Commit 1fd3ae8c authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jakub Kicinski
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ipv6/udp: support externally provided ubufs 



Teach ipv6/udp how to use external ubuf_info provided in msghdr and
also prepare it for managed frags by sprinkling
skb_zcopy_downgrade_managed() when it could mix managed and not managed
frags.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Signed-off-by: default avatarJakub Kicinski <kuba@kernel.org>
parent c445f31b

net/ipv6/ip6_output.c

+31 −13
Original line number Diff line number Diff line
@@ -1542,7 +1542,23 @@ static int __ip6_append_data(struct sock *sk, 
	    rt->dst.dev->features & (NETIF_F_IPV6_CSUM | NETIF_F_HW_CSUM))

		csummode = CHECKSUM_PARTIAL;



	if (flags & MSG_ZEROCOPY && length && sock_flag(sk, SOCK_ZEROCOPY)) {

	if ((flags & MSG_ZEROCOPY) && length) {

		struct msghdr *msg = from;



		if (getfrag == ip_generic_getfrag && msg->msg_ubuf) {

			if (skb_zcopy(skb) && msg->msg_ubuf != skb_zcopy(skb))

				return -EINVAL;



			/* Leave uarg NULL if can't zerocopy, callers should

			 * be able to handle it.

			 */

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

			    csummode == CHECKSUM_PARTIAL) {

				paged = true;

				zc = true;

				uarg = msg->msg_ubuf;

			}

		} else if (sock_flag(sk, SOCK_ZEROCOPY)) {

			uarg = msg_zerocopy_realloc(sk, length, skb_zcopy(skb));

			if (!uarg)

				return -ENOBUFS;
@@ -1556,6 +1572,7 @@ static int __ip6_append_data(struct sock *sk, 
				skb_zcopy_set(skb, uarg, &extra_uref);

			}

		}

	}



	/*

	 * Let's try using as much space as possible.
@@ -1747,13 +1764,14 @@ static int __ip6_append_data(struct sock *sk, 
				err = -EFAULT;

				goto error;

			}

		} else if (!uarg || !uarg->zerocopy) {

		} else if (!zc) {

			int i = skb_shinfo(skb)->nr_frags;



			err = -ENOMEM;

			if (!sk_page_frag_refill(sk, pfrag))

				goto error;



			skb_zcopy_downgrade_managed(skb);

			if (!skb_can_coalesce(skb, i, pfrag->page,

					      pfrag->offset)) {

				err = -EMSGSIZE;