e1000e: fix division by zero on jumbo MTUs

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>
Tested-by: Aaron Brown <aaron.f.brown@intel.com>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Orabug: 26243014
(cherry picked from commit b77ac46bbae862dcb3f51296825c940404c69b0f)
Signed-off-by: Jack Vogel <jack.vogel@oracle.com>
Reviewed-by: Ethan Zhao <ethan.zhao@oracle.com>

diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 3c7d06210c27b3a571471ff5664cfb3fc79e24aa..b0a5b2eaa07a269c2fa509317862b24c94b1eb68 100644 (file)
--- 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;
        }