[PATCH 1/2] ipv6: fib: hide unused 'pn' variable

[PATCH 1/2] ipv6: fib: hide unused 'pn' variable

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

When CONFIG_IPV6_SUBTREES is disabled, the only user is hidden, causing
a 'make W=1' warning:

net/ipv6/ip6_fib.c: In function 'fib6_add':
net/ipv6/ip6_fib.c:1388:32: error: variable 'pn' set but not used [-Werror=unused-but-set-variable]

Add another #ifdef around the variable declaration, matching the other
uses in this file.

Fixes: 66729e18df08 ("[IPV6] ROUTE: Make sure we have fn->leaf when adding a node on subtree.")
Link: https://lore.kernel.org/netdev/20240322131746.904943-1-arnd@kernel.org/
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 net/ipv6/ip6_fib.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/net/ipv6/ip6_fib.c b/net/ipv6/ip6_fib.c
index ddd8e3c2df4a..31d77885bcae 100644
--- a/net/ipv6/ip6_fib.c
+++ b/net/ipv6/ip6_fib.c
@@ -1386,7 +1386,10 @@ int fib6_add(struct fib6_node *root, struct fib6_info *rt,
 	     struct nl_info *info, struct netlink_ext_ack *extack)
 {
 	struct fib6_table *table = rt->fib6_table;
-	struct fib6_node *fn, *pn = NULL;
+	struct fib6_node *fn;
+#ifdef CONFIG_IPV6_SUBTREES
+	struct fib6_node *pn = NULL;
+#endif
 	int err = -ENOMEM;
 	int allow_create = 1;
 	int replace_required = 0;
@@ -1410,9 +1413,9 @@ int fib6_add(struct fib6_node *root, struct fib6_info *rt,
 		goto out;
 	}
 
+#ifdef CONFIG_IPV6_SUBTREES
 	pn = fn;
 
-#ifdef CONFIG_IPV6_SUBTREES
 	if (rt->fib6_src.plen) {
 		struct fib6_node *sn;
 
-- 
2.39.2

[PATCH 2/2] ipv4/route: avoid unused-but-set-variable warning

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

The log_martians variable is only used in an #ifdef, causing a 'make W=1'
warning with gcc:

net/ipv4/route.c: In function 'ip_rt_send_redirect':
net/ipv4/route.c:880:13: error: variable 'log_martians' set but not used [-Werror=unused-but-set-variable]

Change the #ifdef to an equivalent IS_ENABLED() to let the compiler
see where the variable is used.

Fixes: 30038fc61adf ("net: ip_rt_send_redirect() optimization")
Reviewed-by: David Ahern <dsahern@kernel.org>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 net/ipv4/route.c | 4 +---
 1 file changed, 1 insertion(+), 3 deletions(-)

diff --git a/net/ipv4/route.c b/net/ipv4/route.c
index c8f76f56dc16..d36ace160d42 100644
--- a/net/ipv4/route.c
+++ b/net/ipv4/route.c
@@ -926,13 +926,11 @@ void ip_rt_send_redirect(struct sk_buff *skb)
 		icmp_send(skb, ICMP_REDIRECT, ICMP_REDIR_HOST, gw);
 		peer->rate_last = jiffies;
 		++peer->n_redirects;
-#ifdef CONFIG_IP_ROUTE_VERBOSE
-		if (log_martians &&
+		if (IS_ENABLED(CONFIG_IP_ROUTE_VERBOSE) && log_martians &&
 		    peer->n_redirects == ip_rt_redirect_number)
 			net_warn_ratelimited("host %pI4/if%d ignores redirects for %pI4 to %pI4\n",
 					     &ip_hdr(skb)->saddr, inet_iif(skb),
 					     &ip_hdr(skb)->daddr, &gw);
-#endif
 	}
 out_put_peer:
 	inet_putpeer(peer);
-- 
2.39.2

Re: [PATCH 2/2] ipv4/route: avoid unused-but-set-variable warning

[Eric Dumazet]

On Mon, Apr 8, 2024 at 9:42 AM Arnd Bergmann <arnd@kernel.org> wrote:
>
> From: Arnd Bergmann <arnd@arndb.de>
>
> The log_martians variable is only used in an #ifdef, causing a 'make W=1'
> warning with gcc:
>
> net/ipv4/route.c: In function 'ip_rt_send_redirect':
> net/ipv4/route.c:880:13: error: variable 'log_martians' set but not used [-Werror=unused-but-set-variable]
>
> Change the #ifdef to an equivalent IS_ENABLED() to let the compiler
> see where the variable is used.
>
> Fixes: 30038fc61adf ("net: ip_rt_send_redirect() optimization")
> Reviewed-by: David Ahern <dsahern@kernel.org>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---

A Fixes: tag like this seems overkill, I doubt W=1 was the norm for
old kernels...

Reviewed-by: Eric Dumazet <edumazet@google.com>

Thanks.

Re: [PATCH 1/2] ipv6: fib: hide unused 'pn' variable

[Eric Dumazet]

On Mon, Apr 8, 2024 at 9:42 AM Arnd Bergmann <arnd@kernel.org> wrote:
>
> From: Arnd Bergmann <arnd@arndb.de>
>
> When CONFIG_IPV6_SUBTREES is disabled, the only user is hidden, causing
> a 'make W=1' warning:
>
> net/ipv6/ip6_fib.c: In function 'fib6_add':
> net/ipv6/ip6_fib.c:1388:32: error: variable 'pn' set but not used [-Werror=unused-but-set-variable]
>
> Add another #ifdef around the variable declaration, matching the other
> uses in this file.
>
> Fixes: 66729e18df08 ("[IPV6] ROUTE: Make sure we have fn->leaf when adding a node on subtree.")
> Link: https://lore.kernel.org/netdev/20240322131746.904943-1-arnd@kernel.org/
> Reviewed-by: David Ahern <dsahern@kernel.org>
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>

It is unfortunate we add an #ifdef just to avoid a warning.

Reviewed-by: Eric Dumazet <edumazet@google.com>

Re: [PATCH 1/2] ipv6: fib: hide unused 'pn' variable

[patchwork-bot+netdevbpf]

Hello:

This series was applied to netdev/net.git (main)
by Paolo Abeni <pabeni@redhat.com>:

On Mon,  8 Apr 2024 09:42:02 +0200 you wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> When CONFIG_IPV6_SUBTREES is disabled, the only user is hidden, causing
> a 'make W=1' warning:
> 
> net/ipv6/ip6_fib.c: In function 'fib6_add':
> net/ipv6/ip6_fib.c:1388:32: error: variable 'pn' set but not used [-Werror=unused-but-set-variable]
> 
> [...]

Here is the summary with links:
  - [1/2] ipv6: fib: hide unused 'pn' variable
    https://git.kernel.org/netdev/net/c/74043489fcb5
  - [2/2] ipv4/route: avoid unused-but-set-variable warning
    https://git.kernel.org/netdev/net/c/cf1b7201df59

You are awesome, thank you!
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