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_iterator {
        struct ma_state mas;
        struct sample_mgr *mgr;
};

\#define SAMPLE_ITERATOR(name, __mgr, start)                    \
        struct sample_iterator name = {                         \
                .mas = MA_STATE_INIT(&(__mgr)->mt, start, 0),   \
                .mgr = __mgr,                                   \
        }

\#define sample_iter_for_each_range(it__, entry__, end__) \
        mas_for_each(&(it__).mas, entry__, end__)

--

struct sample *sample;
SAMPLE_ITERATOR(si, min);

sample_iter_for_each_range(&si, sample, max) {
        frob(mgr, sample);
}

Signed-off-by: Danilo Krummrich <d...@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 1fadb5f5978b..87d55334f1c2 100644
--- a/include/linux/maple_tree.h
+++ b/include/linux/maple_tree.h
@@ -423,8 +423,8 @@ 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_INIT(mt, first, end)                                  \
+       {                                                               \
                .tree = mt,                                             \
                .index = first,                                         \
                .last = end,                                            \
@@ -435,6 +435,9 @@ struct ma_wr_state {
                .mas_flags = 0,                                         \
        }
 
+#define MA_STATE(name, mt, first, end)                                 \
+       struct ma_state name = MA_STATE_INIT(mt, first, end)
+
 #define MA_WR_STATE(name, ma_state, wr_entry)                          \
        struct ma_wr_state name = {                                     \
                .mas = ma_state,                                        \
-- 
2.40.1

Reply via email to