On Tue, Feb 02, 2021 at 07:34:44PM +0200, Camelia Groza wrote:
> The XDP frame's headroom might be large enough to accommodate the
> xdpf backpointer as well as shifting the data to an aligned address.
>
> Try this first before resorting to allocating a new buffer and copying
> the data.
>
> Suggested-by: Maciej Fijalkowski <maciej.fijalkow...@intel.com>
> Signed-off-by: Camelia Groza <camelia.gr...@nxp.com>
Acked-by: Maciej Fijalkowski <maciej.fijalkow...@intel.com>
> ---
> .../net/ethernet/freescale/dpaa/dpaa_eth.c | 20 ++++++++++++++++++-
> 1 file changed, 19 insertions(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
> b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
> index 78dfa05f6d55..d093b56dc30f 100644
> --- a/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
> +++ b/drivers/net/ethernet/freescale/dpaa/dpaa_eth.c
> @@ -2180,8 +2180,9 @@ static int dpaa_a050385_wa_xdpf(struct dpaa_priv *priv,
> struct xdp_frame **init_xdpf)
> {
> struct xdp_frame *new_xdpf, *xdpf = *init_xdpf;
> - void *new_buff;
> + void *new_buff, *aligned_data;
> struct page *p;
> + u32 data_shift;
> int headroom;
>
> /* Check the data alignment and make sure the headroom is large
> @@ -2198,6 +2199,23 @@ static int dpaa_a050385_wa_xdpf(struct dpaa_priv *priv,
> return 0;
> }
>
> + /* Try to move the data inside the buffer just enough to align it and
> + * store the xdpf backpointer. If the available headroom isn't large
> + * enough, resort to allocating a new buffer and copying the data.
> + */
> + aligned_data = PTR_ALIGN_DOWN(xdpf->data, DPAA_FD_DATA_ALIGNMENT);
> + data_shift = xdpf->data - aligned_data;
> +
> + /* The XDP frame's headroom needs to be large enough to accommodate
> + * shifting the data as well as storing the xdpf backpointer.
> + */
> + if (xdpf->headroom >= data_shift + priv->tx_headroom) {
> + memmove(aligned_data, xdpf->data, xdpf->len);
> + xdpf->data = aligned_data;
> + xdpf->headroom = priv->tx_headroom;
> + return 0;
> + }
> +
> /* The new xdp_frame is stored in the new buffer. Reserve enough space
> * in the headroom for storing it along with the driver's private
> * info. The headroom needs to be aligned to DPAA_FD_DATA_ALIGNMENT to
> --
> 2.17.1
>
