/*
* 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));
}
}
EXPORT_SYMBOL_GPL(rds_rdma_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_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;
}
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.
*/
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);
}
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, flags2;
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_irqsave(&rm->m_rs_lock, flags2);
rm->m_rs = NULL;
spin_unlock_irqrestore(&rm->m_rs_lock, flags2);
/*
* 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;
/* 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->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;
}
