diff options
| -rw-r--r-- | lib/maple_tree.c | 44 |
1 files changed, 43 insertions, 1 deletions
diff --git a/lib/maple_tree.c b/lib/maple_tree.c index db61cdd8a649..4a111785360f 100644 --- a/lib/maple_tree.c +++ b/lib/maple_tree.c @@ -5535,9 +5535,51 @@ EXPORT_SYMBOL_GPL(mas_store_prealloc); */ int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp) { + MA_WR_STATE(wr_mas, mas, entry); + unsigned char node_size; + int request = 1; int ret; - mas_node_count_gfp(mas, 1 + mas_mt_height(mas) * 3, gfp); + + if (unlikely(!mas->index && mas->last == ULONG_MAX)) + goto ask_now; + + mas_wr_store_setup(&wr_mas); + wr_mas.content = mas_start(mas); + /* Root expand */ + if (unlikely(mas_is_none(mas) || mas_is_ptr(mas))) + goto ask_now; + + if (unlikely(!mas_wr_walk(&wr_mas))) { + /* Spanning store, use worst case for now */ + request = 1 + mas_mt_height(mas) * 3; + goto ask_now; + } + + /* At this point, we are at the leaf node that needs to be altered. */ + /* Exact fit, no nodes needed. */ + if (wr_mas.r_min == mas->index && wr_mas.r_max == mas->last) + return 0; + + mas_wr_end_piv(&wr_mas); + node_size = mas_wr_new_end(&wr_mas); + if (node_size >= mt_slots[wr_mas.type]) { + /* Split, worst case for now. */ + request = 1 + mas_mt_height(mas) * 2; + goto ask_now; + } + + /* New root needs a singe node */ + if (unlikely(mte_is_root(mas->node))) + goto ask_now; + + /* Potential spanning rebalance collapsing a node, use worst-case */ + if (node_size - 1 <= mt_min_slots[wr_mas.type]) + request = mas_mt_height(mas) * 2 - 1; + + /* node store, slot store needs one node */ +ask_now: + mas_node_count_gfp(mas, request, gfp); mas->mas_flags |= MA_STATE_PREALLOC; if (likely(!mas_is_err(mas))) return 0; |