diff mbox series

[2/3] mm: introduce clear_highpage_tagged

Message ID d6ba060f18999a00052180c2c10536226b50438a.1654011120.git.andreyknvl@google.com (mailing list archive)
State New
Headers show
Series [1/3] mm: rename kernel_init_free_pages to kernel_init_pages | expand

Commit Message

andrey.konovalov@linux.dev May 31, 2022, 3:43 p.m. UTC 
From: Andrey Konovalov <andreyknvl@google.com>

Add a clear_highpage_tagged() helper that does clear_highpage() on a
page potentially tagged by KASAN.

This helper is used by the following patch.

Signed-off-by: Andrey Konovalov <andreyknvl@google.com>
---
 include/linux/highmem.h | 11 +++++++++++
 mm/page_alloc.c         |  8 ++------
 2 files changed, 13 insertions(+), 6 deletions(-)

Comments

Andrew Morton May 31, 2022, 5:52 p.m. UTC | #1 
On Tue, 31 May 2022 17:43:49 +0200 andrey.konovalov@linux.dev wrote:

> From: Andrey Konovalov <andreyknvl@google.com>
> 
> Add a clear_highpage_tagged() helper that does clear_highpage() on a
> page potentially tagged by KASAN.

clear_highpage_kasan_tagged() would be a better name, no?

--- a/include/linux/highmem.h~mm-introduce-clear_highpage_tagged-fix
+++ a/include/linux/highmem.h
@@ -243,7 +243,7 @@ static inline void clear_highpage(struct
 	kunmap_local(kaddr);
 }
 
-static inline void clear_highpage_tagged(struct page *page)
+static inline void clear_highpage_kasan_tagged(struct page *page)
 {
 	u8 tag;
 
--- a/mm/page_alloc.c~mm-introduce-clear_highpage_tagged-fix
+++ a/mm/page_alloc.c
@@ -1311,7 +1311,7 @@ static void kernel_init_pages(struct pag
 	/* s390's use of memset() could override KASAN redzones. */
 	kasan_disable_current();
 	for (i = 0; i < numpages; i++)
-		clear_highpage_tagged(page + i);
+		clear_highpage_kasan_tagged(page + i);
 	kasan_enable_current();
 }
Andrey Konovalov May 31, 2022, 7:24 p.m. UTC | #2 
On Tue, May 31, 2022 at 7:52 PM Andrew Morton <akpm@linux-foundation.org> wrote:
>
> On Tue, 31 May 2022 17:43:49 +0200 andrey.konovalov@linux.dev wrote:
>
> > From: Andrey Konovalov <andreyknvl@google.com>
> >
> > Add a clear_highpage_tagged() helper that does clear_highpage() on a
> > page potentially tagged by KASAN.
>
> clear_highpage_kasan_tagged() would be a better name, no?

Sounds good! Will include into v2.

I also noticed there's an extra empty line at the end of the function
I need to fix.

>
> --- a/include/linux/highmem.h~mm-introduce-clear_highpage_tagged-fix
> +++ a/include/linux/highmem.h
> @@ -243,7 +243,7 @@ static inline void clear_highpage(struct
>         kunmap_local(kaddr);
>  }
>
> -static inline void clear_highpage_tagged(struct page *page)
> +static inline void clear_highpage_kasan_tagged(struct page *page)
>  {
>         u8 tag;
>
> --- a/mm/page_alloc.c~mm-introduce-clear_highpage_tagged-fix
> +++ a/mm/page_alloc.c
> @@ -1311,7 +1311,7 @@ static void kernel_init_pages(struct pag
>         /* s390's use of memset() could override KASAN redzones. */
>         kasan_disable_current();
>         for (i = 0; i < numpages; i++)
> -               clear_highpage_tagged(page + i);
> +               clear_highpage_kasan_tagged(page + i);
>         kasan_enable_current();
>  }
>
> _
>
diff mbox series

Patch

diff --git a/include/linux/highmem.h b/include/linux/highmem.h
index 3af34de54330..df76a0db7cec 100644
--- a/include/linux/highmem.h
+++ b/include/linux/highmem.h
@@ -243,6 +243,17 @@  static inline void clear_highpage(struct page *page)
 	kunmap_local(kaddr);
 }
 
+static inline void clear_highpage_tagged(struct page *page)
+{
+	u8 tag;
+
+	tag = page_kasan_tag(page);
+	page_kasan_tag_reset(page);
+	clear_highpage(page);
+	page_kasan_tag_set(page, tag);
+
+}
+
 #ifndef __HAVE_ARCH_TAG_CLEAR_HIGHPAGE
 
 static inline void tag_clear_highpage(struct page *page)
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 66ef8c310dce..d82ea983a7a3 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -1302,12 +1302,8 @@  static void kernel_init_pages(struct page *page, int numpages)
 
 	/* s390's use of memset() could override KASAN redzones. */
 	kasan_disable_current();
-	for (i = 0; i < numpages; i++) {
-		u8 tag = page_kasan_tag(page + i);
-		page_kasan_tag_reset(page + i);
-		clear_highpage(page + i);
-		page_kasan_tag_set(page + i, tag);
-	}
+	for (i = 0; i < numpages; i++)
+		clear_highpage_tagged(page + i);
 	kasan_enable_current();
 }