The patch titled
Subject: mm/highmem: align-down to page the address for kunmap_flush_on_unmap()
has been added to the -mm mm-unstable branch. Its filename is
mm-highmem-align-down-to-page-the-address-for-kunmap_flush_on_unmap.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-highmem-align-down-to-page-the-address-for-kunmap_flush_on_unmap.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: "Fabio M. De Francesco" <fmdefrancesco@xxxxxxxxx>
Subject: mm/highmem: align-down to page the address for kunmap_flush_on_unmap()
Date: Thu, 26 Jan 2023 15:33:46 +0100
If ARCH_HAS_FLUSH_ON_KUNMAP is defined (PA-RISC case), __kunmap_local()
calls kunmap_flush_on_unmap(). The latter currently flushes the wrong
address (as confirmed by Matthew Wilcox and Helge Deller). Al Viro
proposed to call kunmap_flush_on_unmap() on an aligned-down to page
address in order to fix this issue. Consensus has been reached on this
solution.
Therefore, if ARCH_HAS_FLUSH_ON_KUNMAP is defined, call
kunmap_flush_on_unmap() on an aligned-down to page address computed with
the PTR_ALIGN_DOWN() macro.
Link: https://lkml.kernel.org/r/20230126143346.12086-1-fmdefrancesco@xxxxxxxxx
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@xxxxxxxxx>
Fixes: f3ba3c710ac5 ("mm/highmem: Provide kmap_local*")
Suggested-by: Al Viro <viro@xxxxxxxxxxxxxxxxxx>
Cc: Ira Weiny <ira.weiny@xxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Helge Deller <deller@xxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Alexander Potapenko <glider@xxxxxxxxxx>
Cc: Andrey Konovalov <andreyknvl@xxxxxxxxx>
Cc: Bagas Sanjaya <bagasdotme@xxxxxxxxx>
Cc: David Sterba <dsterba@xxxxxxxx>
Cc: "Fabio M. De Francesco" <fmdefrancesco@xxxxxxxxx>
Cc: Kees Cook <keescook@xxxxxxxxxxxx>
Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Tony Luck <tony.luck@xxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/highmem-internal.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/include/linux/highmem-internal.h~mm-highmem-align-down-to-page-the-address-for-kunmap_flush_on_unmap
+++ a/include/linux/highmem-internal.h
@@ -200,7 +200,7 @@ static inline void *kmap_local_pfn(unsig
static inline void __kunmap_local(const void *addr)
{
#ifdef ARCH_HAS_FLUSH_ON_KUNMAP
- kunmap_flush_on_unmap(addr);
+ kunmap_flush_on_unmap(PTR_ALIGN_DOWN(addr, PAGE_SIZE));
#endif
}
_
Patches currently in -mm which might be from fmdefrancesco@xxxxxxxxx are
mm-highmem-add-notes-about-conversions-from-kmap_atomic.patch
mm-highmem-add-notes-about-conversions-from-kmap_atomic-v3.patch
mm-highmem-align-down-to-page-the-address-for-kunmap_flush_on_unmap.patch
