The memory management (mm) subsystem is a fundamental low-level component
of the Linux kernel. Establishing const-correctness at this foundational
level enables higher-level subsystems, such as filesystems and drivers,
to also adopt const-correctness in their interfaces. This patch lays
the groundwork for broader const-correctness throughout the kernel
by starting with the core mm subsystem.
This patch adds const qualifiers to ptdesc and folio pointer parameters
in mm_types.h functions that do not modify the referenced memory,
improving type safety and enabling compiler optimizations.
Functions improved:
- ptdesc_pmd_pts_count()
- folio_get_private()
Signed-off-by: Max Kellermann <max.kellermann@xxxxxxxxx>
Reviewed-by: Vishal Moola (Oracle) <vishal.moola@xxxxxxxxx>
---
include/linux/mm_types.h | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
index d934a3a5b443..46e27ee14bcf 100644
--- a/include/linux/mm_types.h
+++ b/include/linux/mm_types.h
@@ -632,7 +632,7 @@ static inline void ptdesc_pmd_pts_dec(struct ptdesc *ptdesc)
atomic_dec(&ptdesc->pt_share_count);
}
-static inline int ptdesc_pmd_pts_count(struct ptdesc *ptdesc)
+static inline int ptdesc_pmd_pts_count(const struct ptdesc *const ptdesc)
{
return atomic_read(&ptdesc->pt_share_count);
}
@@ -660,7 +660,7 @@ static inline void set_page_private(struct page *page, unsigned long private)
page->private = private;
}
-static inline void *folio_get_private(struct folio *folio)
+static inline void *folio_get_private(const struct folio *const folio)
{
return folio->private;
}
--
2.47.2
