On Thu, Aug 03, 2006 at 04:40:34PM +0200, Eric Dumazet ([EMAIL PROTECTED]) wrote: > > + mutex_lock(&u->ctl_mutex); > > + while (num < max_nr && ((k = kqueue_dequeue_ready(u)) != NULL)) { > > + if (copy_to_user(buf + num*sizeof(struct ukevent), > > + &k->event, sizeof(struct ukevent))) { > > + cerr = -EINVAL; > > + break; > > + } > > > It seems quite wrong to hold ctl_mutex while doing a copy_to_user() (of > possibly a large amount of data) : A thread can sleep on a page fault and > other threads cannot make progress.
I would not call that wrong - system prevents some threads from removing kevents which are counted to be transfered to the userspace, i.e. when dequeuing was awakened and it had seen some events it is possible, that when it will dequeue them part will be removed by other thread, so I prevent this. > Eric -- Evgeniy Polyakov - To unsubscribe from this list: send the line "unsubscribe netdev" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html