skmsg: Extract __tcp_bpf_recvmsg() and tcp_bpf_wait_data()

Although these two functions are only used by TCP, they are not
specific to TCP at all, both operate on skmsg and ingress_msg,
so fit in net/core/skmsg.c very well.

And we will need them for non-TCP, so rename and move them to
skmsg.c and export them to modules.

Signed-off-by: Cong Wang <cong.wang@bytedance.com>
Signed-off-by: Alexei Starovoitov <ast@kernel.org>
Link: https://lore.kernel.org/bpf/20210331023237.41094-13-xiyou.wangcong@gmail.com

1 files changed, 2 insertions, 98 deletions

diff --git a/net/ipv4/tcp_bpf.c b/net/ipv4/tcp_bpf.c
index ac8cfbaeacd2..3d622a0d0753 100644
--- a/net/ipv4/tcp_bpf.c
+++ b/net/ipv4/tcp_bpf.c
@@ -10,80 +10,6 @@
 #include <net/inet_common.h>
 #include <net/tls.h>
 
-int __tcp_bpf_recvmsg(struct sock *sk, struct sk_psock *psock,
-		      struct msghdr *msg, int len, int flags)
-{
-	struct iov_iter *iter = &msg->msg_iter;
-	int peek = flags & MSG_PEEK;
-	struct sk_msg *msg_rx;
-	int i, copied = 0;
-
-	msg_rx = sk_psock_peek_msg(psock);
-	while (copied != len) {
-		struct scatterlist *sge;
-
-		if (unlikely(!msg_rx))
-			break;
-
-		i = msg_rx->sg.start;
-		do {
-			struct page *page;
-			int copy;
-
-			sge = sk_msg_elem(msg_rx, i);
-			copy = sge->length;
-			page = sg_page(sge);
-			if (copied + copy > len)
-				copy = len - copied;
-			copy = copy_page_to_iter(page, sge->offset, copy, iter);
-			if (!copy)
-				return copied ? copied : -EFAULT;
-
-			copied += copy;
-			if (likely(!peek)) {
-				sge->offset += copy;
-				sge->length -= copy;
-				if (!msg_rx->skb)
-					sk_mem_uncharge(sk, copy);
-				msg_rx->sg.size -= copy;
-
-				if (!sge->length) {
-					sk_msg_iter_var_next(i);
-					if (!msg_rx->skb)
-						put_page(page);
-				}
-			} else {
-				/* Lets not optimize peek case if copy_page_to_iter
-				 * didn't copy the entire length lets just break.
-				 */
-				if (copy != sge->length)
-					return copied;
-				sk_msg_iter_var_next(i);
-			}
-
-			if (copied == len)
-				break;
-		} while (i != msg_rx->sg.end);
-
-		if (unlikely(peek)) {
-			msg_rx = sk_psock_next_msg(psock, msg_rx);
-			if (!msg_rx)
-				break;
-			continue;
-		}
-
-		msg_rx->sg.start = i;
-		if (!sge->length && msg_rx->sg.start == msg_rx->sg.end) {
-			msg_rx = sk_psock_dequeue_msg(psock);
-			kfree_sk_msg(msg_rx);
-		}
-		msg_rx = sk_psock_peek_msg(psock);
-	}
-
-	return copied;
-}
-EXPORT_SYMBOL_GPL(__tcp_bpf_recvmsg);
-
 static int bpf_tcp_ingress(struct sock *sk, struct sk_psock *psock,
 			   struct sk_msg *msg, u32 apply_bytes, int flags)
 {
@@ -237,28 +163,6 @@ static bool tcp_bpf_stream_read(const struct sock *sk)
 	return !empty;
 }
 
-static int tcp_bpf_wait_data(struct sock *sk, struct sk_psock *psock,
-			     int flags, long timeo, int *err)
-{
-	DEFINE_WAIT_FUNC(wait, woken_wake_function);
-	int ret = 0;
-
-	if (sk->sk_shutdown & RCV_SHUTDOWN)
-		return 1;
-
-	if (!timeo)
-		return ret;
-
-	add_wait_queue(sk_sleep(sk), &wait);
-	sk_set_bit(SOCKWQ_ASYNC_WAITDATA, sk);
-	ret = sk_wait_event(sk, &timeo,
-			    !list_empty(&psock->ingress_msg) ||
-			    !skb_queue_empty(&sk->sk_receive_queue), &wait);
-	sk_clear_bit(SOCKWQ_ASYNC_WAITDATA, sk);
-	remove_wait_queue(sk_sleep(sk), &wait);
-	return ret;
-}
-
 static int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 		    int nonblock, int flags, int *addr_len)
 {
@@ -278,13 +182,13 @@ static int tcp_bpf_recvmsg(struct sock *sk, struct msghdr *msg, size_t len,
 	}
 	lock_sock(sk);
 msg_bytes_ready:
-	copied = __tcp_bpf_recvmsg(sk, psock, msg, len, flags);
+	copied = sk_msg_recvmsg(sk, psock, msg, len, flags);
 	if (!copied) {
 		int data, err = 0;
 		long timeo;
 
 		timeo = sock_rcvtimeo(sk, nonblock);
-		data = tcp_bpf_wait_data(sk, psock, flags, timeo, &err);
+		data = sk_msg_wait_data(sk, psock, flags, timeo, &err);
 		if (data) {
 			if (!sk_psock_queue_empty(psock))
 				goto msg_bytes_ready;