Mapping dirty helpers have, so far, been only used on X86, but
a port of vmwgfx to ARM64 exposed a problem which results
in a compilation error on ARM64 systems:
mm/mapping_dirty_helpers.c: In function ‘wp_clean_pud_entry’:
mm/mapping_dirty_helpers.c:172:32: error: implicit declaration of function
‘pud_dirty’; did you mean ‘pmd_dirty’? [-Werror=implicit-function-declaration]
This is due to the fact that mapping_dirty_helpers code assumes
that pud_dirty is always defined, which is not the case for
architectures that don't define CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD.
ARM64 arch is a little inconsistent when it comes to PUD
hugepage helpers, e.g. it defines pud_young but not pud_dirty
but regardless of that the core kernel code shouldn't assume
that any of the PUD hugepage helpers are available unless
CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD is defined. This
prevents compilation errors whenever one of the drivers
is ported to new architectures.
Signed-off-by: Zack Rusin <za...@vmware.com>
Cc: Andrew Morton <a...@linux-foundation.org>
Cc: Thomas Hellström (Intel) <thomas...@shipmail.org>
Cc: linux...@kvack.org
Cc: linux-kernel@vger.kernel.org
---
mm/mapping_dirty_helpers.c | 2 ++
1 file changed, 2 insertions(+)
diff --git a/mm/mapping_dirty_helpers.c b/mm/mapping_dirty_helpers.c
index b59054ef2e10..b890854ec761 100644
--- a/mm/mapping_dirty_helpers.c
+++ b/mm/mapping_dirty_helpers.c
@@ -165,10 +165,12 @@ static int wp_clean_pud_entry(pud_t *pud, unsigned long
addr, unsigned long end,
return 0;
}
+#ifdef CONFIG_HAVE_ARCH_TRANSPARENT_HUGEPAGE_PUD
/* Huge pud */
walk->action = ACTION_CONTINUE;
if (pud_trans_huge(pudval) || pud_devmap(pudval))
WARN_ON(pud_write(pudval) || pud_dirty(pudval));
+#endif
return 0;
}
--
2.27.0
