mac80211: only bother printing highest data rate on debugfs if its set

IEEE-802.11n spec says the RX highest data rate field does
not specify the highest supported RX data rate if its not set.
Ignore it if not set then. Refer to section 7.3.56.4

Cc: johannes@sipsolutions.net
Signed-off-by: Luis R. Rodriguez <lrodriguez@atheros.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>

1 files changed, 10 insertions, 2 deletions

diff --git a/net/mac80211/debugfs_sta.c b/net/mac80211/debugfs_sta.c
index c833b6ce9902..0d4a759ba72c 100644
--- a/net/mac80211/debugfs_sta.c
+++ b/net/mac80211/debugfs_sta.c
@@ -218,11 +218,19 @@ static ssize_t sta_ht_capa_read(struct file *file, char __user *userbuf,
                 p += scnprintf(p, sizeof(buf)+buf-p, "ampdu factor/density: %d/%d\n",
                                 htc->ampdu_factor, htc->ampdu_density);
                 p += scnprintf(p, sizeof(buf)+buf-p, "MCS mask:");
+
                 for (i = 0; i < IEEE80211_HT_MCS_MASK_LEN; i++)
                         p += scnprintf(p, sizeof(buf)+buf-p, " %.2x",
                                         htc->mcs.rx_mask[i]);
-                p += scnprintf(p, sizeof(buf)+buf-p, "\nMCS rx highest: %d\n",
-                                le16_to_cpu(htc->mcs.rx_highest));
+                p += scnprintf(p, sizeof(buf)+buf-p, "\n");
+
+                /* If not set this is meaningless */
+                if (le16_to_cpu(htc->mcs.rx_highest)) {
+                        p += scnprintf(p, sizeof(buf)+buf-p,
+                                       "MCS rx highest: %d Mbps\n",
+                                       le16_to_cpu(htc->mcs.rx_highest));
+                }
+
                 p += scnprintf(p, sizeof(buf)+buf-p, "MCS tx params: %x\n",
                                 htc->mcs.tx_params);
         }