This is a note to let you know that I've just added the patch titled
e1000e: Separate signaling for link check/link up
to the 4.4-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
e1000e-separate-signaling-for-link-check-link-up.patch
and it can be found in the queue-4.4 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
>From 19110cfbb34d4af0cdfe14cd243f3b09dc95b013 Mon Sep 17 00:00:00 2001
From: Benjamin Poirier <bpoirier@xxxxxxxx>
Date: Fri, 21 Jul 2017 11:36:26 -0700
Subject: e1000e: Separate signaling for link check/link up
From: Benjamin Poirier <bpoirier@xxxxxxxx>
commit 19110cfbb34d4af0cdfe14cd243f3b09dc95b013 upstream.
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@xxxxxxxxxxxxxxxxxxx>
Signed-off-by: Benjamin Poirier <bpoirier@xxxxxxxx>
Tested-by: Aaron Brown <aaron.f.brown@xxxxxxxxx>
Signed-off-by: Jeff Kirsher <jeffrey.t.kirsher@xxxxxxxxx>
Signed-off-by: Amit Pundir <amit.pundir@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/net/ethernet/intel/e1000e/mac.c | 11 ++++++++---
drivers/net/ethernet/intel/e1000e/netdev.c | 2 +-
2 files changed, 9 insertions(+), 4 deletions(-)
--- 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 e
* 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
* 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
* 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;
}
/**
--- a/drivers/net/ethernet/intel/e1000e/netdev.c
+++ b/drivers/net/ethernet/intel/e1000e/netdev.c
@@ -5017,7 +5017,7 @@ static bool e1000e_has_link(struct e1000
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;
}
Patches currently in stable-queue which might be from bpoirier@xxxxxxxx are
queue-4.4/e1000e-fix-error-path-in-link-detection.patch
queue-4.4/e1000e-separate-signaling-for-link-check-link-up.patch
queue-4.4/e1000e-fix-return-value-test.patch