linux-kernel - Re: [PATCH v2] wireguard: allowedips: Use kfree_rcu() instead of call

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Message-ID: <af6253a8-5b21-4e32-84bf-62d11c7ce251@redhat.com>
Date: Tue, 7 Oct 2025 14:55:07 +0200
From: Paolo Abeni <pabeni@...hat.com>
To: Fushuai Wang <wangfushuai@...du.com>, Jason@...c4.com,
 andrew+netdev@...n.ch, davem@...emloft.net, edumazet@...gle.com,
 kuba@...nel.org
Cc: wireguard@...ts.zx2c4.com, netdev@...r.kernel.org,
 linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] wireguard: allowedips: Use kfree_rcu() instead of
 call_rcu()

On 10/5/25 3:39 PM, Fushuai Wang wrote:
> Replace call_rcu() + kmem_cache_free() with kfree_rcu() to simplify
> the code and reduce function size.
> 
> Signed-off-by: Fushuai Wang <wangfushuai@...du.com>
> ---
>  drivers/net/wireguard/allowedips.c | 9 ++-------
>  1 file changed, 2 insertions(+), 7 deletions(-)
> 
> diff --git a/drivers/net/wireguard/allowedips.c b/drivers/net/wireguard/allowedips.c
> index 09f7fcd7da78..5ece9acad64d 100644
> --- a/drivers/net/wireguard/allowedips.c
> +++ b/drivers/net/wireguard/allowedips.c
> @@ -48,11 +48,6 @@ static void push_rcu(struct allowedips_node **stack,
>  	}
>  }
>  
> -static void node_free_rcu(struct rcu_head *rcu)
> -{
> -	kmem_cache_free(node_cache, container_of(rcu, struct allowedips_node, rcu));
> -}
> -
>  static void root_free_rcu(struct rcu_head *rcu)
>  {
>  	struct allowedips_node *node, *stack[MAX_ALLOWEDIPS_DEPTH] = {
> @@ -271,13 +266,13 @@ static void remove_node(struct allowedips_node *node, struct mutex *lock)
>  	if (free_parent)
>  		child = rcu_dereference_protected(parent->bit[!(node->parent_bit_packed & 1)],
>  						  lockdep_is_held(lock));
> -	call_rcu(&node->rcu, node_free_rcu);
> +	kfree_rcu(node, rcu);
>  	if (!free_parent)
>  		return;
>  	if (child)
>  		child->parent_bit_packed = parent->parent_bit_packed;
>  	*(struct allowedips_node **)(parent->parent_bit_packed & ~3UL) = child;
> -	call_rcu(&parent->rcu, node_free_rcu);
> +	kfree_rcu(parent, rcu);
>  }
>  
>  static int remove(struct allowedips_node __rcu **trie, u8 bits, const u8 *key,

This is net-next material, and net-next is currently closed for the
merge window, but I guess Jason will take this patch in his tree.

Cheers,

Paolo