[PATCH 3.17 12/25] PCI: pciehp: Fix wait time in timeout message

[Greg Kroah-Hartman]

3.17-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Yinghai Lu <yinghai@xxxxxxxxxx>

commit d433889cd5a0933fbd90f1e65bff5a8d7963cc52 upstream.

When we warned about a timeout on a hotplug command, we previously printed
the time between calls to pcie_write_cmd(), without accounting for any time
spent actually waiting.  Consider this sequence:

  pcie_write_cmd
    write SLTCTL
    cmd_started = jiffies          # T1

  pcie_write_cmd
    pcie_wait_cmd
      now = jiffies                # T2
      wait_event_timeout           # we may wait here
      if (timeout)
        ctrl_info("Timeout on command issued %u msec ago",
                  jiffies_to_msecs(now - cmd_started))

We previously printed (T2 - T1), but that doesn't include the time spent in
wait_event_timeout().

Fix this by using the current jiffies value, not the one cached before
calling wait_event_timeout().

[bhelgaas: changelog, use current jiffies instead of adding timeout]
Fixes: 40b960831cfa ("PCI: pciehp: Compute timeout from hotplug command start time")
Signed-off-by: Yinghai Lu <yinghai@xxxxxxxxxx>
Signed-off-by: Bjorn Helgaas <bhelgaas@xxxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
 drivers/pci/hotplug/pciehp_hpc.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/drivers/pci/hotplug/pciehp_hpc.c
+++ b/drivers/pci/hotplug/pciehp_hpc.c
@@ -173,7 +173,7 @@ static void pcie_wait_cmd(struct control
 	if (!rc)
 		ctrl_info(ctrl, "Timeout on hotplug command %#010x (issued %u msec ago)\n",
 			  ctrl->slot_ctrl,
-			  jiffies_to_msecs(now - ctrl->cmd_started));
+			  jiffies_to_msecs(jiffies - ctrl->cmd_started));
 }
 
 /**


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