Re: [PATCHv2 3/4] staging: android: ion: Add an ioctl for ABI checking

From	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Newsgroups	linux.kernel
Subject	Re: [PATCHv2 3/4] staging: android: ion: Add an ioctl for ABI checking
Date	2016-09-02 08:20 +0200
Message-ID	<scPZv-4cw-3@gated-at.bofh.it> (permalink)
References	<scIY1-7U6-1@gated-at.bofh.it> <scIY1-7U6-5@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On Thu, Sep 01, 2016 at 03:40:43PM -0700, Laura Abbott wrote:
> 
> The current Ion ioctls lack a good way to tell what ioctls are
> available. Introduce an ioctl to give an ABI version. This way when the
> ABI inevitably gets screwed up userspace will have a way to tell what
> version of the screw up is available.

This worries me.  Why do we need this?  Shouldn't any "new" abi changes
just add on, and not change existing ioctl structure calls?  Or worst
case, you remove an ioctl and then userspace "knows" that when the call
fails.

And who is the major userspace user of this interface?  Who controls it?
How are we keeping things in sync here?

thanks,

greg k-h

Thread

[PATCHv2 0/4] New Ion ioctls Laura Abbott <labbott@redhat.com> - 2016-09-02 00:50 +0200
  [PATCHv2 4/4] staging: android: ion: Add ioctl to query available heaps Laura Abbott <labbott@redhat.com> - 2016-09-02 00:50 +0200
    Re: [PATCHv2 4/4] staging: android: ion: Add ioctl to query  available heaps Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-09-02 08:20 +0200
      Re: [PATCHv2 4/4] staging: android: ion: Add ioctl to query available  heaps Laura Abbott <labbott@redhat.com> - 2016-09-02 22:50 +0200
        Re: [PATCHv2 4/4] staging: android: ion: Add ioctl to query  available heaps Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-09-03 15:00 +0200
  [PATCHv2 1/4] staging: android: ion: Drop heap type masks Laura Abbott <labbott@redhat.com> - 2016-09-02 00:50 +0200
    Re: [PATCHv2 1/4] staging: android: ion: Drop heap type masks Brian Starkey <brian.starkey@arm.com> - 2016-09-02 15:50 +0200
      Re: [PATCHv2 1/4] staging: android: ion: Drop heap type masks Laura Abbott <labbott@redhat.com> - 2016-09-02 21:40 +0200
        Re: [PATCHv2 1/4] staging: android: ion: Drop heap type masks Brian Starkey <brian.starkey@arm.com> - 2016-09-05 13:30 +0200
          Re: [PATCHv2 1/4] staging: android: ion: Drop heap type masks Laura Abbott <labbott@redhat.com> - 2016-09-07 00:20 +0200
            Re: [PATCHv2 1/4] staging: android: ion: Drop heap type masks Brian Starkey <brian.starkey@arm.com> - 2016-09-07 11:00 +0200
  [PATCHv2 3/4] staging: android: ion: Add an ioctl for ABI checking Laura Abbott <labbott@redhat.com> - 2016-09-02 00:50 +0200
    Re: [PATCHv2 3/4] staging: android: ion: Add an ioctl for ABI  checking Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-09-02 08:20 +0200
      Re: [PATCHv2 3/4] staging: android: ion: Add an ioctl for ABI  checking Laura Abbott <labbott@redhat.com> - 2016-09-02 22:30 +0200
    Re: [Linaro-mm-sig] [PATCHv2 3/4] staging: android: ion: Add an ioctl for ABI checking Arnd Bergmann <arnd@arndb.de> - 2016-09-02 11:10 +0200
      Re: [Linaro-mm-sig] [PATCHv2 3/4] staging: android: ion: Add an ioctl  for ABI checking Laura Abbott <labbott@redhat.com> - 2016-09-02 22:40 +0200
        Re: [Linaro-mm-sig] [PATCHv2 3/4] staging: android: ion: Add an ioctl for ABI checking Arnd Bergmann <arnd@arndb.de> - 2016-09-02 23:40 +0200
          Re: [Linaro-mm-sig] [PATCHv2 3/4] staging: android: ion: Add an ioctl  for ABI checking Laura Abbott <labbott@redhat.com> - 2016-09-03 00:20 +0200
  [PATCHv2 2/4] staging: android: ion: Pull out ion ioctls to a separate file Laura Abbott <labbott@redhat.com> - 2016-09-02 00:50 +0200
    Re: [PATCHv2 2/4] staging: android: ion: Pull out ion ioctls to a  separate file Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-09-02 14:50 +0200
      Re: [PATCHv2 2/4] staging: android: ion: Pull out ion ioctls to a  separate file Laura Abbott <labbott@redhat.com> - 2016-09-02 22:00 +0200

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