Add an bvec specialised and optimised path in zerocopy_sg_from_iter.
It'll be used later for {get,put}_page() optimisations.
Signed-off-by: Pavel Begunkov <asml.silence@xxxxxxxxx>
---
net/core/datagram.c | 47 +++++++++++++++++++++++++++++++++++++++++++++
1 file changed, 47 insertions(+)
diff --git a/net/core/datagram.c b/net/core/datagram.c
index 50f4faeea76c..5237cb533bb4 100644
--- a/net/core/datagram.c
+++ b/net/core/datagram.c
@@ -613,11 +613,58 @@ int skb_copy_datagram_from_iter(struct sk_buff *skb, int offset,
}
EXPORT_SYMBOL(skb_copy_datagram_from_iter);
+static int __zerocopy_sg_from_bvec(struct sock *sk, struct sk_buff *skb,
+ struct iov_iter *from, size_t length)
+{
+ int frag = skb_shinfo(skb)->nr_frags;
+ int ret = 0;
+ struct bvec_iter bi;
+ ssize_t copied = 0;
+ unsigned long truesize = 0;
+
+ 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);
+ get_page(v.bv_page);
+ skb_fill_page_desc(skb, 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;
+
+ 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 __zerocopy_sg_from_iter(struct sock *sk, struct sk_buff *skb,
struct iov_iter *from, size_t length)
{
int frag = skb_shinfo(skb)->nr_frags;
+ if (iov_iter_is_bvec(from))
+ return __zerocopy_sg_from_bvec(sk, skb, from, length);
+
while (length && iov_iter_count(from)) {
struct page *pages[MAX_SKB_FRAGS];
struct page *last_head = NULL;
--
2.36.1
