linux/net/rds/send.c
Sowmini Varadhan 5916e2c155 RDS: TCP: Enable multipath RDS for TCP
Use RDS probe-ping to compute how many paths may be used with
the peer, and to synchronously start the multiple paths. If mprds is
supported, hash outgoing traffic to one of multiple paths in rds_sendmsg()
when multipath RDS is supported by the transport.

CC: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: Sowmini Varadhan <sowmini.varadhan@oracle.com>
Acked-by: Santosh Shilimkar <santosh.shilimkar@oracle.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
2016-07-15 11:36:58 -07:00

1251 lines
33 KiB
C

/*
* 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/moduleparam.h>
#include <linux/gfp.h>
#include <net/sock.h>
#include <linux/in.h>
#include <linux/list.h>
#include <linux/ratelimit.h>
#include <linux/export.h>
#include <linux/sizes.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 = SZ_1K;
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_path_reset(struct rds_conn_path *cp)
{
struct rds_message *rm, *tmp;
unsigned long flags;
if (cp->cp_xmit_rm) {
rm = cp->cp_xmit_rm;
cp->cp_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);
}
cp->cp_xmit_sg = 0;
cp->cp_xmit_hdr_off = 0;
cp->cp_xmit_data_off = 0;
cp->cp_xmit_atomic_sent = 0;
cp->cp_xmit_rdma_sent = 0;
cp->cp_xmit_data_sent = 0;
cp->cp_conn->c_map_queued = 0;
cp->cp_unacked_packets = rds_sysctl_max_unacked_packets;
cp->cp_unacked_bytes = rds_sysctl_max_unacked_bytes;
/* Mark messages as retransmissions, and move them to the send q */
spin_lock_irqsave(&cp->cp_lock, flags);
list_for_each_entry_safe(rm, tmp, &cp->cp_retrans, m_conn_item) {
set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
set_bit(RDS_MSG_RETRANSMITTED, &rm->m_flags);
}
list_splice_init(&cp->cp_retrans, &cp->cp_send_queue);
spin_unlock_irqrestore(&cp->cp_lock, flags);
}
EXPORT_SYMBOL_GPL(rds_send_path_reset);
static int acquire_in_xmit(struct rds_conn_path *cp)
{
return test_and_set_bit(RDS_IN_XMIT, &cp->cp_flags) == 0;
}
static void release_in_xmit(struct rds_conn_path *cp)
{
clear_bit(RDS_IN_XMIT, &cp->cp_flags);
smp_mb__after_atomic();
/*
* 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(&cp->cp_waitq))
wake_up_all(&cp->cp_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_conn_path *cp)
{
struct rds_connection *conn = cp->cp_conn;
struct rds_message *rm;
unsigned long flags;
unsigned int tmp;
struct scatterlist *sg;
int ret = 0;
LIST_HEAD(to_be_dropped);
int batch_count;
unsigned long send_gen = 0;
restart:
batch_count = 0;
/*
* 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(cp)) {
rds_stats_inc(s_send_lock_contention);
ret = -ENOMEM;
goto out;
}
/*
* we record the send generation after doing the xmit acquire.
* if someone else manages to jump in and do some work, we'll use
* this to avoid a goto restart farther down.
*
* The acquire_in_xmit() check above ensures that only one
* caller can increment c_send_gen at any time.
*/
cp->cp_send_gen++;
send_gen = cp->cp_send_gen;
/*
* rds_conn_shutdown() sets the conn state and then tests RDS_IN_XMIT,
* we do the opposite to avoid races.
*/
if (!rds_conn_path_up(cp)) {
release_in_xmit(cp);
ret = 0;
goto out;
}
if (conn->c_trans->xmit_path_prepare)
conn->c_trans->xmit_path_prepare(cp);
/*
* spin trying to push headers and data down the connection until
* the connection doesn't make forward progress.
*/
while (1) {
rm = cp->cp_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;
rm->m_inc.i_conn_path = cp;
rm->m_inc.i_conn = cp->cp_conn;
cp->cp_xmit_rm = rm;
}
/*
* If not already working on one, grab the next message.
*
* cp_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;
batch_count++;
/* we want to process as big a batch as we can, but
* we also want to avoid softlockups. If we've been
* through a lot of messages, lets back off and see
* if anyone else jumps in
*/
if (batch_count >= send_batch_count)
goto over_batch;
spin_lock_irqsave(&cp->cp_lock, flags);
if (!list_empty(&cp->cp_send_queue)) {
rm = list_entry(cp->cp_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,
&cp->cp_retrans);
}
spin_unlock_irqrestore(&cp->cp_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(&cp->cp_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(&cp->cp_lock, flags);
continue;
}
/* Require an ACK every once in a while */
len = ntohl(rm->m_inc.i_hdr.h_len);
if (cp->cp_unacked_packets == 0 ||
cp->cp_unacked_bytes < len) {
__set_bit(RDS_MSG_ACK_REQUIRED, &rm->m_flags);
cp->cp_unacked_packets =
rds_sysctl_max_unacked_packets;
cp->cp_unacked_bytes =
rds_sysctl_max_unacked_bytes;
rds_stats_inc(s_send_ack_required);
} else {
cp->cp_unacked_bytes -= len;
cp->cp_unacked_packets--;
}
cp->cp_xmit_rm = rm;
}
/* The transport either sends the whole rdma or none of it */
if (rm->rdma.op_active && !cp->cp_xmit_rdma_sent) {
rm->m_final_op = &rm->rdma;
/* 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);
ret = conn->c_trans->xmit_rdma(conn, &rm->rdma);
if (ret) {
clear_bit(RDS_MSG_MAPPED, &rm->m_flags);
wake_up_interruptible(&rm->m_flush_wait);
break;
}
cp->cp_xmit_rdma_sent = 1;
}
if (rm->atomic.op_active && !cp->cp_xmit_atomic_sent) {
rm->m_final_op = &rm->atomic;
/* 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);
ret = conn->c_trans->xmit_atomic(conn, &rm->atomic);
if (ret) {
clear_bit(RDS_MSG_MAPPED, &rm->m_flags);
wake_up_interruptible(&rm->m_flush_wait);
break;
}
cp->cp_xmit_atomic_sent = 1;
}
/*
* 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 && !cp->cp_xmit_data_sent) {
rm->m_final_op = &rm->data;
ret = conn->c_trans->xmit(conn, rm,
cp->cp_xmit_hdr_off,
cp->cp_xmit_sg,
cp->cp_xmit_data_off);
if (ret <= 0)
break;
if (cp->cp_xmit_hdr_off < sizeof(struct rds_header)) {
tmp = min_t(int, ret,
sizeof(struct rds_header) -
cp->cp_xmit_hdr_off);
cp->cp_xmit_hdr_off += tmp;
ret -= tmp;
}
sg = &rm->data.op_sg[cp->cp_xmit_sg];
while (ret) {
tmp = min_t(int, ret, sg->length -
cp->cp_xmit_data_off);
cp->cp_xmit_data_off += tmp;
ret -= tmp;
if (cp->cp_xmit_data_off == sg->length) {
cp->cp_xmit_data_off = 0;
sg++;
cp->cp_xmit_sg++;
BUG_ON(ret != 0 && cp->cp_xmit_sg ==
rm->data.op_nents);
}
}
if (cp->cp_xmit_hdr_off == sizeof(struct rds_header) &&
(cp->cp_xmit_sg == rm->data.op_nents))
cp->cp_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 || cp->cp_xmit_data_sent) {
cp->cp_xmit_rm = NULL;
cp->cp_xmit_sg = 0;
cp->cp_xmit_hdr_off = 0;
cp->cp_xmit_data_off = 0;
cp->cp_xmit_rdma_sent = 0;
cp->cp_xmit_atomic_sent = 0;
cp->cp_xmit_data_sent = 0;
rds_message_put(rm);
}
}
over_batch:
if (conn->c_trans->xmit_path_complete)
conn->c_trans->xmit_path_complete(cp);
release_in_xmit(cp);
/* 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.
*
* We have an extra generation check here so that if someone manages
* to jump in after our release_in_xmit, we'll see that they have done
* some work and we will skip our goto
*/
if (ret == 0) {
smp_mb();
if ((test_bit(0, &conn->c_map_queued) ||
!list_empty(&cp->cp_send_queue)) &&
send_gen == cp->cp_send_gen) {
rds_stats_inc(s_send_lock_queue_raced);
if (batch_count < send_batch_count)
goto restart;
queue_delayed_work(rds_wq, &cp->cp_send_w, 1);
}
}
out:
return ret;
}
EXPORT_SYMBOL_GPL(rds_send_xmit);
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(&notifier->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(&notifier->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 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;
if (rs)
sock_hold(rds_rs_to_sk(rs));
}
if (!rs)
goto unlock_and_drop;
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(&notifier->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.
*/
void rds_send_path_drop_acked(struct rds_conn_path *cp, u64 ack,
is_acked_func is_acked)
{
struct rds_message *rm, *tmp;
unsigned long flags;
LIST_HEAD(list);
spin_lock_irqsave(&cp->cp_lock, flags);
list_for_each_entry_safe(rm, tmp, &cp->cp_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_atomic();
spin_unlock_irqrestore(&cp->cp_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_path_drop_acked);
void rds_send_drop_acked(struct rds_connection *conn, u64 ack,
is_acked_func is_acked)
{
WARN_ON(conn->c_trans->t_mp_capable);
rds_send_path_drop_acked(&conn->c_path[0], ack, is_acked);
}
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;
struct rds_conn_path *cp;
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_atomic();
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;
if (conn->c_trans->t_mp_capable)
cp = rm->m_inc.i_conn_path;
else
cp = &conn->c_path[0];
spin_lock_irqsave(&cp->cp_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(&cp->cp_lock, flags);
spin_lock_irqsave(&rm->m_rs_lock, flags);
rm->m_rs = NULL;
spin_unlock_irqrestore(&rm->m_rs_lock, flags);
continue;
}
list_del_init(&rm->m_conn_item);
spin_unlock_irqrestore(&cp->cp_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);
/* just in case the code above skipped this message
* because RDS_MSG_ON_CONN wasn't set, run it again here
* taking m_rs_lock is the only thing that keeps us
* from racing with ack processing.
*/
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);
}
}
/*
* 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_conn_path *cp,
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;
rm->m_inc.i_conn_path = cp;
rds_message_addref(rm);
spin_lock(&cp->cp_lock);
rm->m_inc.i_hdr.h_sequence = cpu_to_be64(cp->cp_next_tx_seq++);
list_add_tail(&rm->m_conn_item, &cp->cp_send_queue);
set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
spin_unlock(&cp->cp_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_each_cmsghdr(cmsg, msg) {
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_each_cmsghdr(cmsg, msg) {
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;
}
static void rds_send_ping(struct rds_connection *conn);
static int rds_send_mprds_hash(struct rds_sock *rs, struct rds_connection *conn)
{
int hash;
if (conn->c_npaths == 0)
hash = RDS_MPATH_HASH(rs, RDS_MPATH_WORKERS);
else
hash = RDS_MPATH_HASH(rs, conn->c_npaths);
if (conn->c_npaths == 0 && hash != 0) {
rds_send_ping(conn);
if (conn->c_npaths == 0) {
wait_event_interruptible(conn->c_hs_waitq,
(conn->c_npaths != 0));
}
if (conn->c_npaths == 1)
hash = 0;
}
return hash;
}
int rds_sendmsg(struct socket *sock, struct msghdr *msg, size_t payload_len)
{
struct sock *sk = sock->sk;
struct rds_sock *rs = rds_sk_to_rs(sk);
DECLARE_SOCKADDR(struct sockaddr_in *, usin, 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);
struct rds_conn_path *cpath;
/* 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);
}
lock_sock(sk);
if (daddr == 0 || rs->rs_bound_addr == 0) {
release_sock(sk);
ret = -ENOTCONN; /* XXX not a great errno */
goto out;
}
release_sock(sk);
if (payload_len > rds_sk_sndbuf(rs)) {
ret = -EMSGSIZE;
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_iter);
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(sock_net(sock->sk),
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) {
printk_ratelimited(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) {
printk_ratelimited(KERN_NOTICE "atomic_op %p conn xmit_atomic %p\n",
&rm->atomic, conn->c_trans->xmit_atomic);
ret = -EOPNOTSUPP;
goto out;
}
if (conn->c_trans->t_mp_capable)
cpath = &conn->c_path[rds_send_mprds_hash(rs, conn)];
else
cpath = &conn->c_path[0];
rds_conn_path_connect_if_down(cpath);
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, cpath, rm, rs->rs_bound_port,
dport, &queued)) {
rds_stats_inc(s_send_queue_full);
if (nonblock) {
ret = -EAGAIN;
goto out;
}
timeo = wait_event_interruptible_timeout(*sk_sleep(sk),
rds_send_queue_rm(rs, conn, cpath, 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);
ret = rds_send_xmit(cpath);
if (ret == -ENOMEM || ret == -EAGAIN)
queue_delayed_work(rds_wq, &cpath->cp_send_w, 1);
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;
}
/*
* send out a probe. Can be shared by rds_send_ping,
* rds_send_pong, rds_send_hb.
* rds_send_hb should use h_flags
* RDS_FLAG_HB_PING|RDS_FLAG_ACK_REQUIRED
* or
* RDS_FLAG_HB_PONG|RDS_FLAG_ACK_REQUIRED
*/
int
rds_send_probe(struct rds_conn_path *cp, __be16 sport,
__be16 dport, u8 h_flags)
{
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 = cp->cp_conn->c_faddr;
rm->data.op_active = 1;
rds_conn_path_connect_if_down(cp);
ret = rds_cong_wait(cp->cp_conn->c_fcong, dport, 1, NULL);
if (ret)
goto out;
spin_lock_irqsave(&cp->cp_lock, flags);
list_add_tail(&rm->m_conn_item, &cp->cp_send_queue);
set_bit(RDS_MSG_ON_CONN, &rm->m_flags);
rds_message_addref(rm);
rm->m_inc.i_conn = cp->cp_conn;
rm->m_inc.i_conn_path = cp;
rds_message_populate_header(&rm->m_inc.i_hdr, sport, dport,
cp->cp_next_tx_seq);
rm->m_inc.i_hdr.h_flags |= h_flags;
cp->cp_next_tx_seq++;
if (RDS_HS_PROBE(sport, dport) && cp->cp_conn->c_trans->t_mp_capable) {
u16 npaths = RDS_MPATH_WORKERS;
rds_message_add_extension(&rm->m_inc.i_hdr,
RDS_EXTHDR_NPATHS, &npaths,
sizeof(npaths));
}
spin_unlock_irqrestore(&cp->cp_lock, flags);
rds_stats_inc(s_send_queued);
rds_stats_inc(s_send_pong);
/* schedule the send work on rds_wq */
queue_delayed_work(rds_wq, &cp->cp_send_w, 1);
rds_message_put(rm);
return 0;
out:
if (rm)
rds_message_put(rm);
return ret;
}
int
rds_send_pong(struct rds_conn_path *cp, __be16 dport)
{
return rds_send_probe(cp, 0, dport, 0);
}
void
rds_send_ping(struct rds_connection *conn)
{
unsigned long flags;
struct rds_conn_path *cp = &conn->c_path[0];
spin_lock_irqsave(&cp->cp_lock, flags);
if (conn->c_ping_triggered) {
spin_unlock_irqrestore(&cp->cp_lock, flags);
return;
}
conn->c_ping_triggered = 1;
spin_unlock_irqrestore(&cp->cp_lock, flags);
rds_send_probe(&conn->c_path[0], RDS_FLAG_PROBE_PORT, 0, 0);
}