new file mode 100644
@@ -0,0 +1,1003 @@
+/*
+ * 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>
+#include <net/sock.h>
+#include <linux/in.h>
+#include <linux/list.h>
+
+#include "rds.h"
+#include "rdma.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;
+
+ 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;
+ if (rm != NULL &&
+ conn->c_xmit_hdr_off == sizeof(struct rds_header) &&
+ conn->c_xmit_sg == rm->m_nents) {
+ 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;
+
+ /* 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.
+ */
+ if (rm == NULL && test_and_clear_bit(0, &conn->c_map_queued)) {
+ if (conn->c_trans->xmit_cong_map != NULL) {
+ 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.
+ */
+ if (rm == NULL) {
+ 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);
+
+ if (rm == NULL) {
+ 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.
+ */
+ if (rm->m_rdma_op
+ && test_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags)) {
+ 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);
+ if (conn->c_unacked_packets == 0
+ || conn->c_unacked_bytes < len) {
+ __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;
+ }
+
+ /*
+ * 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.
+ */
+ if (rm->m_rdma_op && !conn->c_xmit_rdma_sent) {
+ ret = conn->c_trans->xmit_rdma(conn, rm->m_rdma_op);
+ 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) ||
+ conn->c_xmit_sg < rm->m_nents) {
+ 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;
+ }
+
+ sg = &rm->m_sg[conn->c_xmit_sg];
+ 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 &&
+ conn->c_xmit_sg == rm->m_nents);
+ }
+ }
+ }
+ }
+
+ /* 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;
+
+ spin_lock(&rm->m_rs_lock);
+
+ ro = rm->m_rdma_op;
+ if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags)
+ && ro && ro->r_notify && ro->r_notifier) {
+ 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(¬ifier->n_list, &rs->rs_notify_queue);
+ spin_unlock(&rs->rs_lock);
+
+ ro->r_notifier = NULL;
+ }
+
+ spin_unlock(&rm->m_rs_lock);
+
+ if (rs) {
+ rds_wake_sk_sleep(rs);
+ sock_put(rds_rs_to_sk(rs));
+ }
+}
+
+/*
+ * 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;
+
+ ro = rm->m_rdma_op;
+ if (ro && ro->r_notify && ro->r_notifier) {
+ 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) {
+ if (rm->m_rdma_op == op) {
+ atomic_inc(&rm->m_refcount);
+ found = rm;
+ goto out;
+ }
+ }
+
+ list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
+ if (rm->m_rdma_op == op) {
+ atomic_inc(&rm->m_refcount);
+ found = rm;
+ break;
+ }
+ }
+
+out:
+ spin_unlock_irqrestore(&conn->c_lock, flags);
+
+ return found;
+}
+
+/*
+ * 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)
+{
+ unsigned long flags = 0; /* silence gcc :P */
+ struct rds_sock *rs = NULL;
+ struct rds_message *rm;
+
+ local_irq_save(flags);
+ while (!list_empty(messages)) {
+ 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.
+ */
+ spin_lock(&rm->m_rs_lock);
+ if (!test_bit(RDS_MSG_ON_SOCK, &rm->m_flags))
+ goto unlock_and_drop;
+
+ if (rs != rm->m_rs) {
+ if (rs) {
+ spin_unlock(&rs->rs_lock);
+ rds_wake_sk_sleep(rs);
+ sock_put(rds_rs_to_sk(rs));
+ }
+ rs = rm->m_rs;
+ spin_lock(&rs->rs_lock);
+ sock_hold(rds_rs_to_sk(rs));
+ }
+
+ if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) {
+ struct rds_rdma_op *ro = rm->m_rdma_op;
+ struct rds_notifier *notifier;
+
+ list_del_init(&rm->m_sock_item);
+ rds_send_sndbuf_remove(rs, rm);
+
+ if (ro && ro->r_notifier
+ && (status || ro->r_notify)) {
+ notifier = ro->r_notifier;
+ list_add_tail(¬ifier->n_list,
+ &rs->rs_notify_queue);
+ if (!notifier->n_status)
+ notifier->n_status = status;
+ rm->m_rdma_op->r_notifier = NULL;
+ }
+ rds_message_put(rm);
+ rm->m_rs = NULL;
+ }
+
+unlock_and_drop:
+ spin_unlock(&rm->m_rs_lock);
+ rds_message_put(rm);
+ }
+
+ if (rs) {
+ spin_unlock(&rs->rs_lock);
+ rds_wake_sk_sleep(rs);
+ sock_put(rds_rs_to_sk(rs));
+ }
+ local_irq_restore(flags);
+}
+
+/*
+ * 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);
+}
+
+void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
+{
+ struct rds_message *rm, *tmp;
+ struct rds_connection *conn;
+ unsigned long flags;
+ LIST_HEAD(list);
+ int wake = 0;
+
+ /* 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;
+
+ wake = 1;
+ list_move(&rm->m_sock_item, &list);
+ rds_send_sndbuf_remove(rs, rm);
+ clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags);
+
+ /* If this is a RDMA operation, notify the app. */
+ __rds_rdma_send_complete(rs, rm, RDS_RDMA_CANCELED);
+ }
+
+ /* order flag updates with the rs lock */
+ if (wake)
+ smp_mb__after_clear_bit();
+
+ spin_unlock_irqrestore(&rs->rs_lock, flags);
+
+ if (wake)
+ rds_wake_sk_sleep(rs);
+
+ conn = NULL;
+
+ /* now remove the messages from the conn list as needed */
+ list_for_each_entry(rm, &list, m_sock_item) {
+ /* We do this here rather than in the loop above, so that
+ * we don't have to nest m_rs_lock under rs->rs_lock */
+ spin_lock(&rm->m_rs_lock);
+ rm->m_rs = NULL;
+ spin_unlock(&rm->m_rs_lock);
+
+ /*
+ * If we see this flag cleared then we're *sure* that someone
+ * else beat us to removing it 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.
+ */
+ if (!test_bit(RDS_MSG_ON_CONN, &rm->m_flags))
+ continue;
+
+ if (conn != rm->m_inc.i_conn) {
+ if (conn)
+ spin_unlock_irqrestore(&conn->c_lock, flags);
+ conn = rm->m_inc.i_conn;
+ spin_lock_irqsave(&conn->c_lock, flags);
+ }
+
+ if (test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) {
+ list_del_init(&rm->m_conn_item);
+ rds_message_put(rm);
+ }
+ }
+
+ if (conn)
+ spin_unlock_irqrestore(&conn->c_lock, flags);
+
+ 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;
+}
+
+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
+ * rm->m_rdma_cookie and rm->m_rdma_mr.
+ */
+ 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;
+
+ 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;
+ long timeo = sock_rcvtimeo(sk, nonblock);
+
+ /* 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;
+ }
+
+ rm = rds_message_copy_from_user(msg->msg_iov, payload_len);
+ if (IS_ERR(rm)) {
+ ret = PTR_ERR(rm);
+ rm = NULL;
+ goto out;
+ }
+
+ rm->m_daddr = daddr;
+
+ /* Parse any control messages the user may have included. */
+ ret = rds_cmsg_send(rs, rm, msg, &allocated_mr);
+ if (ret)
+ goto out;
+
+ /* 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;
+ }
+
+ if ((rm->m_rdma_cookie || rm->m_rdma_op)
+ && conn->c_trans->xmit_rdma == NULL) {
+ if (printk_ratelimit())
+ printk(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
+ rm->m_rdma_op, conn->c_trans->xmit_rdma);
+ 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.
+ */
+ if (rds_conn_state(conn) == RDS_CONN_DOWN
+ && !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
+ queue_delayed_work(rds_wq, &conn->c_conn_w, 0);
+
+ ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);
+ if (ret)
+ goto out;
+
+ 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;
+ }
+
+ timeo = wait_event_interruptible_timeout(*sk->sk_sleep,
+ 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);
+ if (rm == NULL) {
+ 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.
+ */
+ if (rds_conn_state(conn) == RDS_CONN_DOWN
+ && !test_and_set_bit(RDS_RECONNECT_PENDING, &conn->c_flags))
+ 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;
+}
This is the code to send an RDS datagram. Signed-off-by: Andy Grover <andy.grover@oracle.com> --- net/rds/send.c | 1003 ++++++++++++++++++++++++++++++++++++++++++++++++++++++++ 1 files changed, 1003 insertions(+), 0 deletions(-) create mode 100644 net/rds/send.c