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Sender: Guenter Roeck <groeck7@gmail.com>
Date:   Sun, 29 Oct 2023 10:09:30 -0700
From:   Guenter Roeck <linux@roeck-us.net>
To:     Chuyi Zhou <zhouchuyi@bytedance.com>
Cc:     bpf@vger.kernel.org, ast@kernel.org, daniel@iogearbox.net,
        andrii@kernel.org, martin.lau@kernel.org, tj@kernel.org,
        linux-kernel@vger.kernel.org
Subject: Re: [RESEND PATCH bpf-next v6 2/8] bpf: Introduce css_task
 open-coded iterator kfuncs
Message-ID: <bf2add1f-a9e4-46ac-b1ac-5b6ad9f0ed86@roeck-us.net>
References: <20231018061746.111364-1-zhouchuyi@bytedance.com>
 <20231018061746.111364-3-zhouchuyi@bytedance.com>
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On Wed, Oct 18, 2023 at 02:17:40PM +0800, Chuyi Zhou wrote:
> This patch adds kfuncs bpf_iter_css_task_{new,next,destroy} which allow
> creation and manipulation of struct bpf_iter_css_task in open-coded
> iterator style. These kfuncs actually wrapps css_task_iter_{start,next,
> end}. BPF programs can use these kfuncs through bpf_for_each macro for
> iteration of all tasks under a css.
> 
> css_task_iter_*() would try to get the global spin-lock *css_set_lock*, so
> the bpf side has to be careful in where it allows to use this iter.
> Currently we only allow it in bpf_lsm and bpf iter-s.
> 
> Signed-off-by: Chuyi Zhou <zhouchuyi@bytedance.com>
> Acked-by: Tejun Heo <tj@kernel.org>

With this patch in linux-next:

Building m68k:defconfig ... failed
--------------
Error log:
kernel/bpf/task_iter.c: In function 'bpf_iter_css_task_new':
kernel/bpf/task_iter.c:917:14: error: 'CSS_TASK_ITER_PROCS' undeclared (first use in this function)
  917 |         case CSS_TASK_ITER_PROCS | CSS_TASK_ITER_THREADED:
      |              ^~~~~~~~~~~~~~~~~~~
kernel/bpf/task_iter.c:917:14: note: each undeclared identifier is reported only once for each function it appears in
kernel/bpf/task_iter.c:917:36: error: 'CSS_TASK_ITER_THREADED' undeclared (first use in this function)
  917 |         case CSS_TASK_ITER_PROCS | CSS_TASK_ITER_THREADED:

My apologies for the noise if this has already been reported and/or fixed.

Guenter