Re: [PATCH] mdadm: Deprecate the obsolete --auto-detect option

[Mariusz Tkaczyk <mtkaczyk@kernel.org>]

On Wed, 28 Oct 2026 12:52:30 +0000
"Masalkhi, Abd Alrhman" <abd.masalkhi@gatech.edu> wrote:

> Hi Mariusz,
> 
> On Wed, Oct 28, 2026 at 10:03 +0100, Mariusz Tkaczyk wrote:
> > On Thu, 15 Oct 2026 13:03:59 +0000
> > "Masalkhi, Abd Alrhman" <abd.masalkhi@gatech.edu> wrote:
> >  
> >> From: Abd-Alrhman Masalkhi <abd.masalkhi@gatech.edu>
> >> 
> >> --auto-detect opened md0 (9:0) and issued the RAID_AUTORUN ioctl to
> >> ask the kernel to start the arrays it had auto-detected. The kernel
> >> removed this ioctl in commit d82fa81c2364 ("md: replace the
> >> RAID_AUTORUN ioctl with a direct function call"). Before that, it
> >> worked only when md was built into the kernel. Since then,
> >> md_ioctl()  
> >
> > Redhat still builds-in md into kernel so there is chance that
> > someone is using it.
> >
> >  
> >> has rejected it with ENOTTY, making --auto-detect ineffective on
> >> current kernels.  
> >
> >
> > Hello,
> > Do you mind to submit github PRs for mdadm patches?
> > https://github.com/md-raid-utilities/mdadm
> >  
> 
> Sure, I will submit the next version as a GitHub pull request.
> 
> One question, should I also send the RFC patches for updating mdadm to
> use the new UAPI to the mailing list, or is submitting GitHub PRs
> sufficient?


In this particular case there is nothing interesting we are going to do
with kernel or any problem that needs to be coordinated with kernel.
Just take new UAPI and use it once is available so I don't think kernel
list messaging is needed.

I forgot to say, the problem you are challenging is very legacy. With
proposed change, we will not need to open the device and generate
unnecessary events (and problems) anymore! I'm glad to see someone
working on it.

Mariusz