On Mon, Oct 09, 2000 at 02:21:09AM +0100, Kenn Humborg wrote:
> On Mon, Oct 09, 2000 at 02:20:27AM +0200, Andi Kleen wrote:
> > 2.4 TCP code relies on current being valid in a softirq.
>
> And what the hell does TCP need current for anyway?
I think the only reference is in tcp_input.c, tcp_data_queue().
This does:
2483 /* Queue data for delivery to the user.
2484 * Packets in sequence go to the receive queue.
2485 * Out of sequence packets to the out_of_order_queue.
2486 */
2487 if (TCP_SKB_CB(skb)->seq == tp->rcv_nxt) {
2488 /* Ok. In sequence. */
2489 **** if (tp->ucopy.task == current &&
2490 tp->copied_seq == tp->rcv_nxt &&
2491 tp->ucopy.len &&
2492 sk->lock.users &&
2493 !tp->urg_data) {
2494 int chunk = min(skb->len, tp->ucopy.len);
2495
2496 **** __set_current_state(TASK_RUNNING);
Hmmm... I think I like the idea of having a different current for
interrupt context code. It looks like it's either that, slowing
down get_current() by checking for interrupt or kernel stack, or
devoting a register to current.
Must sleep on this...
Later,
Kenn
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