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From: Xiaoming Ni <nixiaoming@huawei.com>
To: Peter Xu <peterx@redhat.com>
Cc: <aarcange@redhat.com>, <akpm@linux-foundation.org>,
	<cracauer@cons.org>, <dplotnikov@virtuozzo.com>,
	<gokhale2@llnl.gov>, <hannes@cmpxchg.org>, <hughd@google.com>,
	<jglisse@redhat.com>, <kirill@shutemov.name>,
	<linux-kernel@vger.kernel.org>, <linux-mm@kvack.org>,
	<maxime.coquelin@redhat.com>, <mcfadden8@llnl.gov>,
	<mcgrof@kernel.org>, <mgorman@suse.de>, <mike.kravetz@oracle.com>,
	<pbonzini@redhat.com>, <rppt@linux.vnet.ibm.com>,
	<xemul@virtuozzo.com>, <keescook@chromium.org>
Subject: Re: [PATCH v2 1/1] userfaultfd/sysctl: add vm.unprivileged_userfaultfd
Date: Thu, 28 May 2020 16:50:49 +0800	[thread overview]
Message-ID: <a5aa7dfd-b4a9-0ab2-9392-d7889897382f@huawei.com> (raw)
In-Reply-To: <20200527142143.GC1194141@xz-x1>

On 2020/5/27 22:21, Peter Xu wrote:
> On Wed, May 27, 2020 at 02:54:13PM +0800, Xiaoming Ni wrote:
>>
>> On Tue, Mar 19, 2019 at 11:07:22AM +0800, Peter Xu wrote:
>>> Add a global sysctl knob "vm.unprivileged_userfaultfd" to control
>>> whether userfaultfd is allowed by unprivileged users.  When this is
>>> set to zero, only privileged users (root user, or users with the
>>> CAP_SYS_PTRACE capability) will be able to use the userfaultfd
>>> syscalls.
>>
>> Hello
> 
> Hi, Xiaoming,
> 
>> I am a bit confused about this patch, can you help to answer it.
>>
>> Why the sysctl interface of fs/userfaultfd.c belongs to vm_table instead of
>> fs_table ?
>>
>> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=cefdca0a86be517bc390fc4541e3674b8e7803b0
> 
> Because I think it makes more sense to put the new key into where it suites
> better, irrelevant to which directory the variable is declared.  To me,
> unprivileged_userfaultfd is definitely more suitable for vm rather than fs,
> because userfaultfd is really about memory management rather than file system.
> 
> Thanks,
> 

Thank you for your answer
Since userfaultfd and vm are more closely related, will there be 
consideration to move fs/userfaultfd.c to the mm directory in the future?

Thanks
Xiaoming Ni


  reply	other threads:[~2020-05-28  8:50 UTC|newest]

Thread overview: 25+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-05-27  6:54 [PATCH v2 1/1] userfaultfd/sysctl: add vm.unprivileged_userfaultfd Xiaoming Ni
2020-05-27 14:21 ` Peter Xu
2020-05-28  8:50   ` Xiaoming Ni [this message]
2020-05-28 12:49     ` Peter Xu
  -- strict thread matches above, loose matches on Subject: below --
2019-03-19  3:07 [PATCH v2 0/1] userfaultfd: allow to forbid unprivileged users Peter Xu
2019-03-19  3:07 ` [PATCH v2 1/1] userfaultfd/sysctl: add vm.unprivileged_userfaultfd Peter Xu
2019-03-19  3:07   ` Peter Xu
2019-03-19  7:11   ` Mike Rapoport
2019-03-19  7:11     ` Mike Rapoport
2019-03-19 18:07     ` Andrea Arcangeli
2019-03-19 18:07       ` Andrea Arcangeli
2019-03-19 18:02   ` Andrew Morton
2019-03-19 18:02     ` Andrew Morton
2019-03-19 18:28     ` Dr. David Alan Gilbert
2019-03-19 18:28       ` Dr. David Alan Gilbert
2019-03-20  0:20       ` Peter Xu
2019-03-20  0:20         ` Peter Xu
2019-03-20 19:01       ` Andrea Arcangeli
2019-03-20 19:01         ` Andrea Arcangeli
2019-03-21 13:43         ` Luis Chamberlain
2019-03-21 13:43           ` Luis Chamberlain
2019-03-21 21:06           ` Andrea Arcangeli
2019-03-21 21:06             ` Andrea Arcangeli
2019-04-23 22:19     ` Kees Cook
2019-04-23 22:19       ` Kees Cook
2019-04-23 22:19       ` Kees Cook

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