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Date: Mon, 26 Feb 2018 11:31:18 +0900
From: Benjamin Poirier <bpoirier@...e.com>
To: Jeff Kirsher <jeffrey.t.kirsher@...el.com>
Cc: Alexander Duyck <alexander.duyck@...il.com>,
intel-wired-lan@...ts.osuosl.org, netdev@...r.kernel.org,
linux-kernel@...r.kernel.org
Subject: [RFC PATCH] e1000e: Fix link check race condition.
Alex reported the following race condition:
/* link goes up... interrupt... schedule watchdog */
\ e1000_watchdog_task
\ e1000e_has_link
\ hw->mac.ops.check_for_link() === e1000e_check_for_copper_link
\ e1000e_phy_has_link_generic(..., &link)
link = true
/* link goes down... interrupt */
\ e1000_msix_other
hw->mac.get_link_status = true
/* link is up */
mac->get_link_status = false
link_active = true
/* link_active is true, wrongly, and stays so because
* get_link_status is false */
Avoid this problem by making sure that we don't set get_link_status = false
after having checked the link.
It seems this problem has been present since the introduction of e1000e.
Link: https://lkml.org/lkml/2018/1/29/338
Reported-by: Alexander Duyck <alexander.duyck@...il.com>
Signed-off-by: Benjamin Poirier <bpoirier@...e.com>
---
drivers/net/ethernet/intel/e1000e/ich8lan.c | 41 ++++++++++++++++-------------
drivers/net/ethernet/intel/e1000e/mac.c | 14 +++++++---
2 files changed, 33 insertions(+), 22 deletions(-)
diff --git a/drivers/net/ethernet/intel/e1000e/ich8lan.c b/drivers/net/ethernet/intel/e1000e/ich8lan.c
index ff308b05d68c..3c2c4f87e075 100644
--- a/drivers/net/ethernet/intel/e1000e/ich8lan.c
+++ b/drivers/net/ethernet/intel/e1000e/ich8lan.c
@@ -1386,6 +1386,7 @@ static s32 e1000_check_for_copper_link_ich8lan(struct e1000_hw *hw)
*/
if (!mac->get_link_status)
return 1;
+ mac->get_link_status = false;
/* First we want to see if the MII Status Register reports
* link. If so, then we want to get the current speed/duplex
@@ -1393,12 +1394,12 @@ static s32 e1000_check_for_copper_link_ich8lan(struct e1000_hw *hw)
*/
ret_val = e1000e_phy_has_link_generic(hw, 1, 0, &link);
if (ret_val)
- return ret_val;
+ goto out;
if (hw->mac.type == e1000_pchlan) {
ret_val = e1000_k1_gig_workaround_hv(hw, link);
if (ret_val)
- return ret_val;
+ goto out;
}
/* When connected at 10Mbps half-duplex, some parts are excessively
@@ -1431,7 +1432,7 @@ static s32 e1000_check_for_copper_link_ich8lan(struct e1000_hw *hw)
ret_val = hw->phy.ops.acquire(hw);
if (ret_val)
- return ret_val;
+ goto out;
if (hw->mac.type == e1000_pch2lan)
emi_addr = I82579_RX_CONFIG;
@@ -1453,7 +1454,7 @@ static s32 e1000_check_for_copper_link_ich8lan(struct e1000_hw *hw)
hw->phy.ops.release(hw);
if (ret_val)
- return ret_val;
+ goto out;
if (hw->mac.type >= e1000_pch_spt) {
u16 data;
@@ -1462,14 +1463,14 @@ static s32 e1000_check_for_copper_link_ich8lan(struct e1000_hw *hw)
if (speed == SPEED_1000) {
ret_val = hw->phy.ops.acquire(hw);
if (ret_val)
- return ret_val;
+ goto out;
ret_val = e1e_rphy_locked(hw,
PHY_REG(776, 20),
&data);
if (ret_val) {
hw->phy.ops.release(hw);
- return ret_val;
+ goto out;
}
ptr_gap = (data & (0x3FF << 2)) >> 2;
@@ -1483,18 +1484,18 @@ static s32 e1000_check_for_copper_link_ich8lan(struct e1000_hw *hw)
}
hw->phy.ops.release(hw);
if (ret_val)
- return ret_val;
+ goto out;
} else {
ret_val = hw->phy.ops.acquire(hw);
if (ret_val)
- return ret_val;
+ goto out;
ret_val = e1e_wphy_locked(hw,
PHY_REG(776, 20),
0xC023);
hw->phy.ops.release(hw);
if (ret_val)
- return ret_val;
+ goto out;
}
}
@@ -1521,7 +1522,7 @@ static s32 e1000_check_for_copper_link_ich8lan(struct e1000_hw *hw)
(hw->adapter->pdev->device == E1000_DEV_ID_PCH_I218_V3)) {
ret_val = e1000_k1_workaround_lpt_lp(hw, link);
if (ret_val)
- return ret_val;
+ goto out;
}
if (hw->mac.type >= e1000_pch_lpt) {
/* Set platform power management values for
@@ -1529,7 +1530,7 @@ static s32 e1000_check_for_copper_link_ich8lan(struct e1000_hw *hw)
*/
ret_val = e1000_platform_pm_pch_lpt(hw, link);
if (ret_val)
- return ret_val;
+ goto out;
}
/* Clear link partner's EEE ability */
@@ -1551,22 +1552,22 @@ static s32 e1000_check_for_copper_link_ich8lan(struct e1000_hw *hw)
ew32(FEXTNVM6, fextnvm6);
}
- if (!link)
+ if (!link) {
+ mac->get_link_status = true;
return 0; /* No link detected */
-
- mac->get_link_status = false;
+ }
switch (hw->mac.type) {
case e1000_pch2lan:
ret_val = e1000_k1_workaround_lv(hw);
if (ret_val)
- return ret_val;
+ goto out;
/* fall-thru */
case e1000_pchlan:
if (hw->phy.type == e1000_phy_82578) {
ret_val = e1000_link_stall_workaround_hv(hw);
if (ret_val)
- return ret_val;
+ goto out;
}
/* Workaround for PCHx parts in half-duplex:
@@ -1595,7 +1596,7 @@ static s32 e1000_check_for_copper_link_ich8lan(struct e1000_hw *hw)
if (hw->phy.type > e1000_phy_82579) {
ret_val = e1000_set_eee_pchlan(hw);
if (ret_val)
- return ret_val;
+ goto out;
}
/* If we are forcing speed/duplex, then we simply return since
@@ -1618,10 +1619,14 @@ static s32 e1000_check_for_copper_link_ich8lan(struct e1000_hw *hw)
ret_val = e1000e_config_fc_after_link_up(hw);
if (ret_val) {
e_dbg("Error configuring flow control\n");
- return ret_val;
+ goto out;
}
return 1;
+
+out:
+ mac->get_link_status = true;
+ return ret_val;
}
static s32 e1000_get_variants_ich8lan(struct e1000_adapter *adapter)
diff --git a/drivers/net/ethernet/intel/e1000e/mac.c b/drivers/net/ethernet/intel/e1000e/mac.c
index db735644b312..60c8beaf5cb3 100644
--- a/drivers/net/ethernet/intel/e1000e/mac.c
+++ b/drivers/net/ethernet/intel/e1000e/mac.c
@@ -427,6 +427,7 @@ s32 e1000e_check_for_copper_link(struct e1000_hw *hw)
*/
if (!mac->get_link_status)
return 1;
+ mac->get_link_status = false;
/* First we want to see if the MII Status Register reports
* link. If so, then we want to get the current speed/duplex
@@ -434,12 +435,13 @@ s32 e1000e_check_for_copper_link(struct e1000_hw *hw)
*/
ret_val = e1000e_phy_has_link_generic(hw, 1, 0, &link);
if (ret_val)
- return ret_val;
+ goto out;
- if (!link)
+ if (!link) {
+ mac->get_link_status = true;
return 0; /* No link detected */
+ }
- mac->get_link_status = false;
/* Check if there was DownShift, must be checked
* immediately after link-up
@@ -466,10 +468,14 @@ s32 e1000e_check_for_copper_link(struct e1000_hw *hw)
ret_val = e1000e_config_fc_after_link_up(hw);
if (ret_val) {
e_dbg("Error configuring flow control\n");
- return ret_val;
+ goto out;
}
return 1;
+
+out:
+ mac->get_link_status = true;
+ return ret_val;
}
/**
--
2.16.1
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