On Tue, Jan 09 2018 at 6:41pm -0500, Mike Snitzer <snitzer@xxxxxxxxxx> wrote: > On Tue, Jan 09 2018 at 6:04pm -0500, > Bart Van Assche <Bart.VanAssche@xxxxxxx> wrote: > > > On Tue, 2018-01-09 at 17:10 -0500, Mike Snitzer wrote: > > > diff --git a/block/blk-sysfs.c b/block/blk-sysfs.c > > > index 870484eaed1f..0b0dda8e2420 100644 > > > --- a/block/blk-sysfs.c > > > +++ b/block/blk-sysfs.c > > > @@ -919,8 +919,20 @@ int blk_register_queue(struct gendisk *disk) > > > ret = 0; > > > unlock: > > > mutex_unlock(&q->sysfs_lock); > > > + > > > + /* > > > + * Take an extra ref on queue which will be put on disk_release() > > > + * so that it sticks around as long as @disk is there. > > > + */ > > > + WARN_ON_ONCE(!blk_get_queue(q)); > > > + > > > + WARN_ON(sysfs_create_link(&dev->kobj, > > > + &q->backing_dev_info->dev->kobj, > > > + "bdi")); > > > + > > > return ret; > > > } > > > +EXPORT_SYMBOL_GPL(blk_register_queue); > > > > Hello Mike, > > > > So the sysfs_create_link() call is moved from register_disk() into > > blk_register_queue() but the sysfs_remove_link() call stays in del_gendisk()? > > Are you sure that you want this asymmetry? > > My focus was on the add_disk() side of things, due to disk->queue > possibly being NULL on add. But on remove all was basically left > unmodified (aside from removing the WARN_ON). > > I dont think the asymmetry is a big deal but I can fix it. I'll wait > for more feedback before sending out a v2 though. But while reviewing this asymetry I found that the sysfs_create_link() that I moved to blk_register_queue() needs to be guarded against GENHD_FL_HIDDEN -- I didn't notice the GENHD_FL_HIDDEN early return in register_disk(). I'll get that fixed up. But unrelated to my patch: I think I found another curious imbalance, in current upstream code, relative to GENHD_FL_HIDDEN. bdi_register_owner() is only called if !GENHD_FL_HIDDEN but bdi_unregister() is called unconditionally. Not sure what is needed to address that issue because I'd have thought that the bdi would be needed regardless of GENHD_FL_HIDDEN. Christoph? -- dm-devel mailing list dm-devel@xxxxxxxxxx https://www.redhat.com/mailman/listinfo/dm-devel
