[PATCH 5.4 179/270] selftests/powerpc: Squash spurious errors due to device removal

From: Greg Kroah-Hartman
Date: Mon Aug 17 2020 - 14:13:03 EST


From: Oliver O'Halloran <oohall@xxxxxxxxx>

[ Upstream commit 5f8cf6475828b600ff6d000e580c961ac839cc61 ]

For drivers that don't have the error handling callbacks we implement
recovery by removing the device and re-probing it. This causes the sysfs
directory for the PCI device to be removed which causes the following
spurious error to be printed when checking the PE state:

Breaking 0005:03:00.0...
./eeh-basic.sh: line 13: can't open /sys/bus/pci/devices/0005:03:00.0/eeh_pe_state: no such file
0005:03:00.0, waited 0/60
0005:03:00.0, waited 1/60
0005:03:00.0, waited 2/60
0005:03:00.0, waited 3/60
0005:03:00.0, waited 4/60
0005:03:00.0, waited 5/60
0005:03:00.0, waited 6/60
0005:03:00.0, waited 7/60
0005:03:00.0, Recovered after 8 seconds

We currently try to avoid this by checking if the PE state file exists
before reading from it. This is however inherently racy so re-work the
state checking so that we only read from the file once, and we squash any
errors that occur while reading.

Fixes: 85d86c8aa52e ("selftests/powerpc: Add basic EEH selftest")
Signed-off-by: Oliver O'Halloran <oohall@xxxxxxxxx>
Signed-off-by: Michael Ellerman <mpe@xxxxxxxxxxxxxx>
Link: https://lore.kernel.org/r/20200727010127.23698-1-oohall@xxxxxxxxx
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
tools/testing/selftests/powerpc/eeh/eeh-functions.sh | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/tools/testing/selftests/powerpc/eeh/eeh-functions.sh b/tools/testing/selftests/powerpc/eeh/eeh-functions.sh
index f52ed92b53e74..00dc32c0ed75c 100755
--- a/tools/testing/selftests/powerpc/eeh/eeh-functions.sh
+++ b/tools/testing/selftests/powerpc/eeh/eeh-functions.sh
@@ -5,12 +5,17 @@ pe_ok() {
local dev="$1"
local path="/sys/bus/pci/devices/$dev/eeh_pe_state"

- if ! [ -e "$path" ] ; then
+ # if a driver doesn't support the error handling callbacks then the
+ # device is recovered by removing and re-probing it. This causes the
+ # sysfs directory to disappear so read the PE state once and squash
+ # any potential error messages
+ local eeh_state="$(cat $path 2>/dev/null)"
+ if [ -z "$eeh_state" ]; then
return 1;
fi

- local fw_state="$(cut -d' ' -f1 < $path)"
- local sw_state="$(cut -d' ' -f2 < $path)"
+ local fw_state="$(echo $eeh_state | cut -d' ' -f1)"
+ local sw_state="$(echo $eeh_state | cut -d' ' -f2)"

# If EEH_PE_ISOLATED or EEH_PE_RECOVERING are set then the PE is in an
# error state or being recovered. Either way, not ok.
--
2.25.1