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From: Arnd Bergmann <arnd@arndb.de>
To: Saeed Mahameed <saeedm@mellanox.com>,
	Matan Barak <matanb@mellanox.com>,
	Leon Romanovsky <leonro@mellanox.com>
Cc: Arnd Bergmann <arnd@arndb.de>,
	"David S. Miller" <davem@davemloft.net>,
	Or Gerlitz <ogerlitz@mellanox.com>,
	Amir Vadai <amirva@mellanox.com>,
	Maor Gottlieb <maorg@mellanox.com>,
	netdev@vger.kernel.org, linux-rdma@vger.kernel.org,
	linux-kernel@vger.kernel.org
Subject: [PATCH 1/2] net/mlx5e: shut up maybe-uninitialized warning
Date: Fri, 30 Sep 2016 18:17:09 +0200	[thread overview]
Message-ID: <20160930161734.70928-1-arnd@arndb.de> (raw)

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

             reply	other threads:[~2016-09-30 16:17 UTC|newest]

Thread overview: 7+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-09-30 16:17 Arnd Bergmann [this message]
2016-09-30 16:17 ` [PATCH 2/2] mlxsw: spectrum_router: avoid potential uninitialized data usage Arnd Bergmann
2016-09-30 17:57   ` Ido Schimmel
2016-10-01  3:36     ` Arnd Bergmann
2016-10-03  5:56   ` David Miller
2016-10-01 15:08 ` [PATCH 1/2] net/mlx5e: shut up maybe-uninitialized warning Or Gerlitz
2016-10-03  5:56 ` David Miller

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