On Thu, Sep 14, 2023 at 4:12 PM Martin Kelly
<martin.kelly@xxxxxxxxxxxxxxx> wrote:
>
> Add ring__size to get the total size of a given ringbuffer.
>
> Signed-off-by: Martin Kelly <martin.kelly@xxxxxxxxxxxxxxx>
> ---
> tools/lib/bpf/libbpf.h | 8 ++++++++
> tools/lib/bpf/libbpf.map | 1 +
> tools/lib/bpf/ringbuf.c | 5 +++++
> 3 files changed, 14 insertions(+)
>
> diff --git a/tools/lib/bpf/libbpf.h b/tools/lib/bpf/libbpf.h
> index 87e3bad37737..299d98402ad4 100644
> --- a/tools/lib/bpf/libbpf.h
> +++ b/tools/lib/bpf/libbpf.h
> @@ -1290,6 +1290,14 @@ LIBBPF_API unsigned long ring__producer_pos(const struct ring *r);
> */
> LIBBPF_API size_t ring__avail_data_size(const struct ring *r);
>
> +/**
> + * @brief **ring__size()** returns the total size of the ringbuffer.
it's confusing to use "ringbuffer" here, as you refer to ring buffer
*manager* and to ring buffer *map* inside it with this. Let's be more
precise and also maybe mention that this is the size of ring buffer's
map data area (excluding producer/consumer pages)
> + *
> + * @param r A ring object.
> + * @return The total size of the ringbuffer.
> + */
> +LIBBPF_API size_t ring__size(const struct ring *r);
> +
> struct user_ring_buffer_opts {
> size_t sz; /* size of this struct, for forward/backward compatibility */
> };
> diff --git a/tools/lib/bpf/libbpf.map b/tools/lib/bpf/libbpf.map
> index f66d7f0bc224..4ca77e715667 100644
> --- a/tools/lib/bpf/libbpf.map
> +++ b/tools/lib/bpf/libbpf.map
> @@ -404,4 +404,5 @@ LIBBPF_1.3.0 {
> ring__avail_data_size;
> ring__consumer_pos;
> ring__producer_pos;
> + ring__size;
> } LIBBPF_1.2.0;
> diff --git a/tools/lib/bpf/ringbuf.c b/tools/lib/bpf/ringbuf.c
> index f51ad1af6ab8..52c385195f32 100644
> --- a/tools/lib/bpf/ringbuf.c
> +++ b/tools/lib/bpf/ringbuf.c
> @@ -355,6 +355,11 @@ size_t ring__avail_data_size(const struct ring *r)
> return ring__producer_pos(r) - ring__consumer_pos(r);
> }
>
> +size_t ring__size(const struct ring *r)
> +{
> + return r->mask + 1;
> +}
> +
> static void user_ringbuf_unmap_ring(struct user_ring_buffer *rb)
> {
> if (rb->consumer_pos) {
> --
> 2.34.1
>
