From c470bdc1aaf36669e04ba65faf1092b2d1c6cabe Mon Sep 17 00:00:00 2001
From: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Date: Mon, 26 Mar 2018 16:21:04 +0300
Subject: [PATCH] mac80211: don't WARN on bad WMM parameters from buggy APs
Git-commit: c470bdc1aaf36669e04ba65faf1092b2d1c6cabe
Patch-mainline: v4.17-rc1
References: bsc#1051510

Apparently, some APs are buggy enough to send a zeroed
WMM IE. Don't WARN on this since this is not caused by a bug
on the client's system.

This aligns the condition of the WARNING in drv_conf_tx
with the validity check in ieee80211_sta_wmm_params.
We will now pick the default values whenever we get
a zeroed WMM IE.

This has been reported here:
https://bugzilla.kernel.org/show_bug.cgi?id=199161

Fixes: f409079bb678 ("mac80211: sanity check CW_min/CW_max towards driver")
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Acked-by: Takashi Iwai <tiwai@suse.de>

---
 net/mac80211/mlme.c |    3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

--- a/net/mac80211/mlme.c
+++ b/net/mac80211/mlme.c
@@ -1802,7 +1802,8 @@ static bool ieee80211_sta_wmm_params(str
 		params[ac].acm = acm;
 		params[ac].uapsd = uapsd;
 
-		if (params[ac].cw_min > params[ac].cw_max) {
+		if (params->cw_min == 0 ||
+		    params[ac].cw_min > params[ac].cw_max) {
 			sdata_info(sdata,
 				   "AP has invalid WMM params (CWmin/max=%d/%d for ACI %d), using defaults\n",
 				   params[ac].cw_min, params[ac].cw_max, aci);