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

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

[Nathan Chancellor]

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>
---
 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

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

[Nick Desaulniers]

On Thu, Aug 25, 2022 at 11:06 AM Nathan Chancellor <nathan@kernel.org> 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 <ndesaulniers@google.com>

> ---
>  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

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

[Leon Romanovsky]

On Thu, Aug 25, 2022 at 11:06:07AM -0700, Nathan Chancellor 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>
> ---
>  drivers/net/ethernet/mellanox/mlx5/core/en_rep.c | 10 +++-------
>  1 file changed, 3 insertions(+), 7 deletions(-)
> 

Thanks,
Reviewed-by: Leon Romanovsky <leonro@nvidia.com>

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

[patchwork-bot+netdevbpf]

Hello:

This patch was applied to netdev/net-next.git (master)
by Jakub Kicinski <kuba@kernel.org>:

On Thu, 25 Aug 2022 11:06:07 -0700 you 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.
> 
> [...]

Here is the summary with links:
  - [net-next] net/mlx5e: Do not use err uninitialized in mlx5e_rep_add_meta_tunnel_rule()
    https://git.kernel.org/netdev/net-next/c/92f97c00f0ca

You are awesome, thank you!
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