[PATCH drm-next v2 03/16] maple_tree: split up MA_STATE() macro

[Danilo Krummrich <dakr@redhat.com>]

Split up the MA_STATE() macro such that components using the maple tree
can easily inherit from struct ma_state and build custom tree walk
macros to hide their internals from users.

Example:

struct sample_iter {
	struct ma_state mas;
	struct sample_mgr *mgr;
	struct sample_entry *entry;
};

\#define SAMPLE_ITER(name, __mgr) \
	struct sample_iter name = { \
		.mas = __MA_STATE(&(__mgr)->mt, 0, 0),
		.mgr = __mgr,
		.entry = NULL,
	}

\#define sample_iter_for_each_range(it__, start__, end__) \
	for ((it__).mas.index = start__, (it__).entry = mas_find(&(it__).mas, end__ - 1); \
	     (it__).entry; (it__).entry = mas_find(&(it__).mas, end__ - 1))

Signed-off-by: Danilo Krummrich <dakr@redhat.com>
---
 include/linux/maple_tree.h | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/include/linux/maple_tree.h b/include/linux/maple_tree.h
index e594db58a0f1..ca04c900e51a 100644
--- a/include/linux/maple_tree.h
+++ b/include/linux/maple_tree.h
@@ -424,8 +424,8 @@ struct ma_wr_state {
 #define MA_ERROR(err) \
 		((struct maple_enode *)(((unsigned long)err << 2) | 2UL))
 
-#define MA_STATE(name, mt, first, end)					\
-	struct ma_state name = {					\
+#define __MA_STATE(mt, first, end)					\
+	{								\
 		.tree = mt,						\
 		.index = first,						\
 		.last = end,						\
@@ -435,6 +435,9 @@ struct ma_wr_state {
 		.alloc = NULL,						\
 	}
 
+#define MA_STATE(name, mt, first, end)					\
+	struct ma_state name = __MA_STATE(mt, first, end)
+
 #define MA_WR_STATE(name, ma_state, wr_entry)				\
 	struct ma_wr_state name = {					\
 		.mas = ma_state,					\
-- 
2.39.1