By the way: I don't agree with Hellwig, insofar I can judge things, I'm just saying his opinion is valid, and that "Linus agreed on Rust, so therefore we can merge this patch" is not really a valid argument.
If you start with the assumption of a), there are no valid technical challenges to merging it. It's just better for everyone. Before Hellwig put his foot down as "not merging because rust sucks", he made a series of technical arguments against the patch, which were all transparently bullshit. It was those arguments that really raised such a furor, instead of all the other ways some C devs have disdained rust in the kernel in the past, because they were obviously made in bad faith. And when he was called out for them, he just went full "no rust in kernel".
He didn't say this at all. He explicitly and repeatedly said he has no problems with Rust as a language.
And you can't just assert "there are no valid technical reasons". Just because you don't agree with the objections, or even think they're dumb, doesn't mean you can just dismiss them and start ascribing bad faith motives.
"And I also do not want another maintainer. If you want to make Linux impossible to maintain due to a cross-language codebase do that in your driver so that you have to do it instead of spreading this cancer to core subsystems. (where this cancer explicitly is a cross-language codebase and not rust itself, just to escape the flameware brigade)."
Stop spreading this kind of misinformation.
And no, I don't think he came off very well here, but please, give it a good faith reading.[2]
rust/bindings/bindings_helper.h | 1 +
rust/kernel/dma.rs | 271 ++++++++++++++++++++++++++++++++
rust/kernel/lib.rs | 1 +
rejecting such patch is the exact cancer that need to cured. stop misleading people.
And this cause problem. When someone make any change to Linux kernel they suppose to fix all the code they break across all kernel. And if said wrapper accepted then maintaner of DMA will have to make sure that all patches he accepts also fix Rust parts.
So he just dont want extra burden for himself.
if multiple rust based drivers all need to have DMA support, what should they do? each come up with their own little magic?
> And this cause problem. When someone make any change to Linux kernel they suppose to fix all the code they break across all kernel.
this has been explained like 10+ times in this thread - it was made crystal clear to the DMA maintainer that he/she doesn't need to maintain the rust stuff, it is totally okay to break it.
> So he just dont want extra burden for himself
he can just resign. simple and period. no one is ever forcing him/her to be the maintainer when he/she is literally forcing other people to stop developing Linux support for the only powerful & affordable ARM machine for home use.
Sorry to ask, but couldn't it be solved with cargo? I hear all the time about the benefits of Rust tooling and zero-cost abstractions.
Why can't a driver just pull/include the latest-dma-bindings crate and glue the gap with zero-cost abstractions?
If kernel DMA code/API changes, then nothing breaks in the kernel (hopefully) and the "Rust devs will quickly solve the changes" theory can be really proven and tested by quickly updating the bindings AND the updating the drivers.
No, he didnt refer to Rust as cancer, but to Rust in the Linux kernel / the R4L project.
Okay, sorry. He just said there should be no rust in the kernel.
You can ascribe bad faith motivations when someone presents technical objections that are already fully answered in the patch that was submitted, and when this is pointed out, they admit that, but don't retract their objections.
The original objections are specifically not a case of differing values or design ideas. They are nonsensical, the equivalent of 1 = 2.
That's also not what he said; it's "no Rust in kernel/dma". He pretty much explicitly said it's okay for drivers to do their thing in Rust, but with their own wrappers. You can consider that dumb, but you can't shorten that to "no Rust in the kernel".
And "I replied to your objections, therefore the matter is settled" is arrogant beyond belief. People can disagree, you know, because they have different priorities, different preferences, different perspectives, etc.
> Every additional bit that the another language creeps in drastically reduces the maintainability of the kernel as an integrated project. The only reason Linux managed to survive so long is by not having internal boundaries, and adding another language complely breaks this. You might not like my answer, but I will do everything I can do to stop this.
Have you actually taken a look at the patch?
There was NO RUST CODE ADDED TO kernel/dma, they wanted to add a dma wrapper to a rust/ folder.
I'm sorry for not being clearer, but that is specifically not what is going on. The objections were of factual, technical nature. As in, "do not do X". The problem is that the code in question was not doing X, and it was not doing anything that could be construed as doing X. The objections did not arise from differences in priorities, preferences, or perspectives, they were just factually wrong.