mac80211: add support for tx to abort low priority scan requests

Use NL80211_SCAN_FLAG_LOW_PRIORITY flag in mac80211's scan state
machine to prematurely terminate scan operations if outbound
traffic collides. This is useful for marking background scans so
they don't affect throughput.

Signed-off-by: Sam Leffler <sleffler@chromium.org>
Signed-off-by: Amitkumar Karwar <akarwar@marvell.com>
Signed-off-by: Bing Zhao <bzhao@marvell.com>
[set feature flag only if software scan is used]
Signed-off-by: Johannes Berg <johannes.berg@intel.com>

diff --git a/net/mac80211/ieee80211_i.h b/net/mac80211/ieee80211_i.h
index 6327816..02e4793 100644 (file)
--- a/net/mac80211/ieee80211_i.h
+++ b/net/mac80211/ieee80211_i.h
@@ -866,6 +866,7 @@ enum {
  * @SCAN_SUSPEND: Suspend the scan and go back to operating channel to
  *     send out data
  * @SCAN_RESUME: Resume the scan and scan the next channel
+ * @SCAN_ABORT: Abort the scan and go back to operating channel
  */
 enum mac80211_scan_state {
        SCAN_DECISION,
@@ -873,6 +874,7 @@ enum mac80211_scan_state {
        SCAN_SEND_PROBE,
        SCAN_SUSPEND,
        SCAN_RESUME,
+       SCAN_ABORT,
 };
 
 struct ieee80211_local {

diff --git a/net/mac80211/main.c b/net/mac80211/main.c
index 931f14f..ba5a232 100644 (file)
--- a/net/mac80211/main.c
+++ b/net/mac80211/main.c
@@ -602,6 +602,9 @@ struct ieee80211_hw *ieee80211_alloc_hw(size_t priv_data_len,
                           NL80211_FEATURE_SAE |
                           NL80211_FEATURE_HT_IBSS;
 
+       if (!ops->hw_scan)
+               wiphy->features |= NL80211_FEATURE_LOW_PRIORITY_SCAN;
+
        if (!ops->set_key)
                wiphy->flags |= WIPHY_FLAG_IBSS_RSN;
 

diff --git a/net/mac80211/scan.c b/net/mac80211/scan.c
index 987c75d..13d2329 100644 (file)
--- a/net/mac80211/scan.c
+++ b/net/mac80211/scan.c
@@ -466,6 +466,7 @@ static int __ieee80211_start_scan(struct ieee80211_sub_if_data *sdata,
                        sizeof(*local->hw_scan_req) +
                        req->n_channels * sizeof(req->channels[0]);
                local->hw_scan_req->ie = ies;
+               local->hw_scan_req->flags = req->flags;
 
                local->hw_scan_band = 0;
 
@@ -566,6 +567,7 @@ static void ieee80211_scan_state_decision(struct ieee80211_local *local,
        unsigned long min_beacon_int = 0;
        struct ieee80211_sub_if_data *sdata;
        struct ieee80211_channel *next_chan;
+       enum mac80211_scan_state next_scan_state;
 
        /*
         * check if at least one STA interface is associated,
@@ -624,10 +626,18 @@ static void ieee80211_scan_state_decision(struct ieee80211_local *local,
                        usecs_to_jiffies(min_beacon_int * 1024) *
                        local->hw.conf.listen_interval);
 
-       if (associated && (!tx_empty || bad_latency || listen_int_exceeded))
-               local->next_scan_state = SCAN_SUSPEND;
-       else
-               local->next_scan_state = SCAN_SET_CHANNEL;
+       if (associated && !tx_empty) {
+               if (local->scan_req->flags & NL80211_SCAN_FLAG_LOW_PRIORITY)
+                       next_scan_state = SCAN_ABORT;
+               else
+                       next_scan_state = SCAN_SUSPEND;
+       } else if (associated && (bad_latency || listen_int_exceeded)) {
+               next_scan_state = SCAN_SUSPEND;
+       } else {
+               next_scan_state = SCAN_SET_CHANNEL;
+       }
+
+       local->next_scan_state = next_scan_state;
 
        *next_delay = 0;
 }
@@ -798,6 +808,9 @@ void ieee80211_scan_work(struct work_struct *work)
                case SCAN_RESUME:
                        ieee80211_scan_state_resume(local, &next_delay);
                        break;
+               case SCAN_ABORT:
+                       aborted = true;
+                       goto out_complete;
                }
        } while (next_delay == 0);