iwlwifi: mvm: do more useful queue sync accounting

We're currently doing accounting on the queue sync with an
atomic variable that counts down the number of remaining
notifications that we still need.

As we've been hitting issues in this area, modify this to
track a bitmap of queues, not just the number of queues,
and print out the remaining bitmap in the warning.
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: Luca Coelho <luciano.coelho@intel.com>
Link: https://lore.kernel.org/r/iwlwifi.20201209231352.0a3fa177cd6b.I7c69ff999419368266279ec27dd618eb450908b3@changeidSigned-off-by: Luca Coelho <luciano.coelho@intel.com>

drivers/net/wireless/intel/iwlwifi/mvm/mac80211.c

@@ -5100,8 +5100,7 @@ void iwl_mvm_sync_rx_queues_internal(struct iwl_mvm *mvm,
 
 	if (notif->sync) {
 		notif->cookie = mvm->queue_sync_cookie;
-		atomic_set(&mvm->queue_sync_counter,
-			   mvm->trans->num_rx_queues);
+		mvm->queue_sync_state = (1 << mvm->trans->num_rx_queues) - 1;
 	}
 
 	ret = iwl_mvm_notify_rx_queue(mvm, qmask, notif, size, !notif->sync);
@@ -5113,14 +5112,16 @@ void iwl_mvm_sync_rx_queues_internal(struct iwl_mvm *mvm,
 	if (notif->sync) {
 		lockdep_assert_held(&mvm->mutex);
 		ret = wait_event_timeout(mvm->rx_sync_waitq,
-					 atomic_read(&mvm->queue_sync_counter) == 0 ||
+					 READ_ONCE(mvm->queue_sync_state) == 0 ||
 					 iwl_mvm_is_radio_killed(mvm),
 					 HZ);
-		WARN_ON_ONCE(!ret && !iwl_mvm_is_radio_killed(mvm));
+		WARN_ONCE(!ret && !iwl_mvm_is_radio_killed(mvm),
+			  "queue sync: failed to sync, state is 0x%lx\n",
+			  mvm->queue_sync_state);
 	}
 
 out:
-	atomic_set(&mvm->queue_sync_counter, 0);
+	mvm->queue_sync_state = 0;
 	if (notif->sync)
 		mvm->queue_sync_cookie++;
 }

drivers/net/wireless/intel/iwlwifi/mvm/mvm.h

@@ -842,7 +842,7 @@ struct iwl_mvm {
 	unsigned long status;
 
 	u32 queue_sync_cookie;
-	atomic_t queue_sync_counter;
+	unsigned long queue_sync_state;
 	/*
 	 * for beacon filtering -
 	 * currently only one interface can be supported

drivers/net/wireless/intel/iwlwifi/mvm/ops.c

@@ -703,7 +703,7 @@ iwl_op_mode_mvm_start(struct iwl_trans *trans, const struct iwl_cfg *cfg,
 
 	init_waitqueue_head(&mvm->rx_sync_waitq);
 
-	atomic_set(&mvm->queue_sync_counter, 0);
+	mvm->queue_sync_state = 0;
 
 	SET_IEEE80211_DEV(mvm->hw, mvm->trans->dev);
 

drivers/net/wireless/intel/iwlwifi/mvm/rxmq.c

@@ -827,9 +827,13 @@ void iwl_mvm_rx_queue_notif(struct iwl_mvm *mvm, struct napi_struct *napi,
 		WARN_ONCE(1, "Invalid identifier %d", internal_notif->type);
 	}
 
-	if (internal_notif->sync &&
-	    !atomic_dec_return(&mvm->queue_sync_counter))
-		wake_up(&mvm->rx_sync_waitq);
+	if (internal_notif->sync) {
+		WARN_ONCE(!test_and_clear_bit(queue, &mvm->queue_sync_state),
+			  "queue sync: queue %d responded a second time!\n",
+			  queue);
+		if (READ_ONCE(mvm->queue_sync_state) == 0)
+			wake_up(&mvm->rx_sync_waitq);
+	}
 }
 
 static void iwl_mvm_oldsn_workaround(struct iwl_mvm *mvm,