+ m68k-avoid-wunused-but-set-parameter-in-clear_user_page.patch added to mm-hotfixes-unstable branch

+ m68k-avoid-wunused-but-set-parameter-in-clear_user_page.patch added to mm-hotfixes-unstable branch

[Andrew Morton]

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The patch titled
     Subject: m68k: avoid -Wunused-but-set-parameter in clear_user_page()
has been added to the -mm mm-hotfixes-unstable branch.  Its filename is
     m68k-avoid-wunused-but-set-parameter-in-clear_user_page.patch

This patch will shortly appear at
     https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/m68k-avoid-wunused-but-set-parameter-in-clear_user_page.patch

This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm

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------------------------------------------------------
From: =?utf-8?q?Thomas_Wei=C3=9Fschuh?= <linux@weissschuh.net>
Subject: m68k: avoid -Wunused-but-set-parameter in clear_user_page()
Date: Mon, 25 May 2026 10:33:52 +0200

The loop in clear_user_pages() iterates over all pages and calls
clear_user_page() for each of them.  During the loop "vaddr" is modified. 
However on m68k clear_user() is a macro which does not use "vaddr".  The
compiler sees a variable which is modified but never used and emits a
warning for that:

include/linux/highmem.h: In function 'clear_user_pages':
include/linux/highmem.h:234:63: warning: parameter 'vaddr' set but not used [-Wunused-but-set-parameter=]
    static inline void clear_user_pages(void *addr, unsigned long vaddr,

Other architectures use an inline function for clear_user_page() which
avoids the warning.  This is not possible on m68k, as dlush_dcache_page()
is another macro which is not yet defined where clear_user_page() is
defined.  Including cacheflush_mm.h will trigger recursive and lots of
other issues.

So hide the warning with a cast to (void) instead.

While we are here, do the same for copy_user_page().

Link: https://lore.kernel.org/20260525-m68k-clear_user_page-v2-1-0c8981c6eca1@weissschuh.net
Fixes: 62a9f5a85b98 ("mm: introduce clear_pages() and clear_user_pages()")
Signed-off-by: Thomas Weißschuh <linux@weissschuh.net>
Acked-by: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Andreas Schwab <schwab@linux-m68k.org>
Cc: Ankur Arora <ankur.a.arora@oracle.com>
Cc: David Hildenbrand <david@kernel.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---

 arch/m68k/include/asm/page_mm.h |    2 ++
 1 file changed, 2 insertions(+)

--- a/arch/m68k/include/asm/page_mm.h~m68k-avoid-wunused-but-set-parameter-in-clear_user_page
+++ a/arch/m68k/include/asm/page_mm.h
@@ -55,10 +55,12 @@ static inline void clear_page(void *page
 #define clear_user_page(addr, vaddr, page)	\
 	do {	clear_page(addr);		\
 		flush_dcache_page(page);	\
+		(void)(vaddr);			\
 	} while (0)
 #define copy_user_page(to, from, vaddr, page)	\
 	do {	copy_page(to, from);		\
 		flush_dcache_page(page);	\
+		(void)(vaddr);			\
 	} while (0)
 
 extern unsigned long m68k_memoffset;
_

Patches currently in -mm which might be from linux@weissschuh.net are

m68k-avoid-wunused-but-set-parameter-in-clear_user_page.patch