[PATCH v13 10/14] mm/vmalloc: provide fallback arch huge vmap support functions

[Nicholas Piggin <npiggin@xxxxxxxxx>]

If an architecture doesn't support a particular page table level as
a huge vmap page size then allow it to skip defining the support
query function.

Suggested-by: Christoph Hellwig <hch@xxxxxx>
Signed-off-by: Nicholas Piggin <npiggin@xxxxxxxxx>
---
 arch/arm64/include/asm/vmalloc.h   |  7 +++----
 arch/powerpc/include/asm/vmalloc.h |  7 +++----
 arch/x86/include/asm/vmalloc.h     | 13 +++++--------
 include/linux/vmalloc.h            | 24 ++++++++++++++++++++----
 4 files changed, 31 insertions(+), 20 deletions(-)

diff --git a/arch/arm64/include/asm/vmalloc.h b/arch/arm64/include/asm/vmalloc.h
index fc9a12d6cc1a..7a22aeea9bb5 100644
--- a/arch/arm64/include/asm/vmalloc.h
+++ b/arch/arm64/include/asm/vmalloc.h
@@ -4,11 +4,8 @@
 #include <asm/page.h>
 
 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
-static inline bool arch_vmap_p4d_supported(pgprot_t prot)
-{
-	return false;
-}
 
+#define arch_vmap_pud_supported arch_vmap_pud_supported
 static inline bool arch_vmap_pud_supported(pgprot_t prot)
 {
 	/*
@@ -19,11 +16,13 @@ static inline bool arch_vmap_pud_supported(pgprot_t prot)
 	       !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS);
 }
 
+#define arch_vmap_pmd_supported arch_vmap_pmd_supported
 static inline bool arch_vmap_pmd_supported(pgprot_t prot)
 {
 	/* See arch_vmap_pud_supported() */
 	return !IS_ENABLED(CONFIG_PTDUMP_DEBUGFS);
 }
+
 #endif
 
 #endif /* _ASM_ARM64_VMALLOC_H */
diff --git a/arch/powerpc/include/asm/vmalloc.h b/arch/powerpc/include/asm/vmalloc.h
index 3f0c153befb0..4c69ece52a31 100644
--- a/arch/powerpc/include/asm/vmalloc.h
+++ b/arch/powerpc/include/asm/vmalloc.h
@@ -5,21 +5,20 @@
 #include <asm/page.h>
 
 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
-static inline bool arch_vmap_p4d_supported(pgprot_t prot)
-{
-	return false;
-}
 
+#define arch_vmap_pud_supported arch_vmap_pud_supported
 static inline bool arch_vmap_pud_supported(pgprot_t prot)
 {
 	/* HPT does not cope with large pages in the vmalloc area */
 	return radix_enabled();
 }
 
+#define arch_vmap_pmd_supported arch_vmap_pmd_supported
 static inline bool arch_vmap_pmd_supported(pgprot_t prot)
 {
 	return radix_enabled();
 }
+
 #endif
 
 #endif /* _ASM_POWERPC_VMALLOC_H */
diff --git a/arch/x86/include/asm/vmalloc.h b/arch/x86/include/asm/vmalloc.h
index e714b00fc0ca..49ce331f3ac6 100644
--- a/arch/x86/include/asm/vmalloc.h
+++ b/arch/x86/include/asm/vmalloc.h
@@ -6,24 +6,21 @@
 #include <asm/pgtable_areas.h>
 
 #ifdef CONFIG_HAVE_ARCH_HUGE_VMAP
-static inline bool arch_vmap_p4d_supported(pgprot_t prot)
-{
-	return false;
-}
 
+#ifdef CONFIG_X86_64
+#define arch_vmap_pud_supported arch_vmap_pud_supported
 static inline bool arch_vmap_pud_supported(pgprot_t prot)
 {
-#ifdef CONFIG_X86_64
 	return boot_cpu_has(X86_FEATURE_GBPAGES);
-#else
-	return false;
-#endif
 }
+#endif
 
+#define arch_vmap_pmd_supported arch_vmap_pmd_supported
 static inline bool arch_vmap_pmd_supported(pgprot_t prot)
 {
 	return boot_cpu_has(X86_FEATURE_PSE);
 }
+
 #endif
 
 #endif /* _ASM_X86_VMALLOC_H */
diff --git a/include/linux/vmalloc.h b/include/linux/vmalloc.h
index 4b897a4a408b..82b45e1f28ff 100644
--- a/include/linux/vmalloc.h
+++ b/include/linux/vmalloc.h
@@ -78,10 +78,26 @@ struct vmap_area {
 	};
 };
 
-#ifndef CONFIG_HAVE_ARCH_HUGE_VMAP
-static inline bool arch_vmap_p4d_supported(pgprot_t prot) { return false; }
-static inline bool arch_vmap_pud_supported(pgprot_t prot) { return false; }
-static inline bool arch_vmap_pmd_supported(pgprot_t prot) { return false; }
+/* archs that select HAVE_ARCH_HUGE_VMAP should override one or more of these */
+#ifndef arch_vmap_p4d_supported
+static inline bool arch_vmap_p4d_supported(pgprot_t prot)
+{
+	return false;
+}
+#endif
+
+#ifndef arch_vmap_pud_supported
+static inline bool arch_vmap_pud_supported(pgprot_t prot)
+{
+	return false;
+}
+#endif
+
+#ifndef arch_vmap_pmd_supported
+static inline bool arch_vmap_pmd_supported(pgprot_t prot)
+{
+	return false;
+}
 #endif
 
 /*
-- 
2.23.0