maple_tree: Fix several off-by-one errors.

When counting through the slots/pivots, the pivots overflow before the
slots which is an area of confusion sometimes.

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

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index ca7d4245a8901f6114e0bef7da1972e1c2c54d70..5fa94bf2aa39f12dde20c52d6a6cd8362d2730f2 100644 (file)
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -323,7 +323,7 @@ unsigned char ma_data_end_r64(const struct ma_state *ms)
 }
 /* Private
  *
- * Insert entry into a node.
+ * Insert entry into a node that is not visible to readers.
  *
  * This is done by:
  * 1. Calculating the range of slot.
@@ -357,12 +357,11 @@ static int _ma_insert(struct ma_state *ms, void *entry, unsigned char slot)
        if (min != ms->index - 1)
                n_end++;
 
-
        /* Copy the data over */
        while (o_end >= slot) {
                RCU_INIT_POINTER(mr64->slot[n_end],
                                mr64->slot[o_end]);
-               if (n_end < MAPLE_RANGE64_SLOTS - 2)
+               if (n_end < MAPLE_RANGE64_SLOTS - 1)
                        mr64->pivot[n_end] = mr64->pivot[o_end];
                n_end--;
                o_end--;
@@ -455,7 +454,7 @@ static void *mas_coalesce(struct ma_state *mas)
        mn = ma_next_alloc(mas);
        dst = &mn->mr64;
 
-       for (s_slot = 0; s_slot < MAPLE_RANGE64_SLOTS; s_slot++) {
+       for (s_slot = 0; s_slot < MAPLE_RANGE64_SLOTS - 1; s_slot++) {
                if (last == src->pivot[s_slot])
                        continue;
 
@@ -494,7 +493,7 @@ static bool mas_search_slots(struct ma_state *ms, unsigned long val)
        int i = 0;
 
        mr64 = &mt_to_node(ms->node)->mr64;
-       for (i = 0; i < MAPLE_RANGE64_SLOTS - 1; i++) {
+       for (i = 0; i <= MAPLE_RANGE64_SLOTS - 1; i++) {
                if (i != 0 && mr64->pivot[i] == 0) {
                        ma_set_slot(ms, MAPLE_NODE_SLOTS);
                        return false;
@@ -505,7 +504,7 @@ static bool mas_search_slots(struct ma_state *ms, unsigned long val)
        }
 
        if (i == MAPLE_RANGE64_SLOTS - 2) {
-               if (val <= mr64->pivot[i])
+               if (val > mr64->pivot[i])
                        i++;
        }
 
@@ -781,6 +780,8 @@ EXPORT_SYMBOL(mtree_destroy);
 
 
 #ifdef MT_DEBUG
+void mt_dump_node(void *entry, unsigned long min, unsigned long max,
+               unsigned int depth);
 void mt_dump_range(unsigned long min, unsigned long max)
 {
        if (min == max)