[PATCH 4/5] cfg80211: Use 5MHz bandwidth by default when checking usable channels

[Rostislav Lisovy]

Current code checks if the 20MHz BW is allowed for particular
channel -- if it is not, the channel is disabled. Since we
need to use 5/10 MHz channels, this code is modified in the way
that the default BW to check is 5MHz. If 5MHz is greater than
the maximum bandwidth allowed by the channel, the channel is
disabled. Otherwise the channel is used and the flags are set
according to the BW allowed by the channel.

Signed-off-by: Rostislav Lisovy <rostislav.lisovy@xxxxxxxxxxx>
---
 net/wireless/reg.c | 22 +++++++++++++++-------
 1 file changed, 15 insertions(+), 7 deletions(-)

diff --git a/net/wireless/reg.c b/net/wireless/reg.c
index f054137..5f0dd26 100644
--- a/net/wireless/reg.c
+++ b/net/wireless/reg.c
@@ -805,7 +805,7 @@ freq_reg_info_regd(struct wiphy *wiphy, u32 center_freq,
 		if (!band_rule_found)
 			band_rule_found = freq_in_rule_band(fr, center_freq);
 
-		bw_fits = reg_does_bw_fit(fr, center_freq, MHZ_TO_KHZ(20));
+		bw_fits = reg_does_bw_fit(fr, center_freq, MHZ_TO_KHZ(5));
 
 		if (band_rule_found && bw_fits)
 			return rr;
@@ -888,10 +888,10 @@ static void chan_reg_rule_print_dbg(struct ieee80211_channel *chan,
 }
 #endif
 
-/*
- * Note that right now we assume the desired channel bandwidth
- * is always 20 MHz for each individual channel (HT40 uses 20 MHz
- * per channel, the primary and the extension channel).
+/* Find an ieee80211_reg_rule such that a 5MHz channel with frequency
+ * @chan->center_freq fits there.
+ * If there is no such reg_rule, disable the channel, otherwise set the
+ * flags corresponding to the bandwidths allowed in the particular reg_rule
  */
 static void handle_channel(struct wiphy *wiphy,
 			   enum nl80211_reg_initiator initiator,
@@ -944,8 +944,12 @@ static void handle_channel(struct wiphy *wiphy,
 	power_rule = &reg_rule->power_rule;
 	freq_range = &reg_rule->freq_range;
 
+	if (freq_range->max_bandwidth_khz < MHZ_TO_KHZ(10))
+		bw_flags = IEEE80211_CHAN_NO_10MHZ;
+	if (freq_range->max_bandwidth_khz < MHZ_TO_KHZ(20))
+		bw_flags |= IEEE80211_CHAN_NO_20MHZ;
 	if (freq_range->max_bandwidth_khz < MHZ_TO_KHZ(40))
-		bw_flags = IEEE80211_CHAN_NO_HT40;
+		bw_flags |= IEEE80211_CHAN_NO_HT40;
 	if (freq_range->max_bandwidth_khz < MHZ_TO_KHZ(80))
 		bw_flags |= IEEE80211_CHAN_NO_80MHZ;
 	if (freq_range->max_bandwidth_khz < MHZ_TO_KHZ(160))
@@ -1351,8 +1355,12 @@ static void handle_channel_custom(struct wiphy *wiphy,
 	power_rule = &reg_rule->power_rule;
 	freq_range = &reg_rule->freq_range;
 
+	if (freq_range->max_bandwidth_khz < MHZ_TO_KHZ(10))
+		bw_flags = IEEE80211_CHAN_NO_10MHZ;
+	if (freq_range->max_bandwidth_khz < MHZ_TO_KHZ(20))
+		bw_flags |= IEEE80211_CHAN_NO_20MHZ;
 	if (freq_range->max_bandwidth_khz < MHZ_TO_KHZ(40))
-		bw_flags = IEEE80211_CHAN_NO_HT40;
+		bw_flags |= IEEE80211_CHAN_NO_HT40;
 	if (freq_range->max_bandwidth_khz < MHZ_TO_KHZ(80))
 		bw_flags |= IEEE80211_CHAN_NO_80MHZ;
 	if (freq_range->max_bandwidth_khz < MHZ_TO_KHZ(160))
-- 
1.8.5.1

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