Merge branch 'xps-fixes'

Sabrina Dubroca says:

====================
fixes for XPS configuration after Symmetric queue selection

This fixes some bugs introduced by the "Symmetric queue selection
using XPS for Rx queues".

First, the refactoring of the cleanup function skipped resetting the
queue's NUMA node under some conditions.

Second, the accounting on static keys for XPS and RXQS-XPS is
unbalanced, so the static key for XPS won't actually disable itself,
once enabled. The RXQS-XPS static key can actually be disabled by
reconfiguring a device that didn't have RXQS-XPS configured at all.
====================
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

net/core/dev.c

@@ -2175,6 +2175,20 @@ static bool remove_xps_queue_cpu(struct net_device *dev,
 	return active;
 }
 
+static void reset_xps_maps(struct net_device *dev,
+			   struct xps_dev_maps *dev_maps,
+			   bool is_rxqs_map)
+{
+	if (is_rxqs_map) {
+		static_key_slow_dec_cpuslocked(&xps_rxqs_needed);
+		RCU_INIT_POINTER(dev->xps_rxqs_map, NULL);
+	} else {
+		RCU_INIT_POINTER(dev->xps_cpus_map, NULL);
+	}
+	static_key_slow_dec_cpuslocked(&xps_needed);
+	kfree_rcu(dev_maps, rcu);
+}
+
 static void clean_xps_maps(struct net_device *dev, const unsigned long *mask,
 			   struct xps_dev_maps *dev_maps, unsigned int nr_ids,
 			   u16 offset, u16 count, bool is_rxqs_map)
@@ -2186,18 +2200,15 @@ static void clean_xps_maps(struct net_device *dev, const unsigned long *mask,
 	     j < nr_ids;)
 		active |= remove_xps_queue_cpu(dev, dev_maps, j, offset,
 					       count);
-	if (!active) {
-		if (is_rxqs_map) {
-			RCU_INIT_POINTER(dev->xps_rxqs_map, NULL);
-		} else {
-			RCU_INIT_POINTER(dev->xps_cpus_map, NULL);
+	if (!active)
+		reset_xps_maps(dev, dev_maps, is_rxqs_map);
 
-			for (i = offset + (count - 1); count--; i--)
-				netdev_queue_numa_node_write(
-					netdev_get_tx_queue(dev, i),
-							NUMA_NO_NODE);
+	if (!is_rxqs_map) {
+		for (i = offset + (count - 1); count--; i--) {
+			netdev_queue_numa_node_write(
+				netdev_get_tx_queue(dev, i),
+				NUMA_NO_NODE);
 		}
-		kfree_rcu(dev_maps, rcu);
 	}
 }
 
@@ -2234,10 +2245,6 @@ static void netif_reset_xps_queues(struct net_device *dev, u16 offset,
 		       false);
 
 out_no_maps:
-	if (static_key_enabled(&xps_rxqs_needed))
-		static_key_slow_dec_cpuslocked(&xps_rxqs_needed);
-
-	static_key_slow_dec_cpuslocked(&xps_needed);
 	mutex_unlock(&xps_map_mutex);
 	cpus_read_unlock();
 }
@@ -2355,9 +2362,12 @@ int __netif_set_xps_queue(struct net_device *dev, const unsigned long *mask,
 	if (!new_dev_maps)
 		goto out_no_new_maps;
 
-	static_key_slow_inc_cpuslocked(&xps_needed);
-	if (is_rxqs_map)
-		static_key_slow_inc_cpuslocked(&xps_rxqs_needed);
+	if (!dev_maps) {
+		/* Increment static keys at most once per type */
+		static_key_slow_inc_cpuslocked(&xps_needed);
+		if (is_rxqs_map)
+			static_key_slow_inc_cpuslocked(&xps_rxqs_needed);
+	}
 
 	for (j = -1; j = netif_attrmask_next(j, possible_mask, nr_ids),
 	     j < nr_ids;) {
@@ -2455,13 +2465,8 @@ int __netif_set_xps_queue(struct net_device *dev, const unsigned long *mask,
 	}
 
 	/* free map if not active */
-	if (!active) {
-		if (is_rxqs_map)
-			RCU_INIT_POINTER(dev->xps_rxqs_map, NULL);
-		else
-			RCU_INIT_POINTER(dev->xps_cpus_map, NULL);
-		kfree_rcu(dev_maps, rcu);
-	}
+	if (!active)
+		reset_xps_maps(dev, dev_maps, is_rxqs_map);
 
 out_no_maps:
 	mutex_unlock(&xps_map_mutex);