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Merge branch 'rtnetlink-rtnl_lock'

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Jakub Kicinski says:

====================
rtnetlink: move rtnl_lock handling out of af_netlink

With the changes done in commit 5b4b62a169e1 ("rtnetlink: make
the "split" NLM_DONE handling generic") we can also move the
rtnl locking out of af_netlink.
====================

Signed-off-by: David S. Miller <davem@davemloft.net>
This commit is contained in:
David S. Miller 2024-06-10 13:15:40 +01:00
commit 395059c52e
3 changed files with 10 additions and 20 deletions
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1
include/linux/netlink.h
View File

@ -47,7 +47,6 @@ struct netlink_kernel_cfg {
unsigned int groups;
unsigned int flags;
void (*input)(struct sk_buff *skb);
struct mutex *cb_mutex;
int (*bind)(struct net *net, int group);
void (*unbind)(struct net *net, int group);
void (*release) (struct sock *sk, unsigned long *groups);

9
net/core/rtnetlink.c
View File

@ -6486,6 +6486,7 @@ static int rtnl_mdb_del(struct sk_buff *skb, struct nlmsghdr *nlh,
static int rtnl_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
{
const bool needs_lock = !(cb->flags & RTNL_FLAG_DUMP_UNLOCKED);
rtnl_dumpit_func dumpit = cb->data;
int err;
@ -6495,7 +6496,11 @@ static int rtnl_dumpit(struct sk_buff *skb, struct netlink_callback *cb)
if (!dumpit)
return 0;
if (needs_lock)
rtnl_lock();
err = dumpit(skb, cb);
if (needs_lock)
rtnl_unlock();
/* Old dump handlers used to send NLM_DONE as in a separate recvmsg().
* Some applications which parse netlink manually depend on this.
@ -6515,7 +6520,8 @@ static int rtnetlink_dump_start(struct sock *ssk, struct sk_buff *skb,
const struct nlmsghdr *nlh,
struct netlink_dump_control *control)
{
if (control->flags & RTNL_FLAG_DUMP_SPLIT_NLM_DONE) {
if (control->flags & RTNL_FLAG_DUMP_SPLIT_NLM_DONE ||
!(control->flags & RTNL_FLAG_DUMP_UNLOCKED)) {
WARN_ON(control->data);
control->data = control->dump;
control->dump = rtnl_dumpit;
@ -6703,7 +6709,6 @@ static int __net_init rtnetlink_net_init(struct net *net)
struct netlink_kernel_cfg cfg = {
.groups = RTNLGRP_MAX,
.input = rtnetlink_rcv,
.cb_mutex = &rtnl_mutex,
.flags = NL_CFG_F_NONROOT_RECV,
.bind = rtnetlink_bind,
};

20
net/netlink/af_netlink.c
View File

@ -636,8 +636,7 @@ static struct proto netlink_proto = {
};
static int __netlink_create(struct net *net, struct socket *sock,
struct mutex *dump_cb_mutex, int protocol,
int kern)
int protocol, int kern)
{
struct sock *sk;
struct netlink_sock *nlk;
@ -655,7 +654,6 @@ static int __netlink_create(struct net *net, struct socket *sock,
lockdep_set_class_and_name(&nlk->nl_cb_mutex,
nlk_cb_mutex_keys + protocol,
nlk_cb_mutex_key_strings[protocol]);
nlk->dump_cb_mutex = dump_cb_mutex;
init_waitqueue_head(&nlk->wait);
sk->sk_destruct = netlink_sock_destruct;
@ -667,7 +665,6 @@ static int netlink_create(struct net *net, struct socket *sock, int protocol,
int kern)
{
struct module *module = NULL;
struct mutex *cb_mutex;
struct netlink_sock *nlk;
int (*bind)(struct net *net, int group);
void (*unbind)(struct net *net, int group);
@ -696,7 +693,6 @@ static int netlink_create(struct net *net, struct socket *sock, int protocol,
module = nl_table[protocol].module;
else
err = -EPROTONOSUPPORT;
cb_mutex = nl_table[protocol].cb_mutex;
bind = nl_table[protocol].bind;
unbind = nl_table[protocol].unbind;
release = nl_table[protocol].release;
@ -705,7 +701,7 @@ static int netlink_create(struct net *net, struct socket *sock, int protocol,
if (err < 0)
goto out;
err = __netlink_create(net, sock, cb_mutex, protocol, kern);
err = __netlink_create(net, sock, protocol, kern);
if (err < 0)
goto out_module;
@ -2016,7 +2012,6 @@ __netlink_kernel_create(struct net *net, int unit, struct module *module,
struct sock *sk;
struct netlink_sock *nlk;
struct listeners *listeners = NULL;
struct mutex *cb_mutex = cfg ? cfg->cb_mutex : NULL;
unsigned int groups;
BUG_ON(!nl_table);
@ -2027,7 +2022,7 @@ __netlink_kernel_create(struct net *net, int unit, struct module *module,
if (sock_create_lite(PF_NETLINK, SOCK_DGRAM, unit, &sock))
return NULL;
if (__netlink_create(net, sock, cb_mutex, unit, 1) < 0)
if (__netlink_create(net, sock, unit, 1) < 0)
goto out_sock_release_nosk;
sk = sock->sk;
@ -2055,7 +2050,6 @@ __netlink_kernel_create(struct net *net, int unit, struct module *module,
if (!nl_table[unit].registered) {
nl_table[unit].groups = groups;
rcu_assign_pointer(nl_table[unit].listeners, listeners);
nl_table[unit].cb_mutex = cb_mutex;
nl_table[unit].module = module;
if (cfg) {
nl_table[unit].bind = cfg->bind;
@ -2326,17 +2320,9 @@ static int netlink_dump(struct sock *sk, bool lock_taken)
netlink_skb_set_owner_r(skb, sk);
if (nlk->dump_done_errno > 0) {
struct mutex *extra_mutex = nlk->dump_cb_mutex;
cb->extack = &extack;
if (cb->flags & RTNL_FLAG_DUMP_UNLOCKED)
extra_mutex = NULL;
if (extra_mutex)
mutex_lock(extra_mutex);
nlk->dump_done_errno = cb->dump(skb, cb);
if (extra_mutex)
mutex_unlock(extra_mutex);
/* EMSGSIZE plus something already in the skb means
* that there's more to dump but current skb has filled up.