I think Hellwig understands everything very well, he just wants things done his way, for whatever (possibly valid) reason he might have.
Literaly from your quotation: “I assume that we’re good with maintaining the DMA Rust abstractions separately […] No, I’m not” He understands the abstractions would not be in his domain and maintained by someone else, he does not want abstraction at all.
Maybe you are not familiar with the proposal but these “separate rust abstractions” would be a separate module that depends on DMA mapping as a client and deals with cross-language issues, rust drivers would then be clients of this module, it would not be part of the DMA mapping module, it would not be mixed with the DMA code.
But Hellwig doesn’t want an abstraction module at all, Instead he want’s you to “do that [the abstraction] in your driver so that you have to do it [maintain a cross-language codebase]”.
Please notice that the abstraction module would not add any more burden on him than the drivers themselves would, because as of now C code is allowed to break Rust code. It would only remove burden from maintainers of Rust drivers, and even if it weren’t it would be easier to fix just the abstraction instead of every driver.
He also refuses to have other people maintain the abstraction, this too for whatever reason, which accredits his request to not add abstraction he would have to maintain. If the abstraction were part of the core dma mapping code, I think it would be a reasonable request, but it wouldn’t be.
Now, we do not know the reason why he opposes it so much. From his words it looks like he doesn’t want Linux to be a cross-language codebase, which would be a valid reason in itself, but dealing with abstractions in drivers instead of a module doesn’t make it any less cross-language, unless the drivers are out of tree, which they wouldn’t be. Some people (e.g. Hector Martin) think that he’s hoping the Rust for Linux project to fail altogether, and fore rust code to be removed from the kernel, and this obstruction would partake in that. I do not think it is that drastic, I think he just fears that those abstraction would eventually become part of what he has to maintain, and no amount of reassurance or new maintainers would change his mind.
I also don’t think Martin’s brigading is anything productive, and I hope that doesn’t become the reason that rust code gets obstructed from being merged into the kernel, but it sure does focus the attention on these matters.
I think Hellwig understands everything very well, he just wants things done his way, for whatever (possibly valid) reason he might have.
Literaly from your quotation: “I assume that we’re good with maintaining the DMA Rust abstractions separately […] No, I’m not” He understands the abstractions would not be in his domain and maintained by someone else, he does not want abstraction at all.
Maybe you are not familiar with the proposal but these “separate rust abstractions” would be a separate module that depends on DMA mapping as a client and deals with cross-language issues, rust drivers would then be clients of this module, it would not be part of the DMA mapping module, it would not be mixed with the DMA code. But Hellwig doesn’t want an abstraction module at all, Instead he want’s you to “do that [the abstraction] in your driver so that you have to do it [maintain a cross-language codebase]”.
Please notice that the abstraction module would not add any more burden on him than the drivers themselves would, because as of now C code is allowed to break Rust code. It would only remove burden from maintainers of Rust drivers, and even if it weren’t it would be easier to fix just the abstraction instead of every driver.
He also refuses to have other people maintain the abstraction, this too for whatever reason, which accredits his request to not add abstraction he would have to maintain. If the abstraction were part of the core dma mapping code, I think it would be a reasonable request, but it wouldn’t be.
Now, we do not know the reason why he opposes it so much. From his words it looks like he doesn’t want Linux to be a cross-language codebase, which would be a valid reason in itself, but dealing with abstractions in drivers instead of a module doesn’t make it any less cross-language, unless the drivers are out of tree, which they wouldn’t be. Some people (e.g. Hector Martin) think that he’s hoping the Rust for Linux project to fail altogether, and fore rust code to be removed from the kernel, and this obstruction would partake in that. I do not think it is that drastic, I think he just fears that those abstraction would eventually become part of what he has to maintain, and no amount of reassurance or new maintainers would change his mind.
I also don’t think Martin’s brigading is anything productive, and I hope that doesn’t become the reason that rust code gets obstructed from being merged into the kernel, but it sure does focus the attention on these matters.