2021-03-27 22:35:53

by Colin King

[permalink] [raw]
Subject: [PATCH][next] mlxsw: spectrum_router: remove redundant initialization of variable force

From: Colin Ian King <[email protected]>

The variable force is being initialized with a value that is
never read and it is being updated later with a new value. The
initialization is redundant and can be removed.

Addresses-Coverity: ("Unused value")
Signed-off-by: Colin Ian King <[email protected]>
---
drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
index 6ccaa194733b..ff240e3c29f7 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -5059,7 +5059,7 @@ mlxsw_sp_nexthop_obj_bucket_adj_update(struct mlxsw_sp *mlxsw_sp,
{
u16 bucket_index = info->nh_res_bucket->bucket_index;
struct netlink_ext_ack *extack = info->extack;
- bool force = info->nh_res_bucket->force;
+ bool force;
char ratr_pl_new[MLXSW_REG_RATR_LEN];
char ratr_pl[MLXSW_REG_RATR_LEN];
u32 adj_index;
--
2.30.2


2021-03-29 06:06:39

by Dan Carpenter

[permalink] [raw]
Subject: Re: [PATCH][next] mlxsw: spectrum_router: remove redundant initialization of variable force

On Sat, Mar 27, 2021 at 10:33:34PM +0000, Colin King wrote:
> From: Colin Ian King <[email protected]>
>
> The variable force is being initialized with a value that is
> never read and it is being updated later with a new value. The
> initialization is redundant and can be removed.
>
> Addresses-Coverity: ("Unused value")
> Signed-off-by: Colin Ian King <[email protected]>
> ---
> drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
> index 6ccaa194733b..ff240e3c29f7 100644
> --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
> +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
> @@ -5059,7 +5059,7 @@ mlxsw_sp_nexthop_obj_bucket_adj_update(struct mlxsw_sp *mlxsw_sp,
> {
> u16 bucket_index = info->nh_res_bucket->bucket_index;
> struct netlink_ext_ack *extack = info->extack;
> - bool force = info->nh_res_bucket->force;
> + bool force;
> char ratr_pl_new[MLXSW_REG_RATR_LEN];
> char ratr_pl[MLXSW_REG_RATR_LEN];
> u32 adj_index;

Reverse Christmas tree.

regards,
dan carpenter

2021-03-29 07:14:56

by Ido Schimmel

[permalink] [raw]
Subject: Re: [PATCH][next] mlxsw: spectrum_router: remove redundant initialization of variable force

On Sat, Mar 27, 2021 at 10:33:34PM +0000, Colin King wrote:
> From: Colin Ian King <[email protected]>
>
> The variable force is being initialized with a value that is
> never read and it is being updated later with a new value. The
> initialization is redundant and can be removed.
>
> Addresses-Coverity: ("Unused value")
> Signed-off-by: Colin Ian King <[email protected]>
> ---
> drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
> index 6ccaa194733b..ff240e3c29f7 100644
> --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
> +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
> @@ -5059,7 +5059,7 @@ mlxsw_sp_nexthop_obj_bucket_adj_update(struct mlxsw_sp *mlxsw_sp,
> {
> u16 bucket_index = info->nh_res_bucket->bucket_index;
> struct netlink_ext_ack *extack = info->extack;
> - bool force = info->nh_res_bucket->force;
> + bool force;

Actually, there is a bug to be fixed here:

```
diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
index 6ccaa194733b..41259c0004d1 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
@@ -5068,8 +5068,9 @@ mlxsw_sp_nexthop_obj_bucket_adj_update(struct mlxsw_sp *mlxsw_sp,
/* No point in trying an atomic replacement if the idle timer interval
* is smaller than the interval in which we query and clear activity.
*/
- force = info->nh_res_bucket->idle_timer_ms <
- MLXSW_SP_NH_GRP_ACTIVITY_UPDATE_INTERVAL;
+ if (!force && info->nh_res_bucket->idle_timer_ms <
+ MLXSW_SP_NH_GRP_ACTIVITY_UPDATE_INTERVAL)
+ force = true;

adj_index = nh->nhgi->adj_index + bucket_index;
err = mlxsw_sp_nexthop_update(mlxsw_sp, adj_index, nh, force, ratr_pl);
```

We should only fallback to a non-atomic replacement when the current
replacement is atomic and the idle timer is too short.

We currently ignore the value of 'force'. This means that a non-atomic
replacement ('force' is true) can be made atomic if idle timer is larger
than 1 second.

Colin, do you mind if I submit it formally as a fix later this week? I
want to run it through our usual process. Will mention you in
Reported-by, obviously.

> char ratr_pl_new[MLXSW_REG_RATR_LEN];
> char ratr_pl[MLXSW_REG_RATR_LEN];
> u32 adj_index;
> --
> 2.30.2
>

2021-04-09 09:07:17

by Colin King

[permalink] [raw]
Subject: Re: [PATCH][next] mlxsw: spectrum_router: remove redundant initialization of variable force

On 29/03/2021 08:13, Ido Schimmel wrote:
> On Sat, Mar 27, 2021 at 10:33:34PM +0000, Colin King wrote:
>> From: Colin Ian King <[email protected]>
>>
>> The variable force is being initialized with a value that is
>> never read and it is being updated later with a new value. The
>> initialization is redundant and can be removed.
>>
>> Addresses-Coverity: ("Unused value")
>> Signed-off-by: Colin Ian King <[email protected]>
>> ---
>> drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
>> index 6ccaa194733b..ff240e3c29f7 100644
>> --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
>> +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
>> @@ -5059,7 +5059,7 @@ mlxsw_sp_nexthop_obj_bucket_adj_update(struct mlxsw_sp *mlxsw_sp,
>> {
>> u16 bucket_index = info->nh_res_bucket->bucket_index;
>> struct netlink_ext_ack *extack = info->extack;
>> - bool force = info->nh_res_bucket->force;
>> + bool force;
>
> Actually, there is a bug to be fixed here:
>
> ```
> diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
> index 6ccaa194733b..41259c0004d1 100644
> --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
> +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
> @@ -5068,8 +5068,9 @@ mlxsw_sp_nexthop_obj_bucket_adj_update(struct mlxsw_sp *mlxsw_sp,
> /* No point in trying an atomic replacement if the idle timer interval
> * is smaller than the interval in which we query and clear activity.
> */
> - force = info->nh_res_bucket->idle_timer_ms <
> - MLXSW_SP_NH_GRP_ACTIVITY_UPDATE_INTERVAL;
> + if (!force && info->nh_res_bucket->idle_timer_ms <
> + MLXSW_SP_NH_GRP_ACTIVITY_UPDATE_INTERVAL)
> + force = true;
>
> adj_index = nh->nhgi->adj_index + bucket_index;
> err = mlxsw_sp_nexthop_update(mlxsw_sp, adj_index, nh, force, ratr_pl);
> ```
>
> We should only fallback to a non-atomic replacement when the current
> replacement is atomic and the idle timer is too short.
>
> We currently ignore the value of 'force'. This means that a non-atomic
> replacement ('force' is true) can be made atomic if idle timer is larger
> than 1 second.
>
> Colin, do you mind if I submit it formally as a fix later this week? I
> want to run it through our usual process. Will mention you in
> Reported-by, obviously.

Sure. Good idea.

>
>> char ratr_pl_new[MLXSW_REG_RATR_LEN];
>> char ratr_pl[MLXSW_REG_RATR_LEN];
>> u32 adj_index;
>> --
>> 2.30.2
>>

2021-04-09 09:12:59

by Joe Perches

[permalink] [raw]
Subject: Re: [PATCH][next] mlxsw: spectrum_router: remove redundant initialization of variable force

On Mon, 2021-03-29 at 09:04 +0300, Dan Carpenter wrote:
> On Sat, Mar 27, 2021 at 10:33:34PM +0000, Colin King wrote:
> > From: Colin Ian King <[email protected]>
> >
> > The variable force is being initialized with a value that is
> > never read and it is being updated later with a new value. The
> > initialization is redundant and can be removed.
> >
> > Addresses-Coverity: ("Unused value")
> > Signed-off-by: Colin Ian King <[email protected]>
> > ---
> > ?drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c | 2 +-
> > ?1 file changed, 1 insertion(+), 1 deletion(-)
> >
> > diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
> > index 6ccaa194733b..ff240e3c29f7 100644
> > --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
> > +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_router.c
> > @@ -5059,7 +5059,7 @@ mlxsw_sp_nexthop_obj_bucket_adj_update(struct mlxsw_sp *mlxsw_sp,
> > ?{
> > ? u16 bucket_index = info->nh_res_bucket->bucket_index;
> > ? struct netlink_ext_ack *extack = info->extack;
> > - bool force = info->nh_res_bucket->force;
> > + bool force;
> > ? char ratr_pl_new[MLXSW_REG_RATR_LEN];
> > ? char ratr_pl[MLXSW_REG_RATR_LEN];
> > ? u32 adj_index;
>
> Reverse Christmas tree.

Is still terrible style.