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// SPDX-License-Identifier: GPL-2.0
/* Copyright (c) 2021 Cong Wang <cong.wang@bytedance.com> */
#include <linux/skmsg.h>
#include <linux/bpf.h>
#include <net/sock.h>
#include <net/af_unix.h>
static struct proto *unix_prot_saved __read_mostly;
static DEFINE_SPINLOCK(unix_prot_lock);
static struct proto unix_bpf_prot;
static void unix_bpf_rebuild_protos(struct proto *prot, const struct proto *base)
{
*prot = *base;
prot->close = sock_map_close;
}
static void unix_bpf_check_needs_rebuild(struct proto *ops)
{
if (unlikely(ops != smp_load_acquire(&unix_prot_saved))) {
spin_lock_bh(&unix_prot_lock);
if (likely(ops != unix_prot_saved)) {
unix_bpf_rebuild_protos(&unix_bpf_prot, ops);
smp_store_release(&unix_prot_saved, ops);
}
spin_unlock_bh(&unix_prot_lock);
}
}
int unix_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore)
{
if (restore) {
sk->sk_write_space = psock->saved_write_space;
WRITE_ONCE(sk->sk_prot, psock->sk_proto);
return 0;
}
unix_bpf_check_needs_rebuild(psock->sk_proto);
WRITE_ONCE(sk->sk_prot, &unix_bpf_prot);
return 0;
}
void __init unix_bpf_build_proto(void)
{
unix_bpf_rebuild_protos(&unix_bpf_prot, &unix_proto);
}
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