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From:   valdis.kletnieks@vt.edu
To:     Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>
cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: [PATCH] bpf/core.c - silence warning messages
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Date:   Sun, 27 Jan 2019 23:11:15 -0500
Message-ID: <31468.1548648675@turing-police.cc.vt.edu>
Sender: linux-kernel-owner@vger.kernel.org
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Compiling kernel/bpf/core.c with W=1 causes a flood of warnings:

kernel/bpf/core.c:1198:65: warning: initialized field overwritten [-Woverride-init]
 1198 | #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true
      |                                                                 ^~~~
kernel/bpf/core.c:1087:2: note: in expansion of macro 'BPF_INSN_3_TBL'
 1087 |  INSN_3(ALU, ADD,  X),   \
      |  ^~~~~~
kernel/bpf/core.c:1202:3: note: in expansion of macro 'BPF_INSN_MAP'
 1202 |   BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL),
      |   ^~~~~~~~~~~~
kernel/bpf/core.c:1198:65: note: (near initialization for 'public_insntable[12]')
 1198 | #define BPF_INSN_3_TBL(x, y, z) [BPF_##x | BPF_##y | BPF_##z] = true
      |                                                                 ^~~~
kernel/bpf/core.c:1087:2: note: in expansion of macro 'BPF_INSN_3_TBL'
 1087 |  INSN_3(ALU, ADD,  X),   \
      |  ^~~~~~
kernel/bpf/core.c:1202:3: note: in expansion of macro 'BPF_INSN_MAP'
 1202 |   BPF_INSN_MAP(BPF_INSN_2_TBL, BPF_INSN_3_TBL),
      |   ^~~~~~~~~~~~

98 copies of the above.

The attached patch silences the warnings, because we *know* we're overwriting
the default initializer. That leaves bpf/core.c with only 6 other warnings,
which become more visible in comparison.

Signed-off-by: Valdis Kletnieks <valdis.kletnieks@vt.edu>

diff --git a/kernel/bpf/Makefile b/kernel/bpf/Makefile
index 4c2fa3ac56f6..2606665f2cb5 100644
--- a/kernel/bpf/Makefile
+++ b/kernel/bpf/Makefile
@@ -21,3 +21,4 @@ obj-$(CONFIG_CGROUP_BPF) += cgroup.o
 ifeq ($(CONFIG_INET),y)
 obj-$(CONFIG_BPF_SYSCALL) += reuseport_array.o
 endif
+CFLAGS_core.o          += $(call cc-disable-warning, override-init)