Kernel/linux-stable
1
0
Fork 0
mirror of https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git synced 2024-12-28 16:56:26 +00:00
Code Issues Actions Packages Projects Releases Wiki Activity

fib: rules: use READ_ONCE()/WRITE_ONCE() on ops->fib_rules_seq

Browse Source 
Using RTNL to protect ops->fib_rules_seq reads seems a big hammer.

Writes are protected by RTNL.
We can use READ_ONCE() on readers.

Constify 'struct net' argument of fib_rules_seq_read()
and lookup_rules_ops().

Signed-off-by: Eric Dumazet <edumazet@google.com>
Reviewed-by: Kuniyuki Iwashima <kuniyu@amazon.com>
Reviewed-by: David Ahern <dsahern@kernel.org>
Link: https://patch.msgid.link/20241009184405.3752829-2-edumazet@google.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
Eric Dumazet 2024-10-09 18:44:01 +00:00 committed by Jakub Kicinski
parent d677aebd66
commit a716ff52be
2 changed files with 9 additions and 7 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

2
include/net/fib_rules.h
View File

@ -176,7 +176,7 @@ int fib_default_rule_add(struct fib_rules_ops *, u32 pref, u32 table);
bool fib_rule_matchall(const struct fib_rule *rule);
int fib_rules_dump(struct net *net, struct notifier_block *nb, int family,
struct netlink_ext_ack *extack);
unsigned int fib_rules_seq_read(struct net *net, int family);
unsigned int fib_rules_seq_read(const struct net *net, int family);
int fib_nl_newrule(struct sk_buff *skb, struct nlmsghdr *nlh,
struct netlink_ext_ack *extack);

14
net/core/fib_rules.c
View File

@ -101,7 +101,8 @@ static void notify_rule_change(int event, struct fib_rule *rule,
struct fib_rules_ops *ops, struct nlmsghdr *nlh,
u32 pid);
static struct fib_rules_ops *lookup_rules_ops(struct net *net, int family)
static struct fib_rules_ops *lookup_rules_ops(const struct net *net,
int family)
{
struct fib_rules_ops *ops;
@ -370,7 +371,9 @@ static int call_fib_rule_notifiers(struct net *net,
.rule = rule,
};
ops->fib_rules_seq++;
ASSERT_RTNL();
/* Paired with READ_ONCE() in fib_rules_seq() */
WRITE_ONCE(ops->fib_rules_seq, ops->fib_rules_seq + 1);
return call_fib_notifiers(net, event_type, &info.info);
}
@ -397,17 +400,16 @@ int fib_rules_dump(struct net *net, struct notifier_block *nb, int family,
}
EXPORT_SYMBOL_GPL(fib_rules_dump);
unsigned int fib_rules_seq_read(struct net *net, int family)
unsigned int fib_rules_seq_read(const struct net *net, int family)
{
unsigned int fib_rules_seq;
struct fib_rules_ops *ops;
ASSERT_RTNL();
ops = lookup_rules_ops(net, family);
if (!ops)
return 0;
fib_rules_seq = ops->fib_rules_seq;
/* Paired with WRITE_ONCE() in call_fib_rule_notifiers() */
fib_rules_seq = READ_ONCE(ops->fib_rules_seq);
rules_ops_put(ops);
return fib_rules_seq;