Re: + mm-functions-may-simplify-the-use-of-return-values.patch added to mm-unstable branch

[Peter Zijlstra <peterz@infradead.org>]

On Sat, May 07, 2022 at 10:50:26AM -0700, Andrew Morton wrote:
> 
> The patch titled
>      Subject: mm: functions may simplify the use of return values
> has been added to the -mm mm-unstable branch.  Its filename is
>      mm-functions-may-simplify-the-use-of-return-values.patch
> 
> This patch should soon appear in the mm-unstable branch at
>     git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
> 
> Before you just go and hit "reply", please:
>    a) Consider who else should be cc'ed
>    b) Prefer to cc a suitable mailing list as well
>    c) Ideally: find the original patch on the mailing list and do a
>       reply-to-all to that, adding suitable additional cc's
> 
> *** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
> 
> The -mm tree is included into linux-next via the mm-everything
> branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
> and is updated there every 2-3 working days
> 
> ------------------------------------------------------
> From: Li kunyu <kunyu@nfschina.com>
> Subject: mm: functions may simplify the use of return values
> 
> p4d_clear_huge may be optimized for void return type and function usage. 
> vunmap_p4d_range function saves a few steps here.
> 
> Link: https://lkml.kernel.org/r/20220507150630.90399-1-kunyu@nfschina.com
> Signed-off-by: Li kunyu <kunyu@nfschina.com>
> Cc: Dave Hansen <dave.hansen@linux.intel.com>
> Cc: Andy Lutomirski <luto@kernel.org>
> Cc: Peter Zijlstra <peterz@infradead.org>
> Cc: Thomas Gleixner <tglx@linutronix.de>
> Cc: Ingo Molnar <mingo@redhat.com>
> Cc: Borislav Petkov <bp@alien8.de>
> Cc: "H. Peter Anvin" <hpa@zytor.com>
> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

Please, no:

arch/x86/mm/pgtable.c: * p4d_clear_huge - clear kernel P4D mapping when it is set
arch/x86/mm/pgtable.c:int p4d_clear_huge(p4d_t *p4d)
arch/x86/mm/pgtable.c: * pud_clear_huge - clear kernel PUD mapping when it is set
arch/x86/mm/pgtable.c:int pud_clear_huge(pud_t *pud)
arch/x86/mm/pgtable.c: * pmd_clear_huge - clear kernel PMD mapping when it is set
arch/x86/mm/pgtable.c:int pmd_clear_huge(pmd_t *pmd)

why would the p4d one need to be different from the rest?