netdev - Re: [PATCH net-next v1] neighbour: Replace kvzalloc() with kzalloc() when GFP

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Message-ID: <20250216190642.31169-1-kuniyu@amazon.com>
Date: Sun, 16 Feb 2025 11:06:42 -0800
From: Kuniyuki Iwashima <kuniyu@...zon.com>
To: <enjuk@...zon.com>
CC: <davem@...emloft.net>, <edumazet@...gle.com>, <gnaaman@...venets.com>,
	<horms@...nel.org>, <joel.granados@...nel.org>, <kohei.enju@...il.com>,
	<kuba@...nel.org>, <kuniyu@...zon.com>, <linux-kernel@...r.kernel.org>,
	<lizetao1@...wei.com>, <netdev@...r.kernel.org>, <pabeni@...hat.com>
Subject: Re: [PATCH net-next v1] neighbour: Replace kvzalloc() with kzalloc() when GFP_ATOMIC is specified

From: Kohei Enju <enjuk@...zon.com>
Date: Mon, 17 Feb 2025 01:30:16 +0900
> Replace kvzalloc()/kvfree() with kzalloc()/kfree() when GFP_ATOMIC is
> specified, since kvzalloc() doesn't support non-sleeping allocations such
> as GFP_ATOMIC.
> 
> With incompatible gfp flags, kvzalloc() never falls back to the vmalloc
> path and returns immediately after the kmalloc path fails.
> Therefore, using kzalloc() is sufficient in this case.
> 
> Fixes: 41b3caa7c076 ("neighbour: Add hlist_node to struct neighbour")

This commit followed the old hash_buckets allocation, so I'd add

  Fixes: ab101c553bc1 ("neighbour: use kvzalloc()/kvfree()")

too.

Both commits were introduced in v6.13, so there's no difference in terms
of backporting though.

Also, it would be nice to CC mm maintainers in case they have some
comments.


> Signed-off-by: Kohei Enju <enjuk@...zon.com>
> ---
>  net/core/neighbour.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
> 
> diff --git a/net/core/neighbour.c b/net/core/neighbour.c
> index d8dd686b5287..344c9cd168ec 100644
> --- a/net/core/neighbour.c
> +++ b/net/core/neighbour.c
> @@ -518,7 +518,7 @@ static struct neigh_hash_table *neigh_hash_alloc(unsigned int shift)
>  	if (!ret)
>  		return NULL;
>  
> -	hash_heads = kvzalloc(size, GFP_ATOMIC);
> +	hash_heads = kzalloc(size, GFP_ATOMIC);
>  	if (!hash_heads) {
>  		kfree(ret);
>  		return NULL;
> @@ -536,7 +536,7 @@ static void neigh_hash_free_rcu(struct rcu_head *head)
>  						    struct neigh_hash_table,
>  						    rcu);
>  
> -	kvfree(nht->hash_heads);
> +	kfree(nht->hash_heads);
>  	kfree(nht);
>  }
>  
> -- 
> 2.39.5 (Apple Git-154)