* Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx> [241011 17:44]:
> It is possible for a bulk operation (MA_STATE_BULK is set) to enter the
> new_end < mt_min_slots[type] case and set wr_rebalance as a store type.
> This is incorrect as bulk stores do not rebalance per write, but rather
> after the all of the writes are done through the mas_bulk_rebalance()
> path. Therefore, add a check to make sure MA_STATE_BULK is not set
> before we return wr_rebalance as the store type.
>
> Also add a test to make sure wr_rebalance is never the store type when
> doing bulk operations via mas_expected_entries()
>
> Fixes: 5d659bbb52a2 ("maple_tree: introduce mas_wr_store_type()")
> Suggested-by: Liam Howlett <liam.howlett@xxxxxxxxxx>
> Signed-off-by: Sidhartha <sidhartha.kumar@xxxxxxxxxx>
Reviewed-by: Liam Howlett <liam.howlett@xxxxxxxxxx>
> ---
>
> Hi Andrew, this commit is a hotfix for this rc however it has no userspace
> effects as there are no users of the bulk instertion mode.
>
> lib/maple_tree.c | 2 +-
> tools/testing/radix-tree/maple.c | 26 ++++++++++++++++++++++++++
> 2 files changed, 27 insertions(+), 1 deletion(-)
>
> diff --git a/lib/maple_tree.c b/lib/maple_tree.c
> index 4b423330d83c..b3b1d4b8126b 100644
> --- a/lib/maple_tree.c
> +++ b/lib/maple_tree.c
> @@ -4228,7 +4228,7 @@ static inline void mas_wr_store_type(struct ma_wr_state *wr_mas)
>
> /* Potential spanning rebalance collapsing a node */
> if (new_end < mt_min_slots[wr_mas->type]) {
> - if (!mte_is_root(mas->node)) {
> + if (!mte_is_root(mas->node) && !(mas->mas_flags & MA_STATE_BULK)) {
> mas->store_type = wr_rebalance;
> return;
> }
> diff --git a/tools/testing/radix-tree/maple.c b/tools/testing/radix-tree/maple.c
> index 5fde09999be4..551ae6898c1d 100644
> --- a/tools/testing/radix-tree/maple.c
> +++ b/tools/testing/radix-tree/maple.c
> @@ -36317,6 +36317,28 @@ static inline int check_vma_modification(struct maple_tree *mt)
> return 0;
> }
>
> +/*
> + * test to check that bulk stores do not use wr_rebalance as the store
> + * type.
> + */
> +static inline void check_bulk_rebalance(struct maple_tree *mt)
> +{
> + MA_STATE(mas, mt, ULONG_MAX, ULONG_MAX);
> + int max = 10;
> +
> + build_full_tree(mt, 0, 2);
> +
> + /* erase every entry in the tree */
> + do {
> + /* set up bulk store mode */
> + mas_expected_entries(&mas, max);
> + mas_erase(&mas);
> + MT_BUG_ON(mt, mas.store_type == wr_rebalance);
> + } while (mas_prev(&mas, 0) != NULL);
> +
> + mas_destroy(&mas);
> +}
> +
> void farmer_tests(void)
> {
> struct maple_node *node;
> @@ -36328,6 +36350,10 @@ void farmer_tests(void)
> check_vma_modification(&tree);
> mtree_destroy(&tree);
>
> + mt_init(&tree);
> + check_bulk_rebalance(&tree);
> + mtree_destroy(&tree);
> +
> tree.ma_root = xa_mk_value(0);
> mt_dump(&tree, mt_dump_dec);
>
> --
> 2.43.0
>
