Thread (4 messages) 4 messages, 4 authors, 2022-08-31

Re: [PATCH net-next] net/mlx5e: Do not use err uninitialized in mlx5e_rep_add_meta_tunnel_rule()

From: Nick Desaulniers <hidden>
Date: 2022-08-25 18:20:08
Also in: linux-patches, linux-rdma, lkml, llvm

On Thu, Aug 25, 2022 at 11:06 AM Nathan Chancellor [off-list ref] wrote:
Clang warns:

  drivers/net/ethernet/mellanox/mlx5/core/en_rep.c:481:6: error: variable 'err' is used uninitialized whenever 'if' condition is false [-Werror,-Wsometimes-uninitialized]
          if (IS_ERR(flow_rule)) {
              ^~~~~~~~~~~~~~~~~
  drivers/net/ethernet/mellanox/mlx5/core/en_rep.c:489:9: note: uninitialized use occurs here
          return err;
                ^~~
  drivers/net/ethernet/mellanox/mlx5/core/en_rep.c:481:2: note: remove the 'if' if its condition is always true
          if (IS_ERR(flow_rule)) {
          ^~~~~~~~~~~~~~~~~~~~~~~
  drivers/net/ethernet/mellanox/mlx5/core/en_rep.c:474:9: note: initialize the variable 'err' to silence this warning
          int err;
                ^
                  = 0
  1 error generated.

There is little reason to have the 'goto + error variable' construct in
this function. Get rid of it and just return the PTR_ERR value in the if
statement and 0 at the end.

Fixes: 430e2d5e2a98 ("net/mlx5: E-Switch, Move send to vport meta rule creation")
Link: https://github.com/ClangBuiltLinux/linux/issues/1695
Signed-off-by: Nathan Chancellor <nathan@kernel.org>
Thanks for the fix!
Reviewed-by: Nick Desaulniers <redacted>
quoted hunk ↗ jump to hunk
---
 drivers/net/ethernet/mellanox/mlx5/core/en_rep.c | 10 +++-------
 1 file changed, 3 insertions(+), 7 deletions(-)
diff --git a/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c b/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c
index c8617a62e542..a977804137a8 100644
--- a/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c
+++ b/drivers/net/ethernet/mellanox/mlx5/core/en_rep.c
@@ -471,22 +471,18 @@ mlx5e_rep_add_meta_tunnel_rule(struct mlx5e_priv *priv)
        struct mlx5_eswitch_rep *rep = rpriv->rep;
        struct mlx5_flow_handle *flow_rule;
        struct mlx5_flow_group *g;
-       int err;

        g = esw->fdb_table.offloads.send_to_vport_meta_grp;
        if (!g)
                return 0;

        flow_rule = mlx5_eswitch_add_send_to_vport_meta_rule(esw, rep->vport);
-       if (IS_ERR(flow_rule)) {
-               err = PTR_ERR(flow_rule);
-               goto out;
-       }
+       if (IS_ERR(flow_rule))
+               return PTR_ERR(flow_rule);

        rpriv->send_to_vport_meta_rule = flow_rule;

-out:
-       return err;
+       return 0;
 }

 static void
base-commit: c19d893fbf3f2f8fa864ae39652c7fee939edde2
--
2.37.2

-- 
Thanks,
~Nick Desaulniers
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