Re: [PATCH net-next 3/7] rxrpc: Fix locking issue

From: Jakub Kicinski <kuba@kernel.org>
To: David Howells <dhowells@redhat.com>
Cc: netdev@vger.kernel.org, linux-afs@lists.infradead.org,
	linux-kernel@vger.kernel.org
Subject: Re: [PATCH net-next 3/7] rxrpc: Fix locking issue
Date: Fri, 20 May 2022 18:11:18 -0700	[thread overview]
Message-ID: <20220520181118.47ca2bdc@kernel.org> (raw)
In-Reply-To: <165306517397.34989.14593967592142268589.stgit@warthog.procyon.org.uk>

On Fri, 20 May 2022 17:46:13 +0100 David Howells wrote:
> +struct list_head *seq_list_start_rcu(struct list_head *head, loff_t pos)
> +{
> +	struct list_head *lh;
> +
> +	list_for_each_rcu(lh, head)
> +		if (pos-- == 0)
> +			return lh;
> +
> +	return NULL;
> +}
> +EXPORT_SYMBOL(seq_list_start_rcu);
> +
> +struct list_head *seq_list_start_head_rcu(struct list_head *head, loff_t pos)
> +{
> +	if (!pos)
> +		return head;
> +
> +	return seq_list_start_rcu(head, pos - 1);
> +}
> +EXPORT_SYMBOL(seq_list_start_head_rcu);
> +
> +struct list_head *seq_list_next_rcu(void *v, struct list_head *head,
> +				    loff_t *ppos)
> +{
> +	struct list_head *lh;
> +
> +	lh = rcu_dereference(((struct list_head *)v)->next);

Can we use list_next_rcu() here maybe ? to avoid the sparse warning?

> +	++*ppos;
> +	return lh == head ? NULL : lh;
> +}
> +EXPORT_SYMBOL(seq_list_next_rcu);