[RFC PATCH 07/18] mm: add pte_to_page() helper

[Qi Zheng <zhengqi.arch@bytedance.com>]

Add pte_to_page() helper similar to pmd_to_page(), which
will be used to get the struct page of the PTE page table.

Signed-off-by: Qi Zheng <zhengqi.arch@bytedance.com>
---
 include/linux/pgtable.h | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/include/linux/pgtable.h b/include/linux/pgtable.h
index 0928acca6b48..d1218cb1013e 100644
--- a/include/linux/pgtable.h
+++ b/include/linux/pgtable.h
@@ -85,6 +85,14 @@ static inline unsigned long pud_index(unsigned long address)
 #define pgd_index(a)  (((a) >> PGDIR_SHIFT) & (PTRS_PER_PGD - 1))
 #endif
 
+#ifdef CONFIG_FREE_USER_PTE
+static inline struct page *pte_to_page(pte_t *pte)
+{
+	unsigned long mask = ~(PTRS_PER_PTE * sizeof(pte_t) - 1);
+	return virt_to_page((void *)((unsigned long) pte & mask));
+}
+#endif
+
 #if USE_SPLIT_PTE_PTLOCKS
 #if ALLOC_SPLIT_PTLOCKS
 void __init ptlock_cache_init(void);
-- 
2.20.1