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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Felix Fietkau <nbd@nbd.name>,
        Johannes Berg <johannes.berg@intel.com>
Subject: [PATCH 5.12 157/178] mac80211: minstrel_ht: fix sample time check
Date:   Mon, 21 Jun 2021 18:16:11 +0200
Message-Id: <20210621154928.100445782@linuxfoundation.org>
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From: Felix Fietkau <nbd@nbd.name>

commit 1236af327af476731aa548dfcbbefb1a3ec6726a upstream.

We need to skip sampling if the next sample time is after jiffies, not before.
This patch fixes an issue where in some cases only very little sampling (or none
at all) is performed, leading to really bad data rates

Fixes: 80d55154b2f8 ("mac80211: minstrel_ht: significantly redesign the rate probing strategy")
Cc: stable@vger.kernel.org
Signed-off-by: Felix Fietkau <nbd@nbd.name>
Link: https://lore.kernel.org/r/20210617103854.61875-1-nbd@nbd.name
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
---
 net/mac80211/rc80211_minstrel_ht.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

--- a/net/mac80211/rc80211_minstrel_ht.c
+++ b/net/mac80211/rc80211_minstrel_ht.c
@@ -1516,7 +1516,7 @@ minstrel_ht_get_rate(void *priv, struct
 	    (info->control.flags & IEEE80211_TX_CTRL_PORT_CTRL_PROTO))
 		return;
 
-	if (time_is_before_jiffies(mi->sample_time))
+	if (time_is_after_jiffies(mi->sample_time))
 		return;
 
 	mi->sample_time = jiffies + MINSTREL_SAMPLE_INTERVAL;