From 7da0dde68486b2d5bd7c689a9b327b77efecdfd0 Mon Sep 17 00:00:00 2001 From: David Howells Date: Mon, 22 May 2023 13:11:20 +0100 Subject: [PATCH] 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: David Howells cc: Willem de Bruijn cc: David Ahern cc: Jens Axboe cc: Matthew Wilcox Signed-off-by: Jakub Kicinski --- net/ipv4/ip_output.c | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) diff --git a/net/ipv4/ip_output.c b/net/ipv4/ip_output.c index 52fc840..c7db973 100644 --- a/net/ipv4/ip_output.c +++ b/net/ipv4/ip_output.c @@ -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 @@ alloc_new_skb: 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; -- 2.7.4