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From: Tejun Heo <tj@kernel.org>
To: David Ahern <dsahern@gmail.com>
Cc: Alexei Starovoitov <alexei.starovoitov@gmail.com>,
	netdev@vger.kernel.org, daniel@iogearbox.net, ast@kernel.org,
	davem@davemloft.net
Subject: Re: [PATCH v2 net-next 1/8] bpf: Add support for recursively running cgroup sock filters
Date: Thu, 31 Aug 2017 07:22:01 -0700	[thread overview]
Message-ID: <20170831142201.GB1599492@devbig577.frc2.facebook.com> (raw)
In-Reply-To: <bb4398e5-55a3-d63e-ac4d-3f9d7e2efc02@gmail.com>

Hello, David, Alexei.

Sorry about late reply.

On Sun, Aug 27, 2017 at 08:49:23AM -0600, David Ahern wrote:
> On 8/25/17 8:49 PM, Alexei Starovoitov wrote:
> > 
> >> +	if (prog && curr_recursive && !new_recursive)
> >> +		/* if a parent has recursive prog attached, only
> >> +		 * allow recursive programs in descendent cgroup
> >> +		 */
> >> +		return -EINVAL;
> >> +
> >>  	old_prog = cgrp->bpf.prog[type];
> > 
> > ... I'm struggling to completely understand how it interacts
> > with BPF_F_ALLOW_OVERRIDE.
> 
> The 2 flags are completely independent. The existing override logic is
> unchanged. If a program can not be overridden, then the new recursive
> flag is irrelevant.

I'm not sure all four combo of the two flags makes sense.  Can't we
have something simpler like the following?

1. None: No further bpf programs allowed in the subtree.

2. Overridable: If a sub-cgroup installs the same bpf program, this
   one yields to that one.

3. Recursive: If a sub-cgroup installs the same bpf program, that
   cgroup program gets run in addition to this one.

Note that we can have combinations of overridables and recursives -
both allow further programs in the sub-hierarchy and the only
distinction is whether that specific program behaves when that
happens.

Thanks.

-- 
tejun

  parent reply	other threads:[~2017-08-31 14:22 UTC|newest]

Thread overview: 28+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2017-08-25 19:05 [PATCH v2 net-next 0/8] bpf: Add option to set mark and priority in cgroup sock programs David Ahern
2017-08-25 19:05 ` [PATCH v2 net-next 1/8] bpf: Add support for recursively running cgroup sock filters David Ahern
2017-08-26  2:00   ` Daniel Borkmann
2017-08-27 14:22     ` David Ahern
2017-08-26  2:49   ` Alexei Starovoitov
2017-08-27 14:49     ` David Ahern
2017-08-28 23:56       ` Alexei Starovoitov
2017-08-29  0:43         ` David Ahern
2017-08-29  1:12           ` Alexei Starovoitov
2017-08-29  2:22             ` David Ahern
2017-08-29  4:11               ` Alexei Starovoitov
2017-08-30  1:03                 ` David Ahern
2017-08-30  2:58                   ` Alexei Starovoitov
2017-08-30  3:38                     ` David Ahern
2017-08-30  4:11                       ` Alexei Starovoitov
2017-08-31 14:22       ` Tejun Heo [this message]
2017-08-31 20:53         ` David Ahern
2017-09-01  3:27         ` Alexei Starovoitov
2017-09-01 14:11           ` Tejun Heo
2017-08-25 19:05 ` [PATCH v2 net-next 2/8] bpf: Add mark and priority to sock options that can be set David Ahern
2017-08-25 19:05 ` [PATCH v2 net-next 3/8] bpf: Allow cgroup sock filters to use get_current_uid_gid helper David Ahern
2017-08-26  2:30   ` Alexei Starovoitov
2017-08-25 19:05 ` [PATCH v2 net-next 4/8] samples/bpf: Update sock test to allow setting mark and priority David Ahern
2017-08-25 19:05 ` [PATCH v2 net-next 5/8] samples/bpf: Add detach option to test_cgrp2_sock David Ahern
2017-08-25 19:05 ` [PATCH v2 net-next 6/8] samples/bpf: Add option to dump socket settings David Ahern
2017-08-25 19:05 ` [PATCH v2 net-next 7/8] samples/bpf: Add test case for nested socket options David Ahern
2017-08-25 19:05 ` [PATCH v2 net-next 8/8] samples/bpf: Update cgroup socket examples to use uid gid helper David Ahern
2017-08-29 21:53 ` [PATCH v2 net-next 0/8] bpf: Add option to set mark and priority in cgroup sock programs David Miller

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