maple_tree: Efficiencies

Remove unneeded code.
Fix splitting from the back of a node.

Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 13f0c38344d6be726ee1b23b19afe25daf6d1d95..935fae1f07e0bb51c7db321e74494a75b65622d4 100644 (file)
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -500,20 +500,9 @@ static inline void ma_update_rcu_slot(const struct maple_node *mn,
                break;
        }
 }
-static void mas_update_limits(struct ma_state *ms, unsigned char slot,
+static inline void mas_update_limits(struct ma_state *ms, unsigned char slot,
                enum maple_type type)
 {
-       if (slot >= MAPLE_NODE_SLOTS)
-               return;
-
-       if (mas_is_start(ms))
-               return;
-
-       if (ma_is_root(ms->node)) {
-               ms->max = mt_max[type];
-               ms->min = 0;
-       }
-
        if (slot > 0)
                ms->min = _ma_get_pivot(ms->node, slot - 1, type);
 
@@ -646,27 +635,18 @@ static inline struct maple_node *mas_node_cnt(struct ma_state *ms, int count)
 
 static inline void *mas_start(struct ma_state *mas)
 {
-       void *entry;
-
-       if (mas_is_err(mas))
-               return NULL;
-
        if (mas->node == MAS_START) {
-               entry = mas->tree->ma_root;
-               if (!xa_is_node(entry)) {
+               if (!xa_is_node(mas->tree->ma_root)) {
                        if (mas->index > 0)
                                return NULL;
                        mas->node = MAS_ROOT;
                        ma_set_slot(mas, MAPLE_NODE_SLOTS);
+                       return NULL;
                } else {
-                       entry = mt_safe_root(entry);
+                       return mt_safe_root(mas->tree->ma_root);
                }
-
-       } else {
-               entry = mas->node;
        }
-
-       return entry;
+       return mas->node;
 }
 
 static inline unsigned char ma_data_end(const struct maple_node *mn,
@@ -692,8 +672,8 @@ static inline unsigned char ma_data_end(const struct maple_node *mn,
 static inline unsigned char ma_calc_split(struct ma_state *mas,
                struct maple_node **left, struct maple_node **right)
 {
-       unsigned char i, j;
-       unsigned long min = mas->min;
+       char i, j;
+       unsigned long min = mas->max;
        unsigned long max = min;
        enum maple_type type = mt_node_type(mas->node);
        unsigned long pivot_cnt = mt_pivots[type];
@@ -726,13 +706,16 @@ static inline unsigned char ma_calc_split(struct ma_state *mas,
        else
                max = mas->max;
 
-       for (j = data_end - 1; j >= 0; j--) {
+       j = data_end;
+       do {
+               j--;
                min = ma_get_pivot(mas->node, j);
                if ((max - min) > 15) {
                        j++;
                        break;
                }
-       }
+       } while (j > 0);
+
        if (data_end - j >= 4) {
                *left = mt_mk_node(*left, type);
                *right = mt_mk_node(*right, maple_dense);
@@ -1334,7 +1317,6 @@ linear_node:
        ma_set_slot(mas, i);
        return ret;
 }
-
 static inline bool mas_traverse(struct ma_state *mas, enum maple_type type)
 {
        unsigned char slot = ma_get_slot(mas);
@@ -1390,18 +1372,14 @@ static inline void ma_insert(struct ma_state *mas, void *entry)
 
        mas_coalesce(mas);
        if (mas_is_err(mas))
-               goto error;
+               return;
 
        /* Do the insert */
        _ma_insert(mas, entry, slot);
-       if (mas_is_err(mas))
-               goto error;
-
        return;
 
 exists:
        mas_set_err(mas, -EEXIST);
-error:
        return;
 }
 
@@ -1430,17 +1408,11 @@ void *mas_walk(struct ma_state *mas)
                return NULL;
        }
 
-       /* Outside this nodes range, it doesn't exist. */
-       if (mas->min > mas->index ||
-           mas->max < mas->index)
-               return NULL; // FIXME: Retry?
-
        leaf = _mas_walk(mas);
        slot = ma_get_slot(mas);
        if (leaf == true && slot != MAPLE_NODE_SLOTS)
                entry = ma_get_rcu_slot(mas->node, slot);
 
-       ma_set_slot(mas, 0);
        return entry;
 }
 
@@ -1486,9 +1458,7 @@ int ma_erase(struct ma_state *mas)
        }
 
        mas_coalesce(mas);
-       if (mas_is_err(mas))
-               goto error;
-error:
+       /* Error may be returned, but it will be passed through anyways */
        return cnt;
 }