4.9-stable review patch. If anyone has any objections, please let me know.
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From: Benjamin Poirier bpoirier@suse.com
commit e2710dbf0dc1e37d85368e2404049dadda848d5a upstream.
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@gmail.com Signed-off-by: Benjamin Poirier bpoirier@suse.com Acked-by: Alexander Duyck alexander.h.duyck@intel.com Tested-by: Aaron Brown aaron.f.brown@intel.com Signed-off-by: Jeff Kirsher jeffrey.t.kirsher@intel.com Cc: Yanhui He yanhuih@vmware.com Signed-off-by: Ben Hutchings ben@decadent.org.uk Signed-off-by: Greg Kroah-Hartman gregkh@linuxfoundation.org --- drivers/net/ethernet/intel/e1000e/ich8lan.c | 31 +++++++++++++++------------- drivers/net/ethernet/intel/e1000e/mac.c | 14 ++++++------ 2 files changed, 24 insertions(+), 21 deletions(-)
--- a/drivers/net/ethernet/intel/e1000e/ich8lan.c +++ b/drivers/net/ethernet/intel/e1000e/ich8lan.c @@ -1380,6 +1380,7 @@ static s32 e1000_check_for_copper_link_i */ 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 @@ -1387,12 +1388,12 @@ static s32 e1000_check_for_copper_link_i */ 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 @@ -1427,7 +1428,7 @@ static s32 e1000_check_for_copper_link_i
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_i 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_i 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_i } 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_i (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) || (hw->mac.type == e1000_pch_spt)) { @@ -1527,7 +1528,7 @@ static s32 e1000_check_for_copper_link_i */ ret_val = e1000_platform_pm_pch_lpt(hw, link); if (ret_val) - return ret_val; + goto out; }
/* Clear link partner's EEE ability */ @@ -1547,9 +1548,7 @@ static s32 e1000_check_for_copper_link_i }
if (!link) - return 0; /* No link detected */ - - mac->get_link_status = false; + goto out;
switch (hw->mac.type) { case e1000_pch2lan: @@ -1615,6 +1614,10 @@ static s32 e1000_check_for_copper_link_i 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) --- 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 */ 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 e_dbg("Error configuring flow control\n");
return ret_val; + +out: + mac->get_link_status = true; + return ret_val; }
/**