[src/trunk]: src/sys/dev/pci/ixgbe Fix poll mode assumption breaking.

[knakahara <knakahara%NetBSD.org@localhost>]

details:   https://anonhg.NetBSD.org/src/rev/98cc7904e54e
branches:  trunk
changeset: 830113:98cc7904e54e
user:      knakahara <knakahara%NetBSD.org@localhost>
date:      Mon Feb 26 04:19:00 2018 +0000

description:
Fix poll mode assumption breaking.

ixgbe_{enable,disable}_intr() forcibly enable/disable all interrupts
regardless of current state. That can break poll mode assumption,
that is, queue interrupts must not occur while polling Tx/Rx rings.

E.g. "ifconfig ixg0 delete && ifconfig ixg0 192.168.0.1" on heavy
load traffic can causes this issue.

This fix may have 1% or 2% performance impact at short packets.

XXX
ixgbe_rearm_queues() which is called only via watchdog can also break
this poll mode assumption because writing EICS casues interrupts
immediately when interrupt auto mask enabled.
We will fix it with other issues about watchdog later.

ok by msaitoh@n.o.

diffstat:

 sys/dev/pci/ixgbe/ix_txrx.c |   5 ++++-
 sys/dev/pci/ixgbe/ixgbe.c   |  36 ++++++++++++++++++++++++++++--------
 sys/dev/pci/ixgbe/ixgbe.h   |   5 ++++-
 3 files changed, 36 insertions(+), 10 deletions(-)

diffs (131 lines):

diff -r 654aa2e8f4eb -r 98cc7904e54e sys/dev/pci/ixgbe/ix_txrx.c
--- a/sys/dev/pci/ixgbe/ix_txrx.c       Mon Feb 26 01:33:05 2018 +0000
+++ b/sys/dev/pci/ixgbe/ix_txrx.c       Mon Feb 26 04:19:00 2018 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: ix_txrx.c,v 1.32 2018/02/22 10:02:08 msaitoh Exp $ */
+/* $NetBSD: ix_txrx.c,v 1.33 2018/02/26 04:19:00 knakahara Exp $ */
 
 /******************************************************************************
 
@@ -2260,6 +2260,9 @@
                que->me = i;
                que->txr = &adapter->tx_rings[i];
                que->rxr = &adapter->rx_rings[i];
+
+               mutex_init(&que->im_mtx, MUTEX_DEFAULT, IPL_NET);
+               que->im_nest = 0;
        }
 
        return (0);
diff -r 654aa2e8f4eb -r 98cc7904e54e sys/dev/pci/ixgbe/ixgbe.c
--- a/sys/dev/pci/ixgbe/ixgbe.c Mon Feb 26 01:33:05 2018 +0000
+++ b/sys/dev/pci/ixgbe/ixgbe.c Mon Feb 26 04:19:00 2018 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: ixgbe.c,v 1.126 2018/02/22 10:02:08 msaitoh Exp $ */
+/* $NetBSD: ixgbe.c,v 1.127 2018/02/26 04:19:00 knakahara Exp $ */
 
 /******************************************************************************
 
@@ -2384,9 +2384,14 @@
 ixgbe_enable_queue(struct adapter *adapter, u32 vector)
 {
        struct ixgbe_hw *hw = &adapter->hw;
+       struct ix_queue *que = &adapter->queues[vector];
        u64             queue = (u64)(1ULL << vector);
        u32             mask;
 
+       mutex_enter(&que->im_mtx);
+       if (que->im_nest > 0 && --que->im_nest > 0)
+               goto out;
+
        if (hw->mac.type == ixgbe_mac_82598EB) {
                mask = (IXGBE_EIMS_RTX_QUEUE & queue);
                IXGBE_WRITE_REG(hw, IXGBE_EIMS, mask);
@@ -2398,6 +2403,8 @@
                if (mask)
                        IXGBE_WRITE_REG(hw, IXGBE_EIMS_EX(1), mask);
        }
+out:
+       mutex_exit(&que->im_mtx);
 } /* ixgbe_enable_queue */
 
 /************************************************************************
@@ -2407,9 +2414,14 @@
 ixgbe_disable_queue(struct adapter *adapter, u32 vector)
 {
        struct ixgbe_hw *hw = &adapter->hw;
+       struct ix_queue *que = &adapter->queues[vector];
        u64             queue = (u64)(1ULL << vector);
        u32             mask;
 
+       mutex_enter(&que->im_mtx);
+       if (que->im_nest++ > 0)
+               goto  out;
+
        if (hw->mac.type == ixgbe_mac_82598EB) {
                mask = (IXGBE_EIMS_RTX_QUEUE & queue);
                IXGBE_WRITE_REG(hw, IXGBE_EIMC, mask);
@@ -2421,6 +2433,8 @@
                if (mask)
                        IXGBE_WRITE_REG(hw, IXGBE_EIMC_EX(1), mask);
        }
+out:
+       mutex_exit(&que->im_mtx);
 } /* ixgbe_disable_queue */
 
 /************************************************************************
@@ -3427,6 +3441,10 @@
 
        ixgbe_free_transmit_structures(adapter);
        ixgbe_free_receive_structures(adapter);
+       for (int i = 0; i < adapter->num_queues; i++) {
+               struct ix_queue * que = &adapter->queues[i];
+               mutex_destroy(&que->im_mtx);
+       }
        free(adapter->queues, M_DEVBUF);
        free(adapter->mta, M_DEVBUF);
 
@@ -4568,15 +4586,17 @@
 static void
 ixgbe_disable_intr(struct adapter *adapter)
 {
+       struct ix_queue *que = adapter->queues;
+
+       /* disable interrupts other than queues */
+       IXGBE_WRITE_REG(&adapter->hw, IXGBE_EIMC, ~IXGBE_EIMC_RTX_QUEUE);
+
        if (adapter->msix_mem)
                IXGBE_WRITE_REG(&adapter->hw, IXGBE_EIAC, 0);
-       if (adapter->hw.mac.type == ixgbe_mac_82598EB) {
-               IXGBE_WRITE_REG(&adapter->hw, IXGBE_EIMC, ~0);
-       } else {
-               IXGBE_WRITE_REG(&adapter->hw, IXGBE_EIMC, 0xFFFF0000);
-               IXGBE_WRITE_REG(&adapter->hw, IXGBE_EIMC_EX(0), ~0);
-               IXGBE_WRITE_REG(&adapter->hw, IXGBE_EIMC_EX(1), ~0);
-       }
+
+       for (int i = 0; i < adapter->num_queues; i++, que++)
+               ixgbe_disable_queue(adapter, que->msix);
+
        IXGBE_WRITE_FLUSH(&adapter->hw);
 
        return;
diff -r 654aa2e8f4eb -r 98cc7904e54e sys/dev/pci/ixgbe/ixgbe.h
--- a/sys/dev/pci/ixgbe/ixgbe.h Mon Feb 26 01:33:05 2018 +0000
+++ b/sys/dev/pci/ixgbe/ixgbe.h Mon Feb 26 04:19:00 2018 +0000
@@ -1,4 +1,4 @@
-/* $NetBSD: ixgbe.h,v 1.30 2018/02/22 10:02:08 msaitoh Exp $ */
+/* $NetBSD: ixgbe.h,v 1.31 2018/02/26 04:19:00 knakahara Exp $ */
 
 /******************************************************************************
   SPDX-License-Identifier: BSD-3-Clause
@@ -335,6 +335,9 @@
        struct evcnt     irqs;
        char             namebuf[32];
        char             evnamebuf[32];
+
+       kmutex_t         im_mtx;        /* lock for im_nest and this queue's EIMS/EIMC bit */
+       int              im_nest;
 };
 
 /*