Re: [PATCH v2] highmem: Make kunmap_{local,atomic}() take pointers to const void

From: Fabio M. De Francesco
Date: Wed Jun 15 2022 - 01:41:15 EST


On mercoledì 15 giugno 2022 07:12:56 CEST Fabio M. De Francesco wrote:
> kunmap_{local,atomic}() currently take pointers to void. However, this
> is semantically incorrect, since these functions do not change the memory
> their arguments point to.
>
> Therefore, make this semantics explicit by modifying the
> kunmap_{local,atomic}() prototypes to take pointers to const void.
>
> As side effects, compilers will likely produce more efficient code and
> they won't any longer need casts to pointers to void where these
> functions take arguments of type pointer to const void.
>
> Suggested-by: David Sterba <dsterba@xxxxxxx>
> Suggested-by: Ira Weiny <ira.weiny@xxxxxxxxx>
> Signed-off-by: Fabio M. De Francesco <fmdefrancesco@xxxxxxxxx>
> ---
>
> v1->v2: Change the commit message to clearly explain why these functions
> should require pointers to const void. The fundamental argument behind
> the commit message changes is semantic correctness. Other bonuses come as
> side effects. Obviously there are no changes to the code.
>
> Many thanks to David Sterba and Ira Weiny for suggestions and reviews.
>
> include/linux/highmem-internal.h | 10 +++++-----
> mm/highmem.c | 2 +-
> 2 files changed, 6 insertions(+), 6 deletions(-)
>
As said in another email, this is the second version of "[PATCH] highmem:
Make __kunmap_{local,atomic}() take "const void *"". You see that I changed
subject (involuntarily, that was just a mistake when formatting).

This is why I'm writing: make Maintainers find easily which patch this is
the second version of.

Sorry for that unwanted change to the subject.

Thanks,

Fabio