Il 24/09/2014 13:48, Igor Mammedov ha scritto: > usb-storage uses SCSI bus to provide underling storage > (i.e. scsi-disk) and it's hotpluggable. In addition > during usb-storage hotplug bus_add_child() won't allow > to add scsi-disk to SCSI bus owned by usb-storage > if bus is not hotpluggable. > > By default SCSI bus was alway hotpluggable even if > an owner didn't support hotplug. It will change > once BusState.allow_hotplug field is dropped and > SCSI bus will be only hotpluggable only if bus owner > implements HOTPLUG_HANDLER interface. > > So make usb-storage implement HOTPLUG_HANDLER interface > to keep its SCSI bus hotpluggable.
Correct. usb-bot unfortunately is not hot-pluggable because we would plug it with no SCSI LUN inside. The guest would not be able to access it. We would have to delay the presentation of the usb-bot device until after the LUN is there. Perhaps some kind of transaction mechanism? However, usb-storage builds the outer USB device and the inner SCSI device at the same time, so it can be hot-plugged. What you do for usb-storage should also be done for lsi, esp, usb-uas, etc. Paolo
