linuxkpi: Define XA_FLAGS_ALLOC1 in linux/xarray.h

[nc]

Summary

This is needed by the drm-kmod 5.7 update

[• hselasky]

What does this new flag do? Should it be (1U << 2) perhaps?

[nc]

In D30747#691142, @hselasky wrote:

What does this new flag do? Should it be (1U << 2) perhaps?

See:

https://www.kernel.org/doc/html/v5.5/core-api/xarray.html#allocating-xarrays
https://www.kernel.org/doc/html/v5.5/core-api/xarray.html#c.DEFINE_XARRAY_ALLOC1

[nc]

I chose (1U << 1) mainly for compatibility with Linux, but it could also be (1U << 2).

See: https://github.com/openbsd/src/search?q=XA_FLAGS_ALLOC1

[manu]

How is this needed ? We don't use xarray in drm gem yet.

[• hselasky]

OK.

This flag must be "1U << 2" in FreeBSD, and you must implement it in the xarray code like they do on Linux, by reserving index 0 from allocation.

--HPS

[nc]

Use (1U << 2) as per @hselasky's request.

[• hselasky]

Like said, this is a feature, so you need to implement this in the xarray C-code too. It is not enough just to define this flag!

[• hselasky]

I think this can be abandoned now?