From: Max Kellermann <max.kellermann@ionos.com>
To: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: akpm@linux-foundation.org, david@redhat.com,
axelrasmussen@google.com, yuanchu@google.com,
willy@infradead.org, hughd@google.com, mhocko@suse.com,
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surenb@google.com, vishal.moola@gmail.com,
linux@armlinux.org.uk, James.Bottomley@hansenpartnership.com,
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mpe@ellerman.id.au, nysal@linux.ibm.com,
linux-arm-kernel@lists.infradead.org,
linux-parisc@vger.kernel.org, linux-s390@vger.kernel.org,
sparclinux@vger.kernel.org, linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v5 02/12] mm: constify pagemap related test functions for improved const-correctness
Date: Mon, 1 Sep 2025 16:50:50 +0200 [thread overview]
Message-ID: <CAKPOu+_aj3wA14VaZo8_k+ukw0OafsSz_Bxa120SQbYi4SqR7g@mail.gmail.com> (raw)
In-Reply-To: <26cb47bb-df98-4bda-a101-3c27298e4452@lucifer.local>
On Mon, Sep 1, 2025 at 4:25 PM Lorenzo Stoakes
<lorenzo.stoakes@oracle.com> wrote:
> 1. (most useful) Const pointer (const <type> *<param>) means that the dereffed
> value is const, so *<param> = <val> or <param>-><field> = <val> are prohibited.
Only this was what my initial patch was about.
> 2. (less useful) We can't modify the actual pointer value either, so
> e.g. <param> = <new param> is prohibited.
This wasn't my idea, it was Andrew Morton's idea, supported by Yuanchu Xie:
https://lore.kernel.org/lkml/CAJj2-QHVC0QW_4X95LLAnM=1g6apH==-OXZu65SVeBj0tSUcBg@mail.gmail.com/
You know that because you participated in the discussion. In that
thread, nobody objected, so I took the time and adjusted all of my
patches.
There is some value, but of course it's very small.
Note that I added the value-level "const" only to the implementation,
never to prototypes, because it would have no effect there.
next prev parent reply other threads:[~2025-09-01 14:51 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-01 12:30 [PATCH v5 00/12] mm: establish const-correctness for pointer parameters Max Kellermann
2025-09-01 12:30 ` [PATCH v5 01/12] mm: constify shmem related test functions for improved const-correctness Max Kellermann
2025-09-01 13:48 ` David Hildenbrand
2025-09-01 13:58 ` Lorenzo Stoakes
2025-09-01 12:30 ` [PATCH v5 02/12] mm: constify pagemap " Max Kellermann
2025-09-01 13:49 ` David Hildenbrand
2025-09-01 14:39 ` Max Kellermann
2025-09-01 14:09 ` Lorenzo Stoakes
2025-09-01 14:24 ` Lorenzo Stoakes
2025-09-01 14:50 ` Max Kellermann [this message]
2025-09-01 15:14 ` Lorenzo Stoakes
2025-09-01 15:47 ` Vlastimil Babka
2025-09-01 15:52 ` David Hildenbrand
2025-09-01 15:55 ` Lorenzo Stoakes
2025-09-01 12:30 ` [PATCH v5 03/12] mm: constify zone " Max Kellermann
2025-09-01 13:50 ` David Hildenbrand
2025-09-01 14:37 ` Lorenzo Stoakes
2025-09-01 12:30 ` [PATCH v5 04/12] fs: constify mapping " Max Kellermann
2025-09-01 13:50 ` David Hildenbrand
2025-09-01 13:51 ` David Hildenbrand
2025-09-01 14:40 ` Lorenzo Stoakes
2025-09-01 12:30 ` [PATCH v5 05/12] mm: constify process_shares_mm() " Max Kellermann
2025-09-01 14:46 ` Lorenzo Stoakes
2025-09-01 12:30 ` [PATCH v5 06/12] mm, s390: constify mapping related test functions " Max Kellermann
2025-09-01 13:54 ` David Hildenbrand
2025-09-01 14:47 ` Lorenzo Stoakes
2025-09-01 15:02 ` Max Kellermann
2025-09-01 15:11 ` David Hildenbrand
2025-09-01 15:22 ` Max Kellermann
2025-09-01 15:31 ` David Hildenbrand
2025-09-01 12:30 ` [PATCH v5 07/12] parisc: constify mmap_upper_limit() parameter " Max Kellermann
2025-09-01 13:55 ` David Hildenbrand
2025-09-01 14:48 ` Lorenzo Stoakes
2025-09-01 12:30 ` [PATCH v5 08/12] mm: constify arch_pick_mmap_layout() " Max Kellermann
2025-09-01 13:58 ` David Hildenbrand
2025-09-01 14:49 ` Lorenzo Stoakes
2025-09-01 15:06 ` Max Kellermann
2025-09-01 12:30 ` [PATCH v5 09/12] mm: constify ptdesc_pmd_pts_count() and folio_get_private() Max Kellermann
2025-09-01 13:58 ` David Hildenbrand
2025-09-01 14:50 ` Lorenzo Stoakes
2025-09-01 12:30 ` [PATCH v5 10/12] mm: constify various inline test functions for improved const-correctness Max Kellermann
2025-09-01 14:00 ` David Hildenbrand
2025-09-01 15:13 ` Max Kellermann
2025-09-01 12:30 ` [PATCH v5 11/12] mm: constify assert/test functions in mm.h Max Kellermann
2025-09-01 14:06 ` David Hildenbrand
2025-09-01 15:17 ` Max Kellermann
2025-09-01 15:25 ` David Hildenbrand
2025-09-01 12:30 ` [PATCH v5 12/12] mm: constify highmem related functions for improved const-correctness Max Kellermann
2025-09-01 14:51 ` Lorenzo Stoakes
2025-09-01 13:44 ` [PATCH v5 00/12] mm: establish const-correctness for pointer parameters Christian Brauner
2025-09-01 14:32 ` Lorenzo Stoakes
2025-09-02 2:50 ` Matthew Wilcox
2025-09-02 8:15 ` David Hildenbrand
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