Am Mittwoch, 30. September 2009 00:07:25 schrieb Alan Stern: > > I have no problem with exporting this feature at all. It is necessary for > > what you want to do and what you want to do is useful. > > My problem is with the API to user space. I suggest that you add this > > to the storage driver not generic USB code and all is well. > > Do you mean _both_ storage drivers (usb-storage and ub)? What about > future storage drivers (UASP)? You can see why I preferred to add it > in the core... That's a factor. usbfs would still be better. > > You could even make an API that makes the storage driver unregister > > the SCSI host but retain its binding to the device until it tells usbcore > > to disable the port. That closes the race with probe(). > > There is no need to worry about races with probe, as far as usb-storage > is concerned. Probe and unbind are already sufficiently mutually > exclusive. I don't know about ub. You race between "safe unplug" and another probe. Races in between unmounting and unbinding the driver can be fixed in user space. But after unbinding and before "safe unplug" the device can be probed again. That you cannot avoid in user space because it can be triggered by attaching another device which triggers a driver being loaded which cannot be avoided. Putting the API into usbfs fixes this, as usbfs has a concept of claiming a device. Regards Oliver -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
