(Sorry just ignore that. Our existing approach is better) On Thu, 4 Apr 2019, 10:00 Okash Khawaja, <okash.khawaja@xxxxxxxxx> wrote: > On Thu, 4 Apr 2019 00:21:34 +0200 > Samuel Thibault <samuel.thibault@xxxxxxxxxxxx> wrote: > > > But can't just just get the kref in set_selection before using > > cmpxchg? and if that fails, put it back. If it succeeded, the work > > schedule will happen, and either it will manage to take the tty and > > put its kref, or be canceled, and the kref will be put as well. > > Thinking about it, we can also make use of return value of > cancel_work_sync(). It returns true if work was pending. So, if no work > was pending then we don't need to do anything as the kref would be > balanced and the tty would be set to NULL by the time > cancel_work_sync() returns. This would make speakup_cancel_selection() > simpler: > > void speakup_cancel_selection(void) > { > struct tty_struct *tty; > bool was_pending; > > was_pending = cancel_work_sync(&speakup_sel_work.work); > if (!was_pending) > return; > > tty_kref_put(speakup_sel_work.tty); > speakup_sel_work.tty = NULL; > } > > We will still need to get kref before cmpxchg() as you suggested above. > > Let me know what you think. > > Thanks, > Okash > _______________________________________________ Speakup mailing list Speakup@xxxxxxxxxxxxxxxxx http://linux-speakup.org/cgi-bin/mailman/listinfo/speakup