[PATCH 1/2] net/mlx5e: shut up maybe-uninitialized warning

From	Arnd Bergmann <arnd@arndb.de>
Newsgroups	linux.kernel
Subject	[PATCH 1/2] net/mlx5e: shut up maybe-uninitialized warning
Date	2016-09-30 18:20 +0200
Message-ID	<sn8Hv-4bK-3@gated-at.bofh.it> (permalink)
Organization	linux.* mail to news gateway

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Build-testing this driver with -Wmaybe-uninitialized gives a new false-positive
warning that I can't really explain:

drivers/net/ethernet/mellanox/mlx5/core/en_tc.c: In function 'mlx5e_configure_flower':
drivers/net/ethernet/mellanox/mlx5/core/en_tc.c:509:3: error: 'old_attr' may be used uninitialized in this function [-Werror=maybe-uninitialized]

It's obvious from the code that 'old_attr' is initialized whenever 'old'
is non-NULL here. The warning appears with all versions I tested from gcc-4.7
through gcc-6.1, and I could not come up with a way to rewrite the function
in a more readable way that avoids the warning, so I'm adding another
initialization to shut it up.

Fixes: 8b32580df1cb ("net/mlx5e: Add TC vlan action for SRIOV offloads")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
---
 drivers/net/ethernet/mellanox/mlx5/core/en_tc.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
index a350b7171e3d..ce8c54d18906 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_tc.c
@@ -451,7 +451,7 @@ int mlx5e_configure_flower(struct mlx5e_priv *priv, __be16 protocol,
 	struct mlx5e_tc_flow *flow;
 	struct mlx5_flow_spec *spec;
 	struct mlx5_flow_rule *old = NULL;
-	struct mlx5_esw_flow_attr *old_attr;
+	struct mlx5_esw_flow_attr *old_attr = NULL;
 	struct mlx5_eswitch *esw = priv->mdev->priv.eswitch;
 
 	if (esw && esw->mode == SRIOV_OFFLOADS)
-- 
2.9.0

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[PATCH 1/2] net/mlx5e: shut up maybe-uninitialized warning Arnd Bergmann <arnd@arndb.de> - 2016-09-30 18:20 +0200
  Re: [PATCH 1/2] net/mlx5e: shut up maybe-uninitialized warning Or Gerlitz <gerlitz.or@gmail.com> - 2016-10-01 17:10 +0200
  Re: [PATCH 1/2] net/mlx5e: shut up maybe-uninitialized warning David Miller <davem@davemloft.net> - 2016-10-03 08:00 +0200

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