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.du...@gmail.com>
Signed-off-by: Benjamin Poirier <bpoir...@suse.com>
---
drivers/net/ethernet/intel/e1000e/ich8lan.c | 31 ++++++++++++++++-------------
drivers/net/ethernet/intel/e1000e/mac.c | 14 ++++++-------
2 files changed, 24 insertions(+), 21 deletions(-)
diff --git a/drivers/net/ethernet/intel/e1000e/ich8lan.c
b/drivers/net/ethernet/intel/e1000e/ich8lan.c
index d6d4ed7acf03..1dddfb7b2de6 100644
--- a/drivers/net/ethernet/intel/e1000e/ich8lan.c
+++ b/drivers/net/ethernet/intel/e1000e/ich8lan.c
@@ -1383,6 +1383,7 @@ static s32 e1000_check_for_copper_link_ich8lan(struct
e1000_hw *hw)
*/
if (!mac->get_link_status)
return 0;
+ 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
@@ -1390,12 +1391,12 @@ 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
@@ -1428,7 +1429,7 @@ 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;
@@ -1450,7 +1451,7 @@ 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;
@@ -1459,14 +1460,14 @@ 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;
@@ -1480,18 +1481,18 @@ 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;
}
}
@@ -1518,7 +1519,7 @@ 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
@@ -1526,7 +1527,7 @@ 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 */
@@ -1549,9 +1550,7 @@ static s32 e1000_check_for_copper_link_ich8lan(struct
e1000_hw *hw)
}
if (!link)
- return 0; /* No link detected */
-
- mac->get_link_status = false;
+ goto out;
switch (hw->mac.type) {
case e1000_pch2lan:
@@ -1617,6 +1616,10 @@ static s32 e1000_check_for_copper_link_ich8lan(struct
e1000_hw *hw)
e_dbg("Error configuring flow control\n");
return ret_val;
+
+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 b322011ec282..5bdc3a2d4fd7 100644
--- a/drivers/net/ethernet/intel/e1000e/mac.c
+++ b/drivers/net/ethernet/intel/e1000e/mac.c
@@ -424,19 +424,15 @@ s32 e1000e_check_for_copper_link(struct e1000_hw *hw)
*/
if (!mac->get_link_status)
return 0;
+ 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
* of the PHY.
*/
ret_val = e1000e_phy_has_link_generic(hw, 1, 0, &link);
- if (ret_val)
- return ret_val;
-
- if (!link)
- return 0; /* No link detected */
-
- mac->get_link_status = false;
+ if (ret_val || !link)
+ goto out;
/* Check if there was DownShift, must be checked
* immediately after link-up
@@ -465,6 +461,10 @@ s32 e1000e_check_for_copper_link(struct e1000_hw *hw)
e_dbg("Error configuring flow control\n");
return ret_val;
+
+out:
+ mac->get_link_status = true;
+ return ret_val;
}
/**
--
2.16.2
