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Date: Wed, 18 Feb 2026 20:11:00 +0200
From: Jarkko Sakkinen <jarkko@kernel.org>
To: Shuah Khan <shuah@kernel.org>
Cc: linux-kselftest@vger.kernel.org, linux-kernel@vger.kernel.org,
	bpf@vger.kernel.org
Subject: Question about redundant copies of json-writer.c
Message-ID: <aZYAtL4Nd3LG8wHb@kernel.org>
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Hi Shuah,

I'm working on a kernel patch set where I need to write JSON.

After looking around a bit, I found this C-module with multiple
redundant copies scattered around tools/:

❯ find -name json_writer.[ch]
./tools/testing/selftests/bpf/json_writer.h
./tools/testing/selftests/bpf/json_writer.c
./tools/bpf/bpftool/json_writer.h
./tools/bpf/bpftool/json_writer.c
./tools/net/ynl/ynltool/json_writer.h
./tools/net/ynl/ynltool/json_writer.c

My (arbitrary) guess is that one in bpftool is the main copy.

Ssince the module is self-contained, I'm dilating towards doing this:

$(OUTPUT)/kcontainerd: kcontainerd.c ../../../bpf/bpftool/json_writer.c \
                     ../../../bpf/bpftool/json_writer.h
       $(CC) $(CFLAGS) $< ../../../bpf/bpftool/json_writer.c -o $@

(and in kcontainerd.c #include "../../../bpf/bpftool/json_writer.h")

I'm just sanity checking this given that json_writer is utilized with
a different pattern :-)

BR, Jarkko