On Mon, Jul 18, 2022 at 12:17 AM Hannes Reinecke <hare@xxxxxxx> wrote:
>
> On 7/18/22 08:34, Christoph Hellwig wrote:
> > This ensures device names don't get prematurely reused. Instead add a
> > deleted flag to skip already deleted devices in mddev_get and other
> > places that only want to see live mddevs.
> >
> > Reported-by; Logan Gunthorpe <logang@xxxxxxxxxxxx>
> > Signed-off-by: Christoph Hellwig <hch@xxxxxx>
> > ---
> > drivers/md/md.c | 56 +++++++++++++++++++++++++++++++++----------------
> > drivers/md/md.h | 1 +
> > 2 files changed, 39 insertions(+), 18 deletions(-)
> >
> > diff --git a/drivers/md/md.c b/drivers/md/md.c
> > index 805f2b4ed9c0d..08cf21ad4c2d7 100644
> > --- a/drivers/md/md.c
> > +++ b/drivers/md/md.c
> > @@ -625,6 +625,10 @@ EXPORT_SYMBOL(md_flush_request);
> >
> > static inline struct mddev *mddev_get(struct mddev *mddev)
> > {
> > + lockdep_assert_held(&all_mddevs_lock);
> > +
> > + if (mddev->deleted)
> > + return NULL;
> > atomic_inc(&mddev->active);
> > return mddev;
> > }
>
> Why can't we use 'atomic_inc_unless_zero' here and do away with the
> additional 'deleted' flag?
Thanks Christoph for the set. And thanks Hannes for the quick review!
I think atomic_inc_unless_zero() should work here. Alternatively, we can
also grab a big from mddev->flags as MD_DELETED.
Thanks,
Song
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