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From: Linus Walleij <linus.walleij@linaro.org>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org, Linus Walleij <linus.walleij@linaro.org>
Subject: [PATCH 5/5] mm: nommu: Pass a pointer to virt_to_page()
Date: Thu, 30 Jun 2022 10:41:24 +0200	[thread overview]
Message-ID: <20220630084124.691207-6-linus.walleij@linaro.org> (raw)
In-Reply-To: <20220630084124.691207-1-linus.walleij@linaro.org>

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/nommu.c: In function 'free_page_series':
  mm/nommu.c:501:50: warning: passing argument 1 of 'virt_to_pfn'
  makes pointer from integer without a cast [-Wint-conversion]
  struct page *page = virt_to_page(from);

Fix this with an explicit cast.

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-mm@kvack.org
Signed-off-by: Linus Walleij <linus.walleij@linaro.org>
---
 mm/nommu.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/mm/nommu.c b/mm/nommu.c
index 9d7afc2d959e..e819cbc21b39 100644
--- a/mm/nommu.c
+++ b/mm/nommu.c
@@ -500,7 +500,7 @@ static void delete_nommu_region(struct vm_region *region)
 static void free_page_series(unsigned long from, unsigned long to)
 {
 	for (; from < to; from += PAGE_SIZE) {
-		struct page *page = virt_to_page(from);
+		struct page *page = virt_to_page((void *)from);
 
 		atomic_long_dec(&mmap_pages_allocated);
 		put_page(page);
-- 
2.36.1



  parent reply	other threads:[~2022-06-30  8:43 UTC|newest]

Thread overview: 11+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-06-30  8:41 [PATCH 0/5] mm: Pass pointers to page accessors Linus Walleij
2022-06-30  8:41 ` [PATCH 1/5] lib/test_free_pages.c: Pass a pointer to virt_to_page() Linus Walleij
2022-06-30  8:41 ` [PATCH 2/5] mm/highmem: " Linus Walleij
2022-06-30  8:41 ` [PATCH 3/5] mm: kfence: " Linus Walleij
2022-06-30  9:23   ` Marco Elver
2022-06-30  8:41 ` [PATCH 4/5] mm: gup: " Linus Walleij
2022-07-01  0:29   ` Jason Gunthorpe
2022-07-01  9:11     ` Linus Walleij
2022-06-30  8:41 ` Linus Walleij [this message]
2022-07-01 23:00 ` [PATCH 0/5] mm: Pass pointers to page accessors Andrew Morton
2022-07-03 13:28   ` Linus Walleij

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