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Subject: Re: [PATCH bpf-next v3 05/14] bpf: Rename BPF_XADD and prepare to
 encode other atomics in .imm
To:     Brendan Jackman <jackmanb@google.com>, <bpf@vger.kernel.org>
CC:     Alexei Starovoitov <ast@kernel.org>,
        Daniel Borkmann <daniel@iogearbox.net>,
        KP Singh <kpsingh@chromium.org>,
        Florent Revest <revest@chromium.org>,
        <linux-kernel@vger.kernel.org>, Jann Horn <jannh@google.com>
References: <20201203160245.1014867-1-jackmanb@google.com>
 <20201203160245.1014867-6-jackmanb@google.com>
From:   Yonghong Song <yhs@fb.com>
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On 12/3/20 8:02 AM, Brendan Jackman wrote:
> A subsequent patch will add additional atomic operations. These new
> operations will use the same opcode field as the existing XADD, with
> the immediate discriminating different operations.
> 
> In preparation, rename the instruction mode BPF_ATOMIC and start
> calling the zero immediate BPF_ADD.
> 
> This is possible (doesn't break existing valid BPF progs) because the
> immediate field is currently reserved MBZ and BPF_ADD is zero.
> 
> All uses are removed from the tree but the BPF_XADD definition is
> kept around to avoid breaking builds for people including kernel
> headers.
> 
> Signed-off-by: Brendan Jackman <jackmanb@google.com>

Acked-by: Yonghong Song <yhs@fb.com>

> Change-Id: Ib78f54acba37f7196cbf6c35ffa1c40805cb0d87

As pointed by Andrii earlier, this 'Change-Id' is weird. I didn't
see it in other submitted patches.