diff options
Diffstat (limited to 'net/rds/send.c')
| -rw-r--r-- | net/rds/send.c | 1133 |
1 files changed, 1133 insertions, 0 deletions
diff --git a/net/rds/send.c b/net/rds/send.c new file mode 100644 index 00000000..c803341f --- /dev/null +++ b/net/rds/send.c @@ -0,0 +1,1133 @@ +/* + * 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 <linux/gfp.h> +#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"); + +static void rds_send_remove_from_sock(struct list_head *messages, int status); + +/* + * Reset the send state. Callers must ensure that this doesn't race with + * rds_send_xmit(). + */ +void rds_send_reset(struct rds_connection *conn) +{ + struct rds_message *rm, *tmp; + 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(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; + + 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); +} + +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 conscious 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; + struct scatterlist *sg; + int ret = 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. + */ + 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 doesn't make forward progress. + */ + while (1) { + + rm = conn->c_xmit_rm; + + /* + * If between sending messages, we can send a pending congestion + * map update. + */ + 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; + } + + /* + * 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) { + 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) + 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->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); + 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; + } + + /* 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 (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, + 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->data.op_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->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; + } + + /* + * 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); + + release_in_xmit(conn); + + /* 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); + } + + /* + * 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_lock_queue_raced); + goto restart; + } + } +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; +} + +/* + * 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 rm_rdma_op *ro; + struct rds_notifier *notifier; + unsigned long flags; + + spin_lock_irqsave(&rm->m_rs_lock, flags); + + 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)); + + 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->op_notifier = NULL; + } + + 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); + +/* + * 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; + unsigned long flags; + + spin_lock_irqsave(&rm->m_rs_lock, flags); + + 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(¬ifier->n_list, &rs->rs_notify_queue); + spin_unlock(&rs->rs_lock); + + ao->op_notifier = NULL; + } + + 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_atomic_send_complete); + +/* + * 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_send_complete(struct rds_sock *rs, struct rds_message *rm, int status) +{ + 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; + } + + 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 */ +} + +/* + * 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 rm_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->rdma == 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->rdma == op) { + atomic_inc(&rm->m_refcount); + found = rm; + break; + } + } + +out: + spin_unlock_irqrestore(&conn->c_lock, flags); + + return found; +} +EXPORT_SYMBOL_GPL(rds_send_get_message); + +/* + * 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. + */ +static void rds_send_remove_from_sock(struct list_head *messages, int status) +{ + unsigned long flags; + struct rds_sock *rs = NULL; + struct rds_message *rm; + + while (!list_empty(messages)) { + int was_on_sock = 0; + + 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_irqsave(&rm->m_rs_lock, flags); + 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)); + } + spin_lock(&rs->rs_lock); + + if (test_and_clear_bit(RDS_MSG_ON_SOCK, &rm->m_flags)) { + 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->op_active && ro->op_notifier && + (ro->op_notify || (ro->op_recverr && status))) { + notifier = ro->op_notifier; + list_add_tail(¬ifier->n_list, + &rs->rs_notify_queue); + if (!notifier->n_status) + notifier->n_status = status; + rm->rdma.op_notifier = NULL; + } + was_on_sock = 1; + rm->m_rs = NULL; + } + spin_unlock(&rs->rs_lock); + +unlock_and_drop: + spin_unlock_irqrestore(&rm->m_rs_lock, flags); + rds_message_put(rm); + if (was_on_sock) + rds_message_put(rm); + } + + 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); +} +EXPORT_SYMBOL_GPL(rds_send_drop_acked); + +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); + + /* 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 */ + smp_mb__after_clear_bit(); + + spin_unlock_irqrestore(&rs->rs_lock, flags); + + if (list_empty(&list)) + return; + + /* Remove the messages from the conn */ + list_for_each_entry(rm, &list, m_sock_item) { + + conn = rm->m_inc.i_conn; + + spin_lock_irqsave(&conn->c_lock, flags); + /* + * 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_and_clear_bit(RDS_MSG_ON_CONN, &rm->m_flags)) { + spin_unlock_irqrestore(&conn->c_lock, flags); + continue; + } + list_del_init(&rm->m_conn_item); + spin_unlock_irqrestore(&conn->c_lock, flags); + + /* + * Couldn't grab m_rs_lock in top loop (lock ordering), + * but we can now. + */ + spin_lock_irqsave(&rm->m_rs_lock, flags); + + spin_lock(&rs->rs_lock); + __rds_send_complete(rs, rm, RDS_RDMA_CANCELED); + spin_unlock(&rs->rs_lock); + + 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); + 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; +} + +/* + * 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) +{ + 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->rdma.m_rdma_cookie and rm->rdma.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; + 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; + } + + 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_sndtimeo(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)) { + 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; + } + + /* 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)); + if (!rm->data.op_sg) { + ret = -ENOMEM; + goto out; + } + 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. + * 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; + } + + /* Parse any control messages the user may have included. */ + ret = rds_cmsg_send(rs, rm, msg, &allocated_mr); + if (ret) + goto out; + + 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->rdma, conn->c_trans->xmit_rdma); + ret = -EOPNOTSUPP; + goto out; + } + + if (rm->atomic.op_active && !conn->c_trans->xmit_atomic) { + if (printk_ratelimit()) + printk(KERN_NOTICE "atomic_op %p conn xmit_atomic %p\n", + &rm->atomic, conn->c_trans->xmit_atomic); + ret = -EOPNOTSUPP; + goto out; + } + + rds_conn_connect_if_down(conn); + + ret = rds_cong_wait(conn->c_fcong, dport, nonblock, rs); + if (ret) { + rs->rs_seen_congestion = 1; + 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_sleep(sk), + 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_xmit(conn); + + 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) { + ret = -ENOMEM; + goto out; + } + + rm->m_daddr = conn->c_faddr; + rm->data.op_active = 1; + + rds_conn_connect_if_down(conn); + + 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); + + if (!test_bit(RDS_LL_SEND_FULL, &conn->c_flags)) + rds_send_xmit(conn); + + rds_message_put(rm); + return 0; + +out: + if (rm) + rds_message_put(rm); + return ret; +} |