* Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx> [231212 14:46]:
> mas_preallocate() defaults to requesting 1 node for preallocation and then
> ,depending on the type of store, will update the request variable. There
> isn't a check for a slot store type, so slot stores are preallocating the
> default 1 node. Slot stores do not require any additional nodes, so add a
> check for the slot store case that will bypass node_count_gfp(). Update
> the tests to reflect that slot stores do not require allocations.
>
> User visible effects of this bug include increased memory usage from the
> unneeded node that was allocated.
>
> Fixes: 0b8bb544b1a7 ("maple_tree: update mas_preallocate() testing")
> Signed-off-by: Sidhartha Kumar <sidhartha.kumar@xxxxxxxxxx>
Reviewed-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
> ---
> This patch passes the maple tree test suite. A seperate patch will be sent
> for a 6.6 stable backport as the node_end field was moved from the
> ma_wr_state to the ma_state in a recent patch which is not in 6.6.
>
>
> lib/maple_tree.c | 6 ++++++
> tools/testing/radix-tree/maple.c | 2 +-
> 2 files changed, 7 insertions(+), 1 deletion(-)
>
> diff --git a/lib/maple_tree.c b/lib/maple_tree.c
> index e6954fa75eb5..e4a39beb1018 100644
> --- a/lib/maple_tree.c
> +++ b/lib/maple_tree.c
> @@ -5475,6 +5475,12 @@ int mas_preallocate(struct ma_state *mas, void *entry, gfp_t gfp)
>
> mas_wr_end_piv(&wr_mas);
> node_size = mas_wr_new_end(&wr_mas);
> +
> + /* Slot store, does not require additional nodes */
> + if ((node_size == mas->end) && ((!mt_in_rcu(mas->tree))
> + || (wr_mas.offset_end - mas->offset == 1)))
> + return 0;
> +
> if (node_size >= mt_slots[wr_mas.type]) {
> /* Split, worst case for now. */
> request = 1 + mas_mt_height(mas) * 2;
> diff --git a/tools/testing/radix-tree/maple.c b/tools/testing/radix-tree/maple.c
> index 687886cebd9d..f1caf4bcf937 100644
> --- a/tools/testing/radix-tree/maple.c
> +++ b/tools/testing/radix-tree/maple.c
> @@ -35545,7 +35545,7 @@ static noinline void __init check_prealloc(struct maple_tree *mt)
> MT_BUG_ON(mt, mas_preallocate(&mas, ptr, GFP_KERNEL) != 0);
> allocated = mas_allocated(&mas);
> height = mas_mt_height(&mas);
> - MT_BUG_ON(mt, allocated != 1);
> + MT_BUG_ON(mt, allocated != 0);
> mas_store_prealloc(&mas, ptr);
> MT_BUG_ON(mt, mas_allocated(&mas) != 0);
>
> --
> 2.42.0
>
