[PATCH net-next] lwtunnel: Add lwtunnel_encap_type_check() helper

[PATCH net-next] lwtunnel: Add lwtunnel_encap_type_check() helper

[Yue Haibing]

Consolidate encap_type check to dedicated helper for code clean.

Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
---
 net/core/lwtunnel.c | 46 ++++++++++++++++++++++-----------------------
 1 file changed, 22 insertions(+), 24 deletions(-)

diff --git a/net/core/lwtunnel.c b/net/core/lwtunnel.c
index f9d76d85d04f..f9453f278715 100644
--- a/net/core/lwtunnel.c
+++ b/net/core/lwtunnel.c
@@ -79,10 +79,18 @@ EXPORT_SYMBOL_GPL(lwtunnel_state_alloc);
 static const struct lwtunnel_encap_ops __rcu *
 		lwtun_encaps[LWTUNNEL_ENCAP_MAX + 1] __read_mostly;
 
+static inline int lwtunnel_encap_type_check(unsigned int encap_type)
+{
+	if (encap_type == LWTUNNEL_ENCAP_NONE ||
+	    encap_type > LWTUNNEL_ENCAP_MAX)
+		return -EINVAL;
+	return 0;
+}
+
 int lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops *ops,
 			   unsigned int num)
 {
-	if (num > LWTUNNEL_ENCAP_MAX)
+	if (lwtunnel_encap_type_check(num) < 0)
 		return -ERANGE;
 
 	return !cmpxchg((const struct lwtunnel_encap_ops **)
@@ -96,8 +104,7 @@ int lwtunnel_encap_del_ops(const struct lwtunnel_encap_ops *ops,
 {
 	int ret;
 
-	if (encap_type == LWTUNNEL_ENCAP_NONE ||
-	    encap_type > LWTUNNEL_ENCAP_MAX)
+	if (lwtunnel_encap_type_check(encap_type) < 0)
 		return -ERANGE;
 
 	ret = (cmpxchg((const struct lwtunnel_encap_ops **)
@@ -117,10 +124,10 @@ int lwtunnel_build_state(struct net *net, u16 encap_type,
 {
 	const struct lwtunnel_encap_ops *ops;
 	bool found = false;
-	int ret = -EINVAL;
+	int ret;
 
-	if (encap_type == LWTUNNEL_ENCAP_NONE ||
-	    encap_type > LWTUNNEL_ENCAP_MAX) {
+	ret = lwtunnel_encap_type_check(encap_type);
+	if (ret < 0) {
 		NL_SET_ERR_MSG_ATTR(extack, encap,
 				    "Unknown LWT encapsulation type");
 		return ret;
@@ -152,10 +159,10 @@ EXPORT_SYMBOL_GPL(lwtunnel_build_state);
 int lwtunnel_valid_encap_type(u16 encap_type, struct netlink_ext_ack *extack)
 {
 	const struct lwtunnel_encap_ops *ops;
-	int ret = -EINVAL;
+	int ret;
 
-	if (encap_type == LWTUNNEL_ENCAP_NONE ||
-	    encap_type > LWTUNNEL_ENCAP_MAX) {
+	ret = lwtunnel_encap_type_check(encap_type);
+	if (ret < 0) {
 		NL_SET_ERR_MSG(extack, "Unknown lwt encapsulation type");
 		return ret;
 	}
@@ -236,8 +243,7 @@ int lwtunnel_fill_encap(struct sk_buff *skb, struct lwtunnel_state *lwtstate,
 	if (!lwtstate)
 		return 0;
 
-	if (lwtstate->type == LWTUNNEL_ENCAP_NONE ||
-	    lwtstate->type > LWTUNNEL_ENCAP_MAX)
+	if (lwtunnel_encap_type_check(lwtstate->type) < 0)
 		return 0;
 
 	nest = nla_nest_start_noflag(skb, encap_attr);
@@ -275,8 +281,7 @@ int lwtunnel_get_encap_size(struct lwtunnel_state *lwtstate)
 	if (!lwtstate)
 		return 0;
 
-	if (lwtstate->type == LWTUNNEL_ENCAP_NONE ||
-	    lwtstate->type > LWTUNNEL_ENCAP_MAX)
+	if (lwtunnel_encap_type_check(lwtstate->type) < 0)
 		return 0;
 
 	rcu_read_lock();
@@ -303,8 +308,7 @@ int lwtunnel_cmp_encap(struct lwtunnel_state *a, struct lwtunnel_state *b)
 	if (a->type != b->type)
 		return 1;
 
-	if (a->type == LWTUNNEL_ENCAP_NONE ||
-	    a->type > LWTUNNEL_ENCAP_MAX)
+	if (lwtunnel_encap_type_check(a->type) < 0)
 		return 0;
 
 	rcu_read_lock();
@@ -339,9 +343,7 @@ int lwtunnel_output(struct net *net, struct sock *sk, struct sk_buff *skb)
 		goto drop;
 	}
 	lwtstate = dst->lwtstate;
-
-	if (lwtstate->type == LWTUNNEL_ENCAP_NONE ||
-	    lwtstate->type > LWTUNNEL_ENCAP_MAX) {
+	if (lwtunnel_encap_type_check(lwtstate->type) < 0) {
 		ret = 0;
 		goto out;
 	}
@@ -393,9 +395,7 @@ int lwtunnel_xmit(struct sk_buff *skb)
 	}
 
 	lwtstate = dst->lwtstate;
-
-	if (lwtstate->type == LWTUNNEL_ENCAP_NONE ||
-	    lwtstate->type > LWTUNNEL_ENCAP_MAX) {
+	if (lwtunnel_encap_type_check(lwtstate->type) < 0) {
 		ret = 0;
 		goto out;
 	}
@@ -446,9 +446,7 @@ int lwtunnel_input(struct sk_buff *skb)
 		goto drop;
 	}
 	lwtstate = dst->lwtstate;
-
-	if (lwtstate->type == LWTUNNEL_ENCAP_NONE ||
-	    lwtstate->type > LWTUNNEL_ENCAP_MAX)
+	if (lwtunnel_encap_type_check(lwtstate->type) < 0)
 		return 0;
 
 	ret = -EOPNOTSUPP;
-- 
2.34.1

Re: [PATCH net-next] lwtunnel: Add lwtunnel_encap_type_check() helper

[Simon Horman]

On Wed, Jun 25, 2025 at 06:24:13PM +0800, Yue Haibing wrote:
> Consolidate encap_type check to dedicated helper for code clean.
> 
> Signed-off-by: Yue Haibing <yuehaibing@huawei.com>
> ---
>  net/core/lwtunnel.c | 46 ++++++++++++++++++++++-----------------------
>  1 file changed, 22 insertions(+), 24 deletions(-)
> 
> diff --git a/net/core/lwtunnel.c b/net/core/lwtunnel.c
> index f9d76d85d04f..f9453f278715 100644
> --- a/net/core/lwtunnel.c
> +++ b/net/core/lwtunnel.c
> @@ -79,10 +79,18 @@ EXPORT_SYMBOL_GPL(lwtunnel_state_alloc);
>  static const struct lwtunnel_encap_ops __rcu *
>  		lwtun_encaps[LWTUNNEL_ENCAP_MAX + 1] __read_mostly;
>  
> +static inline int lwtunnel_encap_type_check(unsigned int encap_type)

Please don't use the inline keyword in .c files unless there
is a demonstratable - usually performance - reason to do so.
Which I don't think that is hte case here.

Rather, let the compiler inine functions as it sees fit.

> +{
> +	if (encap_type == LWTUNNEL_ENCAP_NONE ||
> +	    encap_type > LWTUNNEL_ENCAP_MAX)
> +		return -EINVAL;
> +	return 0;
> +}
> +

I'm not entirely sure if this change is worth the churn.
But if it is, perhaps a helper of the following form is simpler.

(Completely untested!)

static bool lwtunnel_encap_type_invalid(unsigned int encap_type)
{
	return encap_type == LWTUNNEL_ENCAP_NONE ||
	       encap_type > LWTUNNEL_ENCAP_MAX;
}


>  int lwtunnel_encap_add_ops(const struct lwtunnel_encap_ops *ops,
>  			   unsigned int num)
>  {
> -	if (num > LWTUNNEL_ENCAP_MAX)
> +	if (lwtunnel_encap_type_check(num) < 0)

Which can then be used like this:

	if (lwtunnel_encap_type_invalid(num))

>  		return -ERANGE;
>  
>  	return !cmpxchg((const struct lwtunnel_encap_ops **)

...

-- 
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