[PATCH] net/af_xdp: make compatible with libbpf v0.8.0

[Andrew Rybchenko]

On 6/24/22 13:23, Ciara Loftus wrote:
> libbpf v0.8.0 deprecates the bpf_get_link_xdp_id and bpf_set_link_xdp_fd
> functions. Use meson to detect if libbpf >= v0.7.0 is linked and if so, use
> the recommended replacement functions bpf_xdp_query_id, bpf_xdp_attach
> and bpf_xdp_detach which are available to use since libbpf v0.7.0.
> 
> Also prevent linking with libbpf versions > v0.8.0.
> 
> Signed-off-by: Ciara Loftus <ciara.loftus at intel.com>
> ---
>   doc/guides/nics/af_xdp.rst          |  3 ++-
>   drivers/net/af_xdp/compat.h         | 36 ++++++++++++++++++++++++++++-
>   drivers/net/af_xdp/meson.build      |  7 ++----
>   drivers/net/af_xdp/rte_eth_af_xdp.c | 19 +++------------
>   4 files changed, 42 insertions(+), 23 deletions(-)

Don't we need to mention these changes in release notes?

> 
> diff --git a/doc/guides/nics/af_xdp.rst b/doc/guides/nics/af_xdp.rst
> index 56681c8365..9edb48df67 100644
> --- a/doc/guides/nics/af_xdp.rst
> +++ b/doc/guides/nics/af_xdp.rst
> @@ -43,7 +43,8 @@ Prerequisites
>   This is a Linux-specific PMD, thus the following prerequisites apply:
>   
>   *  A Linux Kernel (version > v4.18) with XDP sockets configuration enabled;
> -*  Both libxdp >=v1.2.2 and libbpf libraries installed, or, libbpf <=v0.6.0
> +*  Both libxdp >=v1.2.2 and libbpf <=v0.8.0 libraries installed, or, libbpf
> +   <=v0.6.0.
>   *  If using libxdp, it requires an environment variable called
>      LIBXDP_OBJECT_PATH to be set to the location of where libxdp placed its bpf
>      object files. This is usually in /usr/local/lib/bpf or /usr/local/lib64/bpf.
> diff --git a/drivers/net/af_xdp/compat.h b/drivers/net/af_xdp/compat.h
> index 28ea64aeaa..8f4ac8b5ea 100644
> --- a/drivers/net/af_xdp/compat.h
> +++ b/drivers/net/af_xdp/compat.h
> @@ -60,7 +60,7 @@ tx_syscall_needed(struct xsk_ring_prod *q __rte_unused)
>   }
>   #endif
>   
> -#ifdef RTE_NET_AF_XDP_LIBBPF_OBJ_OPEN
> +#ifdef RTE_NET_AF_XDP_LIBBPF_V070

Typically version-based checks are considered as bad. Isn't it
better use feature-based checks/defines?