ctl: Add CTL_IO_ASSERT wrapper macro

[jhb]

Summary

Currently, this pattern is commonly used to assert that a union ctl_io
is a SCSI request. In the future it will be used to assert other
types.

Suggested by: imp
Sponsored by: Chelsio Communications

[jhb]

sys/cam/ctl/ctl_io.h

595

I also added a CTL_IO_ASSERT_NVME(io) that I use later in this series.

However, I still end up with a few places that want to assert the io_type is 2 different types (e.g. NVME or NVME_ADMIN, or NVME or SCSI). I wonder if it makes sense to get a bit fancy and instead add a couple of helper macros that take a VA_ARGS number of types so you can say something like:

CTL_IO_ASSERT_TYPE(SCSI);
CTL_IO_ASSERT_TYPE(NVME);
CTL_IO_ASSERT_TYPE(SCSI, NVME);

Where the last one asserts that the type is either SCSI or NVME. Under the hood there would be a CTL_IO_ASSERT_TYPE_1 and CTL_IO_ASSERT_TYPE_2 and CTL_IO_ASSERT would pick the right backing macro based on the number of arguments passed similar to how CTR maps to CTRn.

[imp]

sys/cam/ctl/ctl_io.h

595

It would be cool if we could...

[jhb]

Rework macro to allow for one or more types as var-args