[PATCH 1/2] netfilter: nft_socket: fix an unused variable warning

[PATCH 1/2] netfilter: nft_socket: fix an unused variable warning

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

The variable is only used in an #ifdef, causing a harmless warning:

net/netfilter/nft_socket.c: In function 'nft_socket_init':
net/netfilter/nft_socket.c:137:27: error: unused variable 'level' [-Werror=unused-variable]
  137 |         unsigned int len, level;
      |                           ^~~~~

Move it into the same #ifdef block.

Fixes: e0bb96db96f8 ("netfilter: nft_socket: add support for cgroupsv2")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 net/netfilter/nft_socket.c | 7 +++++--
 1 file changed, 5 insertions(+), 2 deletions(-)

diff --git a/net/netfilter/nft_socket.c b/net/netfilter/nft_socket.c
index 9c169d100651..f9c5ff6024e0 100644
--- a/net/netfilter/nft_socket.c
+++ b/net/netfilter/nft_socket.c
@@ -134,7 +134,7 @@ static int nft_socket_init(const struct nft_ctx *ctx,
 			   const struct nlattr * const tb[])
 {
 	struct nft_socket *priv = nft_expr_priv(expr);
-	unsigned int len, level;
+	unsigned int len;
 
 	if (!tb[NFTA_SOCKET_DREG] || !tb[NFTA_SOCKET_KEY])
 		return -EINVAL;
@@ -160,7 +160,9 @@ static int nft_socket_init(const struct nft_ctx *ctx,
 		len = sizeof(u32);
 		break;
 #ifdef CONFIG_CGROUPS
-	case NFT_SOCKET_CGROUPV2:
+	case NFT_SOCKET_CGROUPV2: {
+		unsigned int level;
+
 		if (!tb[NFTA_SOCKET_LEVEL])
 			return -EINVAL;
 
@@ -171,6 +173,7 @@ static int nft_socket_init(const struct nft_ctx *ctx,
 		priv->level = level;
 		len = sizeof(u64);
 		break;
+	}
 #endif
 	default:
 		return -EOPNOTSUPP;
-- 
2.29.2

[PATCH 2/2] netfilter: nft_socket: fix build with CONFIG_SOCK_CGROUP_DATA=n

[Arnd Bergmann]

From: Arnd Bergmann <arnd@arndb.de>

In some configurations, the sock_cgroup_ptr() function is not available:

net/netfilter/nft_socket.c: In function 'nft_sock_get_eval_cgroupv2':
net/netfilter/nft_socket.c:47:16: error: implicit declaration of function 'sock_cgroup_ptr'; did you mean 'obj_cgroup_put'? [-Werror=implicit-function-declaration]
   47 |         cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
      |                ^~~~~~~~~~~~~~~
      |                obj_cgroup_put
net/netfilter/nft_socket.c:47:14: error: assignment to 'struct cgroup *' from 'int' makes pointer from integer without a cast [-Werror=int-conversion]
   47 |         cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
      |              ^

Change the caller to match the same #ifdef check, only calling it
when the function is defined.

Fixes: e0bb96db96f8 ("netfilter: nft_socket: add support for cgroupsv2")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
I don't actually know what the right fix is for this, I only checked
that my patch fixes the build failure. Is is possible that the function
should always be defined.

Please make sure you review carefully before applying.
---
 net/netfilter/nft_socket.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/net/netfilter/nft_socket.c b/net/netfilter/nft_socket.c
index f9c5ff6024e0..d601974c9d2e 100644
--- a/net/netfilter/nft_socket.c
+++ b/net/netfilter/nft_socket.c
@@ -34,7 +34,7 @@ static void nft_socket_wildcard(const struct nft_pktinfo *pkt,
 	}
 }
 
-#ifdef CONFIG_CGROUPS
+#ifdef CONFIG_SOCK_CGROUP_DATA
 static noinline bool
 nft_sock_get_eval_cgroupv2(u32 *dest, const struct nft_pktinfo *pkt, u32 level)
 {
@@ -106,7 +106,7 @@ static void nft_socket_eval(const struct nft_expr *expr,
 		}
 		nft_socket_wildcard(pkt, regs, sk, dest);
 		break;
-#ifdef CONFIG_CGROUPS
+#ifdef CONFIG_SOCK_CGROUP_DATA
 	case NFT_SOCKET_CGROUPV2:
 		if (!nft_sock_get_eval_cgroupv2(dest, pkt, priv->level)) {
 			regs->verdict.code = NFT_BREAK;
-- 
2.29.2

Re: [PATCH 2/2] netfilter: nft_socket: fix build with CONFIG_SOCK_CGROUP_DATA=n

[Pablo Neira Ayuso]

On Tue, Apr 27, 2021 at 09:45:19PM +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> In some configurations, the sock_cgroup_ptr() function is not available:
> 
> net/netfilter/nft_socket.c: In function 'nft_sock_get_eval_cgroupv2':
> net/netfilter/nft_socket.c:47:16: error: implicit declaration of function 'sock_cgroup_ptr'; did you mean 'obj_cgroup_put'? [-Werror=implicit-function-declaration]
>    47 |         cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
>       |                ^~~~~~~~~~~~~~~
>       |                obj_cgroup_put
> net/netfilter/nft_socket.c:47:14: error: assignment to 'struct cgroup *' from 'int' makes pointer from integer without a cast [-Werror=int-conversion]
>    47 |         cgrp = sock_cgroup_ptr(&sk->sk_cgrp_data);
>       |              ^
> 
> Change the caller to match the same #ifdef check, only calling it
> when the function is defined.
> 
> Fixes: e0bb96db96f8 ("netfilter: nft_socket: add support for cgroupsv2")
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> ---
> I don't actually know what the right fix is for this, I only checked
> that my patch fixes the build failure. Is is possible that the function
> should always be defined.
> 
> Please make sure you review carefully before applying.

LGTM.

Applied, thanks Arnd.

Re: [PATCH 1/2] netfilter: nft_socket: fix an unused variable warning

[Pablo Neira Ayuso]

On Tue, Apr 27, 2021 at 09:45:18PM +0200, Arnd Bergmann wrote:
> From: Arnd Bergmann <arnd@arndb.de>
> 
> The variable is only used in an #ifdef, causing a harmless warning:
> 
> net/netfilter/nft_socket.c: In function 'nft_socket_init':
> net/netfilter/nft_socket.c:137:27: error: unused variable 'level' [-Werror=unused-variable]
>   137 |         unsigned int len, level;
>       |                           ^~~~~
> 
> Move it into the same #ifdef block.

Applied, thanks Arnd.