[ECOS] eth_drv_send() called recursively
Xiaochen Zhou
zhouxiaochen@h3c.com
Thu May 24 09:43:00 GMT 2007
Hi,everyone:
Here is ethernet packet sending flow in our ecos application:
1. eth_drv_send() call my_eth_driver_send()
2. my_eth_driver_send() call eth_drv_tx_done()
3. eth_drv_tx_done() call eth_drv_send()
eth_drv_send() and eth_drv_tx_done() are implemented in
io/eth/current/src/net/eth_drv.c
eth_drv_tx_done(struct eth_drv_sc *sc, CYG_ADDRESS key, int status)
{
....
eth_drv_send(ifp);
....
eth_drv_send(struct ifnet *ifp)
{
....
while ((sc->funs->can_send)(sc) > 0) {
IF_DEQUEUE(&ifp->if_snd, m0);
if (m0 == 0) {
break;
}
....
}
If sending queue has many mbufs (we using queue for QOS application),
sending thread will call eth_drv_send() recursively, the stack of packet
sending thread will overflow.
Can anyone tell me why call eth_drv_send() in eth_drv_tx_done()? In
eth_drv_send(), there are a loop to call IF_DEQUEUE(), so I think it is
useless and harmful. Can I delete "eth_drv_send(ifp)" line in
eth_drv_tx_done()?
Thanks!
Xiaochen Zhou
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