char devices without SI_UNMAPPED?

[Alan Somers]

On Sun, Dec 13, 2020 at 11:20 AM Warner Losh <imp at bsdimp.com> wrote:

>
>
> On Sun, Dec 13, 2020 at 11:18 AM Ian Lepore <ian at freebsd.org> wrote:
>
>> On Sun, 2020-12-13 at 10:27 -0700, alan somers wrote:
>> > I'm trying to exercise the aio code that handles character devices
>> > that
>> > don't set the SI_UNMAPPED flag.  But I can't find any.  Are there any
>> > remaining character devices that don't allow unmapped I/O?
>> >
>> > -Alan
>> >
>>
>> I assume you mean disk-like devices?  Probably mmcsd, flash/at45d,
>> flash/mx25l.
>>
>
Hm.  I don't have any of those.


>
> There are times that it's disabled administratively as well, but that may
> be on a per-I/O basis.
> vfs.zfs.vol.unmap_enabled: 1
>

This one doesn't seem to work.  It looks like the only functionality it
gates these days is DIOCGDELETE.


> vfs.unmapped_buf_allowed: 1
>

Well, this one works.  Thanks for the tip.  Unfortunately, it's a tunable,
so I can't use it for any kind of automated testing.


>
> "Why do you ask?" is the next question...
>
> Warner
>