1 files changed, 331 insertions, 213 deletions

diff --git a/net/rds/send.c b/net/rds/send.c
index 9c1c6bcaa6c9..9b951a0ab6b7 100644
--- a/net/rds/send.c
+++ b/net/rds/send.c
@@ -37,7 +37,6 @@
 #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
@@ -54,7 +53,8 @@ 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.
+ * Reset the send state.  Callers must ensure that this doesn't race with
+ * rds_send_xmit().
  */
 void rds_send_reset(struct rds_connection *conn)
 {
@@ -62,18 +62,22 @@ void rds_send_reset(struct rds_connection *conn)
 	unsigned long flags;
 
 	if (conn->c_xmit_rm) {
+		rm = conn->c_xmit_rm;
+		conn->c_xmit_rm = NULL;
 		/* 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;
+		rds_message_unmapped(rm);
+		rds_message_put(rm);
 	}
+
 	conn->c_xmit_sg = 0;
 	conn->c_xmit_hdr_off = 0;
 	conn->c_xmit_data_off = 0;
+	conn->c_xmit_atomic_sent = 0;
 	conn->c_xmit_rdma_sent = 0;
+	conn->c_xmit_data_sent = 0;
 
 	conn->c_map_queued = 0;
 
@@ -90,6 +94,25 @@ void rds_send_reset(struct rds_connection *conn)
 	spin_unlock_irqrestore(&conn->c_lock, flags);
 }
 
+static int acquire_in_xmit(struct rds_connection *conn)
+{
+	return test_and_set_bit(RDS_IN_XMIT, &conn->c_flags) == 0;
+}
+
+static void release_in_xmit(struct rds_connection *conn)
+{
+	clear_bit(RDS_IN_XMIT, &conn->c_flags);
+	smp_mb__after_clear_bit();
+	/*
+	 * We don't use wait_on_bit()/wake_up_bit() because our waking is in a
+	 * hot path and finding waiters is very rare.  We don't want to walk
+	 * the system-wide hashed waitqueue buckets in the fast path only to
+	 * almost never find waiters.
+	 */
+	if (waitqueue_active(&conn->c_waitq))
+		wake_up_all(&conn->c_waitq);
+}
+
 /*
  * We're making the concious trade-off here to only send one message
  * down the connection at a time.
@@ -109,102 +132,69 @@ 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);
 
+restart:
+
 	/*
 	 * 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);
+	if (!acquire_in_xmit(conn)) {
+		rds_stats_inc(s_send_lock_contention);
 		ret = -ENOMEM;
 		goto out;
 	}
 
+	/*
+	 * rds_conn_shutdown() sets the conn state and then tests RDS_IN_XMIT,
+	 * we do the opposite to avoid races.
+	 */
+	if (!rds_conn_up(conn)) {
+		release_in_xmit(conn);
+		ret = 0;
+		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.
+	 * the connection doesn'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;
+	while (1) {
 
-			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 between sending messages, we can send a pending congestion
+		 * map update.
 		 */
-		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;
-			}
-
+		if (!rm && test_and_clear_bit(0, &conn->c_map_queued)) {
 			rm = rds_cong_update_alloc(conn);
 			if (IS_ERR(rm)) {
 				ret = PTR_ERR(rm);
 				break;
 			}
+			rm->data.op_active = 1;
 
 			conn->c_xmit_rm = rm;
 		}
 
 		/*
-		 * Grab the next message from the send queue, if there is one.
+		 * If not already working on one, grab the next message.
 		 *
 		 * 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) {
+		if (!rm) {
 			unsigned int len;
 
 			spin_lock_irqsave(&conn->c_lock, flags);
@@ -224,10 +214,8 @@ int rds_send_xmit(struct rds_connection *conn)
 
 			spin_unlock_irqrestore(&conn->c_lock, flags);
 
-			if (rm == NULL) {
-				was_empty = 1;
+			if (!rm)
 				break;
-			}
 
 			/* Unfortunately, the way Infiniband deals with
 			 * RDMA to a bad MR key is by moving the entire
@@ -236,13 +224,12 @@ int rds_send_xmit(struct rds_connection *conn)
 			 * connection.
 			 * Therefore, we never retransmit messages with RDMA ops.
 			 */
-			if (rm->m_rdma_op &&
+			if (rm->rdma.op_active &&
 			    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;
 			}
 
@@ -263,23 +250,55 @@ int rds_send_xmit(struct rds_connection *conn)
 			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);
+		/* The transport either sends the whole rdma or none of it */
+		if (rm->rdma.op_active && !conn->c_xmit_rdma_sent) {
+			rm->m_final_op = &rm->rdma;
+			ret = conn->c_trans->xmit_rdma(conn, &rm->rdma);
 			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) {
+		if (rm->atomic.op_active && !conn->c_xmit_atomic_sent) {
+			rm->m_final_op = &rm->atomic;
+			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 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;
+		}
+
+		if (rm->data.op_active && !conn->c_xmit_data_sent) {
+			rm->m_final_op = &rm->data;
 			ret = conn->c_trans->xmit(conn, rm,
 						  conn->c_xmit_hdr_off,
 						  conn->c_xmit_sg,
@@ -295,7 +314,7 @@ int rds_send_xmit(struct rds_connection *conn)
 				ret -= tmp;
 			}
 
-			sg = &rm->m_sg[conn->c_xmit_sg];
+			sg = &rm->data.op_sg[conn->c_xmit_sg];
 			while (ret) {
 				tmp = min_t(int, ret, sg->length -
 						      conn->c_xmit_data_off);
@@ -306,49 +325,63 @@ int rds_send_xmit(struct rds_connection *conn)
 					sg++;
 					conn->c_xmit_sg++;
 					BUG_ON(ret != 0 &&
-					       conn->c_xmit_sg == rm->m_nents);
+					       conn->c_xmit_sg == rm->data.op_nents);
 				}
 			}
+
+			if (conn->c_xmit_hdr_off == sizeof(struct rds_header) &&
+			    (conn->c_xmit_sg == rm->data.op_nents))
+				conn->c_xmit_data_sent = 1;
 		}
-	}
 
-	/* 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);
+		/*
+		 * 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);
+		}
+	}
 
 	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);
+	release_in_xmit(conn);
 
-	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;
+	/* Nuke any messages we decided not to retransmit. */
+	if (!list_empty(&to_be_dropped)) {
+		/* irqs on here, so we can put(), unlike above */
+		list_for_each_entry(rm, &to_be_dropped, m_conn_item)
+			rds_message_put(rm);
+		rds_send_remove_from_sock(&to_be_dropped, RDS_RDMA_DROPPED);
 	}
 
-	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);
+	/*
+	 * Other senders can queue a message after we last test the send queue
+	 * but before we clear RDS_IN_XMIT.  In that case they'd back off and
+	 * not try and send their newly queued message.  We need to check the
+	 * send queue after having cleared RDS_IN_XMIT so that their message
+	 * doesn't get stuck on the send queue.
+	 *
+	 * If the transport cannot continue (i.e ret != 0), then it must
+	 * call us when more room is available, such as from the tx
+	 * completion handler.
+	 */
+	if (ret == 0) {
+		smp_mb();
 		if (!list_empty(&conn->c_send_queue)) {
-			rds_stats_inc(s_send_sem_queue_raced);
-			ret = -EAGAIN;
+			rds_stats_inc(s_send_lock_queue_raced);
+			goto restart;
 		}
-		spin_unlock_irqrestore(&conn->c_lock, flags);
 	}
 out:
 	return ret;
@@ -376,52 +409,60 @@ static inline int rds_send_is_acked(struct rds_message *rm, u64 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.
+ * 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.
  */
-int rds_send_acked_before(struct rds_connection *conn, u64 seq)
+void rds_rdma_send_complete(struct rds_message *rm, int status)
 {
-	struct rds_message *rm, *tmp;
-	int ret = 1;
+	struct rds_sock *rs = NULL;
+	struct rm_rdma_op *ro;
+	struct rds_notifier *notifier;
+	unsigned long flags;
 
-	spin_lock(&conn->c_lock);
+	spin_lock_irqsave(&rm->m_rs_lock, flags);
 
-	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;
-	}
+	ro = &rm->rdma;
+	if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) &&
+	    ro->op_active && ro->op_notify && ro->op_notifier) {
+		notifier = ro->op_notifier;
+		rs = rm->m_rs;
+		sock_hold(rds_rs_to_sk(rs));
 
-	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;
+		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->op_notifier = NULL;
 	}
 
-	spin_unlock(&conn->c_lock);
+	spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 
-	return ret;
+	if (rs) {
+		rds_wake_sk_sleep(rs);
+		sock_put(rds_rs_to_sk(rs));
+	}
 }
+EXPORT_SYMBOL_GPL(rds_rdma_send_complete);
 
 /*
- * 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.
+ * Just like above, except looks at atomic op
  */
-void rds_rdma_send_complete(struct rds_message *rm, int status)
+void rds_atomic_send_complete(struct rds_message *rm, int status)
 {
 	struct rds_sock *rs = NULL;
-	struct rds_rdma_op *ro;
+	struct rm_atomic_op *ao;
 	struct rds_notifier *notifier;
+	unsigned long flags;
 
-	spin_lock(&rm->m_rs_lock);
+	spin_lock_irqsave(&rm->m_rs_lock, flags);
 
-	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;
+	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));
 
@@ -430,17 +471,17 @@ void rds_rdma_send_complete(struct rds_message *rm, int status)
 		list_add_tail(&notifier->n_list, &rs->rs_notify_queue);
 		spin_unlock(&rs->rs_lock);
 
-		ro->r_notifier = NULL;
+		ao->op_notifier = NULL;
 	}
 
-	spin_unlock(&rm->m_rs_lock);
+	spin_unlock_irqrestore(&rm->m_rs_lock, flags);
 
 	if (rs) {
 		rds_wake_sk_sleep(rs);
 		sock_put(rds_rs_to_sk(rs));
 	}
 }
-EXPORT_SYMBOL_GPL(rds_rdma_send_complete);
+EXPORT_SYMBOL_GPL(rds_atomic_send_complete);
 
 /*
  * This is the same as rds_rdma_send_complete except we
@@ -448,15 +489,23 @@ EXPORT_SYMBOL_GPL(rds_rdma_send_complete);
  * 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)
+__rds_send_complete(struct rds_sock *rs, struct rds_message *rm, int status)
 {
-	struct rds_rdma_op *ro;
+	struct rm_rdma_op *ro;
+	struct rm_atomic_op *ao;
+
+	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;
+	}
 
-	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;
+	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;
 	}
 
 	/* No need to wake the app - caller does this */
@@ -468,7 +517,7 @@ __rds_rdma_send_complete(struct rds_sock *rs, struct rds_message *rm, int status
  * So speed is not an issue here.
  */
 struct rds_message *rds_send_get_message(struct rds_connection *conn,
-					 struct rds_rdma_op *op)
+					 struct rm_rdma_op *op)
 {
 	struct rds_message *rm, *tmp, *found = NULL;
 	unsigned long flags;
@@ -476,7 +525,7 @@ struct rds_message *rds_send_get_message(struct rds_connection *conn,
 	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) {
+		if (&rm->rdma == op) {
 			atomic_inc(&rm->m_refcount);
 			found = rm;
 			goto out;
@@ -484,7 +533,7 @@ struct rds_message *rds_send_get_message(struct rds_connection *conn,
 	}
 
 	list_for_each_entry_safe(rm, tmp, &conn->c_send_queue, m_conn_item) {
-		if (rm->m_rdma_op == op) {
+		if (&rm->rdma == op) {
 			atomic_inc(&rm->m_refcount);
 			found = rm;
 			break;
@@ -544,19 +593,20 @@ void rds_send_remove_from_sock(struct list_head *messages, int status)
 		spin_lock(&rs->rs_lock);
 
 		if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) {
-			struct rds_rdma_op *ro = rm->m_rdma_op;
+			struct rm_rdma_op *ro = &rm->rdma;
 			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;
+			if (ro->op_active && ro->op_notifier &&
+			       (ro->op_notify || (ro->op_recverr && status))) {
+				notifier = ro->op_notifier;
 				list_add_tail(&notifier->n_list,
 						&rs->rs_notify_queue);
 				if (!notifier->n_status)
 					notifier->n_status = status;
-				rm->m_rdma_op->r_notifier = NULL;
+				rm->rdma.op_notifier = NULL;
 			}
 			was_on_sock = 1;
 			rm->m_rs = NULL;
@@ -619,9 +669,8 @@ 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, flags2;
+	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);
@@ -631,59 +680,54 @@ void rds_send_drop_to(struct rds_sock *rs, struct sockaddr_in *dest)
 			     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);
 	}
 
 	/* order flag updates with the rs lock */
-	if (wake)
-		smp_mb__after_clear_bit();
+	smp_mb__after_clear_bit();
 
 	spin_unlock_irqrestore(&rs->rs_lock, flags);
 
-	conn = NULL;
+	if (list_empty(&list))
+		return;
 
-	/* now remove the messages from the conn list as needed */
+	/* Remove the messages from the conn */
 	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_irqsave(&rm->m_rs_lock, flags2);
-		/* If this is a RDMA operation, notify the app. */
-		spin_lock(&rs->rs_lock);
-		__rds_rdma_send_complete(rs, rm, RDS_RDMA_CANCELED);
-		spin_unlock(&rs->rs_lock);
-		rm->m_rs = NULL;
-		spin_unlock_irqrestore(&rm->m_rs_lock, flags2);
 
+		conn = rm->m_inc.i_conn;
+
+		spin_lock_irqsave(&conn->c_lock, flags);
 		/*
-		 * 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.
+		 * 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.
 		 */
-		if (!test_bit(RDS_MSG_ON_CONN, &rm->m_flags))
+		if (!test_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) {
+			spin_unlock_irqrestore(&conn->c_lock, 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);
 		}
+		list_del_init(&rm->m_conn_item);
+		spin_unlock_irqrestore(&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);
-		}
-	}
+		/*
+		 * Couldn't grab m_rs_lock in top loop (lock ordering),
+		 * but we can now.
+		 */
+		spin_lock_irqsave(&rm->m_rs_lock, flags);
 
-	if (conn)
-		spin_unlock_irqrestore(&conn->c_lock, flags);
+		spin_lock(&rs->rs_lock);
+		__rds_send_complete(rs, rm, RDS_RDMA_CANCELED);
+		spin_unlock(&rs->rs_lock);
 
-	if (wake)
-		rds_wake_sk_sleep(rs);
+		rm->m_rs = NULL;
+		spin_unlock_irqrestore(&rm->m_rs_lock, flags);
+
+		rds_message_put(rm);
+	}
+
+	rds_wake_sk_sleep(rs);
 
 	while (!list_empty(&list)) {
 		rm = list_entry(list.next, struct rds_message, m_sock_item);
@@ -763,6 +807,63 @@ out:
 	return *queued;
 }
 
+/*
+ * 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)
+{
+	struct cmsghdr *cmsg;
+	int size = 0;
+	int cmsg_groups = 0;
+	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:
+			cmsg_groups |= 1;
+			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:
+			cmsg_groups |= 2;
+			/* these are valid but do no add any size */
+			break;
+
+		case RDS_CMSG_ATOMIC_CSWP:
+		case RDS_CMSG_ATOMIC_FADD:
+		case RDS_CMSG_MASKED_ATOMIC_CSWP:
+		case RDS_CMSG_MASKED_ATOMIC_FADD:
+			cmsg_groups |= 1;
+			size += sizeof(struct scatterlist);
+			break;
+
+		default:
+			return -EINVAL;
+		}
+
+	}
+
+	size += ceil(data_len, PAGE_SIZE) * sizeof(struct scatterlist);
+
+	/* Ensure (DEST, MAP) are never used with (ARGS, ATOMIC) */
+	if (cmsg_groups == 3)
+		return -EINVAL;
+
+	return size;
+}
+
 static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
 			 struct msghdr *msg, int *allocated_mr)
 {
@@ -777,7 +878,7 @@ static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
 			continue;
 
 		/* As a side effect, RDMA_DEST and RDMA_MAP will set
-		 * rm->m_rdma_cookie and rm->m_rdma_mr.
+		 * rm->rdma.m_rdma_cookie and rm->rdma.m_rdma_mr.
 		 */
 		switch (cmsg->cmsg_type) {
 		case RDS_CMSG_RDMA_ARGS:
@@ -793,6 +894,12 @@ static int rds_cmsg_send(struct rds_sock *rs, struct rds_message *rm,
 			if (!ret)
 				*allocated_mr = 1;
 			break;
+		case RDS_CMSG_ATOMIC_CSWP:
+		case RDS_CMSG_ATOMIC_FADD:
+		case RDS_CMSG_MASKED_ATOMIC_CSWP:
+		case RDS_CMSG_MASKED_ATOMIC_FADD:
+			ret = rds_cmsg_atomic(rs, rm, cmsg);
+			break;
 
 		default:
 			return -EINVAL;
@@ -850,13 +957,26 @@ int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
 		goto out;
 	}
 
-	rm = rds_message_copy_from_user(msg->msg_iov, payload_len);
-	if (IS_ERR(rm)) {
-		ret = PTR_ERR(rm);
-		rm = NULL;
+	/* 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;
 		goto out;
 	}
 
+	/* 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;
+
 	rm->m_daddr = daddr;
 
 	/* rds_conn_create has a spinlock that runs with IRQ off.
@@ -879,22 +999,23 @@ int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
 	if (ret)
 		goto out;
 
-	if ((rm->m_rdma_cookie || rm->m_rdma_op) &&
-	    conn->c_trans->xmit_rdma == NULL) {
+	if (rm->rdma.op_active && !conn->c_trans->xmit_rdma) {
 		if (printk_ratelimit())
 			printk(KERN_NOTICE "rdma_op %p conn xmit_rdma %p\n",
-				rm->m_rdma_op, conn->c_trans->xmit_rdma);
+			       &rm->rdma, 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);
+	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);
+		ret = -EOPNOTSUPP;
+		goto out;
+	}
+
+	rds_conn_connect_if_down(conn);
 
 	ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs);
 	if (ret) {
@@ -938,7 +1059,7 @@ int rds_sendmsg(struct kiocb *iocb, struct socket *sock, struct msghdr *msg,
 	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_send_xmit(conn);
 
 	rds_message_put(rm);
 	return payload_len;
@@ -966,20 +1087,15 @@ rds_send_pong(struct rds_connection *conn, __be16 dport)
 	int ret = 0;
 
 	rm = rds_message_alloc(0, GFP_ATOMIC);
-	if (rm == NULL) {
+	if (!rm) {
 		ret = -ENOMEM;
 		goto out;
 	}
 
 	rm->m_daddr = conn->c_faddr;
+	rm->data.op_active = 1;
 
-	/* 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);
+	rds_conn_connect_if_down(conn);
 
 	ret = rds_cong_wait(conn->c_fcong, dport, 1, NULL);
 	if (ret)
@@ -999,7 +1115,9 @@ rds_send_pong(struct rds_connection *conn, __be16 dport)
 	rds_stats_inc(s_send_queued);
 	rds_stats_inc(s_send_pong);
 
-	queue_delayed_work(rds_wq, &conn->c_send_w, 0);
+	if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags))
+		rds_send_xmit(conn);
+
 	rds_message_put(rm);
 	return 0;