kern/55814: setroot(9) doesn't show "root on xxNa" if RB_ASKNAME is specified

[Izumi Tsutsui <tsutsui%ceres.dti.ne.jp@localhost>]

>Number:         55814
>Category:       kern
>Synopsis:       setroot(9) doesn't show "root on xxNa" if RB_ASKNAME is specified
>Confidential:   no
>Severity:       non-critical
>Priority:       medium
>Responsible:    kern-bug-people
>State:          open
>Class:          sw-bug
>Submitter-Id:   net
>Arrival-Date:   Thu Nov 19 15:10:00 +0000 2020
>Originator:     Izumi Tsutsui
>Release:        NetBSD 9.1
>Organization:
>Environment:
System: NetBSD mirage 9.1 NetBSD 9.1 (GENERIC) #0: Sun Oct 18 19:24:30 UTC 2020 mkrepro%mkrepro.NetBSD.org@localhost:/usr/src/sys/arch/i386/compile/GENERIC i386
Architecture: i386 but maybe MI
Machine: i386 but maybe MI
>Description:
When a kernel is boot with RB_ASKNAME (or no bootinfo),
setroot(9) longer show "root on wd0a" etc.
but only show " dumps on wd0b" etc.

>How-To-Repeat:
Boot kernels wit RB_ASKNAME.

NetBSD/dreamcast 8.0:
 https://dmesgd.nycbug.org/index.cgi?do=view&id=4618
---
wd0 at atabus0 drive 1
wd0: <SDCFHS-032G>
wd0: drive supports 1-sector PIO transfers, LBA48 addressing
wd0: 30535 MB, 62041 cyl, 16 head, 63 sec, 512 bytes/sect x 62537328 sectors
wd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 5 (Ultra/100)
root device: wd0
dump device (default wd0b): 
file system (default generic): 
root on wd0a dumps on wd0b
root file system type: ffs
---

NetBSD/dreamcast 9.0:
 https://dmesgd.nycbug.org/index.cgi?do=view&id=5406
---
wd0 at atabus0 drive 1
wd0: <SDCFHS-032G>
wd0: drive supports 1-sector PIO transfers, LBA48 addressing
wd0: 30535 MB, 62041 cyl, 16 head, 63 sec, 512 bytes/sect x 62537328 sectors
wd0: drive supports PIO mode 4, DMA mode 2, Ultra-DMA mode 5 (Ultra/100)root device: wd0a
dump device (default wd0b): 
file system (default generic): 
 dumps on wd0b
root file system type: ffs
---

>Fix:
Maybe something wrong in the following "no functional" change?

http://cvsweb.netbsd.org/bsdweb.cgi/src/sys/kern/kern_subr.c#rev1.221
> Refactor setroot, no functional change intended.
> 
> setroot
> - prepare special cases
> - loop until root is set
> 
> setroot_nfs
> - special case for disk boot + NFS root
> 
> setroot_ask
> - Prompt user
> 
> setroot_root
> - set root device
> 
> setroot_dump
> - set dump device

---
Izumi Tsutsui