[bpf-next,09/14] libbpf: add ring__size

Commit Message

Martin Kelly Sept. 14, 2023, 11:11 p.m. UTC

Add ring__size to get the total size of a given ringbuffer.

Signed-off-by: Martin Kelly <[e-mail]>
---
 tools/lib/bpf/libbpf.h   | 8 ++++++++
 tools/lib/bpf/libbpf.map | 1 +
 tools/lib/bpf/ringbuf.c  | 5 +++++
 3 files changed, 14 insertions(+)

Comments

Andrii Nakryiko Sept. 21, 2023, 1:28 a.m. UTC | #1

On Thu, Sep 14, 2023 at 4:12 PM Martin Kelly
<[e-mail]> wrote:
>
> Add ring__size to get the total size of a given ringbuffer.
>
> Signed-off-by: Martin Kelly <[e-mail]>
> ---
>  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
>

Patch

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.
+ *
+ * @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) {