On Wed, Apr 17, 2019 at 02:24:06PM -0400, Alan Stern wrote: > On Wed, 17 Apr 2019, Raul Rangel wrote: > > > > > Also where would be a good place to document this? > > > > > > Documentation/ABI/ is a good start. > > I'll add something to Documentation/ABI/testing/xhci-uevent > > Your patch will apply to all host controllers, not just xhci. The > documentation filename should reflect this. Perhaps "usb-uevent"? I realized that after I had sent the email :) I'll do usb-uevent. > > > > Why do you need to lock something that is "dead"? And why is the idr > > > lock the correct one here? > > We need to ensure that root_hub is not null. Though I'm not sure the > > lock is entirely necessary in this case. usb_remove_hcd stops the work > > item before it sets the rhdev to null. The reason I picked > > usb_bus_idr_lock was because it's the same lock that usb_remove_hcd uses > > when setting rhdev = NULL. > > > > Alan, what do you think? Should I remove the lock? > > You're both right; the lock isn't needed because the work is stopped > before the root hub gets removed. Acquiring the lock doesn't do any > harm, but it isn't needed so you probably should remove it. In fact, > you don't even need to test for whether hcd->self.root_hub is > non-NULL. Sounds good, I'll clean it up. > > Alan Stern > >
