[Intel-wired-lan] [PATCH] e1000e: fix division by zero on jumbo MTUs

[Intel-wired-lan] [PATCH] e1000e: fix division by zero on jumbo MTUs

[Leonid Bloch]

From: Dmitry Fleytman <dmitry@daynix.com>

This patch fixes possible division by zero in receive
interrupt handler when working without adaptive interrupt
moderation.

The adaptive interrupt moderation mechanism is typically
disabled on jumbo MTUs.

Signed-off-by: Dmitry Fleytman <dmitry@daynix.com>
Signed-off-by: Leonid Bloch <leonid@daynix.com>
---
 drivers/net/ethernet/intel/e1000e/netdev.c | 6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index faf4b3f..a60dce1 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -1959,8 +1959,10 @@ static irqreturn_t e1000_intr_msix_rx(int __always_unused irq, void *data)
 	 * previous interrupt.
 	 */
 	if (rx_ring->set_itr) {
-		writel(1000000000 / (rx_ring->itr_val * 256),
-		       rx_ring->itr_register);
+		u32 itr = rx_ring->itr_val ?
+			1000000000 / (rx_ring->itr_val * 256) : 0;
+
+		writel(itr, rx_ring->itr_register);
 		rx_ring->set_itr = 0;
 	}
 
-- 
2.4.3

[Intel-wired-lan] [PATCH] e1000e: fix division by zero on jumbo MTUs

[Brown, Aaron F]

> From: netdev-owner at vger.kernel.org [mailto:netdev-
> owner at vger.kernel.org] On Behalf Of Leonid Bloch
> Sent: Tuesday, October 13, 2015 2:48 AM
> To: linux-kernel at vger.kernel.org
> Cc: Kirsher, Jeffrey T <jeffrey.t.kirsher@intel.com>; Brandeburg, Jesse
> <jesse.brandeburg@intel.com>; Nelson, Shannon
> <shannon.nelson@intel.com>; Wyborny, Carolyn
> <carolyn.wyborny@intel.com>; Skidmore, Donald C
> <donald.c.skidmore@intel.com>; Vick, Matthew <matthew.vick@intel.com>;
> Ronciak, John <john.ronciak@intel.com>; Williams, Mitch A
> <mitch.a.williams@intel.com>; intel-wired-lan at lists.osuosl.org;
> netdev at vger.kernel.org; Dmitry Fleytman <dmitry@daynix.com>
> Subject: [PATCH] e1000e: fix division by zero on jumbo MTUs
> 
> From: Dmitry Fleytman <dmitry@daynix.com>
> 
> This patch fixes possible division by zero in receive
> interrupt handler when working without adaptive interrupt
> moderation.
> 
> The adaptive interrupt moderation mechanism is typically
> disabled on jumbo MTUs.
> 
> Signed-off-by: Dmitry Fleytman <dmitry@daynix.com>
> Signed-off-by: Leonid Bloch <leonid@daynix.com>
> ---
>  drivers/net/ethernet/intel/e1000e/netdev.c | 6 ++++--
>  1 file changed, 4 insertions(+), 2 deletions(-)

Tested-by: Aaron Brown <aaron.f.brown@intel.com>