1 files changed, 12 insertions, 0 deletions

diff --git a/net/mac80211/debugfs_netdev.c b/net/mac80211/debugfs_netdev.c
index 6ed0455902c6..b0fc205411c1 100644
--- a/net/mac80211/debugfs_netdev.c
+++ b/net/mac80211/debugfs_netdev.c
@@ -424,6 +424,7 @@ static ssize_t ieee80211_if_parse_tsf(
         struct ieee80211_local *local = sdata->local;
         unsigned long long tsf;
         int ret;
+        int tsf_is_delta = 0;
 
         if (strncmp(buf, "reset", 5) == 0) {
                 if (local->ops->reset_tsf) {
@@ -431,9 +432,20 @@ static ssize_t ieee80211_if_parse_tsf(
                         wiphy_info(local->hw.wiphy, "debugfs reset TSF\n");
                 }
         } else {
+                if (buflen > 10 && buf[1] == '=') {
+                        if (buf[0] == '+')
+                                tsf_is_delta = 1;
+                        else if (buf[0] == '-')
+                                tsf_is_delta = -1;
+                        else
+                                return -EINVAL;
+                        buf += 2;
+                }
                 ret = kstrtoull(buf, 10, &tsf);
                 if (ret < 0)
                         return -EINVAL;
+                if (tsf_is_delta)
+                        tsf = drv_get_tsf(local, sdata) + tsf_is_delta * tsf;
                 if (local->ops->set_tsf) {
                         drv_set_tsf(local, sdata, tsf);
                         wiphy_info(local->hw.wiphy,