[PATCH] bpf: fix -Wshadow warnings

[PATCH] bpf: fix -Wshadow warnings

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

There are thousands of warnings about one macro in a W=2 build:

include/linux/filter.h:561:6: warning: declaration of 'ret' shadows a previous local [-Wshadow]

Prefix all the locals in that macro with __ to avoid most of
these warnings.

Fixes: 492ecee892c2 ("bpf: enable program stats")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 include/linux/filter.h | 22 +++++++++++-----------
 1 file changed, 11 insertions(+), 11 deletions(-)

diff --git a/include/linux/filter.h b/include/linux/filter.h
index 954f279fde01..20ba04583eaa 100644
--- a/include/linux/filter.h
+++ b/include/linux/filter.h
@@ -558,21 +558,21 @@ struct sk_filter {
 DECLARE_STATIC_KEY_FALSE(bpf_stats_enabled_key);
 
 #define __BPF_PROG_RUN(prog, ctx, dfunc)	({			\
-	u32 ret;							\
+	u32 __ret;							\
 	cant_migrate();							\
 	if (static_branch_unlikely(&bpf_stats_enabled_key)) {		\
-		struct bpf_prog_stats *stats;				\
-		u64 start = sched_clock();				\
-		ret = dfunc(ctx, (prog)->insnsi, (prog)->bpf_func);	\
-		stats = this_cpu_ptr(prog->aux->stats);			\
-		u64_stats_update_begin(&stats->syncp);			\
-		stats->cnt++;						\
-		stats->nsecs += sched_clock() - start;			\
-		u64_stats_update_end(&stats->syncp);			\
+		struct bpf_prog_stats *__stats;				\
+		u64 __start = sched_clock();				\
+		__ret = dfunc(ctx, (prog)->insnsi, (prog)->bpf_func);	\
+		__stats = this_cpu_ptr(prog->aux->stats);		\
+		u64_stats_update_begin(&__stats->syncp);		\
+		__stats->cnt++;						\
+		__stats->nsecs += sched_clock() - __start;		\
+		u64_stats_update_end(&__stats->syncp);			\
 	} else {							\
-		ret = dfunc(ctx, (prog)->insnsi, (prog)->bpf_func);	\
+		__ret = dfunc(ctx, (prog)->insnsi, (prog)->bpf_func);	\
 	}								\
-	ret; })
+	__ret; })
 
 #define BPF_PROG_RUN(prog, ctx)						\
 	__BPF_PROG_RUN(prog, ctx, bpf_dispatcher_nop_func)
-- 
2.27.0

Re: [PATCH] bpf: fix -Wshadow warnings

[Andrii Nakryiko]

On Mon, Oct 26, 2020 at 12:37 PM Arnd Bergmann <arnd@kernel.org> wrote:
>
> From: Arnd Bergmann <arnd@arndb.de>
>
> There are thousands of warnings about one macro in a W=2 build:
>
> include/linux/filter.h:561:6: warning: declaration of 'ret' shadows a previous local [-Wshadow]
>
> Prefix all the locals in that macro with __ to avoid most of
> these warnings.
>
> Fixes: 492ecee892c2 ("bpf: enable program stats")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---

Acked-by: Andrii Nakryiko <andrii@kernel.org>

>  include/linux/filter.h | 22 +++++++++++-----------
>  1 file changed, 11 insertions(+), 11 deletions(-)
>
> diff --git a/include/linux/filter.h b/include/linux/filter.h
> index 954f279fde01..20ba04583eaa 100644
> --- a/include/linux/filter.h
> +++ b/include/linux/filter.h
> @@ -558,21 +558,21 @@ struct sk_filter {
>  DECLARE_STATIC_KEY_FALSE(bpf_stats_enabled_key);
>
>  #define __BPF_PROG_RUN(prog, ctx, dfunc)       ({                      \
> -       u32 ret;                                                        \
> +       u32 __ret;                                                      \
>         cant_migrate();                                                 \
>         if (static_branch_unlikely(&bpf_stats_enabled_key)) {           \
> -               struct bpf_prog_stats *stats;                           \
> -               u64 start = sched_clock();                              \
> -               ret = dfunc(ctx, (prog)->insnsi, (prog)->bpf_func);     \
> -               stats = this_cpu_ptr(prog->aux->stats);                 \
> -               u64_stats_update_begin(&stats->syncp);                  \
> -               stats->cnt++;                                           \
> -               stats->nsecs += sched_clock() - start;                  \
> -               u64_stats_update_end(&stats->syncp);                    \
> +               struct bpf_prog_stats *__stats;                         \
> +               u64 __start = sched_clock();                            \
> +               __ret = dfunc(ctx, (prog)->insnsi, (prog)->bpf_func);   \
> +               __stats = this_cpu_ptr(prog->aux->stats);               \
> +               u64_stats_update_begin(&__stats->syncp);                \
> +               __stats->cnt++;                                         \
> +               __stats->nsecs += sched_clock() - __start;              \
> +               u64_stats_update_end(&__stats->syncp);                  \
>         } else {                                                        \
> -               ret = dfunc(ctx, (prog)->insnsi, (prog)->bpf_func);     \
> +               __ret = dfunc(ctx, (prog)->insnsi, (prog)->bpf_func);   \
>         }                                                               \
> -       ret; })
> +       __ret; })
>
>  #define BPF_PROG_RUN(prog, ctx)                                                \
>         __BPF_PROG_RUN(prog, ctx, bpf_dispatcher_nop_func)
> --
> 2.27.0
>

Re: [PATCH] bpf: fix -Wshadow warnings

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to bpf/bpf.git (refs/heads/master):

On Mon, 26 Oct 2020 17:20:50 +0100 you wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> There are thousands of warnings about one macro in a W=2 build:
> 
> include/linux/filter.h:561:6: warning: declaration of 'ret' shadows a previous local [-Wshadow]
> 
> Prefix all the locals in that macro with __ to avoid most of
> these warnings.
> 
> [...]

Here is the summary with links:
  - bpf: fix -Wshadow warnings
    https://git.kernel.org/bpf/bpf/c/343a3e8bc635

You are awesome, thank you!
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