linux-kernel - Re: [PATCH v5 06/12] mm, s390: constify mapping related test functions for improved const-correctness

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite for Android: free password hash cracker in your pocket

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Message-ID: <CAKPOu+8SdvDAcNS12TjHWq_QL6pXnw4Pnhrq2_4DgJg8ASc67A@mail.gmail.com>
Date: Mon, 1 Sep 2025 17:22:45 +0200
From: Max Kellermann <max.kellermann@...os.com>
To: David Hildenbrand <david@...hat.com>
Cc: akpm@...ux-foundation.org, axelrasmussen@...gle.com, yuanchu@...gle.com, 
	willy@...radead.org, hughd@...gle.com, mhocko@...e.com, 
	linux-kernel@...r.kernel.org, linux-mm@...ck.org, lorenzo.stoakes@...cle.com, 
	Liam.Howlett@...cle.com, vbabka@...e.cz, rppt@...nel.org, surenb@...gle.com, 
	vishal.moola@...il.com, linux@...linux.org.uk, 
	James.Bottomley@...senpartnership.com, deller@....de, agordeev@...ux.ibm.com, 
	gerald.schaefer@...ux.ibm.com, hca@...ux.ibm.com, gor@...ux.ibm.com, 
	borntraeger@...ux.ibm.com, svens@...ux.ibm.com, davem@...emloft.net, 
	andreas@...sler.com, dave.hansen@...ux.intel.com, luto@...nel.org, 
	peterz@...radead.org, tglx@...utronix.de, mingo@...hat.com, bp@...en8.de, 
	x86@...nel.org, hpa@...or.com, chris@...kel.net, jcmvbkbc@...il.com, 
	viro@...iv.linux.org.uk, brauner@...nel.org, jack@...e.cz, weixugc@...gle.com, 
	baolin.wang@...ux.alibaba.com, rientjes@...gle.com, shakeel.butt@...ux.dev, 
	thuth@...hat.com, broonie@...nel.org, osalvador@...e.de, jfalempe@...hat.com, 
	mpe@...erman.id.au, nysal@...ux.ibm.com, linux-arm-kernel@...ts.infradead.org, 
	linux-parisc@...r.kernel.org, linux-s390@...r.kernel.org, 
	sparclinux@...r.kernel.org, linux-fsdevel@...r.kernel.org
Subject: Re: [PATCH v5 06/12] mm, s390: constify mapping related test
 functions for improved const-correctness

On Mon, Sep 1, 2025 at 5:11 PM David Hildenbrand <david@...hat.com> wrote:
> >> Should this also be *const ?
> >
> > No. These are function protoypes. A "const" on a parameter value
> > (pointer address, not pointed-to memory) makes no sense on a
> > prototype.
>
> But couldn't you argue the same about variable names? In most (not all
> :) ) we keep declaration + definition in sync. So thus my confusion.

Variable names in the prototypes have no effect either, but they serve
as useful documentation.

Whereas the "const" on a parameter value documents nothing - it's an
implementation detail whether the function would like to modify
parameter values. That implementation detail has no effect for the
caller.

Of course, we could have "const" in the prototype as well. This boils
down to personal taste. It's not my taste (has no use, has no effect,
documents nothing, only adds noise for no gain), so I didn't add it.
If you prefer to have that, I'll leave my taste and home and add it,
but only after you guys make up your minds about whether you want to
have const parameters at all.