maple_tree: simplify and clean up mas_wr_node_store()

Simplify and clean up mas_wr_node_store(), remove unnecessary code.

Link: https://lkml.kernel.org/r/20230524031247.65949-10-zhangpeng.00@bytedance.com
Signed-off-by: Peng Zhang <zhangpeng.00@bytedance.com>
Reviewed-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/lib/maple_tree.c b/lib/maple_tree.c
index 1a2b9bb..bfffbb7 100644 (file)
--- a/lib/maple_tree.c
+++ b/lib/maple_tree.c
@@ -4074,52 +4074,27 @@ static inline int mas_wr_spanning_store(struct ma_wr_state *wr_mas)
  *
  * Return: True if stored, false otherwise
  */
-static inline bool mas_wr_node_store(struct ma_wr_state *wr_mas)
+static inline bool mas_wr_node_store(struct ma_wr_state *wr_mas,
+                                    unsigned char new_end)
 {
        struct ma_state *mas = wr_mas->mas;
        void __rcu **dst_slots;
        unsigned long *dst_pivots;
-       unsigned char dst_offset;
-       unsigned char new_end = wr_mas->node_end;
-       unsigned char offset;
-       unsigned char node_slots = mt_slots[wr_mas->type];
+       unsigned char dst_offset, offset_end = wr_mas->offset_end;
        struct maple_node reuse, *newnode;
-       unsigned char copy_size, max_piv = mt_pivots[wr_mas->type];
+       unsigned char copy_size, node_pivots = mt_pivots[wr_mas->type];
        bool in_rcu = mt_in_rcu(mas->tree);
 
-       offset = mas->offset;
-       if (mas->last == wr_mas->r_max) {
-               /* runs right to the end of the node */
-               if (mas->last == mas->max)
-                       new_end = offset;
-               /* don't copy this offset */
-               wr_mas->offset_end++;
-       } else if (mas->last < wr_mas->r_max) {
-               /* new range ends in this range */
-               if (unlikely(wr_mas->r_max == ULONG_MAX))
-                       mas_bulk_rebalance(mas, wr_mas->node_end, wr_mas->type);
-
-               new_end++;
-       } else {
-               if (wr_mas->end_piv == mas->last)
-                       wr_mas->offset_end++;
-
-               new_end -= wr_mas->offset_end - offset - 1;
-       }
-
-       /* new range starts within a range */
-       if (wr_mas->r_min < mas->index)
-               new_end++;
-
-       /* Not enough room */
-       if (new_end >= node_slots)
-               return false;
-
-       /* Not enough data. */
+       /* Check if there is enough data. The room is enough. */
        if (!mte_is_root(mas->node) && (new_end <= mt_min_slots[wr_mas->type]) &&
            !(mas->mas_flags & MA_STATE_BULK))
                return false;
 
+       if (mas->last == wr_mas->end_piv)
+               offset_end++; /* don't copy this offset */
+       else if (unlikely(wr_mas->r_max == ULONG_MAX))
+               mas_bulk_rebalance(mas, wr_mas->node_end, wr_mas->type);
+
        /* set up node. */
        if (in_rcu) {
                mas_node_count(mas, 1);
@@ -4136,47 +4111,36 @@ static inline bool mas_wr_node_store(struct ma_wr_state *wr_mas)
        dst_pivots = ma_pivots(newnode, wr_mas->type);
        dst_slots = ma_slots(newnode, wr_mas->type);
        /* Copy from start to insert point */
-       memcpy(dst_pivots, wr_mas->pivots, sizeof(unsigned long) * (offset + 1));
-       memcpy(dst_slots, wr_mas->slots, sizeof(void *) * (offset + 1));
-       dst_offset = offset;
+       memcpy(dst_pivots, wr_mas->pivots, sizeof(unsigned long) * mas->offset);
+       memcpy(dst_slots, wr_mas->slots, sizeof(void *) * mas->offset);
 
        /* Handle insert of new range starting after old range */
        if (wr_mas->r_min < mas->index) {
-               mas->offset++;
-               rcu_assign_pointer(dst_slots[dst_offset], wr_mas->content);
-               dst_pivots[dst_offset++] = mas->index - 1;
+               rcu_assign_pointer(dst_slots[mas->offset], wr_mas->content);
+               dst_pivots[mas->offset++] = mas->index - 1;
        }
 
        /* Store the new entry and range end. */
-       if (dst_offset < max_piv)
-               dst_pivots[dst_offset] = mas->last;
-       mas->offset = dst_offset;
-       rcu_assign_pointer(dst_slots[dst_offset], wr_mas->entry);
+       if (mas->offset < node_pivots)
+               dst_pivots[mas->offset] = mas->last;
+       rcu_assign_pointer(dst_slots[mas->offset], wr_mas->entry);
 
        /*
         * this range wrote to the end of the node or it overwrote the rest of
         * the data
         */
-       if (wr_mas->offset_end > wr_mas->node_end || mas->last >= mas->max) {
-               new_end = dst_offset;
+       if (offset_end > wr_mas->node_end)
                goto done;
-       }
 
-       dst_offset++;
+       dst_offset = mas->offset + 1;
        /* Copy to the end of node if necessary. */
-       copy_size = wr_mas->node_end - wr_mas->offset_end + 1;
-       memcpy(dst_slots + dst_offset, wr_mas->slots + wr_mas->offset_end,
+       copy_size = wr_mas->node_end - offset_end + 1;
+       memcpy(dst_slots + dst_offset, wr_mas->slots + offset_end,
               sizeof(void *) * copy_size);
-       if (dst_offset < max_piv) {
-               if (copy_size > max_piv - dst_offset)
-                       copy_size = max_piv - dst_offset;
-
-               memcpy(dst_pivots + dst_offset,
-                      wr_mas->pivots + wr_mas->offset_end,
-                      sizeof(unsigned long) * copy_size);
-       }
+       memcpy(dst_pivots + dst_offset, wr_mas->pivots + offset_end,
+              sizeof(unsigned long) * (copy_size - 1));
 
-       if ((wr_mas->node_end == node_slots - 1) && (new_end < node_slots - 1))
+       if (new_end < node_pivots)
                dst_pivots[new_end] = mas->max;
 
 done:
@@ -4378,7 +4342,8 @@ static inline void mas_wr_modify(struct ma_wr_state *wr_mas)
 
        if (new_end == wr_mas->node_end && mas_wr_slot_store(wr_mas))
                return;
-       else if (mas_wr_node_store(wr_mas))
+
+       if (mas_wr_node_store(wr_mas, new_end))
                return;
 
        if (mas_is_err(mas))