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From: Yonghong Song <yhs@fb.com>
To: Dave Marchevsky <davemarchevsky@fb.com>, bpf@vger.kernel.org
Cc: Alexei Starovoitov <ast@kernel.org>,
	Daniel Borkmann <daniel@iogearbox.net>,
	Andrii Nakryiko <andrii@kernel.org>,
	Kernel Team <kernel-team@fb.com>,
	Kumar Kartikeya Dwivedi <memxor@gmail.com>
Subject: Re: [PATCH v2 bpf-next 1/2] bpf: Allow ringbuf memory to be used as map key
Date: Wed, 14 Sep 2022 18:21:26 +0100	[thread overview]
Message-ID: <11249f5c-2179-27c2-6595-59afe88a8bf2@fb.com> (raw)
In-Reply-To: <20220914123600.927632-1-davemarchevsky@fb.com>



On 9/14/22 1:35 PM, Dave Marchevsky wrote:
> This patch adds support for the following pattern:
> 
>    struct some_data *data = bpf_ringbuf_reserve(&ringbuf, sizeof(struct some_data, 0));
>    if (!data)
>      return;
>    bpf_map_lookup_elem(&another_map, &data->some_field);
>    bpf_ringbuf_submit(data);
> 
> Currently the verifier does not consider bpf_ringbuf_reserve's
> PTR_TO_MEM | MEM_ALLOC ret type a valid key input to bpf_map_lookup_elem.
> Since PTR_TO_MEM is by definition a valid region of memory, it is safe
> to use it as a key for lookups.
> 
> Signed-off-by: Dave Marchevsky <davemarchevsky@fb.com>

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

      parent reply	other threads:[~2022-09-14 17:21 UTC|newest]

Thread overview: 9+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-09-14 12:35 [PATCH v2 bpf-next 1/2] bpf: Allow ringbuf memory to be used as map key Dave Marchevsky
2022-09-14 12:36 ` [PATCH v2 bpf-next 2/2] selftests/bpf: Add test verifying bpf_ringbuf_reserve retval use in map ops Dave Marchevsky
2022-09-15 10:24   ` Alexei Starovoitov
2022-09-19 22:53   ` Yonghong Song
2022-09-19 23:22     ` Kumar Kartikeya Dwivedi
2022-09-20  5:50       ` Yonghong Song
2022-09-22 14:27         ` Dave Marchevsky
2022-09-22 16:59           ` Yonghong Song
2022-09-14 17:21 ` Yonghong Song [this message]

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