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kernel: fix receiver overflow for 82574L under load

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Under heavy load it's possible to overrun the 82574L. When this
happens, Other Interrupt happens and that's erroneously interpreted
as a Link Status Change.

    http://patchwork.ozlabs.org/patch/792260/

Signed-off-by: Philip Prindeville <philipp@redfish-solutions.com>
This commit is contained in:
Philip Prindeville 2017-08-11 18:59:52 -06:00 committed by John Crispin
parent 1c4a116a30
commit a0c05a7c94
1 changed files with 327 additions and 0 deletions
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327
target/linux/generic/pending-4.9/190-e100e-avoid-receiver-interrupt-bursts.patch Normal file
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@ -0,0 +1,327 @@
Subject: [1/5] e1000e: Fix error path in link detection
From: Benjamin Poirier <bpoirier@suse.com>
X-Patchwork-Id: 792259
Message-Id: <20170721183627.13373-1-bpoirier@suse.com>
To: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: netdev@vger.kernel.org, intel-wired-lan@lists.osuosl.org,
linux-kernel@vger.kernel.org,
Lennart Sorensen <lsorense@csclub.uwaterloo.ca>
Date: Fri, 21 Jul 2017 11:36:23 -0700
In case of error from e1e_rphy(), the loop will exit early and "success"
will be set to true erroneously.
Signed-off-by: Benjamin Poirier <bpoirier@suse.com>
---
drivers/net/ethernet/intel/e1000e/phy.c | 7 ++++---
1 file changed, 4 insertions(+), 3 deletions(-)
diff --git a/drivers/net/ethernet/intel/e1000e/phy.c b/drivers/net/ethernet/intel/e1000e/phy.c
index d78d47b41a71..86ff0969efb6 100644
--- a/drivers/net/ethernet/intel/e1000e/phy.c
+++ b/drivers/net/ethernet/intel/e1000e/phy.c
@@ -1744,6 +1744,7 @@ s32 e1000e_phy_has_link_generic(struct e1000_hw *hw, u32 iterations,
s32 ret_val = 0;
u16 i, phy_status;
+ *success = false;
for (i = 0; i < iterations; i++) {
/* Some PHYs require the MII_BMSR register to be read
* twice due to the link bit being sticky. No harm doing
@@ -1763,16 +1764,16 @@ s32 e1000e_phy_has_link_generic(struct e1000_hw *hw, u32 iterations,
ret_val = e1e_rphy(hw, MII_BMSR, &phy_status);
if (ret_val)
break;
- if (phy_status & BMSR_LSTATUS)
+ if (phy_status & BMSR_LSTATUS) {
+ *success = true;
break;
+ }
if (usec_interval >= 1000)
msleep(usec_interval / 1000);
else
udelay(usec_interval);
}
- *success = (i < iterations);
-
return ret_val;
}
Subject: [2/5] e1000e: Fix wrong comment related to link detection
From: Benjamin Poirier <bpoirier@suse.com>
X-Patchwork-Id: 792257
Message-Id: <20170721183627.13373-2-bpoirier@suse.com>
To: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: netdev@vger.kernel.org, intel-wired-lan@lists.osuosl.org,
linux-kernel@vger.kernel.org,
Lennart Sorensen <lsorense@csclub.uwaterloo.ca>
Date: Fri, 21 Jul 2017 11:36:24 -0700
Reading e1000e_check_for_copper_link() shows that get_link_status is set to
false after link has been detected. Therefore, it stays TRUE until then.
Signed-off-by: Benjamin Poirier <bpoirier@suse.com>
---
drivers/net/ethernet/intel/e1000e/netdev.c | 4 ++--
1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 2dcb5463d9b8..58a87134d2e5 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -5074,7 +5074,7 @@ static bool e1000e_has_link(struct e1000_adapter *adapter)
/* get_link_status is set on LSC (link status) interrupt or
* Rx sequence error interrupt. get_link_status will stay
- * false until the check_for_link establishes link
+ * true until the check_for_link establishes link
* for copper adapters ONLY
*/
switch (hw->phy.media_type) {
@@ -5092,7 +5092,7 @@ static bool e1000e_has_link(struct e1000_adapter *adapter)
break;
case e1000_media_type_internal_serdes:
ret_val = hw->mac.ops.check_for_link(hw);
- link_active = adapter->hw.mac.serdes_has_link;
+ link_active = hw->mac.serdes_has_link;
break;
default:
case e1000_media_type_unknown:
Content-Transfer-Encoding: 7bit
Subject: [3/5] e1000e: Fix return value test
From: Benjamin Poirier <bpoirier@suse.com>
X-Patchwork-Id: 792258
Message-Id: <20170721183627.13373-3-bpoirier@suse.com>
To: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: netdev@vger.kernel.org, intel-wired-lan@lists.osuosl.org,
linux-kernel@vger.kernel.org,
Lennart Sorensen <lsorense@csclub.uwaterloo.ca>
Date: Fri, 21 Jul 2017 11:36:25 -0700
All the helpers return -E1000_ERR_PHY.
Signed-off-by: Benjamin Poirier <bpoirier@suse.com>
---
drivers/net/ethernet/intel/e1000e/netdev.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 58a87134d2e5..fc6a1d9999b2 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -5099,7 +5099,7 @@ static bool e1000e_has_link(struct e1000_adapter *adapter)
break;
}
- if ((ret_val == E1000_ERR_PHY) && (hw->phy.type == e1000_phy_igp_3) &&
+ if ((ret_val == -E1000_ERR_PHY) && (hw->phy.type == e1000_phy_igp_3) &&
(er32(CTRL) & E1000_PHY_CTRL_GBE_DISABLE)) {
/* See e1000_kmrn_lock_loss_workaround_ich8lan() */
e_info("Gigabit has been disabled, downgrading speed\n");
Content-Transfer-Encoding: 7bit
Subject: [4/5] e1000e: Separate signaling for link check/link up
From: Benjamin Poirier <bpoirier@suse.com>
X-Patchwork-Id: 792262
Message-Id: <20170721183627.13373-4-bpoirier@suse.com>
To: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: netdev@vger.kernel.org, intel-wired-lan@lists.osuosl.org,
linux-kernel@vger.kernel.org,
Lennart Sorensen <lsorense@csclub.uwaterloo.ca>
Date: Fri, 21 Jul 2017 11:36:26 -0700
Lennart reported the following race condition:
\ e1000_watchdog_task
\ e1000e_has_link
\ hw->mac.ops.check_for_link() === e1000e_check_for_copper_link
/* link is up */
mac->get_link_status = false;
/* interrupt */
\ e1000_msix_other
hw->mac.get_link_status = true;
link_active = !hw->mac.get_link_status
/* link_active is false, wrongly */
This problem arises because the single flag get_link_status is used to
signal two different states: link status needs checking and link status is
down.
Avoid the problem by using the return value of .check_for_link to signal
the link status to e1000e_has_link().
Reported-by: Lennart Sorensen <lsorense@csclub.uwaterloo.ca>
Signed-off-by: Benjamin Poirier <bpoirier@suse.com>
---
drivers/net/ethernet/intel/e1000e/mac.c | 11 ++++++++---
drivers/net/ethernet/intel/e1000e/netdev.c | 2 +-
2 files changed, 9 insertions(+), 4 deletions(-)
diff --git a/drivers/net/ethernet/intel/e1000e/mac.c b/drivers/net/ethernet/intel/e1000e/mac.c
index b322011ec282..f457c5703d0c 100644
--- a/drivers/net/ethernet/intel/e1000e/mac.c
+++ b/drivers/net/ethernet/intel/e1000e/mac.c
@@ -410,6 +410,9 @@ void e1000e_clear_hw_cntrs_base(struct e1000_hw *hw)
* Checks to see of the link status of the hardware has changed. If a
* change in link status has been detected, then we read the PHY registers
* to get the current speed/duplex if link exists.
+ *
+ * Returns a negative error code (-E1000_ERR_*) or 0 (link down) or 1 (link
+ * up).
**/
s32 e1000e_check_for_copper_link(struct e1000_hw *hw)
{
@@ -423,7 +426,7 @@ s32 e1000e_check_for_copper_link(struct e1000_hw *hw)
* Change or Rx Sequence Error interrupt.
*/
if (!mac->get_link_status)
- return 0;
+ return 1;
/* First we want to see if the MII Status Register reports
* link. If so, then we want to get the current speed/duplex
@@ -461,10 +464,12 @@ s32 e1000e_check_for_copper_link(struct e1000_hw *hw)
* different link partner.
*/
ret_val = e1000e_config_fc_after_link_up(hw);
- if (ret_val)
+ if (ret_val) {
e_dbg("Error configuring flow control\n");
+ return ret_val;
+ }
- return ret_val;
+ return 1;
}
/**
diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index fc6a1d9999b2..5a8ab1136566 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -5081,7 +5081,7 @@ static bool e1000e_has_link(struct e1000_adapter *adapter)
case e1000_media_type_copper:
if (hw->mac.get_link_status) {
ret_val = hw->mac.ops.check_for_link(hw);
- link_active = !hw->mac.get_link_status;
+ link_active = ret_val > 0;
} else {
link_active = true;
}
Content-Transfer-Encoding: 7bit
Subject: [5/5] e1000e: Avoid receiver overrun interrupt bursts
From: Benjamin Poirier <bpoirier@suse.com>
X-Patchwork-Id: 792260
Message-Id: <20170721183627.13373-5-bpoirier@suse.com>
To: Jeff Kirsher <jeffrey.t.kirsher@intel.com>
Cc: netdev@vger.kernel.org, intel-wired-lan@lists.osuosl.org,
linux-kernel@vger.kernel.org,
Lennart Sorensen <lsorense@csclub.uwaterloo.ca>
Date: Fri, 21 Jul 2017 11:36:27 -0700
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>
---
drivers/net/ethernet/intel/e1000e/defines.h | 1 +
drivers/net/ethernet/intel/e1000e/netdev.c | 33 +++++++++++++++++++++++------
2 files changed, 27 insertions(+), 7 deletions(-)
diff --git a/drivers/net/ethernet/intel/e1000e/defines.h b/drivers/net/ethernet/intel/e1000e/defines.h
index 0641c0098738..afb7ebe20b24 100644
--- 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 */
diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
index 5a8ab1136566..803edd1a6401 100644
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -1910,12 +1910,30 @@ static irqreturn_t e1000_msix_other(int __always_unused irq, void *data)
struct net_device *netdev = data;
struct e1000_adapter *adapter = netdev_priv(netdev);
struct e1000_hw *hw = &adapter->hw;
+ u32 icr;
+ bool enable = 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);
+ }
+ }
- 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);
+ if (enable && !test_bit(__E1000_DOWN, &adapter->state)) {
ew32(IMS, E1000_IMS_OTHER);
}
@@ -2687,7 +2705,8 @@ static int e1000e_poll(struct napi_struct *napi, int weight)
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 +4223,7 @@ static void e1000e_trigger_lsc(struct e1000_adapter *adapter)
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);
}