linux-kernel - [PATCH 05/10] riscv: mm: Skip pgtable level check in {pud,p4d}_alloc

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Message-ID: <20241219164425.2277022-6-kevin.brodsky@arm.com>
Date: Thu, 19 Dec 2024 16:44:20 +0000
From: Kevin Brodsky <kevin.brodsky@....com>
To: linux-mm@...ck.org
Cc: Kevin Brodsky <kevin.brodsky@....com>,
	Andrew Morton <akpm@...ux-foundation.org>,
	Catalin Marinas <catalin.marinas@....com>,
	Dave Hansen <dave.hansen@...ux.intel.com>,
	Linus Walleij <linus.walleij@...aro.org>,
	Andy Lutomirski <luto@...nel.org>,
	Peter Zijlstra <peterz@...radead.org>,
	"Mike Rapoport (IBM)" <rppt@...nel.org>,
	Ryan Roberts <ryan.roberts@....com>,
	Thomas Gleixner <tglx@...utronix.de>,
	Will Deacon <will@...nel.org>,
	Matthew Wilcox <willy@...radead.org>,
	linux-alpha@...r.kernel.org,
	linux-arch@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org,
	linux-csky@...r.kernel.org,
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	linux-m68k@...ts.linux-m68k.org,
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	linux-openrisc@...r.kernel.org,
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Subject: [PATCH 05/10] riscv: mm: Skip pgtable level check in {pud,p4d}_alloc_one

{pmd,pud,p4d}_alloc_one() is never called if the corresponding page
table level is folded, as {pmd,pud,p4d}_alloc() already does the
required check. We can therefore remove the runtime page table level
checks in {pud,p4d}_alloc_one. The PUD helper becomes equivalent to
the generic version, so we remove it altogether.

This is consistent with the way arm64 and x86 handle this situation
(runtime check in p4d_free() only).

Signed-off-by: Kevin Brodsky <kevin.brodsky@....com>
---
 arch/riscv/include/asm/pgalloc.h | 22 ++++------------------
 1 file changed, 4 insertions(+), 18 deletions(-)

diff --git a/arch/riscv/include/asm/pgalloc.h b/arch/riscv/include/asm/pgalloc.h
index f52264304f77..8ad0bbe838a2 100644
--- a/arch/riscv/include/asm/pgalloc.h
+++ b/arch/riscv/include/asm/pgalloc.h
@@ -12,7 +12,6 @@
 #include <asm/tlb.h>
 
 #ifdef CONFIG_MMU
-#define __HAVE_ARCH_PUD_ALLOC_ONE
 #define __HAVE_ARCH_PUD_FREE
 #include <asm-generic/pgalloc.h>
 
@@ -88,15 +87,6 @@ static inline void pgd_populate_safe(struct mm_struct *mm, pgd_t *pgd,
 	}
 }
 
-#define pud_alloc_one pud_alloc_one
-static inline pud_t *pud_alloc_one(struct mm_struct *mm, unsigned long addr)
-{
-	if (pgtable_l4_enabled)
-		return __pud_alloc_one(mm, addr);
-
-	return NULL;
-}
-
 #define pud_free pud_free
 static inline void pud_free(struct mm_struct *mm, pud_t *pud)
 {
@@ -118,15 +108,11 @@ static inline void __pud_free_tlb(struct mmu_gather *tlb, pud_t *pud,
 #define p4d_alloc_one p4d_alloc_one
 static inline p4d_t *p4d_alloc_one(struct mm_struct *mm, unsigned long addr)
 {
-	if (pgtable_l5_enabled) {
-		gfp_t gfp = GFP_PGTABLE_USER;
-
-		if (mm == &init_mm)
-			gfp = GFP_PGTABLE_KERNEL;
-		return (p4d_t *)get_zeroed_page(gfp);
-	}
+	gfp_t gfp = GFP_PGTABLE_USER;
 
-	return NULL;
+	if (mm == &init_mm)
+		gfp = GFP_PGTABLE_KERNEL;
+	return (p4d_t *)get_zeroed_page(gfp);
 }
 
 static inline void __p4d_free(struct mm_struct *mm, p4d_t *p4d)
-- 
2.47.0