From: Andrew Morton <akpm@linux-foundation•org>
To: Stephen Rothwell <sfr@canb•auug.org.au>
Cc: Max Kellermann <max.kellermann@ionos•com>,
Linux Kernel Mailing List <linux-kernel@vger•kernel.org>,
Linux Next Mailing List <linux-next@vger•kernel.org>,
Lorenzo Stoakes <lorenzo.stoakes@oracle•com>,
David Hildenbrand <david@redhat•com>,
Vlastimil Babka <vbabka@suse•cz>, Mike Rapoport <rppt@kernel•org>,
Matthew Wilcox <willy@infradead•org>
Subject: Re: linux-next: build warning after merge of the mm-unstable tree
Date: Wed, 3 Sep 2025 19:59:47 -0700 [thread overview]
Message-ID: <20250903195947.97af912dc103f8a055e73537@linux-foundation.org> (raw)
In-Reply-To: <20250904121438.3d2daab2@canb.auug.org.au>
On Thu, 4 Sep 2025 12:14:38 +1000 Stephen Rothwell <sfr@canb•auug.org.au> wrote:
> After merging the mm-unstable tree, today's linux-next build (arm
> multi_v7_defconfig) produced this warning:
>
> In file included from include/linux/highmem.h:14,
> from include/linux/bvec.h:10,
> from include/linux/blk_types.h:10,
> from include/linux/writeback.h:13,
> from include/linux/memcontrol.h:23,
> from include/linux/swap.h:9,
> from include/linux/suspend.h:5,
> from arch/arm/mach-highbank/pm.c:9:
> include/linux/highmem-internal.h: In function 'kmap_local_folio':
> include/linux/highmem-internal.h:86:46: warning: passing argument 1 of 'folio_page' discards 'const' qualifier from pointer target type [-Wdiscarded-qualifiers]
> 86 | const struct page *page = folio_page(folio, offset / PAGE_SIZE);
> | ^~~~~
> In file included from include/linux/mmzone.h:23,
> from include/linux/swap.h:7:
> include/linux/page-flags.h:319:53: note: expected 'struct folio *' but argument is of type 'const struct folio *'
> 319 | static inline struct page *folio_page(struct folio *folio, unsigned long n)
Yeah, thanks, folio_page() is a problem. I'll do the below nasty for
now, but nasty.
--- a/include/linux/page-flags.h~mm-constify-highmem-related-functions-for-improved-const-correctness-fix
+++ a/include/linux/page-flags.h
@@ -316,9 +316,9 @@ static __always_inline unsigned long _co
* check that the page number lies within @folio; the caller is presumed
* to have a reference to the page.
*/
-static inline struct page *folio_page(struct folio *folio, unsigned long n)
+static inline struct page *folio_page(const struct folio *folio, unsigned long n)
{
- return &folio->page + n;
+ return (struct page *)(&folio->page + n);
}
static __always_inline int PageTail(const struct page *page)
_
next prev parent reply other threads:[~2025-09-04 2:59 UTC|newest]
Thread overview: 24+ messages / expand[flat|nested] mbox.gz Atom feed top
2025-09-04 2:14 linux-next: build warning after merge of the mm-unstable tree Stephen Rothwell
2025-09-04 2:59 ` Andrew Morton [this message]
2025-09-04 6:33 ` David Hildenbrand
-- strict thread matches above, loose matches on Subject: below --
2025-11-07 3:39 Stephen Rothwell
2025-11-07 6:51 ` Randy Dunlap
2025-10-20 2:49 Stephen Rothwell
2025-10-20 2:45 Stephen Rothwell
2025-10-20 3:41 ` Baoquan He
2025-10-20 4:19 ` Bagas Sanjaya
2025-09-12 4:12 Stephen Rothwell
2025-09-12 4:58 ` Balbir Singh
2025-07-15 8:55 Stephen Rothwell
2025-07-15 18:54 ` SeongJae Park
2025-07-10 7:54 Stephen Rothwell
2025-07-10 22:30 ` Andrew Morton
2025-07-10 22:49 ` Stephen Rothwell
2025-07-11 0:36 ` Randy Dunlap
2025-07-11 6:28 ` David Hildenbrand
2025-07-10 7:50 Stephen Rothwell
2025-07-11 9:57 ` David Hildenbrand
2025-06-10 4:33 Stephen Rothwell
2025-06-10 4:35 ` Christoph Hellwig
2025-05-09 9:43 Stephen Rothwell
2025-05-09 20:31 ` Andrew Morton
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