Commit 7da0dde6 authored by David Howells's avatar David Howells Committed by Jakub Kicinski
Browse files

ip, udp: Support MSG_SPLICE_PAGES 



Make IP/UDP sendmsg() support MSG_SPLICE_PAGES.  This causes pages to be
spliced from the source iterator.

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: Willem de Bruijn <willemdebruijn.kernel@gmail.com>
cc: David Ahern <dsahern@kernel.org>
cc: Jens Axboe <axboe@kernel.dk>
cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent 5367f9bb

net/ipv4/ip_output.c

+17 −0
Original line number Diff line number Diff line
@@ -1048,6 +1048,14 @@ static int __ip_append_data(struct sock *sk, 
				skb_zcopy_set(skb, uarg, &extra_uref);

			}

		}

	} else if ((flags & MSG_SPLICE_PAGES) && length) {

		if (inet->hdrincl)

			return -EPERM;

		if (rt->dst.dev->features & NETIF_F_SG)

			/* We need an empty buffer to attach stuff to */

			paged = true;

		else

			flags &= ~MSG_SPLICE_PAGES;

	}



	cork->length += length;
@@ -1207,6 +1215,15 @@ static int __ip_append_data(struct sock *sk, 
				err = -EFAULT;

				goto error;

			}

		} else if (flags & MSG_SPLICE_PAGES) {

			struct msghdr *msg = from;



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

						   sk->sk_allocation);

			if (err < 0)

				goto error;

			copy = err;

			wmem_alloc_delta += copy;

		} else if (!zc) {

			int i = skb_shinfo(skb)->nr_frags;