Commit a0dbf5f8 authored by David Howells's avatar David Howells Committed by Jakub Kicinski
Browse files

af_unix: Support MSG_SPLICE_PAGES 



Make AF_UNIX sendmsg() support MSG_SPLICE_PAGES, splicing in pages from the
source iterator if possible and copying the data in otherwise.

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

Signed-off-by: default avatarDavid Howells <dhowells@redhat.com>
cc: Kuniyuki Iwashima <kuniyu@amazon.com>
cc: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent c49cf266

net/unix/af_unix.c

+33 −16
Original line number Diff line number Diff line
@@ -2200,6 +2200,11 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, 
	while (sent < len) {

		size = len - sent;



		if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES)) {

			skb = sock_alloc_send_pskb(sk, 0, 0,

						   msg->msg_flags & MSG_DONTWAIT,

						   &err, 0);

		} else {

			/* Keep two messages in the pipe so it schedules better */

			size = min_t(int, size, (sk->sk_sndbuf >> 1) - 64);
@@ -2213,6 +2218,7 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, 
			skb = sock_alloc_send_pskb(sk, size - data_len, data_len,

						   msg->msg_flags & MSG_DONTWAIT, &err,

						   get_order(UNIX_SKB_FRAGS_SZ));

		}

		if (!skb)

			goto out_err;
@@ -2224,6 +2230,16 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, 
		}

		fds_sent = true;



		if (unlikely(msg->msg_flags & MSG_SPLICE_PAGES)) {

			err = skb_splice_from_iter(skb, &msg->msg_iter, size,

						   sk->sk_allocation);

			if (err < 0) {

				kfree_skb(skb);

				goto out_err;

			}

			size = err;

			refcount_add(size, &sk->sk_wmem_alloc);

		} else {

			skb_put(skb, size - data_len);

			skb->data_len = data_len;

			skb->len = size;
@@ -2232,6 +2248,7 @@ static int unix_stream_sendmsg(struct socket *sock, struct msghdr *msg, 
				kfree_skb(skb);

				goto out_err;

			}

		}



		unix_state_lock(other);