mac80211: fix and optimize MCS mask handling

Currently the code always copies the configured MCS mask (even if it is
set to default), but only uses it if legacy rates were also masked out.
Fix this by adding a flag that tracks whether the configured MCS mask is
set to default or not.
Optimize the code further by storing a pointer to the configured rate
mask in txrc instead of using memcpy.

Signed-off-by: Felix Fietkau <nbd@openwrt.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

1 files changed, 6 insertions, 3 deletions

diff --git a/net/mac80211/rate.c b/net/mac80211/rate.c
index dd88381c53b7..5d545dd2d050 100644
--- a/net/mac80211/rate.c
+++ b/net/mac80211/rate.c
@@ -460,9 +460,12 @@ void rate_control_get_rate(struct ieee80211_sub_if_data *sdata,
          * the common case.
          */
         mask = sdata->rc_rateidx_mask[info->band];
-        memcpy(mcs_mask, sdata->rc_rateidx_mcs_mask[info->band],
-               sizeof(mcs_mask));
-        if (mask != (1 << txrc->sband->n_bitrates) - 1) {
+        if (mask != (1 << txrc->sband->n_bitrates) - 1 || txrc->rate_idx_mcs_mask) {
+                if (txrc->rate_idx_mcs_mask)
+                        memcpy(mcs_mask, txrc->rate_idx_mcs_mask, sizeof(mcs_mask));
+                else
+                        memset(mcs_mask, 0xff, sizeof(mcs_mask));
+
                 if (sta) {
                         /* Filter out rates that the STA does not support */
                         mask &= sta->sta.supp_rates[info->band];