Comment by steveklabnik
10 months ago
Rust is only allowed for drivers, because that sidesteps the platform support questions.
DMA is needed for an overwhelming number of useful drivers.
If you can’t use DMA from Rust, then you can’t really properly evaluate the usefulness of Rust, hence the effort is basically dead.
People can just include their own dma.rs in driver/.../mydriver/
Whether that's a good or bad approach is besides the point. It's what was suggested as an alternative, and clearly it's something that would work. "You can't use DMA from Rust" is just not true.
If it was a good approach, the C folks would have copied around C files instead of having common core code. They did not do that though, because it'd be counter productive due to increasing maintenance burden.
Everyone knows it would increase maintenance burden, decrease reliability, and increase the amount of apparent churn of rust code in the linux kernel.
Everyone knows you could start the crude way today and refactor the duplication later after it proves itself, if you actually wanted to proceed rather than throw fits.
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I don't know the better way to ask this question, so I'm just going to ask it:
"Congratulations, you're right, and nobody cares."
Now what? Just complain that the kernel isn't hospitable to Rust, and hope 15 years from now we're all using some Linux-compatible kernel built ground-up in Rust?
I genuinely want to know where you go from this position.
I am trying to explain why someone would say this.
I think Rust in Linux makes sense, but honestly, Rust doesn’t need Linux to be successful, and I barely use Linux personally. If they decide Rust for Linux is not a thing, that’s for the folks who work on and care about Linux to deal with. This isn’t my fight, I am just observing.
I’ve been primarily a Windows user for many years now, but I do use some WSL. My main OS is already shipping Rust, and in the actual kernel, without all of this wailing and gnashing of teeth. (That said I respect the approach Linux is taking here, I don't think it's inherently bad.)
Oh, and honestly, what I believe is happening here is just that, from Linus's perspective, folks should know that because this isn't in Hellwig's part of the tree, his NACK doesn't actually matter, and he'll just end up pulling this patch in anyway. There's no need to intervene because there isn't actually obstruction going on. The internet is just going wild about this drama because they fundamentally misunderstand how kernel development works, and because people are slinging mud on the LKML. That's why he only commented on Hector's behavior.
I can see that perspective, though I would prefer a different management style, but that's also why (among other reasons) I don't care to contribute to the kernel.