The patch titled
Subject: mm: gup: pass a pointer to virt_to_page()
has been added to the -mm mm-unstable branch. Its filename is
mm-gup-pass-a-pointer-to-virt_to_page.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-gup-pass-a-pointer-to-virt_to_page.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Linus Walleij <linus.walleij@xxxxxxxxxx>
Subject: mm: gup: pass a pointer to virt_to_page()
Date: Thu, 30 Jun 2022 10:41:23 +0200
Functions that work on a pointer to virtual memory such as virt_to_pfn()
and users of that function such as virt_to_page() are supposed to pass a
pointer to virtual memory, ideally a (void *) or other pointer. However
since many architectures implement virt_to_pfn() as a macro, this function
becomes polymorphic and accepts both a (unsigned long) and a (void *).
If we instead implement a proper virt_to_pfn(void *addr) function the
following happens (occurred on arch/arm):
mm/gup.c: In function '__get_user_pages_locked':
mm/gup.c:1599:49: warning: passing argument 1 of 'virt_to_pfn'
makes pointer from integer without a cast [-Wint-conversion]
pages[i] = virt_to_page(start);
Fix this with an explicit cast.
Link: https://lkml.kernel.org/r/20220630084124.691207-5-linus.walleij@xxxxxxxxxx
Signed-off-by: Linus Walleij <linus.walleij@xxxxxxxxxx>
Reviewed-by: Jason Gunthorpe <jgg@xxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Cc: Marco Elver <elver@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/gup.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/mm/gup.c~mm-gup-pass-a-pointer-to-virt_to_page
+++ a/mm/gup.c
@@ -1705,7 +1705,7 @@ static long __get_user_pages_locked(stru
goto finish_or_fault;
if (pages) {
- pages[i] = virt_to_page(start);
+ pages[i] = virt_to_page((void *)start);
if (pages[i])
get_page(pages[i]);
}
_
Patches currently in -mm which might be from linus.walleij@xxxxxxxxxx are
lib-test_free_pagesc-pass-a-pointer-to-virt_to_page.patch
mm-highmem-pass-a-pointer-to-virt_to_page.patch
mm-kfence-pass-a-pointer-to-virt_to_page.patch
mm-gup-pass-a-pointer-to-virt_to_page.patch
mm-nommu-pass-a-pointer-to-virt_to_page.patch
