the sock.  If we race
		 * with their flag update we'll get the lock and then really
		 * see that the flag has been cleared.
		 *
		 * The message spinlock makes sure nobody clears rm->m_rs
		 * while we're messing with it. It does not prevent the
		 * message from being removed from the socket, though.
		 */
580
		spin_lock_irqsave(&rm->m_rs_lock, flags);
A
Andy Grover 已提交
581 582 583 584 585 586 587 588 589 590 591
		if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags))
			goto unlock_and_drop;

		if (rs != rm->m_rs) {
			if (rs) {
				rds_wake_sk_sleep(rs);
				sock_put(rds_rs_to_sk(rs));
			}
			rs = rm->m_rs;
			sock_hold(rds_rs_to_sk(rs));
		}
T
Tina Yang 已提交
592
		spin_lock(&rs->rs_lock);
A
Andy Grover 已提交
593 594

		if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) {
595
			struct rds_rdma_op *ro = &rm->rdma.m_rdma_op;
A
Andy Grover 已提交
596 597 598 599 600
			struct rds_notifier *notifier;

			list_del_init(&rm->m_sock_item);
			rds_send_sndbuf_remove(rs, rm);

601
			if (ro->r_active && ro->r_notifier &&
602
			    (ro->r_notify || (ro->r_recverr && status))) {
A
Andy Grover 已提交
603 604 605 606 607
				notifier = ro->r_notifier;
				list_add_tail(&notifier->n_list,
						&rs->rs_notify_queue);
				if (!notifier->n_status)
					notifier->n_status = status;
608
				rm->rdma.m_rdma_op.r_notifier = NULL;
A
Andy Grover 已提交
609
			}
610
			was_on_sock = 1;
A
Andy Grover 已提交
611 612
			rm->m_rs = NULL;
		}
T
Tina Yang 已提交
613
		spin_unlock(&rs->rs_lock);
A
Andy Grover 已提交
614 615

unlock_and_drop:
616
		spin_unlock_irqrestore(&rm->m_rs_lock, flags);
A
Andy Grover 已提交
617
		rds_message_put(rm);
618 619
		if (was_on_sock)
			rds_message_put(rm);
A
Andy Grover 已提交
620 621 622 623 624 625 626 627 628 629 630 631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664
	}

	if (rs) {
		rds_wake_sk_sleep(rs);
		sock_put(rds_rs_to_sk(rs));
	}
}

/*
 * Transports call here when they've determined that the receiver queued
 * messages up to, and including, the given sequence number.  Messages are
 * moved to the retrans queue when rds_send_xmit picks them off the send
 * queue. This means that in the TCP case, the message may not have been
 * assigned the m_ack_seq yet - but that's fine as long as tcp_is_acked
 * checks the RDS_MSG_HAS_ACK_SEQ bit.
 *
 * XXX It's not clear to me how this is safely serialized with socket
 * destruction.  Maybe it should bail if it sees SOCK_DEAD.
 */
void rds_send_drop_acked(struct rds_connection *conn, u64 ack,
			 is_acked_func is_acked)
{
	struct rds_message *rm, *tmp;
	unsigned long flags;
	LIST_HEAD(list);

	spin_lock_irqsave(&conn->c_lock, flags);

	list_for_each_entry_safe(rm, tmp, &conn->c_retrans, m_conn_item) {
		if (!rds_send_is_acked(rm, ack, is_acked))
			break;

		list_move(&rm->m_conn_item, &list);
		clear_bit(RDS_MSG_ON_CONN, &rm->m_flags);
	}

	/* order flag updates with spin locks */
	if (!list_empty(&list))
		smp_mb__after_clear_bit();

	spin_unlock_irqrestore(&conn->c_lock, flags);

	/* now remove the messages from the sock list as needed */
	rds_send_remove_from_sock(&list, RDS_RDMA_SUCCESS);
}
A
Andy Grover 已提交
665
EXPORT_SYMBOL_GPL(rds_send_drop_acked);
A
Andy Grover 已提交
666 667 668 669 670

void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
{
	struct rds_message *rm, *tmp;
	struct rds_connection *conn;
671
	unsigned long flags;
A
Andy Grover 已提交
672 673 674 675 676 677 678 679 680 681 682 683 684 685 686 687
	LIST_HEAD(list);

	/* get all the messages we're dropping under the rs lock */
	spin_lock_irqsave(&rs->rs_lock, flags);

	list_for_each_entry_safe(rm, tmp, &rs->rs_send_queue, m_sock_item) {
		if (dest && (dest->sin_addr.s_addr != rm->m_daddr ||
			     dest->sin_port != rm->m_inc.i_hdr.h_dport))
			continue;

		list_move(&rm->m_sock_item, &list);
		rds_send_sndbuf_remove(rs, rm);
		clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
	}

	/* order flag updates with the rs lock */
688
	smp_mb__after_clear_bit();
A
Andy Grover 已提交
689 690 691

	spin_unlock_irqrestore(&rs->rs_lock, flags);

692 693
	if (list_empty(&list))
		return;
A
Andy Grover 已提交
694

695
	/* Remove the messages from the conn */
A
Andy Grover 已提交
696
	list_for_each_entry(rm, &list, m_sock_item) {
697 698

		conn = rm->m_inc.i_conn;
A
Andy Grover 已提交
699

700
		spin_lock_irqsave(&conn->c_lock, flags);
A
Andy Grover 已提交
701
		/*
702 703 704
		 * Maybe someone else beat us to removing rm from the conn.
		 * If we race with their flag update we'll get the lock and
		 * then really see that the flag has been cleared.
A
Andy Grover 已提交
705
		 */
706 707
		if (!test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) {
			spin_unlock_irqrestore(&conn->c_lock, flags);
A
Andy Grover 已提交
708 709
			continue;
		}
710 711
		list_del_init(&rm->m_conn_item);
		spin_unlock_irqrestore(&conn->c_lock, flags);
A
Andy Grover 已提交
712

713 714 715 716
		/*
		 * Couldn't grab m_rs_lock in top loop (lock ordering),
		 * but we can now.
		 */
717
		spin_lock_irqsave(&rm->m_rs_lock, flags);
A
Andy Grover 已提交
718

719 720 721 722 723
		spin_lock(&rs->rs_lock);
		__rds_rdma_send_complete(rs, rm, RDS_RDMA_CANCELED);
		spin_unlock(&rs->rs_lock);

		rm->m_rs = NULL;
724
		spin_unlock_irqrestore(&rm->m_rs_lock, flags);
725 726 727

		rds_message_put(rm);
	}
A
Andy Grover 已提交
728

729
	rds_wake_sk_sleep(rs);
730

A
Andy Grover 已提交
731 732 733 734 735 736 737 738 739 740 741 742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808
	while (!list_empty(&list)) {
		rm = list_entry(list.next, struct rds_message, m_sock_item);
		list_del_init(&rm->m_sock_item);

		rds_message_wait(rm);
		rds_message_put(rm);
	}
}

/*
 * we only want this to fire once so we use the callers 'queued'.  It's
 * possible that another thread can race with us and remove the
 * message from the flow with RDS_CANCEL_SENT_TO.
 */
static int rds_send_queue_rm(struct rds_sock *rs, struct rds_connection *conn,
			     struct rds_message *rm, __be16 sport,
			     __be16 dport, int *queued)
{
	unsigned long flags;
	u32 len;

	if (*queued)
		goto out;

	len = be32_to_cpu(rm->m_inc.i_hdr.h_len);

	/* this is the only place which holds both the socket's rs_lock
	 * and the connection's c_lock */
	spin_lock_irqsave(&rs->rs_lock, flags);

	/*
	 * If there is a little space in sndbuf, we don't queue anything,
	 * and userspace gets -EAGAIN. But poll() indicates there's send
	 * room. This can lead to bad behavior (spinning) if snd_bytes isn't
	 * freed up by incoming acks. So we check the *old* value of
	 * rs_snd_bytes here to allow the last msg to exceed the buffer,
	 * and poll() now knows no more data can be sent.
	 */
	if (rs->rs_snd_bytes < rds_sk_sndbuf(rs)) {
		rs->rs_snd_bytes += len;

		/* let recv side know we are close to send space exhaustion.
		 * This is probably not the optimal way to do it, as this
		 * means we set the flag on *all* messages as soon as our
		 * throughput hits a certain threshold.
		 */
		if (rs->rs_snd_bytes >= rds_sk_sndbuf(rs) / 2)
			__set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);

		list_add_tail(&rm->m_sock_item, &rs->rs_send_queue);
		set_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
		rds_message_addref(rm);
		rm->m_rs = rs;

		/* The code ordering is a little weird, but we're
		   trying to minimize the time we hold c_lock */
		rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport, 0);
		rm->m_inc.i_conn = conn;
		rds_message_addref(rm);

		spin_lock(&conn->c_lock);
		rm->m_inc.i_hdr.h_sequence = cpu_to_be64(conn->c_next_tx_seq++);
		list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
		set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
		spin_unlock(&conn->c_lock);

		rdsdebug("queued msg %p len %d, rs %p bytes %d seq %llu\n",
			 rm, len, rs, rs->rs_snd_bytes,
			 (unsigned long long)be64_to_cpu(rm->m_inc.i_hdr.h_sequence));

		*queued = 1;
	}

	spin_unlock_irqrestore(&rs->rs_lock, flags);
out:
	return *queued;
}

809 810 811 812 813 814
/*
 * rds_message is getting to be quite complicated, and we'd like to allocate
 * it all in one go. This figures out how big it needs to be up front.
 */
static int rds_rm_size(struct msghdr *msg, int data_len)
{
815
	struct cmsghdr *cmsg;
816
	int size = 0;
817 818 819 820 821 822 823 824 825 826 827 828 829 830 831 832 833 834 835 836 837 838
	int retval;

	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
		if (!CMSG_OK(msg, cmsg))
			return -EINVAL;

		if (cmsg->cmsg_level != SOL_RDS)
			continue;

		switch (cmsg->cmsg_type) {
		case RDS_CMSG_RDMA_ARGS:
			retval = rds_rdma_extra_size(CMSG_DATA(cmsg));
			if (retval < 0)
				return retval;
			size += retval;
			break;

		case RDS_CMSG_RDMA_DEST:
		case RDS_CMSG_RDMA_MAP:
			/* these are valid but do no add any size */
			break;

A
Andy Grover 已提交
839 840 841 842 843
		case RDS_CMSG_ATOMIC_CSWP:
		case RDS_CMSG_ATOMIC_FADD:
			size += sizeof(struct scatterlist);
			break;

844 845 846 847 848
		default:
			return -EINVAL;
		}

	}
849

850
	size += ceil(data_len, PAGE_SIZE) * sizeof(struct scatterlist);
851 852 853 854

	return size;
}

A
Andy Grover 已提交
855 856 857 858 859 860 861 862 863 864 865 866 867 868
static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
			 struct msghdr *msg, int *allocated_mr)
{
	struct cmsghdr *cmsg;
	int ret = 0;

	for (cmsg = CMSG_FIRSTHDR(msg); cmsg; cmsg = CMSG_NXTHDR(msg, cmsg)) {
		if (!CMSG_OK(msg, cmsg))
			return -EINVAL;

		if (cmsg->cmsg_level != SOL_RDS)
			continue;

		/* As a side effect, RDMA_DEST and RDMA_MAP will set
A
Andy Grover 已提交
869
		 * rm->rdma.m_rdma_cookie and rm->rdma.m_rdma_mr.
A
Andy Grover 已提交
870 871 872 873 874 875 876 877 878 879 880 881 882 883 884
		 */
		switch (cmsg->cmsg_type) {
		case RDS_CMSG_RDMA_ARGS:
			ret = rds_cmsg_rdma_args(rs, rm, cmsg);
			break;

		case RDS_CMSG_RDMA_DEST:
			ret = rds_cmsg_rdma_dest(rs, rm, cmsg);
			break;

		case RDS_CMSG_RDMA_MAP:
			ret = rds_cmsg_rdma_map(rs, rm, cmsg);
			if (!ret)
				*allocated_mr = 1;
			break;
A
Andy Grover 已提交
885 886 887 888
		case RDS_CMSG_ATOMIC_CSWP:
		case RDS_CMSG_ATOMIC_FADD:
			ret = rds_cmsg_atomic(rs, rm, cmsg);
			break;
A
Andy Grover 已提交
889 890 891 892 893 894 895 896 897 898 899 900 901 902 903 904 905 906 907 908 909 910 911 912 913

		default:
			return -EINVAL;
		}

		if (ret)
			break;
	}

	return ret;
}

int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
		size_t payload_len)
{
	struct sock *sk = sock->sk;
	struct rds_sock *rs = rds_sk_to_rs(sk);
	struct sockaddr_in *usin = (struct sockaddr_in *)msg->msg_name;
	__be32 daddr;
	__be16 dport;
	struct rds_message *rm = NULL;
	struct rds_connection *conn;
	int ret = 0;
	int queued = 0, allocated_mr = 0;
	int nonblock = msg->msg_flags & MSG_DONTWAIT;
914
	long timeo = sock_sndtimeo(sk, nonblock);
A
Andy Grover 已提交
915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933 934 935 936 937 938 939 940 941 942 943 944 945

	/* Mirror Linux UDP mirror of BSD error message compatibility */
	/* XXX: Perhaps MSG_MORE someday */
	if (msg->msg_flags & ~(MSG_DONTWAIT | MSG_CMSG_COMPAT)) {
		printk(KERN_INFO "msg_flags 0x%08X\n", msg->msg_flags);
		ret = -EOPNOTSUPP;
		goto out;
	}

	if (msg->msg_namelen) {
		/* XXX fail non-unicast destination IPs? */
		if (msg->msg_namelen < sizeof(*usin) || usin->sin_family != AF_INET) {
			ret = -EINVAL;
			goto out;
		}
		daddr = usin->sin_addr.s_addr;
		dport = usin->sin_port;
	} else {
		/* We only care about consistency with ->connect() */
		lock_sock(sk);
		daddr = rs->rs_conn_addr;
		dport = rs->rs_conn_port;
		release_sock(sk);
	}

	/* racing with another thread binding seems ok here */
	if (daddr == 0 || rs->rs_bound_addr == 0) {
		ret = -ENOTCONN; /* XXX not a great errno */
		goto out;
	}

946 947 948 949 950 951 952 953
	/* size of rm including all sgs */
	ret = rds_rm_size(msg, payload_len);
	if (ret < 0)
		goto out;

	rm = rds_message_alloc(ret, GFP_KERNEL);
	if (!rm) {
		ret = -ENOMEM;
A
Andy Grover 已提交
954 955 956
		goto out;
	}

957 958 959 960 961 962
	rm->data.m_sg = rds_message_alloc_sgs(rm, ceil(payload_len, PAGE_SIZE));
	/* XXX fix this to not allocate memory */
	ret = rds_message_copy_from_user(rm, msg->msg_iov, payload_len);
	if (ret)
		goto out;

A
Andy Grover 已提交
963 964 965 966 967 968 969 970 971 972 973 974 975 976 977 978 979
	rm->m_daddr = daddr;

	/* rds_conn_create has a spinlock that runs with IRQ off.
	 * Caching the conn in the socket helps a lot. */
	if (rs->rs_conn && rs->rs_conn->c_faddr == daddr)
		conn = rs->rs_conn;
	else {
		conn = rds_conn_create_outgoing(rs->rs_bound_addr, daddr,
					rs->rs_transport,
					sock->sk->sk_allocation);
		if (IS_ERR(conn)) {
			ret = PTR_ERR(conn);
			goto out;
		}
		rs->rs_conn = conn;
	}

980 981 982 983 984
	/* Parse any control messages the user may have included. */
	ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
	if (ret)
		goto out;

985
	if ((rm->m_rdma_cookie || rm->rdma.m_rdma_op.r_active) &&
A
Andy Grover 已提交
986
	       !conn->c_trans->xmit_rdma) {
A
Andy Grover 已提交
987 988
		if (printk_ratelimit())
			printk(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
A
Andy Grover 已提交
989 990 991 992 993 994 995 996 997
			       &rm->rdma.m_rdma_op, conn->c_trans->xmit_rdma);
		ret = -EOPNOTSUPP;
		goto out;
	}

	if (rm->atomic.op_active && !conn->c_trans->xmit_atomic) {
		if (printk_ratelimit())
			printk(KERN_NOTICE "atomic_op %p conn xmit_atomic %p\n",
			       &rm->atomic, conn->c_trans->xmit_atomic);
A
Andy Grover 已提交
998 999 1000 1001 1002 1003 1004 1005
		ret = -EOPNOTSUPP;
		goto out;
	}

	/* If the connection is down, trigger a connect. We may
	 * have scheduled a delayed reconnect however - in this case
	 * we should not interfere.
	 */
1006 1007
	if (rds_conn_state(conn) == RDS_CONN_DOWN &&
	    !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
A
Andy Grover 已提交
1008 1009 1010
		queue_delayed_work(rds_wq, &conn->c_conn_w, 0);

	ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);
1011 1012
	if (ret) {
		rs->rs_seen_congestion = 1;
A
Andy Grover 已提交
1013
		goto out;
1014
	}
A
Andy Grover 已提交
1015 1016 1017 1018 1019 1020 1021 1022 1023 1024 1025 1026 1027 1028

	while (!rds_send_queue_rm(rs, conn, rm, rs->rs_bound_port,
				  dport, &queued)) {
		rds_stats_inc(s_send_queue_full);
		/* XXX make sure this is reasonable */
		if (payload_len > rds_sk_sndbuf(rs)) {
			ret = -EMSGSIZE;
			goto out;
		}
		if (nonblock) {
			ret = -EAGAIN;
			goto out;
		}

E
Eric Dumazet 已提交
1029
		timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
A
Andy Grover 已提交
1030 1031 1032 1033 1034 1035 1036 1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050 1051 1052 1053 1054 1055 1056 1057 1058 1059 1060 1061 1062 1063 1064 1065 1066 1067 1068 1069 1070 1071 1072 1073 1074 1075 1076 1077 1078 1079
					rds_send_queue_rm(rs, conn, rm,
							  rs->rs_bound_port,
							  dport,
							  &queued),
					timeo);
		rdsdebug("sendmsg woke queued %d timeo %ld\n", queued, timeo);
		if (timeo > 0 || timeo == MAX_SCHEDULE_TIMEOUT)
			continue;

		ret = timeo;
		if (ret == 0)
			ret = -ETIMEDOUT;
		goto out;
	}

	/*
	 * By now we've committed to the send.  We reuse rds_send_worker()
	 * to retry sends in the rds thread if the transport asks us to.
	 */
	rds_stats_inc(s_send_queued);

	if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
		rds_send_worker(&conn->c_send_w.work);

	rds_message_put(rm);
	return payload_len;

out:
	/* If the user included a RDMA_MAP cmsg, we allocated a MR on the fly.
	 * If the sendmsg goes through, we keep the MR. If it fails with EAGAIN
	 * or in any other way, we need to destroy the MR again */
	if (allocated_mr)
		rds_rdma_unuse(rs, rds_rdma_cookie_key(rm->m_rdma_cookie), 1);

	if (rm)
		rds_message_put(rm);
	return ret;
}

/*
 * Reply to a ping packet.
 */
int
rds_send_pong(struct rds_connection *conn, __be16 dport)
{
	struct rds_message *rm;
	unsigned long flags;
	int ret = 0;

	rm = rds_message_alloc(0, GFP_ATOMIC);
1080
	if (!rm) {
A
Andy Grover 已提交
1081 1082 1083 1084 1085 1086 1087 1088 1089 1090
		ret = -ENOMEM;
		goto out;
	}

	rm->m_daddr = conn->c_faddr;

	/* If the connection is down, trigger a connect. We may
	 * have scheduled a delayed reconnect however - in this case
	 * we should not interfere.
	 */
1091 1092
	if (rds_conn_state(conn) == RDS_CONN_DOWN &&
	    !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
A
Andy Grover 已提交
1093 1094 1095 1096 1097 1098 1099 1100 1101 1102 1103 1104 1105 1106 1107 1108 1109 1110 1111 1112 1113 1114 1115 1116 1117 1118 1119 1120 1121
		queue_delayed_work(rds_wq, &conn->c_conn_w, 0);

	ret = rds_cong_wait(conn->c_fcong, dport, 1, NULL);
	if (ret)
		goto out;

	spin_lock_irqsave(&conn->c_lock, flags);
	list_add_tail(&rm->m_conn_item, &conn->c_send_queue);
	set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
	rds_message_addref(rm);
	rm->m_inc.i_conn = conn;

	rds_message_populate_header(&rm->m_inc.i_hdr, 0, dport,
				    conn->c_next_tx_seq);
	conn->c_next_tx_seq++;
	spin_unlock_irqrestore(&conn->c_lock, flags);

	rds_stats_inc(s_send_queued);
	rds_stats_inc(s_send_pong);

	queue_delayed_work(rds_wq, &conn->c_send_w, 0);
	rds_message_put(rm);
	return 0;

out:
	if (rm)
		rds_message_put(rm);
	return ret;
}