This is a note to let you know that I've just added the patch titled

e1000e: Avoid receiver overrun interrupt bursts

to the 4.14-stable tree which can be found at: http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git%3Ba=su...

The filename of the patch is: e1000e-avoid-receiver-overrun-interrupt-bursts.patch and it can be found in the queue-4.14 subdirectory.

If you, or anyone else, feels it should not be added to the stable tree, please let stable@vger.kernel.org know about it.

From 4aea7a5c5e940c1723add439f4088844cd26196d Mon Sep 17 00:00:00 2001

From: Benjamin Poirier bpoirier@suse.com Date: Fri, 21 Jul 2017 11:36:27 -0700 Subject: e1000e: Avoid receiver overrun interrupt bursts

From: Benjamin Poirier bpoirier@suse.com

commit 4aea7a5c5e940c1723add439f4088844cd26196d upstream.

When e1000e_poll() is not fast enough to keep up with incoming traffic, the adapter (when operating in msix mode) raises the Other interrupt to signal Receiver Overrun.

This is a double problem because 1) at the moment e1000_msix_other() assumes that it is only called in case of Link Status Change and 2) if the condition persists, the interrupt is repeatedly raised again in quick succession.

Ideally we would configure the Other interrupt to not be raised in case of receiver overrun but this doesn't seem possible on this adapter. Instead, we handle the first part of the problem by reverting to the practice of reading ICR in the other interrupt handler, like before commit 16ecba59bc33 ("e1000e: Do not read ICR in Other interrupt"). Thanks to commit 0a8047ac68e5 ("e1000e: Fix msi-x interrupt automask") which cleared IAME from CTRL_EXT, reading ICR doesn't interfere with RxQ0, TxQ0 interrupts anymore. We handle the second part of the problem by not re-enabling the Other interrupt right away when there is overrun. Instead, we wait until traffic subsides, napi polling mode is exited and interrupts are re-enabled.

Reported-by: Lennart Sorensen lsorense@csclub.uwaterloo.ca Fixes: 16ecba59bc33 ("e1000e: Do not read ICR in Other interrupt") Signed-off-by: Benjamin Poirier bpoirier@suse.com Tested-by: Aaron Brown aaron.f.brown@intel.com Signed-off-by: Jeff Kirsher jeffrey.t.kirsher@intel.com Signed-off-by: Amit Pundir amit.pundir@linaro.org Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org

--- drivers/net/ethernet/intel/e1000e/defines.h | 1 drivers/net/ethernet/intel/e1000e/netdev.c | 31 +++++++++++++++++++++------- 2 files changed, 25 insertions(+), 7 deletions(-)

--- a/drivers/net/ethernet/intel/e1000e/defines.h +++ b/drivers/net/ethernet/intel/e1000e/defines.h @@ -398,6 +398,7 @@ #define E1000_ICR_LSC 0x00000004 /* Link Status Change */ #define E1000_ICR_RXSEQ 0x00000008 /* Rx sequence error */ #define E1000_ICR_RXDMT0 0x00000010 /* Rx desc min. threshold (0) */ +#define E1000_ICR_RXO 0x00000040 /* Receiver Overrun */ #define E1000_ICR_RXT0 0x00000080 /* Rx timer intr (ring 0) */ #define E1000_ICR_ECCER 0x00400000 /* Uncorrectable ECC Error */ /* If this bit asserted, the driver should claim the interrupt */ --- a/drivers/net/ethernet/intel/e1000e/netdev.c +++ b/drivers/net/ethernet/intel/e1000e/netdev.c @@ -1910,14 +1910,30 @@ static irqreturn_t e1000_msix_other(int struct net_device *netdev = data; struct e1000_adapter *adapter = netdev_priv(netdev); struct e1000_hw *hw = &adapter->hw; + u32 icr; + bool enable = true;

- hw->mac.get_link_status = true; + icr = er32(ICR); + if (icr & E1000_ICR_RXO) { + ew32(ICR, E1000_ICR_RXO); + enable = false; + /* napi poll will re-enable Other, make sure it runs */ + if (napi_schedule_prep(&adapter->napi)) { + adapter->total_rx_bytes = 0; + adapter->total_rx_packets = 0; + __napi_schedule(&adapter->napi); + } + } + if (icr & E1000_ICR_LSC) { + ew32(ICR, E1000_ICR_LSC); + hw->mac.get_link_status = true; + /* guard against interrupt when we're going down */ + if (!test_bit(__E1000_DOWN, &adapter->state)) + mod_timer(&adapter->watchdog_timer, jiffies + 1); + }

- /* guard against interrupt when we're going down */ - if (!test_bit(__E1000_DOWN, &adapter->state)) { - mod_timer(&adapter->watchdog_timer, jiffies + 1); + if (enable && !test_bit(__E1000_DOWN, &adapter->state)) ew32(IMS, E1000_IMS_OTHER); - }

return IRQ_HANDLED; } @@ -2687,7 +2703,8 @@ static int e1000e_poll(struct napi_struc napi_complete_done(napi, work_done); if (!test_bit(__E1000_DOWN, &adapter->state)) { if (adapter->msix_entries) - ew32(IMS, adapter->rx_ring->ims_val); + ew32(IMS, adapter->rx_ring->ims_val | + E1000_IMS_OTHER); else e1000_irq_enable(adapter); } @@ -4204,7 +4221,7 @@ static void e1000e_trigger_lsc(struct e1 struct e1000_hw *hw = &adapter->hw;

if (adapter->msix_entries) - ew32(ICS, E1000_ICS_OTHER); + ew32(ICS, E1000_ICS_LSC | E1000_ICS_OTHER); else ew32(ICS, E1000_ICS_LSC); }

Patches currently in stable-queue which might be from bpoirier@suse.com are

queue-4.14/e1000e-fix-error-path-in-link-detection.patch queue-4.14/e1000e-separate-signaling-for-link-check-link-up.patch queue-4.14/e1000e-fix-return-value-test.patch queue-4.14/e1000e-avoid-receiver-overrun-interrupt-bursts.patch