Re: [PATCH v2] libbpf: ensure functions with always_inline attribute are inline

Jiri Olsa
2022-08-04T07:13:30Z

On Wed, Aug 03, 2022 at 09:14:03AM -0600, James Hilliard wrote:
> GCC expects the always_inline attribute to only be set on inline
> functions, as such we should make all functions with this attribute
> use the __always_inline macro which makes the function inline and
> sets the attribute.
>
> Fixes errors like:
> /home/buildroot/bpf-next/tools/testing/selftests/bpf/tools/include/bpf/bpf_tracing.h:439:1: error: ‘always_inline’ function might not be inlinable [-Werror=attributes]
> 439 | ____##name(unsigned long long *ctx, ##args)
> | ^~~~
>
> Signed-off-by: James Hilliard <james.hilliard1@gmail.com>
> ---
> Changes v1 -> v2:
> - use __always_inline macro

Acked-by: Jiri Olsa <jolsa@kernel.org>

jirka

> ---
> tools/lib/bpf/bpf_tracing.h | 14 +++++++-------
> tools/lib/bpf/usdt.bpf.h | 4 ++--
> 2 files changed, 9 insertions(+), 9 deletions(-)
>
> diff --git a/tools/lib/bpf/bpf_tracing.h b/tools/lib/bpf/bpf_tracing.h
> index 43ca3aff2292..5fdb93da423b 100644
> --- a/tools/lib/bpf/bpf_tracing.h
> +++ b/tools/lib/bpf/bpf_tracing.h
> @@ -426,7 +426,7 @@ struct pt_regs;
> */
> #define BPF_PROG(name, args...) \
> name(unsigned long long *ctx); \
> -static __attribute__((always_inline)) typeof(name(0)) \
> +static __always_inline typeof(name(0)) \
> ____##name(unsigned long long *ctx, ##args); \
> typeof(name(0)) name(unsigned long long *ctx) \
> { \
> @@ -435,7 +435,7 @@ typeof(name(0)) name(unsigned long long *ctx) \
> return ____##name(___bpf_ctx_cast(args)); \
> _Pragma("GCC diagnostic pop") \
> } \
> -static __attribute__((always_inline)) typeof(name(0)) \
> +static __always_inline typeof(name(0)) \
> ____##name(unsigned long long *ctx, ##args)
>
> struct pt_regs;
> @@ -460,7 +460,7 @@ struct pt_regs;
> */
> #define BPF_KPROBE(name, args...) \
> name(struct pt_regs *ctx); \
> -static __attribute__((always_inline)) typeof(name(0)) \
> +static __always_inline typeof(name(0)) \
> ____##name(struct pt_regs *ctx, ##args); \
> typeof(name(0)) name(struct pt_regs *ctx) \
> { \
> @@ -469,7 +469,7 @@ typeof(name(0)) name(struct pt_regs *ctx) \
> return ____##name(___bpf_kprobe_args(args)); \
> _Pragma("GCC diagnostic pop") \
> } \
> -static __attribute__((always_inline)) typeof(name(0)) \
> +static __always_inline typeof(name(0)) \
> ____##name(struct pt_regs *ctx, ##args)
>
> #define ___bpf_kretprobe_args0() ctx
> @@ -484,7 +484,7 @@ ____##name(struct pt_regs *ctx, ##args)
> */
> #define BPF_KRETPROBE(name, args...) \
> name(struct pt_regs *ctx); \
> -static __attribute__((always_inline)) typeof(name(0)) \
> +static __always_inline typeof(name(0)) \
> ____##name(struct pt_regs *ctx, ##args); \
> typeof(name(0)) name(struct pt_regs *ctx) \
> { \
> @@ -540,7 +540,7 @@ static __always_inline typeof(name(0)) ____##name(struct pt_regs *ctx, ##args)
> #define BPF_KSYSCALL(name, args...) \
> name(struct pt_regs *ctx); \
> extern _Bool LINUX_HAS_SYSCALL_WRAPPER __kconfig; \
> -static __attribute__((always_inline)) typeof(name(0)) \
> +static __always_inline typeof(name(0)) \
> ____##name(struct pt_regs *ctx, ##args); \
> typeof(name(0)) name(struct pt_regs *ctx) \
> { \
> @@ -555,7 +555,7 @@ typeof(name(0)) name(struct pt_regs *ctx) \
> return ____##name(___bpf_syscall_args(args)); \
> _Pragma("GCC diagnostic pop") \
> } \
> -static __attribute__((always_inline)) typeof(name(0)) \
> +static __always_inline typeof(name(0)) \
> ____##name(struct pt_regs *ctx, ##args)
>
> #define BPF_KPROBE_SYSCALL BPF_KSYSCALL
> diff --git a/tools/lib/bpf/usdt.bpf.h b/tools/lib/bpf/usdt.bpf.h
> index 4f2adc0bd6ca..fdfd235e52c4 100644
> --- a/tools/lib/bpf/usdt.bpf.h
> +++ b/tools/lib/bpf/usdt.bpf.h
> @@ -232,7 +232,7 @@ long bpf_usdt_cookie(struct pt_regs *ctx)
> */
> #define BPF_USDT(name, args...) \
> name(struct pt_regs *ctx); \
> -static __attribute__((always_inline)) typeof(name(0)) \
> +static __always_inline typeof(name(0)) \
> ____##name(struct pt_regs *ctx, ##args); \
> typeof(name(0)) name(struct pt_regs *ctx) \
> { \
> @@ -241,7 +241,7 @@ typeof(name(0)) name(struct pt_regs *ctx) \
> return ____##name(___bpf_usdt_args(args)); \
> _Pragma("GCC diagnostic pop") \
> } \
> -static __attribute__((always_inline)) typeof(name(0)) \
> +static __always_inline typeof(name(0)) \
> ____##name(struct pt_regs *ctx, ##args)
>
> #endif /* __USDT_BPF_H__ */
> --
> 2.34.1
>