On Sun, 2017-12-10 at 15:44 +0100, Hannes Reinecke wrote: > You know what, I have been working on a similar patch for quite some > time now; [ ... ] That's very interesting :-) > However, in doing so I have encountered several issues which have been > exposed by that; the most trivial one being that del_gendisk() doesn't > check if GENHD_FL_UP is set, so it'll crash if sd_remove is called > before sd_async_probe() is run. Have you noticed that my patch adds a call to sd_wait_for_probing() before the call to del_gendisk()? That should be sufficient to prevent the crash you described. > The other one is an imbalance between sd_probe and sd_remove; > when sd_probe_async() is called _after_ scsi_device_remove_device() > (which it will as the synchronization is only after device_del() has > been called) it will trip over non-existent sysfs directories in add_disk(). > So one need to short-circuit sd_probe_async() for devices in SDEV_CANCEL > or SDEV_DEL. Same comment here - I think the sd_wait_for_probing() call I inserted in sd_remove() should prevent this scenario. > However, I'm still waiting for a final confirmation on the latter issue, > hence I haven't posted the patchset. > If there's interest I can post them, though. The big question here is how you would like to proceed - should we start from your patch series or start from my patch? Since I have not encountered any of the issues you described with my patch, does that mean that the approach I followed results in more reliable operation? Thanks, Bart.
