For TAP device new skb is created and data from the current skb is copied to it. This adds copying data from non-linear skb to new the skb. Signed-off-by: Arseniy Krasnov <AVKrasnov@xxxxxxxxxxxxxx> --- net/vmw_vsock/virtio_transport_common.c | 43 +++++++++++++++++++++++-- 1 file changed, 40 insertions(+), 3 deletions(-) diff --git a/net/vmw_vsock/virtio_transport_common.c b/net/vmw_vsock/virtio_transport_common.c index a1581c77cf84..05ce97b967ad 100644 --- a/net/vmw_vsock/virtio_transport_common.c +++ b/net/vmw_vsock/virtio_transport_common.c @@ -101,6 +101,39 @@ virtio_transport_alloc_skb(struct virtio_vsock_pkt_info *info, return NULL; } +static void virtio_transport_copy_nonlinear_skb(struct sk_buff *skb, + void *dst, + size_t len) +{ + size_t rest_len = len; + + while (rest_len && virtio_vsock_skb_has_frags(skb)) { + struct bio_vec *curr_vec; + size_t curr_vec_end; + size_t to_copy; + int curr_frag; + int curr_offs; + + curr_frag = VIRTIO_VSOCK_SKB_CB(skb)->curr_frag; + curr_offs = VIRTIO_VSOCK_SKB_CB(skb)->frag_off; + curr_vec = &skb_shinfo(skb)->frags[curr_frag]; + + curr_vec_end = curr_vec->bv_offset + curr_vec->bv_len; + to_copy = min(rest_len, (size_t)(curr_vec_end - curr_offs)); + + memcpy(dst, page_to_virt(curr_vec->bv_page) + curr_offs, + to_copy); + + rest_len -= to_copy; + VIRTIO_VSOCK_SKB_CB(skb)->frag_off += to_copy; + + if (VIRTIO_VSOCK_SKB_CB(skb)->frag_off == (curr_vec_end)) { + VIRTIO_VSOCK_SKB_CB(skb)->curr_frag++; + VIRTIO_VSOCK_SKB_CB(skb)->frag_off = 0; + } + } +} + /* Packet capture */ static struct sk_buff *virtio_transport_build_skb(void *opaque) { @@ -109,7 +142,6 @@ static struct sk_buff *virtio_transport_build_skb(void *opaque) struct af_vsockmon_hdr *hdr; struct sk_buff *skb; size_t payload_len; - void *payload_buf; /* A packet could be split to fit the RX buffer, so we can retrieve * the payload length from the header and the buffer pointer taking @@ -117,7 +149,6 @@ static struct sk_buff *virtio_transport_build_skb(void *opaque) */ pkt_hdr = virtio_vsock_hdr(pkt); payload_len = pkt->len; - payload_buf = pkt->data; skb = alloc_skb(sizeof(*hdr) + sizeof(*pkt_hdr) + payload_len, GFP_ATOMIC); @@ -160,7 +191,13 @@ static struct sk_buff *virtio_transport_build_skb(void *opaque) skb_put_data(skb, pkt_hdr, sizeof(*pkt_hdr)); if (payload_len) { - skb_put_data(skb, payload_buf, payload_len); + if (skb_is_nonlinear(skb)) { + void *data = skb_put(skb, payload_len); + + virtio_transport_copy_nonlinear_skb(skb, data, payload_len); + } else { + skb_put_data(skb, pkt->data, payload_len); + } } return skb; -- 2.25.1