From: Alexei Starovoitov <ast@fb.com>
To: Daniel Borkmann <daniel@iogearbox.net>,
Andrii Nakryiko <andriin@fb.com>,
"bpf@vger.kernel.org" <bpf@vger.kernel.org>,
"netdev@vger.kernel.org" <netdev@vger.kernel.org>
Cc: "andrii.nakryiko@gmail.com" <andrii.nakryiko@gmail.com>,
Kernel Team <Kernel-team@fb.com>,
Johannes Weiner <hannes@cmpxchg.org>,
Rik van Riel <riel@surriel.com>
Subject: Re: [PATCH v4 bpf-next 2/4] bpf: add mmap() support for BPF_MAP_TYPE_ARRAY
Date: Sat, 16 Nov 2019 01:18:34 +0000 [thread overview]
Message-ID: <3eca5e22-f3ec-f05f-0776-4635b14c2a4e@fb.com> (raw)
In-Reply-To: <c79ca69f-84fd-bfc2-71fd-439bc3b94c81@iogearbox.net>
On 11/15/19 4:13 PM, Daniel Borkmann wrote:
>>> Yeah, only for fd array currently. Question is, if we ever reuse that
>>> map_release_uref
>>> callback in future for something else, will we remember that we earlier
>>> missed to add
>>> it here? :/
>>
>> What do you mean 'missed to add' ?
>
> Was saying missed to add the inc/put for the uref counter.
>
>> This is mmap path. Anything that needs releasing (like FDs for
>> prog_array or progs for sockmap) cannot be mmap-able.
>
> Right, I meant if in future we ever have another use case outside of it
> for some reason (unrelated to those maps you mention above). Can we
> guarantee this is never going to happen? Seemed less fragile at least to
> maintain proper count here.
I'm struggling to understand the concern.
map-in-map, xskmap, socket local storage are doing bpf_map_inc(, false)
when they need to hold the map. Why this case is any different?
next prev parent reply other threads:[~2019-11-16 1:18 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-15 4:02 [PATCH v4 bpf-next 0/4] Add support for memory-mapping BPF array maps Andrii Nakryiko
2019-11-15 4:02 ` [PATCH v4 bpf-next 1/4] bpf: switch bpf_map ref counter to 64bit so bpf_map_inc never fails Andrii Nakryiko
2019-11-15 21:47 ` Song Liu
2019-11-15 23:23 ` Daniel Borkmann
2019-11-15 23:27 ` Andrii Nakryiko
2019-11-15 4:02 ` [PATCH v4 bpf-next 2/4] bpf: add mmap() support for BPF_MAP_TYPE_ARRAY Andrii Nakryiko
2019-11-15 4:45 ` Alexei Starovoitov
2019-11-15 5:05 ` Andrii Nakryiko
2019-11-15 5:08 ` Alexei Starovoitov
2019-11-15 5:43 ` Andrii Nakryiko
2019-11-15 16:36 ` Andrii Nakryiko
2019-11-15 20:42 ` Jakub Kicinski
2019-11-15 13:57 ` Johannes Weiner
2019-11-15 23:31 ` Daniel Borkmann
2019-11-15 23:37 ` Alexei Starovoitov
2019-11-15 23:44 ` Daniel Borkmann
2019-11-15 23:47 ` Alexei Starovoitov
2019-11-16 0:13 ` Daniel Borkmann
2019-11-16 1:18 ` Alexei Starovoitov [this message]
2019-11-17 5:57 ` Andrii Nakryiko
2019-11-17 12:07 ` Daniel Borkmann
2019-11-17 17:17 ` Andrii Nakryiko
2019-11-18 13:50 ` Daniel Borkmann
2019-11-15 4:02 ` [PATCH v4 bpf-next 3/4] libbpf: make global data internal arrays mmap()-able, if possible Andrii Nakryiko
2019-11-15 4:02 ` [PATCH v4 bpf-next 4/4] selftests/bpf: add BPF_TYPE_MAP_ARRAY mmap() tests Andrii Nakryiko
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