Re: [RFC PATCH 0/2] kernel/power: fix swap device reference handling in hibernation swap path

[YoungJun Park <youngjun.park@lge.com>]

On Thu, Mar 05, 2026 at 12:24:12PM -0800, Usama Arif wrote:
> On Tue,  3 Mar 2026 01:53:32 +0900 Youngjun Park <youngjun.park@lge.com> wrote:
> 
> > This series addresses two issues in the hibernation swap path.
> > 
> > First, grabbing and releasing the swap device reference on every slot
> > allocation is inefficient across the entire hibernation swap path.
> > 
> > Second, in the uswsusp path, only the swap type value is retrieved at
> > lookup time without holding a reference. If swapoff races after the
> > type is acquired, subsequent slot allocations operate on a stale swap
> > device.
> > 
> > The fix is to hold the swap device reference from the point the swap
> > device is looked up, and release it once at each exit path.
> > 
> >   Patch 1: Release the reference immediately after each slot allocation
> >             as a preparatory step.
> >   Patch 2: Lift the reference acquisition to the lookup site and place
> >             put_swap_device_by_type() at all relevant cleanup paths in
> >             swap.c and user.c.
> 
> Hello!
> 
> I cant comment on the feasibility of the approach, but for proper series,
> you would need to squash the 2 commits, otherwise it would break git
> bisectability.
> 
> Thanks

Thanks for the feedback. :D
I have squashed the commits as suggested and sent the v2 patch.

Best regards,
Youngjun Park