[PATCH v2 bpf-next] libbpf: deprecate btf_ext rec_size APIs

[PATCH v2 bpf-next] libbpf: deprecate btf_ext rec_size APIs

[Dave Marchevsky]

btf_ext__{func,line}_info_rec_size functions are used in conjunction
with already-deprecated btf_ext__reloc_{func,line}_info functions. Since
struct btf_ext is opaque to the user it was necessary to expose rec_size
getters in the past.

btf_ext__reloc_{func,line}_info were deprecated in commit 8505e8709b5ee
("libbpf: Implement generalized .BTF.ext func/line info adjustment")
as they're not compatible with support for multiple programs per
section. It was decided[0] that users of these APIs should implement their
own .btf.ext parsing to access this data, in which case the rec_size
getters are unnecessary. So deprecate them from libbpf 0.7.0 onwards.

  [0] Closes: https://github.com/libbpf/libbpf/issues/277

Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>
---

v2: LIBBPF_DEPRECATED_SINCE -> LIBBPF_DEPRECATED to match
    reloc_{func,line}_info deprecations [Daniel]

 tools/lib/bpf/btf.h | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/tools/lib/bpf/btf.h b/tools/lib/bpf/btf.h
index 96b44d55db6e..b10729fd830c 100644
--- a/tools/lib/bpf/btf.h
+++ b/tools/lib/bpf/btf.h
@@ -168,8 +168,10 @@ int btf_ext__reloc_line_info(const struct btf *btf,
 			     const struct btf_ext *btf_ext,
 			     const char *sec_name, __u32 insns_cnt,
 			     void **line_info, __u32 *cnt);
-LIBBPF_API __u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext);
-LIBBPF_API __u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext);
+LIBBPF_API LIBBPF_DEPRECATED("btf_ext__reloc_func_info is deprecated; write custom func_info parsing to fetch rec_size")
+__u32 btf_ext__func_info_rec_size(const struct btf_ext *btf_ext);
+LIBBPF_API LIBBPF_DEPRECATED("btf_ext__reloc_line_info is deprecated; write custom line_info parsing to fetch rec_size")
+__u32 btf_ext__line_info_rec_size(const struct btf_ext *btf_ext);
 
 LIBBPF_API int btf__find_str(struct btf *btf, const char *s);
 LIBBPF_API int btf__add_str(struct btf *btf, const char *s);
-- 
2.30.2

Re: [PATCH v2 bpf-next] libbpf: deprecate btf_ext rec_size APIs

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to bpf/bpf-next.git (master)
by Daniel Borkmann <daniel@iogearbox.net>:

On Mon, 31 Jan 2022 17:46:10 -0800 you wrote:
> btf_ext__{func,line}_info_rec_size functions are used in conjunction
> with already-deprecated btf_ext__reloc_{func,line}_info functions. Since
> struct btf_ext is opaque to the user it was necessary to expose rec_size
> getters in the past.
> 
> btf_ext__reloc_{func,line}_info were deprecated in commit 8505e8709b5ee
> ("libbpf: Implement generalized .BTF.ext func/line info adjustment")
> as they're not compatible with support for multiple programs per
> section. It was decided[0] that users of these APIs should implement their
> own .btf.ext parsing to access this data, in which case the rec_size
> getters are unnecessary. So deprecate them from libbpf 0.7.0 onwards.
> 
> [...]

Here is the summary with links:
  - [v2,bpf-next] libbpf: deprecate btf_ext rec_size APIs
    https://git.kernel.org/bpf/bpf-next/c/5ee32ea24ce7

You are awesome, thank you!
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