[PATCH 4/5] dax,iomap: Start using dax native zero_page_range()

[Vivek Goyal <vgoyal@redhat.com>]

Get rid of calling block device interface for zeroing in iomap dax
zeroing path and use dax native zeroing interface instead.

Suggested-by: Christoph Hellwig <hch@infradead.org>
Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
---
 fs/dax.c | 45 +++++++++------------------------------------
 1 file changed, 9 insertions(+), 36 deletions(-)

diff --git a/fs/dax.c b/fs/dax.c
index 35631a4d0295..1b9ba6b59cdb 100644
--- a/fs/dax.c
+++ b/fs/dax.c
@@ -1044,19 +1044,6 @@ static vm_fault_t dax_load_hole(struct xa_state *xas,
 	return ret;
 }
 
-static bool dax_range_is_aligned(struct block_device *bdev,
-				 unsigned int offset, unsigned int length)
-{
-	unsigned short sector_size = bdev_logical_block_size(bdev);
-
-	if (!IS_ALIGNED(offset, sector_size))
-		return false;
-	if (!IS_ALIGNED(length, sector_size))
-		return false;
-
-	return true;
-}
-
 int generic_dax_zero_page_range(struct dax_device *dax_dev, pgoff_t pgoff,
 				unsigned int offset, size_t len)
 {
@@ -1076,31 +1063,17 @@ int __dax_zero_page_range(struct block_device *bdev,
 		struct dax_device *dax_dev, sector_t sector,
 		unsigned int offset, unsigned int size)
 {
-	if (dax_range_is_aligned(bdev, offset, size)) {
-		sector_t start_sector = sector + (offset >> 9);
-
-		return blkdev_issue_zeroout(bdev, start_sector,
-				size >> 9, GFP_NOFS, 0);
-	} else {
-		pgoff_t pgoff;
-		long rc, id;
-		void *kaddr;
+	pgoff_t pgoff;
+	long rc, id;
 
-		rc = bdev_dax_pgoff(bdev, sector, PAGE_SIZE, &pgoff);
-		if (rc)
-			return rc;
+	rc = bdev_dax_pgoff(bdev, sector, PAGE_SIZE, &pgoff);
+	if (rc)
+		return rc;
 
-		id = dax_read_lock();
-		rc = dax_direct_access(dax_dev, pgoff, 1, &kaddr, NULL);
-		if (rc < 0) {
-			dax_read_unlock(id);
-			return rc;
-		}
-		memset(kaddr + offset, 0, size);
-		dax_flush(dax_dev, kaddr + offset, size);
-		dax_read_unlock(id);
-	}
-	return 0;
+	id = dax_read_lock();
+	rc = dax_zero_page_range(dax_dev, pgoff, offset, size);
+	dax_read_unlock(id);
+	return rc;
 }
 EXPORT_SYMBOL_GPL(__dax_zero_page_range);
 
-- 
2.18.1