On Mon, Oct 30, 2017 at 02:10:16PM +0100, Jan Kara wrote:
> On Fri 27-10-17 01:36:14, weiping zhang wrote:
> > In order to make error handle more cleaner we call bdi_debug_register
> > before set state to WB_registered, that we can avoid call bdi_unregister
> > in release_bdi().
> >
> > Signed-off-by: weiping zhang <zhangweip...@didichuxing.com>
> > ---
> > mm/backing-dev.c | 7 ++++++-
> > 1 file changed, 6 insertions(+), 1 deletion(-)
> >
> > diff --git a/mm/backing-dev.c b/mm/backing-dev.c
> > index e9d6a1ede12b..54396d53f471 100644
> > --- a/mm/backing-dev.c
> > +++ b/mm/backing-dev.c
> > @@ -893,10 +893,13 @@ int bdi_register_va(struct backing_dev_info *bdi,
> > const char *fmt, va_list args)
> > if (IS_ERR(dev))
> > return PTR_ERR(dev);
> >
> > + if (bdi_debug_register(bdi, dev_name(dev))) {
> > + device_destroy(bdi_class, dev->devt);
> > + return -ENOMEM;
> > + }
> > cgwb_bdi_register(bdi);
> > bdi->dev = dev;
> >
> > - bdi_debug_register(bdi, dev_name(dev));
> > set_bit(WB_registered, &bdi->wb.state);
> >
> > spin_lock_bh(&bdi_lock);
> > @@ -916,6 +919,8 @@ int bdi_register(struct backing_dev_info *bdi, const
> > char *fmt, ...)
> > va_start(args, fmt);
> > ret = bdi_register_va(bdi, fmt, args);
> > va_end(args);
> > + if (ret)
> > + bdi_put(bdi);
>
> Why do you drop bdi reference here in case of error? We didn't do it
> previously if bdi_register_va() failed for other reasons...
>
At first I want add cleanup, because
device_add_disk->bdi_register_owner->bdi_register doen't do clanup. But
I notice that mtd_bdi_init also call bdi_register and do cleanup, so
this bdi_put() is wrong. I'll remove it at V2. Thanks a lot.
--
weiping
