net/mlx5e: Fix a -Wmaybe-uninitialized warning
authorArnd Bergmann <arnd@arndb.de>
Sun, 15 Jan 2017 17:50:46 +0000 (19:50 +0200)
committerDavid S. Miller <davem@davemloft.net>
Mon, 16 Jan 2017 19:48:19 +0000 (14:48 -0500)
commitabeffce90c7f6ce74de9794ad0977a168edf8ef6
treebf99c4705ff510e89f29a21385457a8bfc11b3f0
parent8a367e74c0120ef68c8c70d5a025648c96626dff
net/mlx5e: Fix a -Wmaybe-uninitialized warning

As found by Olof's build bot, we gain a harmless warning about a
potential uninitialized variable reference in mlx5:

drivers/net/ethernet/mellanox/mlx5/core/en_tc.c: In function 'parse_tc_fdb_actions':
drivers/net/ethernet/mellanox/mlx5/core/en_tc.c:769:13: warning: 'out_dev' may be used uninitialized in this function [-Wmaybe-uninitialized]
drivers/net/ethernet/mellanox/mlx5/core/en_tc.c:811:21: note: 'out_dev' was declared here

This was introduced through the addition of an 'IS_ERR/PTR_ERR' pair
that gcc is unfortunately unable to completely figure out.

The problem being gcc cannot tell that if(IS_ERR()) in
mlx5e_route_lookup_ipv4() is equivalent to checking if(err) later,
so it assumes that 'out_dev' is used after the 'return PTR_ERR(rt)'.

The PTR_ERR_OR_ZERO() case by comparison is fairly easy to detect
by gcc, so it can't get that wrong, so it no longer warns.

Hadar Hen Zion already attempted to fix the warning earlier by adding fake
initializations, but that ended up not fully addressing all warnings, so
I'm reverting it now that it is no longer needed.

Link: http://arm-soc.lixom.net/buildlogs/mainline/v4.10-rc3-98-gcff3b2c/
Fixes: a42485eb0ee4 ("net/mlx5e: TC ipv4 tunnel encap offload error flow fixes")
Fixes: a757d108dc1a ("net/mlx5e: Fix kbuild warnings for uninitialized parameters")
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Signed-off-by: Or Gerlitz <ogerlitz@mellanox.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
drivers/net/ethernet/mellanox/mlx5/core/en_tc.c