Re: [PATCH v6 09/10] dax/kmem: add sysfs interface for atomic whole-device hotplug

Gregory Price <[email protected]>
Newsgroups dev.linux.lists.nvdimm,dev.linux.lists.driver-core,org.kernel.vger.linux-cxl,org.kernel.vger.linux-kernel,org.kernel.vger.linux-kselftest,org.kvack.linux-mm
Message-ID <akSyeHnfcDmxnCSz@gourry-fedora-PF4VCD3F>
On Wed, Jul 01, 2026 at 08:13:28AM +0200, Hannes Reinecke wrote:
> On 7/1/26 12:14 AM, Gregory Price wrote:
> > On Tue, Jun 30, 2026 at 05:18:41PM -0400, Gregory Price wrote:
> > > There is no atomic mechanism to offline and remove an entire
> > > multi-block DAX kmem device.  This is presently done in two steps:
> > 
> > ... snip snip snip ...
> > 
> > Sashiko pointed out a false-positive, but adding a fixup patch
> > here that adds additional consistency.
> > 
> > On total failure - release all resources.  This makes the sysfs
> > interface consistent with the probe failure path.
> > 
> 
> Speaking of which ...
> With this patch we now have _two_ interfaces to do the same thing.
> And both will be generating uevents.
> Which is far from ideal (one could easily envision _conflicting_
> udev rules, one set doing an 'online' on the old interface,
> and another set doing an 'offline' on the new interface...)
> Is there a way to not sending uevents for the old interface
> or to make it configurable?

We do not allow "offline" in the new interface.

That fixes the entire issue - the blocks are gone, nothing to poke.

~Gregory
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