Re: [PATCH 4/7] aoe: make dynamic block minor numbers the default

[Ed Cashin <ecashin@coraid.com>]

On Oct 2, 2012, at 5:17 PM, Andrew Morton wrote:
...
>> The static arrangement is still available with aoe_dyndevs=0, and
>> the aoe-stat tool from the userland aoetools package, the user
>> space counterpart to the aoe driver, recognizes the case where
>> there is a mismatch between the minor number in sysfs and the
>> minor number in a special device file.
> 
> Oh.  There we are.
> 
> Again, what are the back-(in)compatibility issues which users might
> encounter with this?

I think the people who care about aoe_dyndevs=0 are the people creating
an initramfs without udev and with AoE targets that have low shelf and
slot numbers for addresses.

They might want a tiny bzImage that can boot off AoE storage using
device nodes prepared in advance with mknod.  The old static mapping
is a nice fit for that use case.

There could be others with a reason not to use udev, but none of those
others have ever communicated with me, if they exist.

It's probably confusing the way I did the commits, making static the
default before explicitly changing it to dynamic, but usually the people
who actually care about this are so technical that I expect them to read
the git logs, and I wanted to leave a paper trail there for anyone reading
later.

-- 
  Ed Cashin
  ecashin@coraid.com