On 2022-01-11 4:02 p.m., Jason Gunthorpe wrote:
On Tue, Jan 11, 2022 at 03:57:07PM -0700, Logan Gunthorpe wrote:
On 2022-01-11 3:53 p.m., Jason Gunthorpe wrote:
I just want to share the whole API that will have to exist to reasonably support this flexible array of intervals data structure..
Is that really worth it? I feel like type safety justifies replicating a bit of iteration and allocation infrastructure. Then there's no silly mistakes of thinking one array is one thing when it is not.
If it is a 'a bit' then sure, but I suspect doing a good job here will be a lot of code here.
Look at how big scatterlist is, for instance.
Yeah, but scatterlist has a ton of cruft; numerous ways to allocate, multiple iterators, developers using it in different ways, etc, etc. It's a big mess. bvec.h is much smaller (though includes stuff that wouldn't necessarily be appropriate here).
Also some things apply to one but not the other. eg: a memcpy to/from function might make sense for a phy_range but makes no sense for a dma_range.
Maybe we could have a generic 64 bit interval arry and then two type wrappers that do dma and physaddr casting? IDK.
Not sure type safety of DMA vs CPU address is critical?
I would argue it is. A DMA address is not a CPU address and should not be treated the same.
Logan