1. 21 Sep, 2023 1 commit
    • Arseniy Krasnov's avatar
      vsock/virtio/vhost: read data from non-linear skb · 0df7cd3c
      Arseniy Krasnov authored
      This is preparation patch for MSG_ZEROCOPY support. It adds handling of
      non-linear skbs by replacing direct calls of 'memcpy_to_msg()' with
      'skb_copy_datagram_iter()'. Main advantage of the second one is that it
      can handle paged part of the skb by using 'kmap()' on each page, but if
      there are no pages in the skb, it behaves like simple copying to iov
      iterator. This patch also adds new field to the control block of skb -
      this value shows current offset in the skb to read next portion of data
      (it doesn't matter linear it or not). Idea behind this field is that
      'skb_copy_datagram_iter()' handles both types of skb internally - it
      just needs an offset from which to copy data from the given skb. This
      offset is incremented on each read from skb. This approach allows to
      simplify handling of both linear and non-linear skbs, because for
      linear skb we need to call 'skb_pull()' after reading data from it,
      while in non-linear case we need to update 'data_len'.
      Signed-off-by: default avatarArseniy Krasnov <avkrasnov@salutedevices.com>
      Reviewed-by: default avatarStefano Garzarella <sgarzare@redhat.com>
      Acked-by: default avatarMichael S. Tsirkin <mst@redhat.com>
      Signed-off-by: default avatarPaolo Abeni <pabeni@redhat.com>
      0df7cd3c
  2. 20 Sep, 2023 39 commits