iwlwifi: mvm: abort scan on sched_scan request

A scheduled scan is a more persistent setting and should take priority
over temporary regular scans. Abort the regular when a sched_scan
request arrives and then request the sched_scan.

The kernel API allows sending a sched_scan without canceling a regular
scan in progress, so this is our way to abstract the FW's limitations.

Make the scan-cancel Rx handler async and flush after invocation to
ensure new scans can't creep in before it.

Signed-off-by: Arik Nemtsov <arikx.nemtsov@intel.com>
Reviewed-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Emmanuel Grumbach <emmanuel.grumbach@intel.com>

4 files changed, 33 insertions, 14 deletions

diff --git a/drivers/net/wireless/iwlwifi/mvm/mac80211.c b/drivers/net/wireless/iwlwifi/mvm/mac80211.c
index fff66ab2cfda..a6df00d675b7 100644
--- a/drivers/net/wireless/iwlwifi/mvm/mac80211.c
+++ b/drivers/net/wireless/iwlwifi/mvm/mac80211.c
@@ -1708,9 +1708,26 @@ static int iwl_mvm_mac_sched_scan_start(struct ieee80211_hw *hw,
 
         mutex_lock(&mvm->mutex);
 
-        if (mvm->scan_status != IWL_MVM_SCAN_NONE) {
-                IWL_DEBUG_SCAN(mvm,
-                               "SCHED SCAN request during internal scan - abort\n");
+        switch (mvm->scan_status) {
+        case IWL_MVM_SCAN_OS:
+                IWL_DEBUG_SCAN(mvm, "Stopping previous scan for sched_scan\n");
+                ret = iwl_mvm_cancel_scan(mvm);
+                if (ret) {
+                        ret = -EBUSY;
+                        goto out;
+                }
+
+                /*
+                 * iwl_mvm_rx_scan_complete() will be called soon but will
+                 * not reset the scan status as it won't be IWL_MVM_SCAN_OS
+                 * any more since we queue the next scan immediately (below).
+                 * We make sure it is called before the next scan starts by
+                 * flushing the async-handlers work.
+                 */
+                break;
+        case IWL_MVM_SCAN_NONE:
+                break;
+        default:
                 ret = -EBUSY;
                 goto out;
         }
@@ -1732,6 +1749,8 @@ err:
         mvm->scan_status = IWL_MVM_SCAN_NONE;
 out:
         mutex_unlock(&mvm->mutex);
+        /* make sure to flush the Rx handler before the next scan arrives */
+        iwl_mvm_wait_for_async_handlers(mvm);
         return ret;
 }
 
diff --git a/drivers/net/wireless/iwlwifi/mvm/mvm.h b/drivers/net/wireless/iwlwifi/mvm/mvm.h
index 4da53c395ad3..e5c1db97acf4 100644
--- a/drivers/net/wireless/iwlwifi/mvm/mvm.h
+++ b/drivers/net/wireless/iwlwifi/mvm/mvm.h
@@ -804,7 +804,7 @@ int iwl_mvm_rx_scan_response(struct iwl_mvm *mvm, struct iwl_rx_cmd_buffer *rxb,
                              struct iwl_device_cmd *cmd);
 int iwl_mvm_rx_scan_complete(struct iwl_mvm *mvm, struct iwl_rx_cmd_buffer *rxb,
                              struct iwl_device_cmd *cmd);
-void iwl_mvm_cancel_scan(struct iwl_mvm *mvm);
+int iwl_mvm_cancel_scan(struct iwl_mvm *mvm);
 
 /* Scheduled scan */
 int iwl_mvm_rx_scan_offload_complete_notif(struct iwl_mvm *mvm,
diff --git a/drivers/net/wireless/iwlwifi/mvm/ops.c b/drivers/net/wireless/iwlwifi/mvm/ops.c
index 05f635572063..39279e1d6ad4 100644
--- a/drivers/net/wireless/iwlwifi/mvm/ops.c
+++ b/drivers/net/wireless/iwlwifi/mvm/ops.c
@@ -226,7 +226,7 @@ static const struct iwl_rx_handlers iwl_mvm_rx_handlers[] = {
         RX_HANDLER(EOSP_NOTIFICATION, iwl_mvm_rx_eosp_notif, false),
 
         RX_HANDLER(SCAN_REQUEST_CMD, iwl_mvm_rx_scan_response, false),
-        RX_HANDLER(SCAN_COMPLETE_NOTIFICATION, iwl_mvm_rx_scan_complete, false),
+        RX_HANDLER(SCAN_COMPLETE_NOTIFICATION, iwl_mvm_rx_scan_complete, true),
         RX_HANDLER(SCAN_OFFLOAD_COMPLETE,
                    iwl_mvm_rx_scan_offload_complete_notif, true),
         RX_HANDLER(MATCH_FOUND_NOTIFICATION, iwl_mvm_rx_sched_scan_results,
diff --git a/drivers/net/wireless/iwlwifi/mvm/scan.c b/drivers/net/wireless/iwlwifi/mvm/scan.c
index a2cd54b57e67..945398ba39b4 100644
--- a/drivers/net/wireless/iwlwifi/mvm/scan.c
+++ b/drivers/net/wireless/iwlwifi/mvm/scan.c
@@ -402,10 +402,13 @@ int iwl_mvm_rx_scan_complete(struct iwl_mvm *mvm, struct iwl_rx_cmd_buffer *rxb,
         struct iwl_rx_packet *pkt = rxb_addr(rxb);
         struct iwl_scan_complete_notif *notif = (void *)pkt->data;
 
+        lockdep_assert_held(&mvm->mutex);
+
         IWL_DEBUG_SCAN(mvm, "Scan complete: status=0x%x scanned channels=%d\n",
                        notif->status, notif->scanned_channels);
 
-        mvm->scan_status = IWL_MVM_SCAN_NONE;
+        if (mvm->scan_status == IWL_MVM_SCAN_OS)
+                mvm->scan_status = IWL_MVM_SCAN_NONE;
         ieee80211_scan_completed(mvm->hw, notif->status != SCAN_COMP_STATUS_OK);
 
         iwl_mvm_unref(mvm, IWL_MVM_REF_SCAN);
@@ -466,7 +469,7 @@ static bool iwl_mvm_scan_abort_notif(struct iwl_notif_wait_data *notif_wait,
         };
 }
 
-void iwl_mvm_cancel_scan(struct iwl_mvm *mvm)
+int iwl_mvm_cancel_scan(struct iwl_mvm *mvm)
 {
         struct iwl_notification_wait wait_scan_abort;
         static const u8 scan_abort_notif[] = { SCAN_ABORT_CMD,
@@ -474,13 +477,13 @@ void iwl_mvm_cancel_scan(struct iwl_mvm *mvm)
         int ret;
 
         if (mvm->scan_status == IWL_MVM_SCAN_NONE)
-                return;
+                return 0;
 
         if (iwl_mvm_is_radio_killed(mvm)) {
                 ieee80211_scan_completed(mvm->hw, true);
                 iwl_mvm_unref(mvm, IWL_MVM_REF_SCAN);
                 mvm->scan_status = IWL_MVM_SCAN_NONE;
-                return;
+                return 0;
         }
 
         iwl_init_notification_wait(&mvm->notif_wait, &wait_scan_abort,
@@ -495,14 +498,11 @@ void iwl_mvm_cancel_scan(struct iwl_mvm *mvm)
                 goto out_remove_notif;
         }
 
-        ret = iwl_wait_notification(&mvm->notif_wait, &wait_scan_abort, 1 * HZ);
-        if (ret)
-                IWL_ERR(mvm, "%s - failed on timeout\n", __func__);
-
-        return;
+        return iwl_wait_notification(&mvm->notif_wait, &wait_scan_abort, HZ);
 
 out_remove_notif:
         iwl_remove_notification(&mvm->notif_wait, &wait_scan_abort);
+        return ret;
 }
 
 int iwl_mvm_rx_scan_offload_complete_notif(struct iwl_mvm *mvm,