Re: [PATCH 1/2] maple_tree: fix alloc node fail issue

From: Wei Yang
Date: Thu Oct 10 2024 - 21:09:57 EST


On Wed, Jun 26, 2024 at 12:06:30PM -0400, Liam R. Howlett wrote:
>From: Jiazi Li <jqqlijiazi@xxxxxxxxx>
>
>In the following code, the second call to the mas_node_count will
>return -ENOMEM:
>
> mas_node_count(mas, MAPLE_ALLOC_SLOTS + 1);
> mas_node_count(mas, MAPLE_ALLOC_SLOTS * 2 + 2);
>
>This is because there may be some full maple_alloc node in current
>maple state. Use full maple_alloc node will make max_req equal to 0.
>And it leads to mt_alloc_bulk return 0.
>As a result, mas_node_count set mas.node to MA_ERROR(-ENOMEM).
>
>Find a non-full maple_alloc node, and if necessary, use this non-full
>node in the next while loop.
>
>Fixes: 54a611b60590 ("Maple Tree: add new data structure")
>Suggested-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>
>Signed-off-by: Jiazi Li <jqqlijiazi@xxxxxxxxx>
>Signed-off-by: Liam R. Howlett <Liam.Howlett@xxxxxxxxxx>

Reviewed-by: Wei Yang <richard.weiyang@xxxxxxxxx>


This looks good to me.

I don't see it is in the master. Not sure this is missed.

--
Wei Yang
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