This will allow preparation steps to be shared

Signed-off-by: Ackerley Tng <ackerleytng@google.com>
---
 include/linux/mm.h |  1 +
 mm/truncate.c      | 26 ++++++++++++++++----------
 2 files changed, 17 insertions(+), 10 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index c4b238a20b76..ffb4788295b4 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3442,6 +3442,7 @@ extern unsigned long vm_unmapped_area(struct vm_unmapped_area_info *info);
 extern void truncate_inode_pages(struct address_space *, loff_t);
 extern void truncate_inode_pages_range(struct address_space *,
 				       loff_t lstart, loff_t lend);
+extern void truncate_inode_pages_final_prepare(struct address_space *);
 extern void truncate_inode_pages_final(struct address_space *);
 
 /* generic vm_area_ops exported for stackable file systems */
diff --git a/mm/truncate.c b/mm/truncate.c
index 4d61fbdd4b2f..28cca86424f8 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -424,16 +424,7 @@ void truncate_inode_pages(struct address_space *mapping, loff_t lstart)
 }
 EXPORT_SYMBOL(truncate_inode_pages);
 
-/**
- * truncate_inode_pages_final - truncate *all* pages before inode dies
- * @mapping: mapping to truncate
- *
- * Called under (and serialized by) inode->i_rwsem.
- *
- * Filesystems have to use this in the .evict_inode path to inform the
- * VM that this is the final truncate and the inode is going away.
- */
-void truncate_inode_pages_final(struct address_space *mapping)
+void truncate_inode_pages_final_prepare(struct address_space *mapping)
 {
 	/*
 	 * Page reclaim can not participate in regular inode lifetime
@@ -454,6 +445,21 @@ void truncate_inode_pages_final(struct address_space *mapping)
 		xa_lock_irq(&mapping->i_pages);
 		xa_unlock_irq(&mapping->i_pages);
 	}
+}
+EXPORT_SYMBOL(truncate_inode_pages_final_prepare);
+
+/**
+ * truncate_inode_pages_final - truncate *all* pages before inode dies
+ * @mapping: mapping to truncate
+ *
+ * Called under (and serialized by) inode->i_rwsem.
+ *
+ * Filesystems have to use this in the .evict_inode path to inform the
+ * VM that this is the final truncate and the inode is going away.
+ */
+void truncate_inode_pages_final(struct address_space *mapping)
+{
+	truncate_inode_pages_final_prepare(mapping);
 
 	truncate_inode_pages(mapping, 0);
 }
-- 
2.46.0.598.g6f2099f65c-goog