[RFC PATCH 12/19] mm: truncate: Expose preparation steps for truncate_inode_pages_final

[Ackerley Tng <ackerleytng@xxxxxxxxxx>]

This will allow preparation steps to be shared

Signed-off-by: Ackerley Tng <ackerleytng@xxxxxxxxxx>
---
 include/linux/mm.h |  1 +
 mm/truncate.c      | 24 ++++++++++++++----------
 2 files changed, 15 insertions(+), 10 deletions(-)

diff --git a/include/linux/mm.h b/include/linux/mm.h
index 1f79667824eb..7a8f6b810de0 100644
--- a/include/linux/mm.h
+++ b/include/linux/mm.h
@@ -3053,6 +3053,7 @@ 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 *mapping);
 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 7b4ea4c4a46b..4a7ae87e03b5 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -449,16 +449,7 @@ 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
@@ -479,7 +470,20 @@ void truncate_inode_pages_final(struct address_space *mapping)
 		xa_lock_irq(&mapping->i_pages);
 		xa_unlock_irq(&mapping->i_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)
+{
+	truncate_inode_pages_final_prepare(mapping);
 	truncate_inode_pages(mapping, 0);
 }
 EXPORT_SYMBOL(truncate_inode_pages_final);
-- 
2.41.0.rc0.172.g3f132b7071-goog