From 6c66b0e7c91a1320c1b85ad8150bdd534eb4ddae Mon Sep 17 00:00:00 2001 From: Dave Marchevsky Date: Fri, 17 Sep 2021 11:29:07 -0700 Subject: [PATCH] libbpf: Use static const fmt string in __bpf_printk The __bpf_printk convenience macro was using a 'char' fmt string holder as it predates support for globals in libbpf. Move to more efficient 'static const char', but provide a fallback to the old way via BPF_NO_GLOBAL_DATA so users on old kernels can still use the macro. Signed-off-by: Dave Marchevsky Signed-off-by: Alexei Starovoitov Acked-by: Andrii Nakryiko Link: https://lore.kernel.org/bpf/20210917182911.2426606-6-davemarchevsky@fb.com --- tools/lib/bpf/bpf_helpers.h | 8 +++++++- 1 file changed, 7 insertions(+), 1 deletion(-) diff --git a/tools/lib/bpf/bpf_helpers.h b/tools/lib/bpf/bpf_helpers.h index 55a308796625..963b1060d944 100644 --- a/tools/lib/bpf/bpf_helpers.h +++ b/tools/lib/bpf/bpf_helpers.h @@ -216,9 +216,15 @@ enum libbpf_tristate { ___param, sizeof(___param)); \ }) +#ifdef BPF_NO_GLOBAL_DATA +#define BPF_PRINTK_FMT_MOD +#else +#define BPF_PRINTK_FMT_MOD static const +#endif + #define __bpf_printk(fmt, ...) \ ({ \ - char ____fmt[] = fmt; \ + BPF_PRINTK_FMT_MOD char ____fmt[] = fmt; \ bpf_trace_printk(____fmt, sizeof(____fmt), \ ##__VA_ARGS__); \ }) -- 2.34.1