On Fri, 2007-10-19 at 12:48 +0800, Herbert Xu wrote: > [IRQ]: Fix synchronize_irq races with IRQ handler > > As it is some callers of synchronize_irq rely on memory barriers > to provide synchronisation against the IRQ handlers. For example, > the tg3 driver does > > tp->irq_sync = 1; > smp_mb(); > synchronize_irq(); > > and then in the IRQ handler: > > if (!tp->irq_sync) > netif_rx_schedule(dev, &tp->napi); > > Unfortunately memory barriers only work well when they come in > pairs. Because we don't actually have memory barriers on the > IRQ path, the memory barrier before the synchronize_irq() doesn't > actually protect us. > > In particular, synchronize_irq() may return followed by the > result of netif_rx_schedule being made visible. > > This patch (mostly written by Linus) fixes this by using spin > locks instead of memory barries on the synchronize_irq() path. > > Signed-off-by: Herbert Xu <[EMAIL PROTECTED]>
Good for me. Acked-by: Benjamin Herrenschmidt <[EMAIL PROTECTED]> Cheers, Ben. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
