[RFC 3/4] bdev: rename iomap aops

[Luis Chamberlain <mcgrof@kernel.org>]

Allow buffer-head and iomap aops to co-exist on a build. Right
now the iomap aops is can only be used if you disable buffer-heads.
In the near future we should be able to dynamically select at runtime
the intended aops based on the nature of the filesystem and device
requirements.

So rename the iomap aops, and select use the new name if buffer-heads
is disabled. This introduces no functional changes.

Signed-off-by: Luis Chamberlain <mcgrof@kernel.org>
---
 block/bdev.c |  4 ++++
 block/blk.h  |  1 +
 block/fops.c | 14 +++++++-------
 3 files changed, 12 insertions(+), 7 deletions(-)

diff --git a/block/bdev.c b/block/bdev.c
index 61d8d2722cda..2b16afc2bd2a 100644
--- a/block/bdev.c
+++ b/block/bdev.c
@@ -408,7 +408,11 @@ struct block_device *bdev_alloc(struct gendisk *disk, u8 partno)
 		return NULL;
 	inode->i_mode = S_IFBLK;
 	inode->i_rdev = 0;
+#ifdef CONFIG_BUFFER_HEAD
 	inode->i_data.a_ops = &def_blk_aops;
+#else
+	inode->i_data.a_ops = &def_blk_aops_iomap;
+#endif
 	mapping_set_gfp_mask(&inode->i_data, GFP_USER);
 
 	bdev = I_BDEV(inode);
diff --git a/block/blk.h b/block/blk.h
index 7ad7cb6ffa01..67bf2fa99fe9 100644
--- a/block/blk.h
+++ b/block/blk.h
@@ -453,6 +453,7 @@ long blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg);
 long compat_blkdev_ioctl(struct file *file, unsigned cmd, unsigned long arg);
 
 extern const struct address_space_operations def_blk_aops;
+extern const struct address_space_operations def_blk_aops_iomap;
 
 int disk_register_independent_access_ranges(struct gendisk *disk);
 void disk_unregister_independent_access_ranges(struct gendisk *disk);
diff --git a/block/fops.c b/block/fops.c
index 24037b493f5f..51f7241ab389 100644
--- a/block/fops.c
+++ b/block/fops.c
@@ -455,13 +455,14 @@ const struct address_space_operations def_blk_aops = {
 	.migrate_folio	= buffer_migrate_folio_norefs,
 	.is_dirty_writeback = buffer_check_dirty_writeback,
 };
-#else /* CONFIG_BUFFER_HEAD */
-static int blkdev_read_folio(struct file *file, struct folio *folio)
+
+#endif /* CONFIG_BUFFER_HEAD */
+static int blkdev_read_folio_iomap(struct file *file, struct folio *folio)
 {
 	return iomap_read_folio(folio, &blkdev_iomap_ops);
 }
 
-static void blkdev_readahead(struct readahead_control *rac)
+static void blkdev_readahead_iomap(struct readahead_control *rac)
 {
 	iomap_readahead(rac, &blkdev_iomap_ops);
 }
@@ -492,18 +493,17 @@ static int blkdev_writepages(struct address_space *mapping,
 	return iomap_writepages(mapping, wbc, &wpc, &blkdev_writeback_ops);
 }
 
-const struct address_space_operations def_blk_aops = {
+const struct address_space_operations def_blk_aops_iomap = {
 	.dirty_folio	= filemap_dirty_folio,
 	.release_folio		= iomap_release_folio,
 	.invalidate_folio	= iomap_invalidate_folio,
-	.read_folio		= blkdev_read_folio,
-	.readahead		= blkdev_readahead,
+	.read_folio		= blkdev_read_folio_iomap,
+	.readahead		= blkdev_readahead_iomap,
 	.writepages		= blkdev_writepages,
 	.is_partially_uptodate  = iomap_is_partially_uptodate,
 	.error_remove_page	= generic_error_remove_page,
 	.migrate_folio		= filemap_migrate_folio,
 };
-#endif /* CONFIG_BUFFER_HEAD */
 
 /*
  * for a block special file file_inode(file)->i_size is zero
-- 
2.39.2