[PATCH 2/3] f2fs:dax: Export interfaces: dax_map/unmap_atomic()

[sunqiuyang <sunqiuyang@huawei.com>]

Export interfaces of dax_map/unmap_atomic() for usage in moving data 
pages of DAX files in garbage collection of F2FS.

Signed-off-by: Qiuyang Sun <sunqiuyang@huawei.com>
---
 fs/dax.c            | 6 ++++--
 include/linux/dax.h | 3 +++
 2 files changed, 7 insertions(+), 2 deletions(-)

diff --git a/fs/dax.c b/fs/dax.c
index 85abd74..615a4c1 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -55,7 +55,7 @@ static int __init init_dax_wait_table(void)
 }
 fs_initcall(init_dax_wait_table);
 
-static long dax_map_atomic(struct block_device *bdev, struct blk_dax_ctl *dax)
+long dax_map_atomic(struct block_device *bdev, struct blk_dax_ctl *dax)
 {
 	struct request_queue *q = bdev->bd_queue;
 	long rc = -EIO;
@@ -72,14 +72,16 @@ static long dax_map_atomic(struct block_device *bdev, struct blk_dax_ctl *dax)
 	}
 	return rc;
 }
+EXPORT_SYMBOL_GPL(dax_map_atomic);
 
-static void dax_unmap_atomic(struct block_device *bdev,
+void dax_unmap_atomic(struct block_device *bdev,
 		const struct blk_dax_ctl *dax)
 {
 	if (IS_ERR(dax->addr))
 		return;
 	blk_queue_exit(bdev->bd_queue);
 }
+EXPORT_SYMBOL_GPL(dax_unmap_atomic);
 
 static int dax_is_pmd_entry(void *entry)
 {
diff --git a/include/linux/dax.h b/include/linux/dax.h
index d8a3dc0..b6451b2 100644
--- a/include/linux/dax.h
+++ b/include/linux/dax.h
@@ -7,6 +7,7 @@
 #include <asm/pgtable.h>
 
 struct iomap_ops;
+struct blk_dax_ctl;
 
 /*
  * We use lowest available bit in exceptional entry for locking, one bit for
@@ -36,6 +37,8 @@ static inline void *dax_radix_locked_entry(sector_t sector, unsigned long flags)
 			RADIX_DAX_ENTRY_LOCK);
 }
 
+long dax_map_atomic(struct block_device *bdev, struct blk_dax_ctl *dax);
+void dax_unmap_atomic(struct block_device *bdev, const struct blk_dax_ctl *dax);
 ssize_t dax_iomap_rw(struct kiocb *iocb, struct iov_iter *iter,
 		const struct iomap_ops *ops);
 int dax_iomap_fault(struct vm_fault *vmf, enum page_entry_size pe_size,
-- 
1.8.3.1