[PATCH net-next v2 2/2] chelsio: Convert chtls_sendpage() to use MSG_SPLICE_PAGES

[David Howells <dhowells@redhat.com>]

Convert chtls_sendpage() to use sendmsg() with MSG_SPLICE_PAGES rather than
directly splicing in the pages itself.

This allows ->sendpage() to be replaced by something that can handle
multiple multipage folios in a single transaction.

Signed-off-by: David Howells <dhowells@redhat.com>
cc: Ayush Sawal <ayush.sawal@chelsio.com>
cc: "David S. Miller" <davem@davemloft.net>
cc: Eric Dumazet <edumazet@google.com>
cc: Jakub Kicinski <kuba@kernel.org>
cc: Paolo Abeni <pabeni@redhat.com>
cc: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
cc: netdev@vger.kernel.org
---

Notes:
    ver #2)
     - Do reverse-xmas tree variables.

 .../chelsio/inline_crypto/chtls/chtls_io.c    | 109 ++----------------
 1 file changed, 7 insertions(+), 102 deletions(-)

diff --git a/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_io.c b/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_io.c
index 1d08386ac916..5724bbbb6ee0 100644
--- a/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_io.c
+++ b/drivers/net/ethernet/chelsio/inline_crypto/chtls/chtls_io.c
@@ -1240,110 +1240,15 @@ int chtls_sendmsg(struct sock *sk, struct msghdr *msg, size_t size)
 int chtls_sendpage(struct sock *sk, struct page *page,
 		   int offset, size_t size, int flags)
 {
-	struct chtls_sock *csk;
-	struct chtls_dev *cdev;
-	int mss, err, copied;
-	struct tcp_sock *tp;
-	long timeo;
-
-	tp = tcp_sk(sk);
-	copied = 0;
-	csk = rcu_dereference_sk_user_data(sk);
-	cdev = csk->cdev;
-	lock_sock(sk);
-	timeo = sock_sndtimeo(sk, flags & MSG_DONTWAIT);
+	struct msghdr msg = { .msg_flags = flags | MSG_SPLICE_PAGES, };
+	struct bio_vec bvec;
 
-	err = sk_stream_wait_connect(sk, &timeo);
-	if (!sk_in_state(sk, TCPF_ESTABLISHED | TCPF_CLOSE_WAIT) &&
-	    err != 0)
-		goto out_err;
-
-	mss = csk->mss;
-	csk_set_flag(csk, CSK_TX_MORE_DATA);
-
-	while (size > 0) {
-		struct sk_buff *skb = skb_peek_tail(&csk->txq);
-		int copy, i;
-
-		if (!skb || (ULP_SKB_CB(skb)->flags & ULPCB_FLAG_NO_APPEND) ||
-		    (copy = mss - skb->len) <= 0) {
-new_buf:
-			if (!csk_mem_free(cdev, sk))
-				goto wait_for_sndbuf;
+	if (flags & MSG_SENDPAGE_NOTLAST)
+		msg.msg_flags |= MSG_MORE;
 
-			if (is_tls_tx(csk)) {
-				skb = get_record_skb(sk,
-						     select_size(sk, size,
-								 flags,
-								 TX_TLSHDR_LEN),
-						     true);
-			} else {
-				skb = get_tx_skb(sk, 0);
-			}
-			if (!skb)
-				goto wait_for_memory;
-			copy = mss;
-		}
-		if (copy > size)
-			copy = size;
-
-		i = skb_shinfo(skb)->nr_frags;
-		if (skb_can_coalesce(skb, i, page, offset)) {
-			skb_frag_size_add(&skb_shinfo(skb)->frags[i - 1], copy);
-		} else if (i < MAX_SKB_FRAGS) {
-			get_page(page);
-			skb_fill_page_desc(skb, i, page, offset, copy);
-		} else {
-			tx_skb_finalize(skb);
-			push_frames_if_head(sk);
-			goto new_buf;
-		}
-
-		skb->len += copy;
-		if (skb->len == mss)
-			tx_skb_finalize(skb);
-		skb->data_len += copy;
-		skb->truesize += copy;
-		sk->sk_wmem_queued += copy;
-		tp->write_seq += copy;
-		copied += copy;
-		offset += copy;
-		size -= copy;
-
-		if (corked(tp, flags) &&
-		    (sk_stream_wspace(sk) < sk_stream_min_wspace(sk)))
-			ULP_SKB_CB(skb)->flags |= ULPCB_FLAG_NO_APPEND;
-
-		if (!size)
-			break;
-
-		if (unlikely(ULP_SKB_CB(skb)->flags & ULPCB_FLAG_NO_APPEND))
-			push_frames_if_head(sk);
-		continue;
-wait_for_sndbuf:
-		set_bit(SOCK_NOSPACE, &sk->sk_socket->flags);
-wait_for_memory:
-		err = csk_wait_memory(cdev, sk, &timeo);
-		if (err)
-			goto do_error;
-	}
-out:
-	csk_reset_flag(csk, CSK_TX_MORE_DATA);
-	if (copied)
-		chtls_tcp_push(sk, flags);
-done:
-	release_sock(sk);
-	return copied;
-
-do_error:
-	if (copied)
-		goto out;
-
-out_err:
-	if (csk_conn_inline(csk))
-		csk_reset_flag(csk, CSK_TX_MORE_DATA);
-	copied = sk_stream_error(sk, flags, err);
-	goto done;
+	bvec_set_page(&bvec, page, size, offset);
+	iov_iter_bvec(&msg.msg_iter, ITER_SOURCE, &bvec, 1, size);
+	return chtls_sendmsg(sk, &msg, size);
 }
 
 static void chtls_select_window(struct sock *sk)