Make IP6/UDP6 sendmsg() support MSG_SPLICE_PAGES. This causes pages to be spliced from the source iterator if possible, copying the data if not. This allows ->sendpage() to be replaced by something that can handle multiple multipage folios in a single transaction. Signed-off-by: David Howells <dhowells@xxxxxxxxxx> cc: Willem de Bruijn <willemdebruijn.kernel@xxxxxxxxx> cc: David Ahern <dsahern@xxxxxxxxxx> cc: "David S. Miller" <davem@xxxxxxxxxxxxx> cc: Eric Dumazet <edumazet@xxxxxxxxxx> cc: Jakub Kicinski <kuba@xxxxxxxxxx> cc: Paolo Abeni <pabeni@xxxxxxxxxx> cc: Jens Axboe <axboe@xxxxxxxxx> cc: Matthew Wilcox <willy@xxxxxxxxxxxxx> cc: netdev@xxxxxxxxxxxxxxx --- Notes: ver #6) - Use common helper. net/ipv6/ip6_output.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/net/ipv6/ip6_output.c b/net/ipv6/ip6_output.c index 9554cf46ed88..c722cb881b2d 100644 --- a/net/ipv6/ip6_output.c +++ b/net/ipv6/ip6_output.c @@ -1589,6 +1589,14 @@ static int __ip6_append_data(struct sock *sk, skb_zcopy_set(skb, uarg, &extra_uref); } } + } else if ((flags & MSG_SPLICE_PAGES) && length) { + if (inet_sk(sk)->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; } /* @@ -1778,6 +1786,15 @@ static int __ip6_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;