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From: David Ahern <dsahern@gmail.com>
To: Jesper Dangaard Brouer <brouer@redhat.com>,
	Alexei Starovoitov <alexei.starovoitov@gmail.com>
Cc: bpf@vger.kernel.org, netdev@vger.kernel.org,
	Daniel Borkmann <borkmann@iogearbox.net>,
	Andrii Nakryiko <andrii.nakryiko@gmail.com>,
	Lorenzo Bianconi <lorenzo@kernel.org>,
	David Miller <davem@davemloft.net>
Subject: Re: [PATCH bpf-next V1] bpf: devmap dynamic map-value area based on BTF
Date: Thu, 4 Jun 2020 10:40:06 -0600	[thread overview]
Message-ID: <205b3716-e571-b38f-614f-86819d153c4e@gmail.com> (raw)
In-Reply-To: <20200604174806.29130b81@carbon>

On 6/4/20 9:48 AM, Jesper Dangaard Brouer wrote:
> I will NOT send a patch that expose this in uapi/bpf.h.  As I explained
> before, this caused the issues for my userspace application, that
> automatically picked-up struct bpf_devmap_val, and started to fail
> (with no code changes), because it needed minus-1 as input.  I fear
> that this will cause more work for me later, when I have to helpout and
> support end-users on e.g. xdp-newbies list, as it will not be obvious
> to end-users why their programs map-insert start to fail.  I have given
> up, so I will not NACK anyone sending such a patch.
> 
> Why is it we need to support file-descriptor zero as a valid
> file-descriptor for a bpf-prog?

That was a nice property of using the id instead of fd. And the init to
-1 is not unique to this; adopters of the bpf_set_link_xdp_fd_opts for
example have to do the same.

  reply	other threads:[~2020-06-04 16:40 UTC|newest]

Thread overview: 10+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-06-03 15:44 [PATCH bpf-next V1] bpf: devmap dynamic map-value area based on BTF Jesper Dangaard Brouer
2020-06-03 16:22 ` Alexei Starovoitov
2020-06-04 15:48   ` Jesper Dangaard Brouer
2020-06-04 16:40     ` David Ahern [this message]
2020-06-04 17:33       ` Alexei Starovoitov
2020-06-05  8:23         ` Jesper Dangaard Brouer
2020-06-05 11:01           ` Toke Høiland-Jørgensen
2020-06-05 17:01             ` Alexei Starovoitov
2020-06-05 16:58           ` Alexei Starovoitov
2020-06-09 12:19             ` Jesper Dangaard Brouer

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