[PATCH] mlx5: avoid unused variable warning

[PATCH] mlx5: avoid unused variable warning

[Arnd Bergmann]

When CONFIG_NET_CLS_ACT is disabled, we get a new warning in the mlx5
ethernet driver because the tc_for_each_action() loop never references
the iterator:

mellanox/mlx5/core/en_tc.c: In function 'mlx5e_stats_flower':
mellanox/mlx5/core/en_tc.c:431:20: error: unused variable 'a' [-Werror=unused-variable]
  struct tc_action *a;

This changes the dummy tc_for_each_action() macro by adding a
cast to void, letting the compiler know that the variable is
intentionally declared but not used here. I could not come up
with a nicer workaround, but this seems to do the trick.

Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Fixes: aad7e08d39bd ("net/mlx5e: Hardware offloaded flower filter statistics support")
Fixes: 00175aec941e ("net/sched: Macro instead of CONFIG_NET_CLS_ACT ifdef")
---
 include/net/act_api.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/include/net/act_api.h b/include/net/act_api.h
index 2cd9e9bb059a..9a9a8edc138f 100644
--- a/include/net/act_api.h
+++ b/include/net/act_api.h
@@ -192,7 +192,7 @@ static inline void tcf_action_stats_update(struct tc_action *a, u64 bytes,
 #else /* CONFIG_NET_CLS_ACT */
 
 #define tc_no_actions(_exts) true
-#define tc_for_each_action(_a, _exts) while (0)
+#define tc_for_each_action(_a, _exts) while ((void)(_a), 0)
 #define tcf_action_stats_update(a, bytes, packets, lastuse)
 
 #endif /* CONFIG_NET_CLS_ACT */
-- 
2.7.0

Re: [PATCH] mlx5: avoid unused variable warning

[Amir Vadai"]

On Wed, May 18, 2016 at 04:21:07PM +0200, Arnd Bergmann wrote:
> When CONFIG_NET_CLS_ACT is disabled, we get a new warning in the mlx5
> ethernet driver because the tc_for_each_action() loop never references
> the iterator:
> 
> mellanox/mlx5/core/en_tc.c: In function 'mlx5e_stats_flower':
> mellanox/mlx5/core/en_tc.c:431:20: error: unused variable 'a' [-Werror=unused-variable]
>   struct tc_action *a;
> 
> This changes the dummy tc_for_each_action() macro by adding a
> cast to void, letting the compiler know that the variable is
> intentionally declared but not used here. I could not come up
> with a nicer workaround, but this seems to do the trick.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Fixes: aad7e08d39bd ("net/mlx5e: Hardware offloaded flower filter statistics support")
> Fixes: 00175aec941e ("net/sched: Macro instead of CONFIG_NET_CLS_ACT ifdef")
> ---
Acked-By: Amir Vadai <amir@vadai.me>

Thanks Arnd.

Re: [PATCH] mlx5: avoid unused variable warning

[David Miller]

From: Arnd Bergmann <arnd@arndb.de>
Date: Wed, 18 May 2016 16:21:07 +0200

> When CONFIG_NET_CLS_ACT is disabled, we get a new warning in the mlx5
> ethernet driver because the tc_for_each_action() loop never references
> the iterator:
> 
> mellanox/mlx5/core/en_tc.c: In function 'mlx5e_stats_flower':
> mellanox/mlx5/core/en_tc.c:431:20: error: unused variable 'a' [-Werror=unused-variable]
>   struct tc_action *a;
> 
> This changes the dummy tc_for_each_action() macro by adding a
> cast to void, letting the compiler know that the variable is
> intentionally declared but not used here. I could not come up
> with a nicer workaround, but this seems to do the trick.
> 
> Signed-off-by: Arnd Bergmann <arnd@arndb.de>
> Fixes: aad7e08d39bd ("net/mlx5e: Hardware offloaded flower filter statistics support")
> Fixes: 00175aec941e ("net/sched: Macro instead of CONFIG_NET_CLS_ACT ifdef")

Applied, thanks Arnd.