netdev - Re: [PATCH 1/2] bpf: do not use KMALLOC_SHIFT

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Message-ID: <58547B6C.6000905@iogearbox.net>
Date:   Sat, 17 Dec 2016 00:40:28 +0100
From:   Daniel Borkmann <daniel@...earbox.net>
To:     Alexei Starovoitov <alexei.starovoitov@...il.com>,
        Michal Hocko <mhocko@...nel.org>
CC:     linux-mm@...ck.org, Cristopher Lameter <cl@...ux.com>,
        Andrew Morton <akpm@...ux-foundation.org>,
        Alexei Starovoitov <ast@...nel.org>, netdev@...r.kernel.org
Subject: Re: [PATCH 1/2] bpf: do not use KMALLOC_SHIFT_MAX

On 12/17/2016 12:23 AM, Alexei Starovoitov wrote:
> On Fri, Dec 16, 2016 at 11:02:35PM +0100, Michal Hocko wrote:
>> On Fri 16-12-16 10:02:10, Alexei Starovoitov wrote:
>>> On Thu, Dec 15, 2016 at 05:47:21PM +0100, Michal Hocko wrote:
>>>> From: Michal Hocko <mhocko@...e.com>
>>>>
>>>> 01b3f52157ff ("bpf: fix allocation warnings in bpf maps and integer
>>>> overflow") has added checks for the maximum allocateable size. It
>>>> (ab)used KMALLOC_SHIFT_MAX for that purpose. While this is not incorrect
>>>> it is not very clean because we already have KMALLOC_MAX_SIZE for this
>>>> very reason so let's change both checks to use KMALLOC_MAX_SIZE instead.
>>>>
>>>> Cc: Alexei Starovoitov <ast@...nel.org>
>>>> Signed-off-by: Michal Hocko <mhocko@...e.com>
>>>
>>> Nack until the patches 1 and 2 are reversed.
>>
>> I do not insist on ordering. The thing is that it shouldn't matter all
>> that much. Or are you worried about bisectability?
>
> This patch 1 strongly depends on patch 2 !
> Therefore order matters.
> The patch 1 by itself is broken.
> The commit log is saying
> '(ab)used KMALLOC_SHIFT_MAX for that purpose .. use KMALLOC_MAX_SIZE instead'
> that is also incorrect. We cannot do that until KMALLOC_MAX_SIZE is fixed.
> So please change the order and fix the commit log to say that KMALLOC_MAX_SIZE
> is actually valid limit now.

Michal, please also Cc netdev on your v2. Looks like the set
originally didn't Cc it (at least I didn't see 2/2). Thanks.