xfs: remove ATTR_ALLOC and XFS_DA_OP_ALLOCVAL

Use a NULL args->value as the indicator to lazily allocate a buffer
instead, and let the caller always free args->value instead of
duplicating the cleanup.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dave Chinner <dchinner@redhat.com>
Reviewed-by: Chandan Rajendra <chandanrlinux@gmail.com>
Reviewed-by: Darrick J. Wong <darrick.wong@oracle.com>
Signed-off-by: Darrick J. Wong <darrick.wong@oracle.com>

fs/xfs/libxfs/xfs_da_btree.h

@@ -88,7 +88,6 @@ typedef struct xfs_da_args {
 #define XFS_DA_OP_ADDNAME	0x0004	/* this is an add operation */
 #define XFS_DA_OP_OKNOENT	0x0008	/* lookup/add op, ENOENT ok, else die */
 #define XFS_DA_OP_CILOOKUP	0x0010	/* lookup to return CI name if found */
-#define XFS_DA_OP_ALLOCVAL	0x0020	/* lookup to alloc buffer if found  */
 #define XFS_DA_OP_INCOMPLETE	0x0040	/* lookup INCOMPLETE attr keys */
 
 #define XFS_DA_OP_FLAGS \
@@ -97,7 +96,6 @@ typedef struct xfs_da_args {
 	{ XFS_DA_OP_ADDNAME,	"ADDNAME" }, \
 	{ XFS_DA_OP_OKNOENT,	"OKNOENT" }, \
 	{ XFS_DA_OP_CILOOKUP,	"CILOOKUP" }, \
-	{ XFS_DA_OP_ALLOCVAL,	"ALLOCVAL" }, \
 	{ XFS_DA_OP_INCOMPLETE,	"INCOMPLETE" }
 
 /*