The patch titled
Subject: highmem: specify that kmap_local_page() is callable from interrupts
has been added to the -mm mm-unstable branch. Its filename is
highmem-specify-that-kmap_local_page-is-callable-from-interrupts.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/highmem-specify-that-kmap_local_page-is-callable-from-interrupts.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: "Fabio M. De Francesco" <fmdefrancesco@xxxxxxxxx>
Subject: highmem: specify that kmap_local_page() is callable from interrupts
Date: Thu, 28 Jul 2022 17:48:39 +0200
In a recent thread about converting kmap() to kmap_local_page(), the
safety of calling kmap_local_page() was questioned.[1]
"any context" should probably be enough detail for users who want to know
whether or not kmap_local_page() can be called from interrupts. However,
Linux still has kmap_atomic() which might make users think they must use
the latter in interrupts.
Add "including interrupts" for better clarity.
[1] https://lore.kernel.org/lkml/3187836.aeNJFYEL58@opensuse/
Link: https://lkml.kernel.org/r/20220728154844.10874-3-fmdefrancesco@xxxxxxxxx
Signed-off-by: Fabio M. De Francesco <fmdefrancesco@xxxxxxxxx>
Suggested-by: Ira Weiny <ira.weiny@xxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Mike Rapoport <rppt@xxxxxxxxxxxxx>
Cc: Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: Catalin Marinas <catalin.marinas@xxxxxxx>
Cc: Jonathan Corbet <corbet@xxxxxxx>
Cc: Peter Collingbourne <pcc@xxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Cc: Will Deacon <will@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/highmem.h | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
--- a/include/linux/highmem.h~highmem-specify-that-kmap_local_page-is-callable-from-interrupts
+++ a/include/linux/highmem.h
@@ -64,7 +64,7 @@ static inline void kmap_flush_unused(voi
*
* Returns: The virtual address of the mapping
*
- * Can be invoked from any context.
+ * Can be invoked from any context, including interrupts.
*
* Requires careful handling when nesting multiple mappings because the map
* management is stack based. The unmap has to be in the reverse order of
_
Patches currently in -mm which might be from fmdefrancesco@xxxxxxxxx are
highmem-remove-unneeded-spaces-in-kmap_local_page-kdocs.patch
highmem-specify-that-kmap_local_page-is-callable-from-interrupts.patch
documentation-mm-dont-kmap-pages-which-cant-come-from-highmem.patch
documentation-mm-avoid-invalid-use-of-addresses-from-kmap_local_page.patch
documentation-mm-prefer-kmap_local_page-and-avoid-kmap.patch
highmem-delete-a-sentence-from-kmap_local_page-kdocs.patch
documentation-mm-add-details-about-kmap_local_page-and-preemption.patch
