5.4-stable review patch. If anyone has any objections, please let me know.
------------------
From: Jing Su jingsusu@didiglobal.com
[ Upstream commit 3a17f23f7c36bac3a3584aaf97d3e3e0b2790396 ]
Executing dql_reset after setting a non-zero value for limit_min can lead to an unreasonable situation where dql->limit is less than dql->limit_min.
For instance, after setting /sys/class/net/eth*/queues/tx-0/byte_queue_limits/limit_min, an ifconfig down/up operation might cause the ethernet driver to call netdev_tx_reset_queue, which in turn invokes dql_reset.
In this case, dql->limit is reset to 0 while dql->limit_min remains non-zero value, which is unexpected. The limit should always be greater than or equal to limit_min.
Signed-off-by: Jing Su jingsusu@didiglobal.com Link: https://patch.msgid.link/Z9qHD1s/NEuQBdgH@pilot-ThinkCentre-M930t-N000 Signed-off-by: Jakub Kicinski kuba@kernel.org Signed-off-by: Sasha Levin sashal@kernel.org --- lib/dynamic_queue_limits.c | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/lib/dynamic_queue_limits.c b/lib/dynamic_queue_limits.c index e659a027036ec..f6807062b32a3 100644 --- a/lib/dynamic_queue_limits.c +++ b/lib/dynamic_queue_limits.c @@ -116,7 +116,7 @@ EXPORT_SYMBOL(dql_completed); void dql_reset(struct dql *dql) { /* Reset all dynamic values */ - dql->limit = 0; + dql->limit = dql->min_limit; dql->num_queued = 0; dql->num_completed = 0; dql->last_obj_cnt = 0;