gnop: add the option for adding a suffix to the name of the device

[oshogbo]

Summary

Thanks to this option we can create more then one gnop provider from
single provider. This may be useful for temporary labeling some data
on the disk.

[markj]

Why don't we just have a "name" parameter that determines the entire gnop provider name?

[allanjude]

In D22304#487863, @markj wrote:

Why don't we just have a "name" parameter that determines the entire gnop provider name?

I like Mark's idea, change the flag to just let you specify the entire name of the resulting provider (the parameter passed to g_new_geomf())

[oshogbo]

I'm fine with naming nop devices any name as long as there is a nop suffix.
Otherwise somebody may do some weird stuff in /dev/.

[markj]

lib/geom/nop/gnop.8

158

Should be "the new provider".

159

I think it would be clearer to refer to it as a suffix. For example, "The suffix .Dq .nop will be appended to the provider name."

sys/geom/nop/g_nop.c

33

param.h is special and should come first in the include order.

91

Why not write these as boolean expressions? if (!islower(name[i]) && !isdigit(name[i])) ...

I do not see why upper case characters should be prohibited.

392

Perhaps include the name in the error message.

[oshogbo]

Address @markj comments.

[oshogbo]

sys/geom/nop/g_nop.c

33

Fixed.

91

style(9) defines so.
I added upper cases.

[bcr]

OK for the manpage.