On Wed, Feb 28, 2018 at 9:14 AM, Andrew Cooper
<andrew.coop...@citrix.com> wrote:
>
> The main purpose of this change is for the subsequent cleanup it enables, but
> it stands on its own merits.
>
> In principle, these hooks are optional, but the SCHED_OP() default aliases a
> memory allocation failure, which causes arinc653 to play the dangerous game of
> passing its priv pointer back, and remembering not to actually free it.
>
> Redefine alloc_domdata to use ERR_PTR() for errors, NULL for nothing, and
> non-NULL for a real allocation, which allows the hook to become properly
> optional. Redefine free_domdata to be idempotent.
>
> For arinc653, this means the dummy hooks can be dropped entirely. For the
> other schedulers, this means returning ERR_PTR(-ENOMEM) instead of NULL for
> memory allocation failures, and modifying the free hooks to cope with a NULL
> pointer. While making the alterations, drop some spurious casts to void *.
>
> Introduce and use proper wrappers for sched_{alloc,free}_domdata(). These are
> strictly better than SCHED_OP(), as the source code is visible to
> grep/cscope/tags, the generated code is better, and there can be proper
> per-hook defaults and checks.
>
> Callers of the alloc hooks are switched to using IS_ERR(), rather than
> checking for NULL.
>
> Signed-off-by: Andrew Cooper <andrew.coop...@citrix.com>
> ---
Acked-by: Meng Xu <men...@cis.upenn.edu>
Thanks,
Meng
-----------
Meng Xu
Ph.D. Candidate in Computer and Information Science
University of Pennsylvania
http://www.cis.upenn.edu/~mengxu/
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