net: rps: remove kfree_rcu_mightsleep() use

Add an rcu_head to sd_flow_limit and rps_sock_flow_table structs
to use the more conventional and predictable k[v]free_rcu().

Signed-off-by: Eric Dumazet <[email protected]>
Reviewed-by: Willem de Bruijn <[email protected]>
Link: https://patch.msgid.link/[email protected]
Signed-off-by: Jakub Kicinski <[email protected]>

Author: edumazet

include/net/rps.h

@@ -57,9 +57,10 @@ struct rps_dev_flow_table {
  * meaning we use 32-6=26 bits for the hash.
  */
 struct rps_sock_flow_table {
-	u32	mask;
+	struct rcu_head	rcu;
+	u32		mask;
 
-	u32	ents[] ____cacheline_aligned_in_smp;
+	u32		ents[] ____cacheline_aligned_in_smp;
 };
 #define	RPS_SOCK_FLOW_TABLE_SIZE(_num) (offsetof(struct rps_sock_flow_table, ents[_num]))
 

net/core/dev.h

@@ -15,6 +15,7 @@ struct cpumask;
 /* Random bits of netdevice that don't need to be exposed */
 #define FLOW_LIMIT_HISTORY	(1 << 7)  /* must be ^2 and !overflow buckets */
 struct sd_flow_limit {
+	struct rcu_head		rcu;
 	unsigned int		count;
 	u8			log_buckets;
 	unsigned int		history_head;

net/core/sysctl_net_core.c

@@ -201,7 +201,7 @@ static int rps_sock_flow_sysctl(const struct ctl_table *table, int write,
 			if (orig_sock_table) {
 				static_branch_dec(&rps_needed);
 				static_branch_dec(&rfs_needed);
-				kvfree_rcu_mightsleep(orig_sock_table);
+				kvfree_rcu(orig_sock_table, rcu);
 			}
 		}
 	}
@@ -239,7 +239,7 @@ static int flow_limit_cpu_sysctl(const struct ctl_table *table, int write,
 				     lockdep_is_held(&flow_limit_update_mutex));
 			if (cur && !cpumask_test_cpu(i, mask)) {
 				RCU_INIT_POINTER(sd->flow_limit, NULL);
-				kfree_rcu_mightsleep(cur);
+				kfree_rcu(cur, rcu);
 			} else if (!cur && cpumask_test_cpu(i, mask)) {
 				cur = kzalloc_node(len, GFP_KERNEL,
 						   cpu_to_node(i));