mm/memory: factor out zapping folio pte into zap_present_folio_pte()

Let's prepare for further changes by factoring it out into a separate
function.

Link: https://lkml.kernel.org/r/20240214204435.167852-5-david@redhat.comSigned-off-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Ryan Roberts <ryan.roberts@arm.com>
Cc: Alexander Gordeev <agordeev@linux.ibm.com>
Cc: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: Christian Borntraeger <borntraeger@linux.ibm.com>
Cc: Christophe Leroy <christophe.leroy@csgroup.eu>
Cc: Heiko Carstens <hca@linux.ibm.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Naveen N. Rao" <naveen.n.rao@linux.ibm.com>
Cc: Nicholas Piggin <npiggin@gmail.com>
Cc: Peter Zijlstra (Intel) <peterz@infradead.org>
Cc: Sven Schnelle <svens@linux.ibm.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Will Deacon <will@kernel.org>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

mm/memory.c

@@ -1530,30 +1530,14 @@ zap_install_uffd_wp_if_needed(struct vm_area_struct *vma,
 	pte_install_uffd_wp_if_needed(vma, addr, pte, pteval);
 }
 
-static inline void zap_present_pte(struct mmu_gather *tlb,
-		struct vm_area_struct *vma, pte_t *pte, pte_t ptent,
-		unsigned long addr, struct zap_details *details,
-		int *rss, bool *force_flush, bool *force_break)
+static inline void zap_present_folio_pte(struct mmu_gather *tlb,
+		struct vm_area_struct *vma, struct folio *folio,
+		struct page *page, pte_t *pte, pte_t ptent, unsigned long addr,
+		struct zap_details *details, int *rss, bool *force_flush,
+		bool *force_break)
 {
 	struct mm_struct *mm = tlb->mm;
 	bool delay_rmap = false;
-	struct folio *folio;
-	struct page *page;
-
-	page = vm_normal_page(vma, addr, ptent);
-	if (!page) {
-		/* We don't need up-to-date accessed/dirty bits. */
-		ptep_get_and_clear_full(mm, addr, pte, tlb->fullmm);
-		arch_check_zapped_pte(vma, ptent);
-		tlb_remove_tlb_entry(tlb, pte, addr);
-		VM_WARN_ON_ONCE(userfaultfd_wp(vma));
-		ksm_might_unmap_zero_page(mm, ptent);
-		return;
-	}
-
-	folio = page_folio(page);
-	if (unlikely(!should_zap_folio(details, folio)))
-		return;
 
 	if (!folio_test_anon(folio)) {
 		ptent = ptep_get_and_clear_full(mm, addr, pte, tlb->fullmm);
@@ -1588,6 +1572,33 @@ static inline void zap_present_pte(struct mmu_gather *tlb,
 	}
 }
 
+static inline void zap_present_pte(struct mmu_gather *tlb,
+		struct vm_area_struct *vma, pte_t *pte, pte_t ptent,
+		unsigned long addr, struct zap_details *details,
+		int *rss, bool *force_flush, bool *force_break)
+{
+	struct mm_struct *mm = tlb->mm;
+	struct folio *folio;
+	struct page *page;
+
+	page = vm_normal_page(vma, addr, ptent);
+	if (!page) {
+		/* We don't need up-to-date accessed/dirty bits. */
+		ptep_get_and_clear_full(mm, addr, pte, tlb->fullmm);
+		arch_check_zapped_pte(vma, ptent);
+		tlb_remove_tlb_entry(tlb, pte, addr);
+		VM_WARN_ON_ONCE(userfaultfd_wp(vma));
+		ksm_might_unmap_zero_page(mm, ptent);
+		return;
+	}
+
+	folio = page_folio(page);
+	if (unlikely(!should_zap_folio(details, folio)))
+		return;
+	zap_present_folio_pte(tlb, vma, folio, page, pte, ptent, addr, details,
+			      rss, force_flush, force_break);
+}
+
 static unsigned long zap_pte_range(struct mmu_gather *tlb,
 				struct vm_area_struct *vma, pmd_t *pmd,
 				unsigned long addr, unsigned long end,