linux-kernel - [PATCH] arm64/hugetlb: Drop TLB flush from get_clear

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Message-Id: <20220510043930.2410985-1-anshuman.khandual@arm.com>
Date:   Tue, 10 May 2022 10:09:30 +0530
From:   Anshuman Khandual <anshuman.khandual@....com>
To:     linux-arm-kernel@...ts.infradead.org
Cc:     steve.capper@....com,
        Anshuman Khandual <anshuman.khandual@....com>,
        Catalin Marinas <catalin.marinas@....com>,
        Will Deacon <will@...nel.org>,
        Mike Kravetz <mike.kravetz@...cle.com>,
        linux-kernel@...r.kernel.org
Subject: [PATCH] arm64/hugetlb: Drop TLB flush from get_clear_flush()

This drops now redundant TLB flush in get_clear_flush() which is no longer
required after recent commit 697a1d44af8b ("tlb: hugetlb: Add more sizes to
tlb_remove_huge_tlb_entry"). It also renames this function i.e dropping off
'_flush' and replacing it with '__contig' as appropriate.

Cc: Catalin Marinas <catalin.marinas@....com>
Cc: Will Deacon <will@...nel.org>
Cc: Mike Kravetz <mike.kravetz@...cle.com>
Cc: linux-arm-kernel@...ts.infradead.org
Cc: linux-kernel@...r.kernel.org
Signed-off-by: Anshuman Khandual <anshuman.khandual@....com>
---
This applies on v5.18-rc6

 arch/arm64/mm/hugetlbpage.c | 16 +++++-----------
 1 file changed, 5 insertions(+), 11 deletions(-)

diff --git a/arch/arm64/mm/hugetlbpage.c b/arch/arm64/mm/hugetlbpage.c
index cbace1c9e137..749435b01a89 100644
--- a/arch/arm64/mm/hugetlbpage.c
+++ b/arch/arm64/mm/hugetlbpage.c
@@ -166,15 +166,14 @@ static inline int num_contig_ptes(unsigned long size, size_t *pgsize)
  *
  * This helper performs the break step.
  */
-static pte_t get_clear_flush(struct mm_struct *mm,
+static pte_t get_clear_contig(struct mm_struct *mm,
 			     unsigned long addr,
 			     pte_t *ptep,
 			     unsigned long pgsize,
 			     unsigned long ncontig)
 {
 	pte_t orig_pte = huge_ptep_get(ptep);
-	bool valid = pte_valid(orig_pte);
-	unsigned long i, saddr = addr;
+	unsigned long i;
 
 	for (i = 0; i < ncontig; i++, addr += pgsize, ptep++) {
 		pte_t pte = ptep_get_and_clear(mm, addr, ptep);
@@ -190,11 +189,6 @@ static pte_t get_clear_flush(struct mm_struct *mm,
 		if (pte_young(pte))
 			orig_pte = pte_mkyoung(orig_pte);
 	}
-
-	if (valid) {
-		struct vm_area_struct vma = TLB_FLUSH_VMA(mm, 0);
-		flush_tlb_range(&vma, saddr, addr);
-	}
 	return orig_pte;
 }
 
@@ -392,7 +386,7 @@ pte_t huge_ptep_get_and_clear(struct mm_struct *mm,
 
 	ncontig = find_num_contig(mm, addr, ptep, &pgsize);
 
-	return get_clear_flush(mm, addr, ptep, pgsize, ncontig);
+	return get_clear_contig(mm, addr, ptep, pgsize, ncontig);
 }
 
 /*
@@ -443,7 +437,7 @@ int huge_ptep_set_access_flags(struct vm_area_struct *vma,
 	if (!__cont_access_flags_changed(ptep, pte, ncontig))
 		return 0;
 
-	orig_pte = get_clear_flush(vma->vm_mm, addr, ptep, pgsize, ncontig);
+	orig_pte = get_clear_contig(vma->vm_mm, addr, ptep, pgsize, ncontig);
 
 	/* Make sure we don't lose the dirty or young state */
 	if (pte_dirty(orig_pte))
@@ -476,7 +470,7 @@ void huge_ptep_set_wrprotect(struct mm_struct *mm,
 	ncontig = find_num_contig(mm, addr, ptep, &pgsize);
 	dpfn = pgsize >> PAGE_SHIFT;
 
-	pte = get_clear_flush(mm, addr, ptep, pgsize, ncontig);
+	pte = get_clear_contig(mm, addr, ptep, pgsize, ncontig);
 	pte = pte_wrprotect(pte);
 
 	hugeprot = pte_pgprot(pte);
-- 
2.20.1