1 files changed, 63 insertions, 0 deletions
diff --git a/c_src/libbcachefs/vstructs.h b/c_src/libbcachefs/vstructs.h
new file mode 100644
index 00000000..2ad338e2
--- /dev/null
+++ b/c_src/libbcachefs/vstructs.h
@@ -0,0 +1,63 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _VSTRUCTS_H
+#define _VSTRUCTS_H
+
+#include "util.h"
+
+/*
+ * NOTE: we can't differentiate between __le64 and u64 with type_is - this
+ * assumes u64 is little endian:
+ */
+#define __vstruct_u64s(_s)						\
+({									\
+	( type_is((_s)->u64s, u64) ? le64_to_cpu((__force __le64) (_s)->u64s)		\
+	: type_is((_s)->u64s, u32) ? le32_to_cpu((__force __le32) (_s)->u64s)		\
+	: type_is((_s)->u64s, u16) ? le16_to_cpu((__force __le16) (_s)->u64s)		\
+	: ((__force u8) ((_s)->u64s)));						\
+})
+
+#define __vstruct_bytes(_type, _u64s)					\
+({									\
+	BUILD_BUG_ON(offsetof(_type, _data) % sizeof(u64));		\
+									\
+	(size_t) (offsetof(_type, _data) + (_u64s) * sizeof(u64));	\
+})
+
+#define vstruct_bytes(_s)						\
+	__vstruct_bytes(typeof(*(_s)), __vstruct_u64s(_s))
+
+#define __vstruct_blocks(_type, _sector_block_bits, _u64s)		\
+	(round_up(__vstruct_bytes(_type, _u64s),			\
+		  512 << (_sector_block_bits)) >> (9 + (_sector_block_bits)))
+
+#define vstruct_blocks(_s, _sector_block_bits)				\
+	__vstruct_blocks(typeof(*(_s)), _sector_block_bits, __vstruct_u64s(_s))
+
+#define vstruct_blocks_plus(_s, _sector_block_bits, _u64s)		\
+	__vstruct_blocks(typeof(*(_s)), _sector_block_bits,		\
+			 __vstruct_u64s(_s) + (_u64s))
+
+#define vstruct_sectors(_s, _sector_block_bits)				\
+	(round_up(vstruct_bytes(_s), 512 << (_sector_block_bits)) >> 9)
+
+#define vstruct_next(_s)						\
+	((typeof(_s))			((u64 *) (_s)->_data + __vstruct_u64s(_s)))
+#define vstruct_last(_s)						\
+	((typeof(&(_s)->start[0]))	((u64 *) (_s)->_data + __vstruct_u64s(_s)))
+#define vstruct_end(_s)							\
+	((void *)			((u64 *) (_s)->_data + __vstruct_u64s(_s)))
+
+#define vstruct_for_each(_s, _i)					\
+	for (typeof(&(_s)->start[0]) _i = (_s)->start;			\
+	     _i < vstruct_last(_s);					\
+	     _i = vstruct_next(_i))
+
+#define vstruct_for_each_safe(_s, _i)					\
+	for (typeof(&(_s)->start[0]) _next, _i = (_s)->start;		\
+	     _i < vstruct_last(_s) && (_next = vstruct_next(_i), true);	\
+	     _i = _next)
+
+#define vstruct_idx(_s, _idx)						\
+	((typeof(&(_s)->start[0])) ((_s)->_data + (_idx)))
+
+#endif /* _VSTRUCTS_H */