[RFC v2 PATCH 12/17] mm: ptep_clear_flush_range_notify() macro for batch operation

[Ryan Roberts <ryan.roberts@arm.com>]

We will soon add support for CoWing large anonymous folios, so create a
ranged version of the ptep_clear_flush_notify() macro in preparation for
that. It is able call mmu_notifier_invalidate_range() once for the
entire range, but still calls ptep_clear_flush() per page since there is
no arch support for a batched version of this API yet.

No functional change intended.

Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
---
 include/linux/mmu_notifier.h | 31 +++++++++++++++++++++++++++++++
 1 file changed, 31 insertions(+)

diff --git a/include/linux/mmu_notifier.h b/include/linux/mmu_notifier.h
index 64a3e051c3c4..527aa89959b4 100644
--- a/include/linux/mmu_notifier.h
+++ b/include/linux/mmu_notifier.h
@@ -595,6 +595,24 @@ static inline void mmu_notifier_range_init_owner(
 	___pte;								\
 })

+#define	ptep_clear_flush_range_notify(__vma, __address, __ptep, __nr)	\
+({									\
+	struct vm_area_struct *___vma = (__vma);			\
+	unsigned long ___addr = (__address) & PAGE_MASK;		\
+	pte_t *___ptep = (__ptep);					\
+	int ___nr = (__nr);						\
+	struct mm_struct *___mm = ___vma->vm_mm;			\
+	int ___i;							\
+									\
+	for (___i = 0; ___i < ___nr; ___i++)				\
+		ptep_clear_flush(___vma,				\
+				___addr + (___i << PAGE_SHIFT),		\
+				___ptep + ___i);			\
+									\
+	mmu_notifier_invalidate_range(___mm, ___addr,			\
+				___addr + (___nr << PAGE_SHIFT));	\
+})
+
 #define pmdp_huge_clear_flush_notify(__vma, __haddr, __pmd)		\
 ({									\
 	unsigned long ___haddr = __haddr & HPAGE_PMD_MASK;		\
@@ -736,6 +754,19 @@ static inline void mmu_notifier_subscriptions_destroy(struct mm_struct *mm)
 #define ptep_clear_young_notify ptep_test_and_clear_young
 #define pmdp_clear_young_notify pmdp_test_and_clear_young
 #define	ptep_clear_flush_notify ptep_clear_flush
+#define	ptep_clear_flush_range_notify(__vma, __address, __ptep, __nr)	\
+({									\
+	struct vm_area_struct *___vma = (__vma);			\
+	unsigned long ___addr = (__address) & PAGE_MASK;		\
+	pte_t *___ptep = (__ptep);					\
+	int ___nr = (__nr);						\
+	int ___i;							\
+									\
+	for (___i = 0; ___i < ___nr; ___i++)				\
+		ptep_clear_flush(___vma,				\
+				___addr + (___i << PAGE_SHIFT),		\
+				___ptep + ___i);			\
+})
 #define pmdp_huge_clear_flush_notify pmdp_huge_clear_flush
 #define pudp_huge_clear_flush_notify pudp_huge_clear_flush
 #define set_pte_at_notify set_pte_at
--
2.25.1