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From:   Jiri Olsa <olsajiri@gmail.com>
Date:   Wed, 3 Aug 2022 10:19:35 +0200
To:     James Hilliard <james.hilliard1@gmail.com>
Cc:     bpf@vger.kernel.org, Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        Andrii Nakryiko <andrii@kernel.org>,
        Martin KaFai Lau <martin.lau@linux.dev>,
        Song Liu <song@kernel.org>, Yonghong Song <yhs@fb.com>,
        John Fastabend <john.fastabend@gmail.com>,
        KP Singh <kpsingh@kernel.org>,
        Stanislav Fomichev <sdf@google.com>,
        Hao Luo <haoluo@google.com>, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] libbpf: ensure functions with always_inline attribute
 are inline
Message-ID: <Yuovl3ycDfflqV9h@krava>
References: <20220802232741.481145-1-james.hilliard1@gmail.com>
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In-Reply-To: <20220802232741.481145-1-james.hilliard1@gmail.com>
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On Tue, Aug 02, 2022 at 05:27:41PM -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
> inline.
> 
> 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>
> ---
>  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..ae67fcee912c 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 inline __attribute__((always_inline)) typeof(name(0))		    \

could you use __always_inline that does exactly that?

jirka

>  ____##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 inline __attribute__((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 inline __attribute__((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 inline __attribute__((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 inline __attribute__((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 inline __attribute__((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 inline __attribute__((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..2bd2d80b3751 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 inline __attribute__((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 inline __attribute__((always_inline)) typeof(name(0))		    \
>  ____##name(struct pt_regs *ctx, ##args)
>  
>  #endif /* __USDT_BPF_H__ */
> -- 
> 2.34.1
>