On Wed, 12 Jun 2019 at 20:05, Maxim Mikityanskiy <maximmi@xxxxxxxxxxxx> wrote:
>
> Make it possible for the application to determine whether the AF_XDP
> socket is running in zero-copy mode. To achieve this, add a new
> getsockopt option XDP_OPTIONS that returns flags. The only flag
> supported for now is the zero-copy mode indicator.
>
Acked-by: Björn Töpel <bjorn.topel@xxxxxxxxx>
> Signed-off-by: Maxim Mikityanskiy <maximmi@xxxxxxxxxxxx>
> Reviewed-by: Tariq Toukan <tariqt@xxxxxxxxxxxx>
> Acked-by: Saeed Mahameed <saeedm@xxxxxxxxxxxx>
> ---
> include/uapi/linux/if_xdp.h | 8 ++++++++
> net/xdp/xsk.c | 20 ++++++++++++++++++++
> tools/include/uapi/linux/if_xdp.h | 8 ++++++++
> 3 files changed, 36 insertions(+)
>
> diff --git a/include/uapi/linux/if_xdp.h b/include/uapi/linux/if_xdp.h
> index caed8b1614ff..faaa5ca2a117 100644
> --- a/include/uapi/linux/if_xdp.h
> +++ b/include/uapi/linux/if_xdp.h
> @@ -46,6 +46,7 @@ struct xdp_mmap_offsets {
> #define XDP_UMEM_FILL_RING 5
> #define XDP_UMEM_COMPLETION_RING 6
> #define XDP_STATISTICS 7
> +#define XDP_OPTIONS 8
>
> struct xdp_umem_reg {
> __u64 addr; /* Start of packet data area */
> @@ -60,6 +61,13 @@ struct xdp_statistics {
> __u64 tx_invalid_descs; /* Dropped due to invalid descriptor */
> };
>
> +struct xdp_options {
> + __u32 flags;
> +};
> +
> +/* Flags for the flags field of struct xdp_options */
> +#define XDP_OPTIONS_ZEROCOPY (1 << 0)
> +
> /* Pgoff for mmaping the rings */
> #define XDP_PGOFF_RX_RING 0
> #define XDP_PGOFF_TX_RING 0x80000000
> diff --git a/net/xdp/xsk.c b/net/xdp/xsk.c
> index b68a380f50b3..35ca531ac74e 100644
> --- a/net/xdp/xsk.c
> +++ b/net/xdp/xsk.c
> @@ -650,6 +650,26 @@ static int xsk_getsockopt(struct socket *sock, int level, int optname,
>
> return 0;
> }
> + case XDP_OPTIONS:
> + {
> + struct xdp_options opts = {};
> +
> + if (len < sizeof(opts))
> + return -EINVAL;
> +
> + mutex_lock(&xs->mutex);
> + if (xs->zc)
> + opts.flags |= XDP_OPTIONS_ZEROCOPY;
> + mutex_unlock(&xs->mutex);
> +
> + len = sizeof(opts);
> + if (copy_to_user(optval, &opts, len))
> + return -EFAULT;
> + if (put_user(len, optlen))
> + return -EFAULT;
> +
> + return 0;
> + }
> default:
> break;
> }
> diff --git a/tools/include/uapi/linux/if_xdp.h b/tools/include/uapi/linux/if_xdp.h
> index caed8b1614ff..faaa5ca2a117 100644
> --- a/tools/include/uapi/linux/if_xdp.h
> +++ b/tools/include/uapi/linux/if_xdp.h
> @@ -46,6 +46,7 @@ struct xdp_mmap_offsets {
> #define XDP_UMEM_FILL_RING 5
> #define XDP_UMEM_COMPLETION_RING 6
> #define XDP_STATISTICS 7
> +#define XDP_OPTIONS 8
>
> struct xdp_umem_reg {
> __u64 addr; /* Start of packet data area */
> @@ -60,6 +61,13 @@ struct xdp_statistics {
> __u64 tx_invalid_descs; /* Dropped due to invalid descriptor */
> };
>
> +struct xdp_options {
> + __u32 flags;
> +};
> +
> +/* Flags for the flags field of struct xdp_options */
> +#define XDP_OPTIONS_ZEROCOPY (1 << 0)
> +
> /* Pgoff for mmaping the rings */
> #define XDP_PGOFF_RX_RING 0
> #define XDP_PGOFF_TX_RING 0x80000000
> --
> 2.19.1
>
