From 67918caebeda415a8a77414d01ad3855011e582c Mon Sep 17 00:00:00 2001
From: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Date: Mon, 12 Oct 2020 17:33:54 +0200
Subject: [PATCH 075/158] tcp: Remove superfluous BH-disable around
listening_hash
Commit
9652dc2eb9e40 ("tcp: relax listening_hash operations")
removed the need to disable bottom half while acquiring
listening_hash.lock. There are still two callers left which disable
bottom half before the lock is acquired.
Drop local_bh_disable() around __inet_hash() which acquires
listening_hash->lock, invoke inet_ehash_nolisten() with disabled BH.
inet_unhash() conditionally acquires listening_hash->lock.
Reported-by: Mike Galbraith <efault@gmx.de>
Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Link: https://lore.kernel.org/linux-rt-users/12d6f9879a97cd56c09fb53dee343cbb14f7f1f7.camel@gmx.de/
Link: https://lkml.kernel.org/r/X9CheYjuXWc75Spa@hirez.programming.kicks-ass.net
---
net/ipv4/inet_hashtables.c | 19 ++++++++++++-------
net/ipv6/inet6_hashtables.c | 5 +----
2 files changed, 13 insertions(+), 11 deletions(-)
Index: linux-5.15.19-rt29/net/ipv4/inet_hashtables.c
===================================================================
@ linux-5.15.19-rt29/net/ipv4/inet_hashtables.c:640 @ int __inet_hash(struct sock *sk, struct
int err = 0;
if (sk->sk_state != TCP_LISTEN) {
+ local_bh_disable();
inet_ehash_nolisten(sk, osk, NULL);
+ local_bh_enable();
return 0;
}
WARN_ON(!sk_unhashed(sk));
@ linux-5.15.19-rt29/net/ipv4/inet_hashtables.c:674 @ int inet_hash(struct sock *sk)
{
int err = 0;
- if (sk->sk_state != TCP_CLOSE) {
- local_bh_disable();
+ if (sk->sk_state != TCP_CLOSE)
err = __inet_hash(sk, NULL);
- local_bh_enable();
- }
return err;
}
@ linux-5.15.19-rt29/net/ipv4/inet_hashtables.c:686 @ void inet_unhash(struct sock *sk)
struct inet_hashinfo *hashinfo = sk->sk_prot->h.hashinfo;
struct inet_listen_hashbucket *ilb = NULL;
spinlock_t *lock;
+ bool state_listen;
if (sk_unhashed(sk))
return;
if (sk->sk_state == TCP_LISTEN) {
+ state_listen = true;
ilb = &hashinfo->listening_hash[inet_sk_listen_hashfn(sk)];
- lock = &ilb->lock;
+ spin_lock(&ilb->lock);
} else {
+ state_listen = false;
lock = inet_ehash_lockp(hashinfo, sk->sk_hash);
+ spin_lock_bh(lock);
}
- spin_lock_bh(lock);
if (sk_unhashed(sk))
goto unlock;
@ linux-5.15.19-rt29/net/ipv4/inet_hashtables.c:712 @ void inet_unhash(struct sock *sk)
__sk_nulls_del_node_init_rcu(sk);
sock_prot_inuse_add(sock_net(sk), sk->sk_prot, -1);
unlock:
- spin_unlock_bh(lock);
+ if (state_listen)
+ spin_unlock(&ilb->lock);
+ else
+ spin_unlock_bh(lock);
}
EXPORT_SYMBOL_GPL(inet_unhash);
Index: linux-5.15.19-rt29/net/ipv6/inet6_hashtables.c
===================================================================
--- linux-5.15.19-rt29.orig/net/ipv6/inet6_hashtables.c
+++ linux-5.15.19-rt29/net/ipv6/inet6_hashtables.c
@ linux-5.15.19-rt29/net/ipv4/inet_hashtables.c:336 @ int inet6_hash(struct sock *sk)
{
int err = 0;
- if (sk->sk_state != TCP_CLOSE) {
- local_bh_disable();
+ if (sk->sk_state != TCP_CLOSE)
err = __inet_hash(sk, NULL);
- local_bh_enable();
- }
return err;
}