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![Oliver Hartkopp](/assets/img/avatar_default.png)
The internal recvmsg() functions have two parameters 'flags' and 'noblock'
that were merged inside skb_recv_datagram(). As a follow up patch to commit
f4b41f062c
("net: remove noblock parameter from skb_recv_datagram()")
this patch removes the separate 'noblock' parameter for recvmsg().
Analogue to the referenced patch for skb_recv_datagram() the 'flags' and
'noblock' parameters are unnecessarily split up with e.g.
err = sk->sk_prot->recvmsg(sk, msg, size, flags & MSG_DONTWAIT,
flags & ~MSG_DONTWAIT, &addr_len);
or in
err = INDIRECT_CALL_2(sk->sk_prot->recvmsg, tcp_recvmsg, udp_recvmsg,
sk, msg, size, flags & MSG_DONTWAIT,
flags & ~MSG_DONTWAIT, &addr_len);
instead of simply using only flags all the time and check for MSG_DONTWAIT
where needed (to preserve for the formerly separated no(n)block condition).
Signed-off-by: Oliver Hartkopp <socketcan@hartkopp.net>
Link: https://lore.kernel.org/r/20220411124955.154876-1-socketcan@hartkopp.net
Signed-off-by: Paolo Abeni <pabeni@redhat.com>
175 lines
4.6 KiB
C
175 lines
4.6 KiB
C
// SPDX-License-Identifier: GPL-2.0
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/* Copyright (c) 2021 Cong Wang <cong.wang@bytedance.com> */
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#include <linux/skmsg.h>
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#include <linux/bpf.h>
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#include <net/sock.h>
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#include <net/af_unix.h>
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#define unix_sk_has_data(__sk, __psock) \
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({ !skb_queue_empty(&__sk->sk_receive_queue) || \
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!skb_queue_empty(&__psock->ingress_skb) || \
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!list_empty(&__psock->ingress_msg); \
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})
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static int unix_msg_wait_data(struct sock *sk, struct sk_psock *psock,
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long timeo)
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{
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DEFINE_WAIT_FUNC(wait, woken_wake_function);
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struct unix_sock *u = unix_sk(sk);
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int ret = 0;
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if (sk->sk_shutdown & RCV_SHUTDOWN)
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return 1;
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if (!timeo)
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return ret;
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add_wait_queue(sk_sleep(sk), &wait);
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sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
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if (!unix_sk_has_data(sk, psock)) {
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mutex_unlock(&u->iolock);
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wait_woken(&wait, TASK_INTERRUPTIBLE, timeo);
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mutex_lock(&u->iolock);
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ret = unix_sk_has_data(sk, psock);
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}
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sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
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remove_wait_queue(sk_sleep(sk), &wait);
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return ret;
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}
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static int __unix_recvmsg(struct sock *sk, struct msghdr *msg,
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size_t len, int flags)
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{
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if (sk->sk_type == SOCK_DGRAM)
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return __unix_dgram_recvmsg(sk, msg, len, flags);
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else
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return __unix_stream_recvmsg(sk, msg, len, flags);
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}
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static int unix_bpf_recvmsg(struct sock *sk, struct msghdr *msg,
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size_t len, int flags, int *addr_len)
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{
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struct unix_sock *u = unix_sk(sk);
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struct sk_psock *psock;
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int copied;
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psock = sk_psock_get(sk);
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if (unlikely(!psock))
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return __unix_recvmsg(sk, msg, len, flags);
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mutex_lock(&u->iolock);
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if (!skb_queue_empty(&sk->sk_receive_queue) &&
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sk_psock_queue_empty(psock)) {
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mutex_unlock(&u->iolock);
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sk_psock_put(sk, psock);
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return __unix_recvmsg(sk, msg, len, flags);
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}
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msg_bytes_ready:
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copied = sk_msg_recvmsg(sk, psock, msg, len, flags);
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if (!copied) {
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long timeo;
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int data;
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timeo = sock_rcvtimeo(sk, flags & MSG_DONTWAIT);
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data = unix_msg_wait_data(sk, psock, timeo);
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if (data) {
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if (!sk_psock_queue_empty(psock))
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goto msg_bytes_ready;
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mutex_unlock(&u->iolock);
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sk_psock_put(sk, psock);
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return __unix_recvmsg(sk, msg, len, flags);
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}
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copied = -EAGAIN;
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}
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mutex_unlock(&u->iolock);
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sk_psock_put(sk, psock);
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return copied;
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}
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static struct proto *unix_dgram_prot_saved __read_mostly;
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static DEFINE_SPINLOCK(unix_dgram_prot_lock);
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static struct proto unix_dgram_bpf_prot;
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static struct proto *unix_stream_prot_saved __read_mostly;
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static DEFINE_SPINLOCK(unix_stream_prot_lock);
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static struct proto unix_stream_bpf_prot;
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static void unix_dgram_bpf_rebuild_protos(struct proto *prot, const struct proto *base)
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{
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*prot = *base;
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prot->close = sock_map_close;
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prot->recvmsg = unix_bpf_recvmsg;
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prot->sock_is_readable = sk_msg_is_readable;
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}
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static void unix_stream_bpf_rebuild_protos(struct proto *prot,
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const struct proto *base)
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{
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*prot = *base;
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prot->close = sock_map_close;
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prot->recvmsg = unix_bpf_recvmsg;
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prot->sock_is_readable = sk_msg_is_readable;
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prot->unhash = sock_map_unhash;
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}
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static void unix_dgram_bpf_check_needs_rebuild(struct proto *ops)
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{
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if (unlikely(ops != smp_load_acquire(&unix_dgram_prot_saved))) {
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spin_lock_bh(&unix_dgram_prot_lock);
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if (likely(ops != unix_dgram_prot_saved)) {
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unix_dgram_bpf_rebuild_protos(&unix_dgram_bpf_prot, ops);
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smp_store_release(&unix_dgram_prot_saved, ops);
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}
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spin_unlock_bh(&unix_dgram_prot_lock);
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}
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}
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static void unix_stream_bpf_check_needs_rebuild(struct proto *ops)
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{
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if (unlikely(ops != smp_load_acquire(&unix_stream_prot_saved))) {
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spin_lock_bh(&unix_stream_prot_lock);
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if (likely(ops != unix_stream_prot_saved)) {
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unix_stream_bpf_rebuild_protos(&unix_stream_bpf_prot, ops);
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smp_store_release(&unix_stream_prot_saved, ops);
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}
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spin_unlock_bh(&unix_stream_prot_lock);
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}
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}
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int unix_dgram_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore)
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{
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if (sk->sk_type != SOCK_DGRAM)
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return -EOPNOTSUPP;
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if (restore) {
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sk->sk_write_space = psock->saved_write_space;
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WRITE_ONCE(sk->sk_prot, psock->sk_proto);
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return 0;
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}
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unix_dgram_bpf_check_needs_rebuild(psock->sk_proto);
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WRITE_ONCE(sk->sk_prot, &unix_dgram_bpf_prot);
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return 0;
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}
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int unix_stream_bpf_update_proto(struct sock *sk, struct sk_psock *psock, bool restore)
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{
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if (restore) {
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sk->sk_write_space = psock->saved_write_space;
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WRITE_ONCE(sk->sk_prot, psock->sk_proto);
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return 0;
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}
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unix_stream_bpf_check_needs_rebuild(psock->sk_proto);
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WRITE_ONCE(sk->sk_prot, &unix_stream_bpf_prot);
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return 0;
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}
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void __init unix_bpf_build_proto(void)
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{
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unix_dgram_bpf_rebuild_protos(&unix_dgram_bpf_prot, &unix_dgram_proto);
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unix_stream_bpf_rebuild_protos(&unix_stream_bpf_prot, &unix_stream_proto);
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}
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