send.c 30.6 KB
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/*
 * 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>
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#include <linux/gfp.h>
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#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;
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	conn->c_xmit_atomic_sent = 0;
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	conn->c_xmit_rdma_sent = 0;
	conn->c_xmit_data_sent = 0;
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	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
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	 * the connection doesn't make forward progress.
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	 */
	while (--send_quota) {

		rm = conn->c_xmit_rm;

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		/*
		 * If between sending messages, we can send a pending congestion
		 * map update.
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		 */
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		if (!rm && test_and_clear_bit(0, &conn->c_map_queued)) {
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			rm = rds_cong_update_alloc(conn);
			if (IS_ERR(rm)) {
				ret = PTR_ERR(rm);
				break;
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			}
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			rm->data.op_active = 1;

			conn->c_xmit_rm = rm;
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		}

		/*
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		 * If not already working on one, grab the next message.
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		 *
		 * 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.
		 */
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		if (!rm) {
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			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);

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			if (!rm) {
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				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.
			 */
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			if (rm->rdma.op_active &&
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			    test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) {
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				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);
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			if (conn->c_unacked_packets == 0 ||
			    conn->c_unacked_bytes < len) {
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				__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;
		}

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		/* The transport either sends the whole rdma or none of it */
		if (rm->rdma.op_active && !conn->c_xmit_rdma_sent) {
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			rm->m_final_op = &rm->rdma;
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			ret = conn->c_trans->xmit_rdma(conn, &rm->rdma);
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			if (ret)
				break;
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			conn->c_xmit_rdma_sent = 1;

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			/* 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);
		}

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		if (rm->atomic.op_active && !conn->c_xmit_atomic_sent) {
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			rm->m_final_op = &rm->atomic;
			ret = conn->c_trans->xmit_atomic(conn, &rm->atomic);
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			if (ret)
				break;
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			conn->c_xmit_atomic_sent = 1;
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			/* 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);
		}

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		/*
		 * A number of cases require an RDS header to be sent
		 * even if there is no data.
		 * We permit 0-byte sends; rds-ping depends on this.
		 * However, if there are exclusively attached silent ops,
		 * we skip the hdr/data send, to enable silent operation.
		 */
		if (rm->data.op_nents == 0) {
			int ops_present;
			int all_ops_are_silent = 1;

			ops_present = (rm->atomic.op_active || rm->rdma.op_active);
			if (rm->atomic.op_active && !rm->atomic.op_silent)
				all_ops_are_silent = 0;
			if (rm->rdma.op_active && !rm->rdma.op_silent)
				all_ops_are_silent = 0;

			if (ops_present && all_ops_are_silent
			    && !rm->m_rdma_cookie)
				rm->data.op_active = 0;
		}

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		if (rm->data.op_active && !conn->c_xmit_data_sent) {
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			rm->m_final_op = &rm->data;
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			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;
			}

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			sg = &rm->data.op_sg[conn->c_xmit_sg];
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			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 &&
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					       conn->c_xmit_sg == rm->data.op_nents);
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				}
			}
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			if (conn->c_xmit_hdr_off == sizeof(struct rds_header) &&
			    (conn->c_xmit_sg == rm->data.op_nents))
				conn->c_xmit_data_sent = 1;
		}

		/*
		 * A rm will only take multiple times through this loop
		 * if there is a data op. Thus, if the data is sent (or there was
		 * none), then we're done with the rm.
		 */
		if (!rm->data.op_active || conn->c_xmit_data_sent) {
			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;
			conn->c_xmit_atomic_sent = 0;
			conn->c_xmit_data_sent = 0;

			rds_message_put(rm);
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		}
	}

	/* 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);

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	if (send_quota == 0 && !was_empty) {
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		/* 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;
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	struct rm_rdma_op *ro;
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	struct rds_notifier *notifier;
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	unsigned long flags;
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	spin_lock_irqsave(&rm->m_rs_lock, flags);
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	ro = &rm->rdma;
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	if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) &&
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	    ro->op_active && ro->op_notify && ro->op_notifier) {
		notifier = ro->op_notifier;
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		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);

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		ro->op_notifier = NULL;
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	}

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	spin_unlock_irqrestore(&rm->m_rs_lock, flags);
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	if (rs) {
		rds_wake_sk_sleep(rs);
		sock_put(rds_rs_to_sk(rs));
	}
}
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EXPORT_SYMBOL_GPL(rds_rdma_send_complete);
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/*
 * 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);

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/*
 * 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
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__rds_send_complete(struct rds_sock *rs, struct rds_message *rm, int status)
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{
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	struct rm_rdma_op *ro;
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	struct rm_atomic_op *ao;
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	ro = &rm->rdma;
	if (ro->op_active && ro->op_notify && ro->op_notifier) {
		ro->op_notifier->n_status = status;
		list_add_tail(&ro->op_notifier->n_list, &rs->rs_notify_queue);
		ro->op_notifier = NULL;
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	}

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	ao = &rm->atomic;
	if (ao->op_active && ao->op_notify && ao->op_notifier) {
		ao->op_notifier->n_status = status;
		list_add_tail(&ao->op_notifier->n_list, &rs->rs_notify_queue);
		ao->op_notifier = NULL;
	}

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	/* 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,
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					 struct rm_rdma_op *op)
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{
	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) {
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		if (&rm->rdma == op) {
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			atomic_inc(&rm->m_refcount);
			found = rm;
			goto out;
		}
	}

	list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
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		if (&rm->rdma == op) {
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			atomic_inc(&rm->m_refcount);
			found = rm;
			break;
		}
	}

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

	return found;
}
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EXPORT_SYMBOL_GPL(rds_send_get_message);
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/*
 * 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)
{
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	unsigned long flags;
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	struct rds_sock *rs = NULL;
	struct rds_message *rm;

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

A
Andy Grover 已提交
577 578 579 580 581 582 583 584 585 586 587 588 589 590
		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.
		 */
591
		spin_lock_irqsave(&rm->m_rs_lock, flags);
A
Andy Grover 已提交
592 593 594 595 596 597 598 599 600 601 602
		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
603
		spin_lock(&rs->rs_lock);
A
Andy Grover 已提交
604 605

		if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) {
A
Andy Grover 已提交
606
			struct rm_rdma_op *ro = &rm->rdma;
A
Andy Grover 已提交
607 608 609 610 611
			struct rds_notifier *notifier;

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

A
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612 613 614
			if (ro->op_active && ro->op_notifier &&
			       (ro->op_notify || (ro->op_recverr && status))) {
				notifier = ro->op_notifier;
A
Andy Grover 已提交
615 616 617 618
				list_add_tail(&notifier->n_list,
						&rs->rs_notify_queue);
				if (!notifier->n_status)
					notifier->n_status = status;
A
Andy Grover 已提交
619
				rm->rdma.op_notifier = NULL;
A
Andy Grover 已提交
620
			}
621
			was_on_sock = 1;
A
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622 623
			rm->m_rs = NULL;
		}
T
Tina Yang 已提交
624
		spin_unlock(&rs->rs_lock);
A
Andy Grover 已提交
625 626

unlock_and_drop:
627
		spin_unlock_irqrestore(&rm->m_rs_lock, flags);
A
Andy Grover 已提交
628
		rds_message_put(rm);
629 630
		if (was_on_sock)
			rds_message_put(rm);
A
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631 632 633 634 635 636 637 638 639 640 641 642 643 644 645 646 647 648 649 650 651 652 653 654 655 656 657 658 659 660 661 662 663 664 665 666 667 668 669 670 671 672 673 674 675
	}

	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
676
EXPORT_SYMBOL_GPL(rds_send_drop_acked);
A
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677 678 679 680 681

void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
{
	struct rds_message *rm, *tmp;
	struct rds_connection *conn;
682
	unsigned long flags;
A
Andy Grover 已提交
683 684 685 686 687 688 689 690 691 692 693 694 695 696 697 698
	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 */
699
	smp_mb__after_clear_bit();
A
Andy Grover 已提交
700 701 702

	spin_unlock_irqrestore(&rs->rs_lock, flags);

703 704
	if (list_empty(&list))
		return;
A
Andy Grover 已提交
705

706
	/* Remove the messages from the conn */
A
Andy Grover 已提交
707
	list_for_each_entry(rm, &list, m_sock_item) {
708 709

		conn = rm->m_inc.i_conn;
A
Andy Grover 已提交
710

711
		spin_lock_irqsave(&conn->c_lock, flags);
A
Andy Grover 已提交
712
		/*
713 714 715
		 * 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
716
		 */
717 718
		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
719 720
			continue;
		}
721 722
		list_del_init(&rm->m_conn_item);
		spin_unlock_irqrestore(&conn->c_lock, flags);
A
Andy Grover 已提交
723

724 725 726 727
		/*
		 * Couldn't grab m_rs_lock in top loop (lock ordering),
		 * but we can now.
		 */
728
		spin_lock_irqsave(&rm->m_rs_lock, flags);
A
Andy Grover 已提交
729

730
		spin_lock(&rs->rs_lock);
731
		__rds_send_complete(rs, rm, RDS_RDMA_CANCELED);
732 733 734
		spin_unlock(&rs->rs_lock);

		rm->m_rs = NULL;
735
		spin_unlock_irqrestore(&rm->m_rs_lock, flags);
736 737 738

		rds_message_put(rm);
	}
A
Andy Grover 已提交
739

740
	rds_wake_sk_sleep(rs);
741

A
Andy Grover 已提交
742 743 744 745 746 747 748 749 750 751 752 753 754 755 756 757 758 759 760 761 762 763 764 765 766 767 768 769 770 771 772 773 774 775 776 777 778 779 780 781 782 783 784 785 786 787 788 789 790 791 792 793 794 795 796 797 798 799 800 801 802 803 804 805 806 807 808 809 810 811 812 813 814 815 816 817 818 819
	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;
}

820 821 822 823 824 825
/*
 * 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)
{
826
	struct cmsghdr *cmsg;
827
	int size = 0;
828
	int cmsg_groups = 0;
829 830 831 832 833 834 835 836 837 838 839
	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:
840
			cmsg_groups |= 1;
841 842 843 844
			retval = rds_rdma_extra_size(CMSG_DATA(cmsg));
			if (retval < 0)
				return retval;
			size += retval;
845

846 847 848 849
			break;

		case RDS_CMSG_RDMA_DEST:
		case RDS_CMSG_RDMA_MAP:
850
			cmsg_groups |= 2;
851 852 853
			/* these are valid but do no add any size */
			break;

A
Andy Grover 已提交
854 855
		case RDS_CMSG_ATOMIC_CSWP:
		case RDS_CMSG_ATOMIC_FADD:
856
			cmsg_groups |= 1;
A
Andy Grover 已提交
857 858 859
			size += sizeof(struct scatterlist);
			break;

860 861 862 863 864
		default:
			return -EINVAL;
		}

	}
865

866
	size += ceil(data_len, PAGE_SIZE) * sizeof(struct scatterlist);
867

868 869 870 871
	/* Ensure (DEST, MAP) are never used with (ARGS, ATOMIC) */
	if (cmsg_groups == 3)
		return -EINVAL;

872 873 874
	return size;
}

A
Andy Grover 已提交
875 876 877 878 879 880 881 882 883 884 885 886 887 888
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
889
		 * rm->rdma.m_rdma_cookie and rm->rdma.m_rdma_mr.
A
Andy Grover 已提交
890 891 892 893 894 895 896 897 898 899 900 901 902 903 904
		 */
		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
905 906 907 908
		case RDS_CMSG_ATOMIC_CSWP:
		case RDS_CMSG_ATOMIC_FADD:
			ret = rds_cmsg_atomic(rs, rm, cmsg);
			break;
A
Andy Grover 已提交
909 910 911 912 913 914 915 916 917 918 919 920 921 922 923 924 925 926 927 928 929 930 931 932 933

		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;
934
	long timeo = sock_sndtimeo(sk, nonblock);
A
Andy Grover 已提交
935 936 937 938 939 940 941 942 943 944 945 946 947 948 949 950 951 952 953 954 955 956 957 958 959 960 961 962 963 964 965

	/* 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;
	}

966 967 968 969 970 971 972 973
	/* 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
974 975 976
		goto out;
	}

977 978 979 980 981 982 983 984
	/* Attach data to the rm */
	if (payload_len) {
		rm->data.op_sg = rds_message_alloc_sgs(rm, ceil(payload_len, PAGE_SIZE));
		ret = rds_message_copy_from_user(rm, msg->msg_iov, payload_len);
		if (ret)
			goto out;
	}
	rm->data.op_active = 1;
985

A
Andy Grover 已提交
986 987 988 989 990 991 992 993 994 995 996 997 998 999 1000 1001 1002
	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;
	}

1003 1004 1005 1006 1007
	/* Parse any control messages the user may have included. */
	ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
	if (ret)
		goto out;

1008
	if (rm->rdma.op_active && !conn->c_trans->xmit_rdma) {
A
Andy Grover 已提交
1009 1010
		if (printk_ratelimit())
			printk(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
A
Andy Grover 已提交
1011
			       &rm->rdma, conn->c_trans->xmit_rdma);
A
Andy Grover 已提交
1012 1013 1014 1015 1016 1017 1018 1019
		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
1020 1021 1022 1023 1024 1025 1026 1027
		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.
	 */
1028 1029
	if (rds_conn_state(conn) == RDS_CONN_DOWN &&
	    !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
A
Andy Grover 已提交
1030 1031 1032
		queue_delayed_work(rds_wq, &conn->c_conn_w, 0);

	ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);
1033 1034
	if (ret) {
		rs->rs_seen_congestion = 1;
A
Andy Grover 已提交
1035
		goto out;
1036
	}
A
Andy Grover 已提交
1037 1038 1039 1040 1041 1042 1043 1044 1045 1046 1047 1048 1049 1050

	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
1051
		timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
A
Andy Grover 已提交
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 1080 1081 1082 1083 1084 1085 1086 1087 1088 1089 1090 1091 1092 1093 1094 1095 1096 1097 1098 1099 1100 1101
					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);
1102
	if (!rm) {
A
Andy Grover 已提交
1103 1104 1105 1106 1107 1108 1109 1110 1111 1112
		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.
	 */
1113 1114
	if (rds_conn_state(conn) == RDS_CONN_DOWN &&
	    !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
A
Andy Grover 已提交
1115 1116 1117 1118 1119 1120 1121 1122 1123 1124 1125 1126 1127 1128 1129 1130 1131 1132 1133 1134 1135 1136 1137 1138 1139 1140 1141 1142 1143
		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;
}