On Wed, Mar 15, 2006 at 05:52:39PM -0500, Alan Stern wrote: > On Wed, 15 Mar 2006, Greg KH wrote: > > > > (It wouldn't be a bad idea to set dev->kobj->dentry to NULL as soon as the > > > dentry is deallocated anyway. Doing that would make bugs a little easier > > > to spot.) > > > > Due to the way that sysfs rebuilds dentrys and inodes on the fly after > > memory pressure pushes them out of the cache, it might be tougher to do > > this than you might originally think :) > > I'll leave the implementation details up to you. :-) > > > > You know, another possibility is that cdc_acm should call > > > tty_unregister_device as soon as the USB device is disconnected. It would > > > make sense; no point leaving a tty visible in sysfs if it's no longer > > > accessible (except through already-opened file descriptors). However I > > > don't know whether the tty subsystem is designed to work that way. > > > > No, do that on the last close, the disconnect should call hangup which > > will allow the userspace code to properly drop the device and then the > > tty layer can be shutdown easily. > > > > The tty layer is _not_ very good at handling dynamic devices, so you > > need to be very careful with this. > > > > I still think it's easier to reference count the whole object, but then > > hey, what do I know... :) > > Isn't acm->used essentially a reference count already? Just change it > from unsigned int to struct kref.
Yes, but you would need to do some of the other sysfs stuff in the "removal" process. I think my previous sysfs patch should solve this in a much simpler way. thanks, greg k-h ------------------------------------------------------- This SF.Net email is sponsored by xPML, a groundbreaking scripting language that extends applications into web and mobile media. Attend the live webcast and join the prime developer group breaking into this new coding territory! http://sel.as-us.falkag.net/sel?cmd=lnk&kid=110944&bid=241720&dat=121642 _______________________________________________ linux-usb-devel@lists.sourceforge.net To unsubscribe, use the last form field at: https://lists.sourceforge.net/lists/listinfo/linux-usb-devel
