This is a note to let you know that I've just added the patch titled
mm: Add PAGE_ALIGN_DOWN macro
to the 5.15-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
mm-add-page_align_down-macro.patch
and it can be found in the queue-5.15 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit edf5b793e14e480399c03adb14a7128f98590271
Author: David Gow <davidgow@xxxxxxxxxx>
Date: Fri Jul 1 17:16:19 2022 +0800
mm: Add PAGE_ALIGN_DOWN macro
[ Upstream commit 335e52c28cf9954d65b819cb68912fd32de3c844 ]
This is just the same as PAGE_ALIGN(), but rounds the address down, not
up.
Suggested-by: Dmitry Vyukov <dvyukov@xxxxxxxxxx>
Signed-off-by: David Gow <davidgow@xxxxxxxxxx>
Acked-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
Signed-off-by: Richard Weinberger <richard@xxxxxx>
Stable-dep-of: be35d91c8880 ("xen: tolerate ACPI NVS memory overlapping with Xen allocated memory")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/include/linux/mm.h b/include/linux/mm.h
index 5692055f202cb..f26b044024416 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -233,6 +233,9 @@ int __add_to_page_cache_locked(struct page *page, struct address_space *mapping,
/* to align the pointer to the (next) page boundary */
#define PAGE_ALIGN(addr) ALIGN(addr, PAGE_SIZE)
+/* to align the pointer to the (prev) page boundary */
+#define PAGE_ALIGN_DOWN(addr) ALIGN_DOWN(addr, PAGE_SIZE)
+
/* test whether an address (unsigned long or pointer) is aligned to PAGE_SIZE */
#define PAGE_ALIGNED(addr) IS_ALIGNED((unsigned long)(addr), PAGE_SIZE)
