Re: [PATCH v12 22/22] rust: maple_tree: implement Send and Sync for MapleTree

Joel Fernandes
2026-05-02T17:36:58Z

On 5/2/2026 11:42 AM, Alexandre Courbot wrote:
> On Sun Apr 26, 2026 at 6:14 AM JST, Joel Fernandes wrote:
>> The C maple_tree struct contains a *mut c_void, which prevents Rust from
>> auto-deriving Send/Sync. Following is an example error message when using
>> MapleTree in nova-core's Vmm.
>>
>> This propagates up through MapleTreeAlloc to Vmm, BarUser, Gpu, and NovaCore,
>> causing NovaCore to fail the Send bound required by pci::Driver:
>
> This patch is not at the right place - the last few patches of the
> series won't build without it.

Right, the maple tree change in an earlier patch makes this one required to
go before it.

> Besides you have sent it separately before this series, so just mention
> it as a dependency in the cover letter, so reviewers can pick it up
> before applying the series and not witness it breaking in the course of
> reviewing it. The cover letter already mentions the bitfield series as a
> dependency, so the same could have been done for this one.

The sending separately bit was actually an early RFC I wanted to get
feedback on. But indeed, now that I have got that I can just post it
independently. I'll post it separately once I am back to work. Thanks,

--
Joel Fernandes