[PATCH] maple_tree: fix alloc node fail issue

[Liam R. Howlett]

* Jiazi Li <jqqlijiazi at gmail.com> [240624 08:01]:
> In the following code, the second call to the mas_node_count will
> return -ENOMEM:
> 
> 	mas_node_count(&maple_tree, 31);
> 	mas_node_count(&maple_tree, 62);

This implies mas_node_count() takes a maple tree, but it takes a maple
state.

> 
> This is because get a node with node_count is MAPLE_ALLOC_SLOTS in
> while loop of mas_alloc_nodes. And this will result in max_req
> is zero in next loop.

This description could use some work on clarity.

Please provide a testcase that reproduces the issue that will go into
tools/testing/radix-tree/maple.c  It looks like it should go around line
460.


> Signed-off-by: Jiazi Li <jiazi.li at transsion.com>

Your Signed-off-by does not match the from address.

Please add a Fixes tag.

> ---
>  lib/maple_tree.c | 4 +++-
>  1 file changed, 3 insertions(+), 1 deletion(-)
> 
> diff --git a/lib/maple_tree.c b/lib/maple_tree.c
> index aa3a5df15b8e..82c236972115 100644
> --- a/lib/maple_tree.c
> +++ b/lib/maple_tree.c
> @@ -1272,7 +1272,9 @@ static inline void mas_alloc_nodes(struct ma_state *mas, gfp_t gfp)
>  
>  		node->node_count += count;
>  		allocated += count;
> -		node = node->slot[0];
> +		do {
> +			node = node->slot[0];
> +		} while (unlikely(node->node_count == MAPLE_ALLOC_SLOTS));

Please change this to an 'if' statement as it would be more clear what's
going on.

>  		requested -= count;
>  	}
>  	mas->alloc->total = allocated;
> -- 
> 2.17.1
>