On Wed, Nov 30, 2011 at 06:04:50PM +0200, Kostik Belousov wrote: > > > I wonder why the waiting_threads stuff is needed at all. The cv could > > > be woken up unconditionally everytime. What is the reason for the cv_wait > > > call in cdevpriv data destructor ? You cannot have a thread doing e.g. > > > read on the file descriptor while destructor is run. > > > > > > > What will prevent you from having a thread stuck in read(), while an > > another > > one close() the fd ? > > > Nothing, but file reference count goes to zero only after the thread > stuck in read is unstuck. Cdevpriv destructor is run only when file > reference count becomes zero, i.e. there can be no any accessing threads, > and new accesses are impossible since file descriptors also own references > on the file.
Right, I was a bit confused, this part can be removed. Regards, Olivier _______________________________________________ freebsd-current@freebsd.org mailing list http://lists.freebsd.org/mailman/listinfo/freebsd-current To unsubscribe, send any mail to "freebsd-current-unsubscr...@freebsd.org"
