[PATCH bpf-next 2/3] libbpf: use weak hidden modifier for USDT BPF-side API functions

[Andrii Nakryiko <andrii@kernel.org>]

Use __weak __hidden for bpf_usdt_xxx() APIs instead of much more
confusing `static inline __noinline`. This was previously impossible due
to libbpf erroring out on CO-RE relocations pointing to eliminated weak
subprogs. Now that previous patch fixed this issue, switch back to
__weak __hidden as it's a more direct way of specifying the desired
behavior.

Signed-off-by: Andrii Nakryiko <andrii@kernel.org>
---
 tools/lib/bpf/usdt.bpf.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/tools/lib/bpf/usdt.bpf.h b/tools/lib/bpf/usdt.bpf.h
index 881a2422a8ef..4181fddb3687 100644
--- a/tools/lib/bpf/usdt.bpf.h
+++ b/tools/lib/bpf/usdt.bpf.h
@@ -103,7 +103,7 @@ int __bpf_usdt_spec_id(struct pt_regs *ctx)
 }
 
 /* Return number of USDT arguments defined for currently traced USDT. */
-static inline __noinline
+__weak __hidden
 int bpf_usdt_arg_cnt(struct pt_regs *ctx)
 {
 	struct __bpf_usdt_spec *spec;
@@ -124,7 +124,7 @@ int bpf_usdt_arg_cnt(struct pt_regs *ctx)
  * Returns 0 on success; negative error, otherwise.
  * On error *res is guaranteed to be set to zero.
  */
-static inline __noinline
+__weak __hidden
 int bpf_usdt_arg(struct pt_regs *ctx, __u64 arg_num, long *res)
 {
 	struct __bpf_usdt_spec *spec;
@@ -204,7 +204,7 @@ int bpf_usdt_arg(struct pt_regs *ctx, __u64 arg_num, long *res)
  * utilizing BPF cookies internally, so user can't use BPF cookie directly
  * for USDT programs and has to use bpf_usdt_cookie() API instead.
  */
-static inline __noinline
+__weak __hidden
 long bpf_usdt_cookie(struct pt_regs *ctx)
 {
 	struct __bpf_usdt_spec *spec;
-- 
2.30.2