linux-stable/net/mptcp/sched.c
Geliang Tang ed1ad86b85 mptcp: register default scheduler
This patch defines the default packet scheduler mptcp_sched_default.
Register it in mptcp_sched_init(), which is invoked in mptcp_proto_init().
Skip deleting this default scheduler in mptcp_unregister_scheduler().

Set msk->sched to the default scheduler when the input parameter of
mptcp_init_sched() is NULL.

Invoke mptcp_sched_default_get_subflow in get_send() and get_retrans()
if the defaut scheduler is set or msk->sched is NULL.

Acked-by: Paolo Abeni <pabeni@redhat.com>
Signed-off-by: Geliang Tang <geliang.tang@suse.com>
Signed-off-by: Mat Martineau <martineau@kernel.org>
Link: https://lore.kernel.org/r/20230821-upstream-net-next-20230818-v1-10-0c860fb256a8@kernel.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
2023-08-22 17:31:19 -07:00

173 lines
3.7 KiB
C

// SPDX-License-Identifier: GPL-2.0
/* Multipath TCP
*
* Copyright (c) 2022, SUSE.
*/
#define pr_fmt(fmt) "MPTCP: " fmt
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/list.h>
#include <linux/rculist.h>
#include <linux/spinlock.h>
#include "protocol.h"
static DEFINE_SPINLOCK(mptcp_sched_list_lock);
static LIST_HEAD(mptcp_sched_list);
static int mptcp_sched_default_get_subflow(struct mptcp_sock *msk,
struct mptcp_sched_data *data)
{
struct sock *ssk;
ssk = data->reinject ? mptcp_subflow_get_retrans(msk) :
mptcp_subflow_get_send(msk);
if (!ssk)
return -EINVAL;
mptcp_subflow_set_scheduled(mptcp_subflow_ctx(ssk), true);
return 0;
}
static struct mptcp_sched_ops mptcp_sched_default = {
.get_subflow = mptcp_sched_default_get_subflow,
.name = "default",
.owner = THIS_MODULE,
};
/* Must be called with rcu read lock held */
struct mptcp_sched_ops *mptcp_sched_find(const char *name)
{
struct mptcp_sched_ops *sched, *ret = NULL;
list_for_each_entry_rcu(sched, &mptcp_sched_list, list) {
if (!strcmp(sched->name, name)) {
ret = sched;
break;
}
}
return ret;
}
int mptcp_register_scheduler(struct mptcp_sched_ops *sched)
{
if (!sched->get_subflow)
return -EINVAL;
spin_lock(&mptcp_sched_list_lock);
if (mptcp_sched_find(sched->name)) {
spin_unlock(&mptcp_sched_list_lock);
return -EEXIST;
}
list_add_tail_rcu(&sched->list, &mptcp_sched_list);
spin_unlock(&mptcp_sched_list_lock);
pr_debug("%s registered", sched->name);
return 0;
}
void mptcp_unregister_scheduler(struct mptcp_sched_ops *sched)
{
if (sched == &mptcp_sched_default)
return;
spin_lock(&mptcp_sched_list_lock);
list_del_rcu(&sched->list);
spin_unlock(&mptcp_sched_list_lock);
}
void mptcp_sched_init(void)
{
mptcp_register_scheduler(&mptcp_sched_default);
}
int mptcp_init_sched(struct mptcp_sock *msk,
struct mptcp_sched_ops *sched)
{
if (!sched)
sched = &mptcp_sched_default;
if (!bpf_try_module_get(sched, sched->owner))
return -EBUSY;
msk->sched = sched;
if (msk->sched->init)
msk->sched->init(msk);
pr_debug("sched=%s", msk->sched->name);
return 0;
}
void mptcp_release_sched(struct mptcp_sock *msk)
{
struct mptcp_sched_ops *sched = msk->sched;
if (!sched)
return;
msk->sched = NULL;
if (sched->release)
sched->release(msk);
bpf_module_put(sched, sched->owner);
}
void mptcp_subflow_set_scheduled(struct mptcp_subflow_context *subflow,
bool scheduled)
{
WRITE_ONCE(subflow->scheduled, scheduled);
}
int mptcp_sched_get_send(struct mptcp_sock *msk)
{
struct mptcp_subflow_context *subflow;
struct mptcp_sched_data data;
msk_owned_by_me(msk);
/* the following check is moved out of mptcp_subflow_get_send */
if (__mptcp_check_fallback(msk)) {
if (msk->first &&
__tcp_can_send(msk->first) &&
sk_stream_memory_free(msk->first)) {
mptcp_subflow_set_scheduled(mptcp_subflow_ctx(msk->first), true);
return 0;
}
return -EINVAL;
}
mptcp_for_each_subflow(msk, subflow) {
if (READ_ONCE(subflow->scheduled))
return 0;
}
data.reinject = false;
if (msk->sched == &mptcp_sched_default || !msk->sched)
return mptcp_sched_default_get_subflow(msk, &data);
return msk->sched->get_subflow(msk, &data);
}
int mptcp_sched_get_retrans(struct mptcp_sock *msk)
{
struct mptcp_subflow_context *subflow;
struct mptcp_sched_data data;
msk_owned_by_me(msk);
/* the following check is moved out of mptcp_subflow_get_retrans */
if (__mptcp_check_fallback(msk))
return -EINVAL;
mptcp_for_each_subflow(msk, subflow) {
if (READ_ONCE(subflow->scheduled))
return 0;
}
data.reinject = true;
if (msk->sched == &mptcp_sched_default || !msk->sched)
return mptcp_sched_default_get_subflow(msk, &data);
return msk->sched->get_subflow(msk, &data);
}