xfs: refactor log recovery item sorting into a generic dispatch structure

Create a generic dispatch structure to delegate recovery of different
log item types into various code modules.  This will enable us to move
code specific to a particular log item type out of xfs_log_recover.c and
into the log item source.

The first operation we virtualize is the log item sorting.

Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>
Reviewed-by: Chandan Babu R <chandanrlinux@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>

fs/xfs/xfs_refcount_item.c

@@ -18,6 +18,7 @@
 #include "xfs_log.h"
 #include "xfs_refcount.h"
 #include "xfs_error.h"
+#include "xfs_log_recover.h"
 
 kmem_zone_t	*xfs_cui_zone;
 kmem_zone_t	*xfs_cud_zone;
@@ -570,3 +571,11 @@ abort_error:
 	xfs_trans_cancel(tp);
 	return error;
 }
+
+const struct xlog_recover_item_ops xlog_cui_item_ops = {
+	.item_type		= XFS_LI_CUI,
+};
+
+const struct xlog_recover_item_ops xlog_cud_item_ops = {
+	.item_type		= XFS_LI_CUD,
+};