IRQ races during change of mtu
- NAPI poll must be enabled prior to IRQ activation or the IRQ handler
will not know what to do with an incoming packet;
- rtl8169_down() needs to try twice to sync with the IRQ handler when
it is not issued under !netif_running() protection.
Both changes make it safe to request a change of mtu on a live device.
Signed-off-by: Francois Romieu <[EMAIL PROTECTED]>
diff -puN drivers/net/r8169.c~r8169-450 drivers/net/r8169.c
--- a/drivers/net/r8169.c~r8169-450 2005-02-23 21:35:21.112521942 +0100
+++ b/drivers/net/r8169.c 2005-02-23 21:35:21.117521120 +0100
@@ -1648,10 +1648,10 @@ static int rtl8169_change_mtu(struct net
if (ret < 0)
goto out;
- rtl8169_hw_start(dev);
-
netif_poll_enable(dev);
+ rtl8169_hw_start(dev);
+
rtl8169_request_timer(dev);
out:
@@ -2352,6 +2352,7 @@ static void rtl8169_down(struct net_devi
{
struct rtl8169_private *tp = netdev_priv(dev);
void __iomem *ioaddr = tp->mmio_addr;
+ unsigned int poll_locked = 0;
rtl8169_delete_timer(dev);
@@ -2359,6 +2360,7 @@ static void rtl8169_down(struct net_devi
flush_scheduled_work();
+core_down:
spin_lock_irq(&tp->lock);
/* Stop the chip's Tx and Rx DMA processes. */
@@ -2375,11 +2377,28 @@ static void rtl8169_down(struct net_devi
synchronize_irq(dev->irq);
- netif_poll_disable(dev);
+ if (!poll_locked) {
+ netif_poll_disable(dev);
+ poll_locked++;
+ }
/* Give a racing hard_start_xmit a few cycles to complete. */
synchronize_kernel();
+ /*
+ * And now for the 50k$ question: are IRQ disabled or not ?
+ *
+ * Two paths lead here:
+ * 1) dev->close
+ * -> netif_running() is available to sync the current code and the
+ * IRQ handler. See rtl8169_interrupt for details.
+ * 2) dev->change_mtu
+ * -> rtl8169_poll can not be issued again and re-enable the
+ * interruptions. Let's simply issue the IRQ down sequence again.
+ */
+ if (RTL_R16(IntrMask))
+ goto core_down;
+
rtl8169_tx_clear(tp);
rtl8169_rx_clear(tp);
_
-
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/
