Re: [PATCH net-next v2 03/15] bpf: report offload info to user space

[Alexei Starovoitov <alexei.starovoitov@gmail.com>]

On Fri, Nov 03, 2017 at 01:56:18PM -0700, Jakub Kicinski wrote:
> Extend struct bpf_prog_info to contain information about program
> being bound to a device.  Since the netdev may get destroyed while
> program still exists we need a flag to indicate the program is
> loaded for a device, even if the device is gone.
> 
> Signed-off-by: Jakub Kicinski <jakub.kicinski@netronome.com>
> Reviewed-by: Simon Horman <simon.horman@netronome.com>
> Reviewed-by: Quentin Monnet <quentin.monnet@netronome.com>
> ---
>  include/linux/bpf.h      |  1 +
>  include/uapi/linux/bpf.h |  6 ++++++
>  kernel/bpf/offload.c     | 12 ++++++++++++
>  kernel/bpf/syscall.c     |  5 +++++
>  4 files changed, 24 insertions(+)
> 
> diff --git a/include/linux/bpf.h b/include/linux/bpf.h
> index e45d43f9ec92..98bacd0fa5cc 100644
> --- a/include/linux/bpf.h
> +++ b/include/linux/bpf.h
> @@ -506,6 +506,7 @@ static inline int cpu_map_enqueue(struct bpf_cpu_map_entry *rcpu,
>  
>  int bpf_prog_offload_compile(struct bpf_prog *prog);
>  void bpf_prog_offload_destroy(struct bpf_prog *prog);
> +u32 bpf_prog_offload_ifindex(struct bpf_prog *prog);
>  
>  #if defined(CONFIG_NET) && defined(CONFIG_BPF_SYSCALL)
>  int bpf_prog_offload_init(struct bpf_prog *prog, union bpf_attr *attr);
> diff --git a/include/uapi/linux/bpf.h b/include/uapi/linux/bpf.h
> index 727a3dba13e6..e92f62cf933a 100644
> --- a/include/uapi/linux/bpf.h
> +++ b/include/uapi/linux/bpf.h
> @@ -894,6 +894,10 @@ enum sk_action {
>  
>  #define BPF_TAG_SIZE	8
>  
> +enum bpf_prog_status {
> +	BPF_PROG_STATUS_DEV_BOUND	= (1 << 0),
> +};
> +
>  struct bpf_prog_info {
>  	__u32 type;
>  	__u32 id;
> @@ -907,6 +911,8 @@ struct bpf_prog_info {
>  	__u32 nr_map_ids;
>  	__aligned_u64 map_ids;
>  	char name[BPF_OBJ_NAME_LEN];
> +	__u32 ifindex;
> +	__u32 status;

why status is needed?
ifindex cannot be zero, so if it's set > 0 would mean
that the program is bound.
Also would be good to have consistent name with prog_load.
imo prog_target_ifindex is too long.
May be call it 'ifindex' both in bpf_attr and in bpf_prog_info ?