Commit 3ff1a0d3 authored by Pavel Begunkov's avatar Pavel Begunkov Committed by Jens Axboe
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io_uring: enable managed frags with register buffers 



io_uring's registered buffers infra has a good performant way of pinning
pages, so let's use SKBFL_MANAGED_FRAG_REFS when our requests are purely
register buffer backed.

Signed-off-by: default avatarPavel Begunkov <asml.silence@gmail.com>
Link: https://lore.kernel.org/r/278731d3f20caf346cfc025fbee0b4c9ee4ed751.1657643355.git.asml.silence@gmail.com


Signed-off-by: default avatarJens Axboe <axboe@kernel.dk>
parent 492dddb4

io_uring/net.c

+55 −1
Original line number Diff line number Diff line
@@ -886,6 +886,60 @@ int io_sendzc_prep(struct io_kiocb *req, const struct io_uring_sqe *sqe) 
	return 0;

}



static int io_sg_from_iter(struct sock *sk, struct sk_buff *skb,

			   struct iov_iter *from, size_t length)

{

	struct skb_shared_info *shinfo = skb_shinfo(skb);

	int frag = shinfo->nr_frags;

	int ret = 0;

	struct bvec_iter bi;

	ssize_t copied = 0;

	unsigned long truesize = 0;



	if (!shinfo->nr_frags)

		shinfo->flags |= SKBFL_MANAGED_FRAG_REFS;



	if (!skb_zcopy_managed(skb) || !iov_iter_is_bvec(from)) {

		skb_zcopy_downgrade_managed(skb);

		return __zerocopy_sg_from_iter(NULL, sk, skb, from, length);

	}



	bi.bi_size = min(from->count, length);

	bi.bi_bvec_done = from->iov_offset;

	bi.bi_idx = 0;



	while (bi.bi_size && frag < MAX_SKB_FRAGS) {

		struct bio_vec v = mp_bvec_iter_bvec(from->bvec, bi);



		copied += v.bv_len;

		truesize += PAGE_ALIGN(v.bv_len + v.bv_offset);

		__skb_fill_page_desc_noacc(shinfo, frag++, v.bv_page,

					   v.bv_offset, v.bv_len);

		bvec_iter_advance_single(from->bvec, &bi, v.bv_len);

	}

	if (bi.bi_size)

		ret = -EMSGSIZE;



	shinfo->nr_frags = frag;

	from->bvec += bi.bi_idx;

	from->nr_segs -= bi.bi_idx;

	from->count = bi.bi_size;

	from->iov_offset = bi.bi_bvec_done;



	skb->data_len += copied;

	skb->len += copied;

	skb->truesize += truesize;



	if (sk && sk->sk_type == SOCK_STREAM) {

		sk_wmem_queued_add(sk, truesize);

		if (!skb_zcopy_pure(skb))

			sk_mem_charge(sk, truesize);

	} else {

		refcount_add(truesize, &skb->sk->sk_wmem_alloc);

	}

	return ret;

}



int io_sendzc(struct io_kiocb *req, unsigned int issue_flags)

{

	struct sockaddr_storage address;
@@ -950,7 +1004,7 @@ int io_sendzc(struct io_kiocb *req, unsigned int issue_flags) 


	msg.msg_flags = msg_flags;

	msg.msg_ubuf = &notif->uarg;

	msg.sg_from_iter = NULL;

	msg.sg_from_iter = io_sg_from_iter;

	ret = sock_sendmsg(sock, &msg);



	if (unlikely(ret < min_ret)) {