linux-kernel - [PATCH] x86: Define only {pud/pmd}_{set/clear}

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Date:   Thu, 13 May 2021 18:27:33 +0000 (UTC)
From:   Christophe Leroy <christophe.leroy@...roup.eu>
To:     Andrew Morton <akpm@...ux-foundation.org>,
        Nicholas Piggin <npiggin@...il.com>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        Mike Rapoport <rppt@...nel.org>, rdunlap@...radead.org
Cc:     linux-arch@...r.kernel.org, linuxppc-dev@...ts.ozlabs.org,
        linux-kernel@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
        sparclinux@...r.kernel.org, linux-mm@...ck.org
Subject: [PATCH] x86: Define only {pud/pmd}_{set/clear}_huge when usefull

When PUD and/or PMD are folded, those functions are useless
and we have a stub in linux/pgtable.h

Reported-by: Randy Dunlap <rdunlap@...radead.org>
Signed-off-by: Christophe Leroy <christophe.leroy@...roup.eu>
---
 arch/x86/mm/pgtable.c | 34 +++++++++++++++++++---------------
 1 file changed, 19 insertions(+), 15 deletions(-)

diff --git a/arch/x86/mm/pgtable.c b/arch/x86/mm/pgtable.c
index d27cf69e811d..1303ff6ef7be 100644
--- a/arch/x86/mm/pgtable.c
+++ b/arch/x86/mm/pgtable.c
@@ -682,6 +682,7 @@ int p4d_clear_huge(p4d_t *p4d)
 }
 #endif
 
+#if CONFIG_PGTABLE_LEVELS > 3
 /**
  * pud_set_huge - setup kernel PUD mapping
  *
@@ -720,6 +721,23 @@ int pud_set_huge(pud_t *pud, phys_addr_t addr, pgprot_t prot)
 	return 1;
 }
 
+/**
+ * pud_clear_huge - clear kernel PUD mapping when it is set
+ *
+ * Returns 1 on success and 0 on failure (no PUD map is found).
+ */
+int pud_clear_huge(pud_t *pud)
+{
+	if (pud_large(*pud)) {
+		pud_clear(pud);
+		return 1;
+	}
+
+	return 0;
+}
+#endif
+
+#if CONFIG_PGTABLE_LEVELS > 2
 /**
  * pmd_set_huge - setup kernel PMD mapping
  *
@@ -750,21 +768,6 @@ int pmd_set_huge(pmd_t *pmd, phys_addr_t addr, pgprot_t prot)
 	return 1;
 }
 
-/**
- * pud_clear_huge - clear kernel PUD mapping when it is set
- *
- * Returns 1 on success and 0 on failure (no PUD map is found).
- */
-int pud_clear_huge(pud_t *pud)
-{
-	if (pud_large(*pud)) {
-		pud_clear(pud);
-		return 1;
-	}
-
-	return 0;
-}
-
 /**
  * pmd_clear_huge - clear kernel PMD mapping when it is set
  *
@@ -779,6 +782,7 @@ int pmd_clear_huge(pmd_t *pmd)
 
 	return 0;
 }
+#endif
 
 #ifdef CONFIG_X86_64
 /**
-- 
2.25.0