mac80211: fix rate mask reset

Coverity reported the strange "if (~...)" condition that's
always true. It suggested that ! was intended instead of ~,
but upon further analysis I'm convinced that what really was
intended was a comparison to 0xff/0xffff (in HT/VHT cases
respectively), since this indicates that all of the rates
are enabled.

Change the comparison accordingly.

I'm guessing this never really mattered because a reset to
not having a rate mask is basically equivalent to having a
mask that enables all rates.

Reported-by: Colin Ian King <colin.king@canonical.com>
Fixes: 2ffbe6d33366 ("mac80211: fix and optimize MCS mask handling")
Fixes: b119ad6e726c ("mac80211: add rate mask logic for vht rates")
Reviewed-by: Colin Ian King <colin.king@canonical.com>
Link: https://lore.kernel.org/r/20210212112213.36b38078f569.I8546a20c80bc1669058eb453e213630b846e107b@changeid
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/cfg.c b/net/mac80211/cfg.c
index c4c70e3..68a0de0 100644 (file)
--- a/net/mac80211/cfg.c
+++ b/net/mac80211/cfg.c
@@ -2950,14 +2950,14 @@ static int ieee80211_set_bitrate_mask(struct wiphy *wiphy,
                        continue;
 
                for (j = 0; j < IEEE80211_HT_MCS_MASK_LEN; j++) {
-                       if (~sdata->rc_rateidx_mcs_mask[i][j]) {
+                       if (sdata->rc_rateidx_mcs_mask[i][j] != 0xff) {
                                sdata->rc_has_mcs_mask[i] = true;
                                break;
                        }
                }
 
                for (j = 0; j < NL80211_VHT_NSS_MAX; j++) {
-                       if (~sdata->rc_rateidx_vht_mcs_mask[i][j]) {
+                       if (sdata->rc_rateidx_vht_mcs_mask[i][j] != 0xffff) {
                                sdata->rc_has_vht_mcs_mask[i] = true;
                                break;
                        }