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Subject: Re: [PATCH v2 0/5] pid: add pidfd_open()
To:     Linus Torvalds <torvalds@linux-foundation.org>
CC:     Jann Horn <jannh@google.com>, Andrew Lutomirski <luto@kernel.org>,
        David Howells <dhowells@redhat.com>, serge@hallyn.com,
        Linux API <linux-api@vger.kernel.org>,
        Linux List Kernel Mailing <linux-kernel@vger.kernel.org>,
        Arnd Bergmann <arnd@arndb.de>,
        "Eric W. Biederman" <ebiederm@xmission.com>,
        Konstantin Khlebnikov <khlebnikov@yandex-team.ru>,
        Kees Cook <keescook@chromium.org>,
        Alexey Dobriyan <adobriyan@gmail.com>,
        Thomas Gleixner <tglx@linutronix.de>,
        Michael Kerrisk-manpages <mtk.manpages@gmail.com>,
        bl0pbl33p@gmail.com, "Dmitry V. Levin" <ldv@altlinux.org>,
        Andrew Morton <akpm@linux-foundation.org>,
        Oleg Nesterov <oleg@redhat.com>,
        nagarathnam.muthusamy@oracle.com, Aleksa Sarai <cyphar@cyphar.com>,
        Al Viro <viro@zeniv.linux.org.uk>,
        Joel Fernandes <joel@joelfernandes.org>, dancol@google.com
From:   Christian Brauner <christian@brauner.io>
Message-ID: <BCD99947-5F55-4116-8F74-D6832E50340B@brauner.io>
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On March 30, 2019 5:09:10 PM GMT+01:00, Linus Torvalds <torvalds@linux-foun=
dation=2Eorg> wrote:
>On Fri, Mar 29, 2019 at 8:54 AM Christian Brauner
><christian@brauner=2Eio> wrote:
>>
>> /* Introduction */
>> This adds the pidfd_open() syscall=2E
>> pidfd_open() allows to retrieve file descriptors for a given pid=2E
>This
>> includes both file descriptors for processes and file descriptors for
>> threads=2E
>
>I'm ok with the pidfd_open() call to just get a pidfd, but that

From=20pure API perspective that's all I care about: independence of procfs=
=2E
Once we have pidfd_open() we can cleanly signal threads etc=2E

>"pidfd_to_profs()" needs to go away=2E
>
>If you want to open the /proc/<pid>/status file, then just do that=2E
>This whole "do one and convert to the other" needs to die=2E No, no, no=
=2E
>
>                   Linus