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From: Linus Torvalds <torvalds@linux-foundation.org>
Date: Tue, 14 May 2024 21:06:06 -0700
Message-ID: <CAHk-=wj2ZJ_YE2CWJ6TXNQoOm+Q6H5LpQNLWmfft+SO21PW5Bg@mail.gmail.com>
Subject: Re: [GIT PULL] Networking for v6.10
To: Jakub Kicinski <kuba@kernel.org>
Cc: davem@davemloft.net, netdev@vger.kernel.org, linux-kernel@vger.kernel.org, 
	pabeni@redhat.com, bpf@vger.kernel.org
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On Tue, 14 May 2024 at 20:32, Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> Why does it do that disgusting
>
>         struct bpf_array *array = container_of(map, struct bpf_array, map);
>         ...
>                 *insn++ = BPF_ALU32_IMM(BPF_AND, BPF_REG_0, array->index_mask);
>
> thing? As far as I can tell, a bpf map can be embedded in many
> different structures, not just that 'bpf_array' thing.

Bah. It still needs to do that array->elem_size, so it's not just the
spectre-v1 code that needs that 'bpf_array' thing.

And the non-percpu case seems to do all the same contortions, so I
don't know why the new percpu array would show issues.

Oh well. I guess the bpf people will figure it out once they come back
from "partying at LSFMM" as you put it.

           Linus