Excerpts from Christoph Hellwig's message of January 24, 2021 9:40 pm:

quoted

diff --git a/arch/arm64/include/asm/vmalloc.h b/arch/arm64/include/asm/vmalloc.h
index 2ca708ab9b20..597b40405319 100644
--- a/arch/arm64/include/asm/vmalloc.h
+++ b/arch/arm64/include/asm/vmalloc.h

@@ -1,4 +1,12 @@
 #ifndef _ASM_ARM64_VMALLOC_H
 #define _ASM_ARM64_VMALLOC_H
 
+#include <asm/page.h>
+
+#ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
+bool arch_vmap_p4d_supported(pgprot_t prot);
+bool arch_vmap_pud_supported(pgprot_t prot);
+bool arch_vmap_pmd_supported(pgprot_t prot);
+#endif

Shouldn't the be inlines or macros?  Also it would be useful
if the architectures would not have to override all functions
but just those that are it actually implements?

It gets better in the next patches. I did it this way again to avoid 
moving a lot of code at the same time as changing name / prototype
slightly.

I didn't see individual generic fallbacks being all that useful really 
at this scale. I don't mind keeping the explicit false.

Also lots of > 80 char lines in the patch.

Yeah there's a few, I can reduce those.

Thanks,
Nick