[Patch bpf v4 2/4] skmsg: extract and reuse sk_msg_is_readable()

[Cong Wang <xiyou.wangcong@xxxxxxxxx>]

From: Cong Wang <cong.wang@xxxxxxxxxxxxx>

tcp_bpf_sock_is_readable() is pretty much generic,
we can extract it and reuse it for non-TCP sockets.

Cc: John Fastabend <john.fastabend@xxxxxxxxx>
Cc: Daniel Borkmann <daniel@xxxxxxxxxxxxx>
Cc: Jakub Sitnicki <jakub@xxxxxxxxxxxxxx>
Cc: Lorenz Bauer <lmb@xxxxxxxxxxxxxx>
Signed-off-by: Cong Wang <cong.wang@xxxxxxxxxxxxx>
---
 include/linux/skmsg.h |  1 +
 net/core/skmsg.c      | 14 ++++++++++++++
 net/ipv4/tcp_bpf.c    | 15 +--------------
 3 files changed, 16 insertions(+), 14 deletions(-)

diff --git a/include/linux/skmsg.h b/include/linux/skmsg.h
index 14ab0c0bc924..1ce9a9eb223b 100644
--- a/include/linux/skmsg.h
+++ b/include/linux/skmsg.h
@@ -128,6 +128,7 @@ int sk_msg_memcopy_from_iter(struct sock *sk, struct iov_iter *from,
 			     struct sk_msg *msg, u32 bytes);
 int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg,
 		   int len, int flags);
+bool sk_msg_is_readable(struct sock *sk);
 
 static inline void sk_msg_check_to_free(struct sk_msg *msg, u32 i, u32 bytes)
 {
diff --git a/net/core/skmsg.c b/net/core/skmsg.c
index 2d6249b28928..a86ef7e844f8 100644
--- a/net/core/skmsg.c
+++ b/net/core/skmsg.c
@@ -474,6 +474,20 @@ int sk_msg_recvmsg(struct sock *sk, struct sk_psock *psock, struct msghdr *msg,
 }
 EXPORT_SYMBOL_GPL(sk_msg_recvmsg);
 
+bool sk_msg_is_readable(struct sock *sk)
+{
+	struct sk_psock *psock;
+	bool empty = true;
+
+	rcu_read_lock();
+	psock = sk_psock(sk);
+	if (likely(psock))
+		empty = list_empty(&psock->ingress_msg);
+	rcu_read_unlock();
+	return !empty;
+}
+EXPORT_SYMBOL_GPL(sk_msg_is_readable);
+
 static struct sk_msg *sk_psock_create_ingress_msg(struct sock *sk,
 						  struct sk_buff *skb)
 {
diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
index 0175dbcb7722..dabbc93e31b6 100644
--- a/net/ipv4/tcp_bpf.c
+++ b/net/ipv4/tcp_bpf.c
@@ -150,19 +150,6 @@ int tcp_bpf_sendmsg_redir(struct sock *sk, struct sk_msg *msg,
 EXPORT_SYMBOL_GPL(tcp_bpf_sendmsg_redir);
 
 #ifdef CONFIG_BPF_SYSCALL
-static bool tcp_bpf_sock_is_readable(struct sock *sk)
-{
-	struct sk_psock *psock;
-	bool empty = true;
-
-	rcu_read_lock();
-	psock = sk_psock(sk);
-	if (likely(psock))
-		empty = list_empty(&psock->ingress_msg);
-	rcu_read_unlock();
-	return !empty;
-}
-
 static int tcp_msg_wait_data(struct sock *sk, struct sk_psock *psock,
 			     long timeo)
 {
@@ -479,7 +466,7 @@ static void tcp_bpf_rebuild_protos(struct proto prot[TCP_BPF_NUM_CFGS],
 	prot[TCP_BPF_BASE].unhash		= sock_map_unhash;
 	prot[TCP_BPF_BASE].close		= sock_map_close;
 	prot[TCP_BPF_BASE].recvmsg		= tcp_bpf_recvmsg;
-	prot[TCP_BPF_BASE].sock_is_readable	= tcp_bpf_sock_is_readable;
+	prot[TCP_BPF_BASE].sock_is_readable	= sk_msg_is_readable;
 
 	prot[TCP_BPF_TX]			= prot[TCP_BPF_BASE];
 	prot[TCP_BPF_TX].sendmsg		= tcp_bpf_sendmsg;
-- 
2.30.2