Re: [PATCH 06/10] staging/android: turn fence_info into a __64 pointer

From	Emil Velikov <emil.l.velikov@gmail.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 06/10] staging/android: turn fence_info into a __64 pointer
Date	2016-01-30 19:10 +0100
Message-ID	<qWI8a-7MQ-7@gated-at.bofh.it> (permalink)
References	<qWoM9-IK-3@gated-at.bofh.it> <qWoMb-IK-31@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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Hi Gustavo,

s/__64/__u64/ in the commit message.

On 29 January 2016 at 23:20, Gustavo Padovan <gustavo@padovan.org> wrote:
> From: Gustavo Padovan <gustavo.padovan@collabora.co.uk>
>
> Making fence_info a pointer enables us to extend the struct in the future
> without breaking the ABI.
>
> Signed-off-by: Gustavo Padovan <gustavo.padovan@collabora.co.uk>

> diff --git a/drivers/staging/android/uapi/sync.h b/drivers/staging/android/uapi/sync.h
> index ed281fc..9f07aa7 100644
> --- a/drivers/staging/android/uapi/sync.h
> +++ b/drivers/staging/android/uapi/sync.h
> @@ -54,7 +54,7 @@ struct sync_file_info {
>         char    name[32];
>         __s32   status;
>
> -       __u8    fence_info[0];
> +       __u64   *fence_info;
I believe you misinterpreted what was meant with "_u64 pointer". As
the storage use for of a pointer varies across 32/64 bit arch, we
explicitly use a variable type that is large enough (and consistent)
for both cases. Thus the above should be

+       __u64   fence_info;

Hope this clarifies things.

-Emil

Thread

[PATCH 00/10] android sync framework: clean up IOCTLs and ABI. Gustavo Padovan <gustavo@padovan.org> - 2016-01-29 22:30 +0100
  [PATCH 04/10] staging/android: remove driver_data from struct fence_info Gustavo Padovan <gustavo@padovan.org> - 2016-01-29 22:30 +0100
  [PATCH 05/10] staging/android: remove len field from struct fence_info Gustavo Padovan <gustavo@padovan.org> - 2016-01-29 22:30 +0100
  [PATCH 06/10] staging/android: turn fence_info into a __64 pointer Gustavo Padovan <gustavo@padovan.org> - 2016-01-29 22:30 +0100
    Re: [PATCH 06/10] staging/android: turn fence_info into a __64 pointer Emil Velikov <emil.l.velikov@gmail.com> - 2016-01-30 19:10 +0100
    Re: [PATCH 06/10] staging/android: turn fence_info into a __64  pointer Maarten Lankhorst <maarten.lankhorst@linux.intel.com> - 2016-02-01 09:50 +0100
      Re: [PATCH 06/10] staging/android: turn fence_info into a __64  pointer Gustavo Padovan <gustavo@padovan.org> - 2016-02-01 19:10 +0100
        Re: [PATCH 06/10] staging/android: turn fence_info into a __64  pointer Gustavo Padovan <gustavo@padovan.org> - 2016-02-02 14:10 +0100
  [PATCH 01/10] staging/android: remove SYNC_WAIT ioctl Gustavo Padovan <gustavo@padovan.org> - 2016-01-29 22:30 +0100
  [PATCH 08/10] staging/android: rename SYNC_IOC_FENCE_INFO Gustavo Padovan <gustavo@padovan.org> - 2016-01-29 22:30 +0100
  [PATCH 09/10] staging/android: add flags member to sync ioctl structs Gustavo Padovan <gustavo@padovan.org> - 2016-01-29 22:30 +0100
    Re: [PATCH 09/10] staging/android: add flags member to sync ioctl structs Emil Velikov <emil.l.velikov@gmail.com> - 2016-01-30 19:20 +0100
      Re: [PATCH 09/10] staging/android: add flags member to sync ioctl  structs Gustavo Padovan <gustavo@padovan.org> - 2016-02-01 14:30 +0100
    Re: [PATCH 09/10] staging/android: add flags member to sync ioctl  structs Maarten Lankhorst <maarten.lankhorst@linux.intel.com> - 2016-02-01 09:50 +0100

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