ip6, udp6: Support MSG_SPLICE_PAGES

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@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: Jakub Kicinski <kuba@kernel.org>
This commit is contained in:
David Howells 2023-05-22 13:11:21 +01:00 committed by Jakub Kicinski
parent 7da0dde684
commit 6d8192bd69

View file

@ -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;