On Sat, Apr 19, 2025 at 06:08:30PM +0530, Nilay Shroff wrote: > > > On 4/18/25 10:06 PM, Ming Lei wrote: > > Move blk_unregister_queue() & device_del() after freeze wait, and prepare > > for unifying elevator switch. > > > > This way is just fine, since bdev has been unhashed at the beginning of > > del_gendisk(), both blk_unregister_queue() & device_del() are dealing > > with kobject & debugfs thing only. > > > > Signed-off-by: Ming Lei <ming.lei@xxxxxxxxxx> > > --- > > block/genhd.c | 6 +++--- > > 1 file changed, 3 insertions(+), 3 deletions(-) > > > > diff --git a/block/genhd.c b/block/genhd.c > > index d22fdc0d5383..86c3db5b9305 100644 > > --- a/block/genhd.c > > +++ b/block/genhd.c > > @@ -749,8 +749,6 @@ static int __del_gendisk(struct gendisk_data *data) > > bdi_unregister(disk->bdi); > > } > > > > - blk_unregister_queue(disk); > > - > > kobject_put(disk->part0->bd_holder_dir); > > kobject_put(disk->slave_dir); > > disk->slave_dir = NULL; > > @@ -759,10 +757,12 @@ static int __del_gendisk(struct gendisk_data *data) > > disk->part0->bd_stamp = 0; > > sysfs_remove_link(block_depr, dev_name(disk_to_dev(disk))); > > pm_runtime_set_memalloc_noio(disk_to_dev(disk), false); > > - device_del(disk_to_dev(disk)); > > > > blk_mq_freeze_queue_wait(q); > > > > + blk_unregister_queue(disk); > > + device_del(disk_to_dev(disk)); > > + > > blk_throtl_cancel_bios(disk); > > > > blk_sync_queue(q); > As we first freeze the queue and then enter blk_unregister_queue which > deals with kobject/debufs, do we need to create memalloc GFP_NOIO scope > while running blk_unregister_queue? I see that device_del already defines > the GFP_NOIO scope. We actually need to do that with the read lock together. Thanks, Ming
