1 files changed, 105 insertions, 0 deletions
diff --git a/fs/bcachefs/darray.h b/fs/bcachefs/darray.h
new file mode 100644
index 0000000000..e367c625f0
--- /dev/null
+++ b/fs/bcachefs/darray.h
@@ -0,0 +1,105 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef _BCACHEFS_DARRAY_H
+#define _BCACHEFS_DARRAY_H
+
+/*
+ * Dynamic arrays:
+ *
+ * Inspired by CCAN's darray
+ */
+
+#include <linux/slab.h>
+
+#define DARRAY_PREALLOCATED(_type, _nr)					\
+struct {								\
+	size_t nr, size;						\
+	_type *data;							\
+	_type preallocated[_nr];					\
+}
+
+#define DARRAY(_type) DARRAY_PREALLOCATED(_type, 0)
+
+typedef DARRAY(char)	darray_char;
+
+int __bch2_darray_resize(darray_char *, size_t, size_t, gfp_t);
+
+static inline int __darray_resize(darray_char *d, size_t element_size,
+				  size_t new_size, gfp_t gfp)
+{
+	return unlikely(new_size > d->size)
+		? __bch2_darray_resize(d, element_size, new_size, gfp)
+		: 0;
+}
+
+#define darray_resize_gfp(_d, _new_size, _gfp)				\
+	unlikely(__darray_resize((darray_char *) (_d), sizeof((_d)->data[0]), (_new_size), _gfp))
+
+#define darray_resize(_d, _new_size)					\
+	darray_resize_gfp(_d, _new_size, GFP_KERNEL)
+
+static inline int __darray_make_room(darray_char *d, size_t t_size, size_t more, gfp_t gfp)
+{
+	return __darray_resize(d, t_size, d->nr + more, gfp);
+}
+
+#define darray_make_room_gfp(_d, _more, _gfp)				\
+	__darray_make_room((darray_char *) (_d), sizeof((_d)->data[0]), (_more), _gfp)
+
+#define darray_make_room(_d, _more)					\
+	darray_make_room_gfp(_d, _more, GFP_KERNEL)
+
+#define darray_room(_d)		((_d).size - (_d).nr)
+
+#define darray_top(_d)		((_d).data[(_d).nr])
+
+#define darray_push_gfp(_d, _item, _gfp)				\
+({									\
+	int _ret = darray_make_room_gfp((_d), 1, _gfp);			\
+									\
+	if (!_ret)							\
+		(_d)->data[(_d)->nr++] = (_item);			\
+	_ret;								\
+})
+
+#define darray_push(_d, _item)	darray_push_gfp(_d, _item, GFP_KERNEL)
+
+#define darray_pop(_d)		((_d)->data[--(_d)->nr])
+
+#define darray_first(_d)	((_d).data[0])
+#define darray_last(_d)		((_d).data[(_d).nr - 1])
+
+#define darray_insert_item(_d, pos, _item)				\
+({									\
+	size_t _pos = (pos);						\
+	int _ret = darray_make_room((_d), 1);				\
+									\
+	if (!_ret)							\
+		array_insert_item((_d)->data, (_d)->nr, _pos, (_item));	\
+	_ret;								\
+})
+
+#define darray_remove_item(_d, _pos)					\
+	array_remove_item((_d)->data, (_d)->nr, (_pos) - (_d)->data)
+
+#define darray_for_each(_d, _i)						\
+	for (_i = (_d).data; _i < (_d).data + (_d).nr; _i++)
+
+#define darray_for_each_reverse(_d, _i)					\
+	for (_i = (_d).data + (_d).nr - 1; _i >= (_d).data; --_i)
+
+#define darray_init(_d)							\
+do {									\
+	(_d)->nr = 0;							\
+	(_d)->size = ARRAY_SIZE((_d)->preallocated);			\
+	(_d)->data = (_d)->size ? (_d)->preallocated : NULL;		\
+} while (0)
+
+#define darray_exit(_d)							\
+do {									\
+	if (!ARRAY_SIZE((_d)->preallocated) ||				\
+	    (_d)->data != (_d)->preallocated)				\
+		kvfree((_d)->data);					\
+	darray_init(_d);						\
+} while (0)
+
+#endif /* _BCACHEFS_DARRAY_H */