On Wed, 30 May 2007 00:20:41 +0200
Francois Romieu <[EMAIL PROTECTED]> wrote:
> Stephen Hemminger <[EMAIL PROTECTED]> :
> ⅜...]
> > Better to just get rid of using the lock as a transmit lock and
> > use netif_tx_lock instead.
> > --- a/drivers/net/b44.c 2007-05-29 09:51:43.000000000 -0700
> > +++ b/drivers/net/b44.c 2007-05-29 14:26:03.000000000 -0700
> > @@ -607,6 +607,7 @@ static void b44_tx(struct b44 *bp)
> > {
> > u32 cur, cons;
> >
> > + netif_tx_lock(bp->dev);
> > cur = br32(bp, B44_DMATX_STAT) & DMATX_STAT_CDMASK;
> > cur /= sizeof(struct dma_desc);
> >
>
> (damn, you are quick)
>
> I am not completely convinced.
>
> 1. netpoll_send_skb (calls netif_tx_trylock(dev))
> -> netpoll_poll(np)
> -> poll_napi(np)
> -> np->dev->poll(np->dev, &budget) ( == b44_poll)
> -> b44_tx
> -> netif_tx_lock(bp->dev) *deadlock*
Netpoll needs to be fixed. (or scrapped), as is it will break drivers
trying to use tx_lock in poll routine. I know sky2 would get borked.
Something like this:
--- a/net/core/netpoll.c 2007-05-08 14:19:32.000000000 -0700
+++ b/net/core/netpoll.c 2007-05-29 15:28:22.000000000 -0700
@@ -250,22 +250,23 @@ static void netpoll_send_skb(struct netp
unsigned long flags;
local_irq_save(flags);
- if (netif_tx_trylock(dev)) {
- /* try until next clock tick */
- for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
- tries > 0; --tries) {
+ /* try until next clock tick */
+ for (tries = jiffies_to_usecs(1)/USEC_PER_POLL;
+ tries > 0; --tries) {
+ if (netif_tx_trylock(dev)) {
if (!netif_queue_stopped(dev))
status = dev->hard_start_xmit(skb, dev);
+ netif_tx_unlock(dev);
if (status == NETDEV_TX_OK)
break;
- /* tickle device maybe there is some cleanup */
- netpoll_poll(np);
-
- udelay(USEC_PER_POLL);
}
- netif_tx_unlock(dev);
+
+ /* tickle device maybe there is some cleanup */
+ netpoll_poll(np);
+
+ udelay(USEC_PER_POLL);
}
local_irq_restore(flags);
}
-
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