linux-kernel - [RFC][PATCH 1/4] arm64: Drop alloc function from create

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Date:	Mon, 25 Jan 2016 08:52:12 -0800
From:	Laura Abbott <labbott@...oraproject.org>
To:	Catalin Marinas <catalin.marinas@....com>,
	Will Deacon <will.deacon@....com>,
	Mark Rutland <mark.rutland@....com>,
	Ard Biesheuvel <ard.biesheuvel@...aro.org>
Cc:	Laura Abbott <labbott@...oraproject.org>,
	linux-arm-kernel@...ts.infradead.org, linux-kernel@...r.kernel.org
Subject: [RFC][PATCH 1/4] arm64: Drop alloc function from create_mapping

create_mapping is only used in fixmap_remap_fdt. All the create_mapping
calls need to happen on existing translation table pages without
additional allocations. Rather than have an alloc function be called
and fail, just set it to NULL and catch it's use.

Signed-off-by: Laura Abbott <labbott@...oraproject.org>
---
 arch/arm64/mm/mmu.c | 14 ++++++++++----
 1 file changed, 10 insertions(+), 4 deletions(-)

diff --git a/arch/arm64/mm/mmu.c b/arch/arm64/mm/mmu.c
index e141762..2d6e7cf 100644
--- a/arch/arm64/mm/mmu.c
+++ b/arch/arm64/mm/mmu.c
@@ -116,7 +116,9 @@ static void alloc_init_pte(pmd_t *pmd, unsigned long addr,
 	pte_t *pte;
 
 	if (pmd_none(*pmd) || pmd_sect(*pmd)) {
-		phys_addr_t pte_phys = pgtable_alloc();
+		phys_addr_t pte_phys;
+		BUG_ON(!pgtable_alloc);
+		pte_phys = pgtable_alloc();
 		pte = pte_fixmap(pte_phys);
 		if (pmd_sect(*pmd))
 			split_pmd(pmd, pte);
@@ -158,7 +160,9 @@ static void alloc_init_pmd(pud_t *pud, unsigned long addr, unsigned long end,
 	 * Check for initial section mappings in the pgd/pud and remove them.
 	 */
 	if (pud_none(*pud) || pud_sect(*pud)) {
-		phys_addr_t pmd_phys = pgtable_alloc();
+		phys_addr_t pmd_phys;
+		BUG_ON(!pgtable_alloc);
+		pmd_phys = pgtable_alloc();
 		pmd = pmd_fixmap(pmd_phys);
 		if (pud_sect(*pud)) {
 			/*
@@ -223,7 +227,9 @@ static void alloc_init_pud(pgd_t *pgd, unsigned long addr, unsigned long end,
 	unsigned long next;
 
 	if (pgd_none(*pgd)) {
-		phys_addr_t pud_phys = pgtable_alloc();
+		phys_addr_t pud_phys;
+		BUG_ON(!pgtable_alloc);
+		pud_phys = pgtable_alloc();
 		__pgd_populate(pgd, pud_phys, PUD_TYPE_TABLE);
 	}
 	BUG_ON(pgd_bad(*pgd));
@@ -319,7 +325,7 @@ static void __init create_mapping(phys_addr_t phys, unsigned long virt,
 		return;
 	}
 	__create_pgd_mapping(init_mm.pgd, phys, virt, size, prot,
-			     early_pgtable_alloc);
+			     NULL);
 }
 
 void __init create_pgd_mapping(struct mm_struct *mm, phys_addr_t phys,
-- 
2.5.0