From 43ce887c5050a3c213450a3058505f6a06519dd4 Mon Sep 17 00:00:00 2001 From: Vladimir Oltean Date: Wed, 24 Jun 2020 16:54:47 +0300 Subject: net: dsa: sja1105: fix tc-gate schedule with single element The sja1105_gating_cfg_time_to_interval function does this, as per the comments: /* The gate entries contain absolute times in their e->interval field. Convert * that to proper intervals (i.e. "0, 5, 10, 15" to "5, 5, 5, 5"). */ To perform that task, it iterates over gating_cfg->entries, at each step updating the interval of the _previous_ entry. So one interval remains to be updated at the end of the loop: the last one (since it isn't "prev" for anyone else). But there was an erroneous check, that the last element's interval should not be updated if it's also the only element. I'm not quite sure why that check was there, but it's clearly incorrect, as a tc-gate schedule with a single element would get an e->interval of zero, regardless of the duration requested by the user. The switch wouldn't even consider this configuration as valid: it will just drop all traffic that matches the rule. Fixes: 834f8933d5dd ("net: dsa: sja1105: implement tc-gate using time-triggered virtual links") Reported-by: Xiaoliang Yang Signed-off-by: Vladimir Oltean Signed-off-by: David S. Miller --- drivers/net/dsa/sja1105/sja1105_vl.c | 3 +-- 1 file changed, 1 insertion(+), 2 deletions(-) diff --git a/drivers/net/dsa/sja1105/sja1105_vl.c b/drivers/net/dsa/sja1105/sja1105_vl.c index 6b1fdc1b46e7..af3565160db6 100644 --- a/drivers/net/dsa/sja1105/sja1105_vl.c +++ b/drivers/net/dsa/sja1105/sja1105_vl.c @@ -75,8 +75,7 @@ sja1105_gating_cfg_time_to_interval(struct sja1105_gating_config *gating_cfg, } last_e = list_last_entry(&gating_cfg->entries, struct sja1105_gate_entry, list); - if (last_e->list.prev != &gating_cfg->entries) - last_e->interval = cycle_time - last_e->interval; + last_e->interval = cycle_time - last_e->interval; } static void sja1105_free_gating_config(struct sja1105_gating_config *gating_cfg) -- cgit v1.2.3-59-g8ed1b