uma: Make the cache alignment mask unsigned

[olce]

Summary

In uma_set_align_mask(), ensure that the passed value doesn't have its
highest bit set, which would lead to problems since keg/zone alignment
is internally stored as signed integers. Such big values do not make
sense anyway and indicate some programming error. A future commit will
introduce checks for this case and other ones.

MFC after: 2 weeks
Sponsored by: The FreeBSD Foundation

In uma_set_align_mask(), check that the passed value doesn't have its
highest bit set, which would lead to problems since keg/zone alignment
is internally stored as signed integers. Such big values do not make
sense anyway and indicate some programming error.

[markj]

sys/arm/arm/cpufunc.c

64–65

As a matter of style I think we prefer to write "unsigned int", though this is admittedly not documented anywhere AFAIK.

sys/vm/uma_core.c

3258–3264

I think some comment or assertion here is appropriate.

[kib]

sys/vm/uma_core.c

3258–3264

As I noted in other place, this should really assert that the mask is 2^x - 1.

[olce]

unsigned => unsigned int

[olce]

Erroneous previous diff

[olce]

sys/vm/uma_core.c

3258–3264

I didn't because this piece of code is changed by a subsequent commit. But ok, here's one.

3258–3264

Yes, already done in a subsequent commit (see D42263).

[olce]

The header sys/vm/_uma_align_mask.h has been renamed to sys/vm/uma_align_mask.h in D42258. Not updating the diff here.