Re: ublk invert part scan bit logic

[Ming Lei <ming.lei@redhat.com>]

On Thu, Feb 12, 2026 at 04:05:27AM -0700, Jens Axboe wrote:
> Hi,
> 
> For ublk, there's this logic in in ublk_ctrl_start_dev():
> 
> /* Skip partition scan if disabled by user */
> if (ub->dev_info.flags & UBLK_F_NO_AUTO_PART_SCAN) {
> 	clear_bit(GD_SUPPRESS_PART_SCAN, &disk->state);
> } else {
> 	/* Schedule async partition scan for trusted daemons */
> 	if (!ub->unprivileged_daemons)
> 		schedule_work(&ub->partition_scan_work);
> }
> 
> where the
> 
> clear_bit(GD_SUPPRESS_PART_SCAN, &disk->state);
> 
> seems reversed? Why is GD_SUPPRESS_PART_SCAN being cleared if
> UBLK_F_NO_AUTO_PART_SCAN is set? Added in:
> 
> 8443e2087e70 ("ublk: add UBLK_F_NO_AUTO_PART_SCAN feature flag")

Yeah, the interface is designed in this way: partition scan is not
done during add disk, and allowed since then on. The selftest code
is written in same way too.

If GD_SUPPRESS_PART_SCAN isn't cleared, userspace can't probe partitions
any more.

However, if you think the interface isn't good, we still can change it
before 7.0 release.


Thanks
Ming