Release 4.11 net/rds/send.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);
}
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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;
}
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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);
}
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| Total | 43 | 100.00% | 3 | 100.00% |
/*
* 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 (test_bit(RDS_MSG_FLUSH, &rm->m_flags) ||
(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;
}
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| Total | 1151 | 100.00% | 22 | 100.00% |
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);
}
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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;
}
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/*
* 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;
unsigned int notify = 0;
spin_lock_irqsave(&rm->m_rs_lock, flags);
notify = rm->rdma.op_notify | rm->data.op_notify;
ro = &rm->rdma;
if (test_bit(RDS_MSG_ON_SOCK, &rm->m_flags) &&
ro->op_active && 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));
}
}
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| Total | 185 | 100.00% | 6 | 100.00% |
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));
}
}
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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 */
}
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/*
* 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(¬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));
}
}
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| Stephen Hemminger | 1 | 0.30% | 1 | 11.11% |
| Total | 330 | 100.00% | 9 | 100.00% |
/*
* 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);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Andy Grover | 112 | 92.56% | 1 | 33.33% |
| Sowmini Varadhan | 8 | 6.61% | 1 | 33.33% |
| Peter Zijlstra | 1 | 0.83% | 1 | 33.33% |
| Total | 121 | 100.00% | 3 | 100.00% |
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);
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Sowmini Varadhan | 40 | 100.00% | 1 | 100.00% |
| Total | 40 | 100.00% | 1 | 100.00% |
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);
}
}
Contributors
| Person | Tokens | Prop | Commits | CommitProp |
| Andy Grover | 307 | 71.56% | 5 | 50.00% |
| Santosh Shilimkar | 52 | 12.12% | 1 | 10.00% |
| Sowmini Varadhan | 38 | 8.86% | 1 | 10.00% |
| Herton Ronaldo Krzesinski | 26 | 6.06% | 1 | 10.00% |
| Tina Yang | 5 | 1.17% | 1 | 10.00% |
| Peter Zijlstra | 1 | 0.23% | 1 | 10.00% |
| Total | 429 | 100.00% | 10 | 100.00% |
/*
* 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(