[PATCH 4.4 016/192] [PATCH 016/135] e1000e: fix division by zero on jumbo MTUs

From	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Newsgroups	linux.kernel
Subject	[PATCH 4.4 016/192] [PATCH 016/135] e1000e: fix division by zero on jumbo MTUs
Date	2016-09-12 19:10 +0200
Message-ID	<sgCU1-6aZ-1@gated-at.bofh.it> (permalink)
References	<sgCU1-6aZ-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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4.4-stable review patch.  If anyone has any objections, please let me know.

------------------

[ Upstream commit b77ac46bbae862dcb3f51296825c940404c69b0f ]

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>
Signed-off-by: Sasha Levin <alexander.levin@verizon.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 drivers/net/ethernet/intel/e1000e/netdev.c |    6 ++++--
 1 file changed, 4 insertions(+), 2 deletions(-)

--- 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(in
 	 * 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;
 	}

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[PATCH 4.4 016/192] [PATCH 016/135] e1000e: fix division by zero on jumbo MTUs Greg Kroah-Hartman <gregkh@linuxfoundation.org> - 2016-09-12 19:10 +0200

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