linux-kernel - [PATCH v3 5/9] mm: introduce do_zap_pte

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Message-Id: <1d8467c1428573cc666ca3150ba66877f7b316cf.1731566457.git.zhengqi.arch@bytedance.com>
Date: Thu, 14 Nov 2024 14:59:56 +0800
From: Qi Zheng <zhengqi.arch@...edance.com>
To: david@...hat.com,
	jannh@...gle.com,
	hughd@...gle.com,
	willy@...radead.org,
	muchun.song@...ux.dev,
	vbabka@...nel.org,
	akpm@...ux-foundation.org,
	peterx@...hat.com
Cc: mgorman@...e.de,
	catalin.marinas@....com,
	will@...nel.org,
	dave.hansen@...ux.intel.com,
	luto@...nel.org,
	peterz@...radead.org,
	x86@...nel.org,
	lorenzo.stoakes@...cle.com,
	linux-mm@...ck.org,
	linux-kernel@...r.kernel.org,
	zokeefe@...gle.com,
	rientjes@...gle.com,
	Qi Zheng <zhengqi.arch@...edance.com>
Subject: [PATCH v3 5/9] mm: introduce do_zap_pte_range()

This commit introduces do_zap_pte_range() to actually zap the PTEs, which
will help improve code readability and facilitate secondary checking of
the processed PTEs in the future.

No functional change.

Signed-off-by: Qi Zheng <zhengqi.arch@...edance.com>
Reviewed-by: Jann Horn <jannh@...gle.com>
Acked-by: David Hildenbrand <david@...hat.com>
---
 mm/memory.c | 39 ++++++++++++++++++++++++---------------
 1 file changed, 24 insertions(+), 15 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 24633d0e1445a..bf5ac8e0b4656 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1679,6 +1679,25 @@ static inline int skip_none_ptes(pte_t *pte, unsigned long addr,
 	return nr;
 }
 
+/* If PTE_MARKER_UFFD_WP is enabled, the uffd-wp PTEs may be re-installed. */
+static inline int do_zap_pte_range(struct mmu_gather *tlb,
+				   struct vm_area_struct *vma, pte_t *pte,
+				   unsigned long addr, unsigned long end,
+				   struct zap_details *details, int *rss,
+				   bool *force_flush, bool *force_break)
+{
+	pte_t ptent = ptep_get(pte);
+	int max_nr = (end - addr) / PAGE_SIZE;
+
+	if (pte_present(ptent))
+		return zap_present_ptes(tlb, vma, pte, ptent, max_nr,
+					addr, details, rss, force_flush,
+					force_break);
+
+	return zap_nonpresent_ptes(tlb, vma, pte, ptent, max_nr, addr,
+					 details, rss);
+}
+
 static unsigned long zap_pte_range(struct mmu_gather *tlb,
 				struct vm_area_struct *vma, pmd_t *pmd,
 				unsigned long addr, unsigned long end,
@@ -1701,9 +1720,6 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
 	flush_tlb_batched_pending(mm);
 	arch_enter_lazy_mmu_mode();
 	do {
-		pte_t ptent = ptep_get(pte);
-		int max_nr;
-
 		if (need_resched())
 			break;
 
@@ -1715,18 +1731,11 @@ static unsigned long zap_pte_range(struct mmu_gather *tlb,
 			pte += nr;
 		}
 
-		max_nr = (end - addr) / PAGE_SIZE;
-		if (pte_present(ptent)) {
-			nr = zap_present_ptes(tlb, vma, pte, ptent, max_nr,
-					      addr, details, rss, &force_flush,
-					      &force_break);
-			if (unlikely(force_break)) {
-				addr += nr * PAGE_SIZE;
-				break;
-			}
-		} else {
-			nr = zap_nonpresent_ptes(tlb, vma, pte, ptent, max_nr,
-						 addr, details, rss);
+		nr = do_zap_pte_range(tlb, vma, pte, addr, end, details,
+				      rss, &force_flush, &force_break);
+		if (unlikely(force_break)) {
+			addr += nr * PAGE_SIZE;
+			break;
 		}
 	} while (pte += nr, addr += PAGE_SIZE * nr, addr != end);
 
-- 
2.20.1