netdev - [PATCH RFC bpf-next 48/52] libbpf: compress Endianness ops with a macro

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Date:   Tue, 28 Jun 2022 21:48:08 +0200
From:   Alexander Lobakin <alexandr.lobakin@...el.com>
To:     Alexei Starovoitov <ast@...nel.org>,
        Daniel Borkmann <daniel@...earbox.net>,
        Andrii Nakryiko <andrii@...nel.org>
Cc:     Alexander Lobakin <alexandr.lobakin@...el.com>,
        Larysa Zaremba <larysa.zaremba@...el.com>,
        Michal Swiatkowski <michal.swiatkowski@...ux.intel.com>,
        Jesper Dangaard Brouer <hawk@...nel.org>,
        Björn Töpel <bjorn@...nel.org>,
        Magnus Karlsson <magnus.karlsson@...el.com>,
        Maciej Fijalkowski <maciej.fijalkowski@...el.com>,
        Jonathan Lemon <jonathan.lemon@...il.com>,
        Toke Hoiland-Jorgensen <toke@...hat.com>,
        Lorenzo Bianconi <lorenzo@...nel.org>,
        "David S. Miller" <davem@...emloft.net>,
        Eric Dumazet <edumazet@...gle.com>,
        Jakub Kicinski <kuba@...nel.org>,
        Paolo Abeni <pabeni@...hat.com>,
        Jesse Brandeburg <jesse.brandeburg@...el.com>,
        John Fastabend <john.fastabend@...il.com>,
        Yajun Deng <yajun.deng@...ux.dev>,
        Willem de Bruijn <willemb@...gle.com>, bpf@...r.kernel.org,
        netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
        xdp-hints@...-project.net
Subject: [PATCH RFC bpf-next 48/52] libbpf: compress Endianness ops with a macro

All of the Endianness helpers for BPF programs have the same
pattern and can be defined using a compression macro, which
will also protect against typos and copy-paste mistakes.
Not speaking of saving locs, of course.
Ahh, if we only could define macros inside other macros.

Signed-off-by: Alexander Lobakin <alexandr.lobakin@...el.com>
---
 tools/lib/bpf/bpf_endian.h | 26 +++++++++-----------------
 1 file changed, 9 insertions(+), 17 deletions(-)

diff --git a/tools/lib/bpf/bpf_endian.h b/tools/lib/bpf/bpf_endian.h
index ec9db4feca9f..b03db6aa3f14 100644
--- a/tools/lib/bpf/bpf_endian.h
+++ b/tools/lib/bpf/bpf_endian.h
@@ -77,23 +77,15 @@
 # error "Fix your compiler's __BYTE_ORDER__?!"
 #endif
 
-#define bpf_htons(x)				\
+#define __bpf_endop(op, x)			\
 	(__builtin_constant_p(x) ?		\
-	 __bpf_constant_htons(x) : __bpf_htons(x))
-#define bpf_ntohs(x)				\
-	(__builtin_constant_p(x) ?		\
-	 __bpf_constant_ntohs(x) : __bpf_ntohs(x))
-#define bpf_htonl(x)				\
-	(__builtin_constant_p(x) ?		\
-	 __bpf_constant_htonl(x) : __bpf_htonl(x))
-#define bpf_ntohl(x)				\
-	(__builtin_constant_p(x) ?		\
-	 __bpf_constant_ntohl(x) : __bpf_ntohl(x))
-#define bpf_cpu_to_be64(x)			\
-	(__builtin_constant_p(x) ?		\
-	 __bpf_constant_cpu_to_be64(x) : __bpf_cpu_to_be64(x))
-#define bpf_be64_to_cpu(x)			\
-	(__builtin_constant_p(x) ?		\
-	 __bpf_constant_be64_to_cpu(x) : __bpf_be64_to_cpu(x))
+	 __bpf_constant_##op(x) : __bpf_##op(x))
+
+#define bpf_htons(x)			__bpf_endop(htons, x)
+#define bpf_ntohs(x)			__bpf_endop(ntohs, x)
+#define bpf_htonl(x)			__bpf_endop(htonl, x)
+#define bpf_ntohl(x)			__bpf_endop(ntohl, x)
+#define bpf_cpu_to_be64(x)		__bpf_endop(cpu_to_be64, x)
+#define bpf_be64_to_cpu(x)		__bpf_endop(be64_to_cpu, x)
 
 #endif /* __BPF_ENDIAN__ */
-- 
2.36.1