isboot: help me understand what CAM is doing

Hi all-

I=E2=80=99m working on a cosmetic bug in isboot-kmod. There is a global =
string called isboot_boot_device which is printed for informational =
purposes and also available via the net.isboot.device sysctl. The string =
is populated in this function: =
https://github.com/jnielsendotnet/isboot/blob/master/src/iscsi.c#L1870.

I don=E2=80=99t know when this changed but historically the string =
comparison on =
https://github.com/jnielsendotnet/isboot/blob/master/src/iscsi.c#L1904 =
would be called once with =E2=80=9Cpass=E2=80=9D and once with =E2=80=9Cda=
=E2=80=9D and the global isboot_boot_device would be correctly populated =
with e.g. =E2=80=9Cda0=E2=80=9D.

That sometimes happens in the current code as well, but on my test =
machine (running 14-STABLE) it is ONLY when I have enabled debug output =
(by setting bootverbose or net.isboot.debug to 1 or higher). Otherwise, =
the string comparison is called only once with =E2=80=9Cprobe=E2=80=9D =
rather than =E2=80=9Cpass=E2=80=9D or =E2=80=9Cda=E2=80=9D. Everything =
still works in this case; the disk is found (at da0 or whatever) and =
mounted, but the isboot_boot_device is never populated (or populated =
with the wrong name like =E2=80=9Cprobe0=E2=80=9D if I mess with what =
the string comparison is looking for.

There is no functional change other than debug messages when debug =
output is enabled, so I=E2=80=99m guessing this is a race condition. But =
since I am still a rank amateur when it comes to kernel programming I =
don=E2=80=99t know where else to look. So my questions are twofold:

1) What is going on here? When does the =E2=80=9Cprobe=E2=80=9D name =
show up in ccb.cgdl.periph_name and why doesn=E2=80=99t the loop ever =
see =E2=80=9Cda=E2=80=9D or =E2=80=9Cpass=E2=80=9D when it does? =
Corollary: does isboot_cam_set_devices() operate in a safe/sane way for =
modern CAM?=20

2) What would be a safer or more reliable way to determine the correct =
device name so it can be written to the isboot_boot_device global =
variable?

Thanks!

JN