Re: [PATCH 3/4] md: fix is_mddev_idle()

[Yu Kuai]

Hi,

在 2025/04/16 15:42, Yu Kuai 写道:
> Hi,
>
> 在 2025/04/16 14:20, Xiao Ni 写道:
> > > +static bool is_rdev_idle(struct md_rdev *rdev, bool init)
> > > +{
> > > +    unsigned long last_events = rdev->last_events;
> > > +
> > > +    if (!bdev_is_partition(rdev->bdev))
> > > +        return true;
> >
> >
> > For md array, I think is_rdev_idle is not useful. Because 
> > mddev->last_events must be increased while upper ios come in and idle 
> > will be set to false. For dm array, mddev->last_events can't work. So 
> > is_rdev_idle is for dm array. If member disk is one partition, 
> > is_rdev_idle alwasy returns true, and is_mddev_idle always return 
> > true. It's a bug here. Do we need to check bdev_is_partition here?
>
> is_rdev_idle() is not used for current array, for example:
>
> sda1 is used for array md0, and user doesn't issue IO to md0, while
> user issues IO to sda2. In this case, is_mddev_idle() still fail for
> array md0 because is_rdev_idle() fail.

Perhaps the name is_rdev_holder_idle() is better.

Thanks,
Kuai

> This is just inherited from the old behaviour.
>
> Thanks,
> Kuai
>
> > Best Regards
> >
> > Xiao
>
> .