From: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx>
[ Upstream commit 2b4cc3d3f4d8ec42961e98568a0afeee96a943ab ]
The check introduced in the commit a5fd39464a40 ("igc: Lift TAPRIO schedule
restriction") can detect a false positive error in some corner case.
For instance,
tc qdisc replace ... taprio num_tc 4
...
sched-entry S 0x01 100000 # slot#1
sched-entry S 0x03 100000 # slot#2
sched-entry S 0x04 100000 # slot#3
sched-entry S 0x08 200000 # slot#4
flags 0x02 # hardware offload
Here the queue#0 (the first queue) is on at the slot#1 and #2,
and off at the slot#3 and #4. Under the current logic, when the slot#4
is examined, validate_schedule() returns *false* since the enablement
count for the queue#0 is two and it is already off at the previous slot
(i.e. #3). But this definition is truely correct.
Let's fix the logic to enforce a strict validation for consecutively-opened
slots.
Fixes: a5fd39464a40 ("igc: Lift TAPRIO schedule restriction")
Signed-off-by: AKASHI Takahiro <takahiro.akashi@xxxxxxxxxx>
Reviewed-by: Kurt Kanzenbach <kurt@xxxxxxxxxxxxx>
Acked-by: Vinicius Costa Gomes <vinicius.gomes@xxxxxxxxx>
Tested-by: Naama Meir <naamax.meir@xxxxxxxxxxxxxxx>
Signed-off-by: Tony Nguyen <anthony.l.nguyen@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---
drivers/net/ethernet/intel/igc/igc_main.c | 20 ++++++++++----------
1 file changed, 10 insertions(+), 10 deletions(-)
diff --git a/drivers/net/ethernet/intel/igc/igc_main.c b/drivers/net/ethernet/intel/igc/igc_main.c
index bde3fea2c442e..e255b0a004f88 100644
--- a/drivers/net/ethernet/intel/igc/igc_main.c
+++ b/drivers/net/ethernet/intel/igc/igc_main.c
@@ -5951,18 +5951,18 @@ static bool validate_schedule(struct igc_adapter *adapter,
if (e->command != TC_TAPRIO_CMD_SET_GATES)
return false;
- for (i = 0; i < adapter->num_tx_queues; i++) {
- if (e->gate_mask & BIT(i))
+ for (i = 0; i < adapter->num_tx_queues; i++)
+ if (e->gate_mask & BIT(i)) {
queue_uses[i]++;
- /* There are limitations: A single queue cannot be
- * opened and closed multiple times per cycle unless the
- * gate stays open. Check for it.
- */
- if (queue_uses[i] > 1 &&
- !(prev->gate_mask & BIT(i)))
- return false;
- }
+ /* There are limitations: A single queue cannot
+ * be opened and closed multiple times per cycle
+ * unless the gate stays open. Check for it.
+ */
+ if (queue_uses[i] > 1 &&
+ !(prev->gate_mask & BIT(i)))
+ return false;
+ }
}
return true;
--
2.39.2
