2018-02-23 13:17:59

by Arnd Bergmann

Subject: [net-next PATCH 1/2] mlxsw: spectrum_kvdl: use div_u64() for 64-bit division

Calculating the number of entries now uses 64-bit arithmetic that
causes a link error on 32-bit architectures:

drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.o: In function `mlxsw_sp_kvdl_init':
spectrum_kvdl.c:(.text+0x51c): undefined reference to `__aeabi_uldivmod'

We could probably use a 32-bit division here as before, but since this is
not in a performance critical path, div_u64() seems cleaner here.

Fixes: 887839e6960d ("mlxsw: spectrum_kvdl: Add support for dynamic partition set")
Signed-off-by: Arnd Bergmann <[email protected]>
---
drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c
index d27fa57ad3c3..6fd701db90c9 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c
@@ -278,7 +278,7 @@ static int mlxsw_sp_kvdl_part_init(struct mlxsw_sp *mlxsw_sp,
resource_size = info->end_index - info->start_index + 1;
}

- nr_entries = resource_size / info->alloc_size;
+ nr_entries = div_u64(resource_size, info->alloc_size);
usage_size = BITS_TO_LONGS(nr_entries) * sizeof(unsigned long);
part = kzalloc(sizeof(*part) + usage_size, GFP_KERNEL);
if (!part)
--
2.9.0

2018-02-23 13:16:54

by Arnd Bergmann

Subject: [net-next PATCH 2/2] mlxsw: spectrum_kvdl: avoid uninitialized variable warning

gcc warns that 'resource_id' is not initialized if we don't come though
any of the three 'case' statements before:

drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c: In function 'mlxsw_sp_kvdl_part_init':
drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c:275:8: error: 'resource_id' may be used uninitialized in this function [-Werror=maybe-uninitialized]

In the current code, that won't happen, but it's more robust to explicitly
handle this by returning a failure from mlxsw_sp_kvdl_part_init.

Fixes: 887839e6960d ("mlxsw: spectrum_kvdl: Add support for dynamic partition set")
Signed-off-by: Arnd Bergmann <[email protected]>
---
drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c | 2 ++
1 file changed, 2 insertions(+)

diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c
index 6fd701db90c9..059eb3214328 100644
--- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c
+++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c
@@ -270,6 +270,8 @@ static int mlxsw_sp_kvdl_part_init(struct mlxsw_sp *mlxsw_sp,
case MLXSW_SP_KVDL_PART_LARGE_CHUNKS:
resource_id = MLXSW_SP_RESOURCE_KVD_LINEAR_LARGE_CHUNKS;
break;
+ default:
+ return -EINVAL;
}

err = devlink_resource_size_get(devlink, resource_id, &resource_size);
--
2.9.0

2018-02-25 10:05:25

by Arkadi Sharshevsky

Subject: Re: [net-next PATCH 1/2] mlxsw: spectrum_kvdl: use div_u64() for 64-bit division

On 02/23/2018 03:15 PM, Arnd Bergmann wrote:
> Calculating the number of entries now uses 64-bit arithmetic that
> causes a link error on 32-bit architectures:
>
> drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.o: In function `mlxsw_sp_kvdl_init':
> spectrum_kvdl.c:(.text+0x51c): undefined reference to `__aeabi_uldivmod'
>
> We could probably use a 32-bit division here as before, but since this is
> not in a performance critical path, div_u64() seems cleaner here.
>
> Fixes: 887839e6960d ("mlxsw: spectrum_kvdl: Add support for dynamic partition set")
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
> drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c | 2 +-
> 1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c
> index d27fa57ad3c3..6fd701db90c9 100644
> --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c
> +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c
> @@ -278,7 +278,7 @@ static int mlxsw_sp_kvdl_part_init(struct mlxsw_sp *mlxsw_sp,
> resource_size = info->end_index - info->start_index + 1;
> }
>
> - nr_entries = resource_size / info->alloc_size;
> + nr_entries = div_u64(resource_size, info->alloc_size);
> usage_size = BITS_TO_LONGS(nr_entries) * sizeof(unsigned long);
> part = kzalloc(sizeof(*part) + usage_size, GFP_KERNEL);
> if (!part)
>

Acked-by: Arkadi Sharshevsky <[email protected]>

2018-02-25 10:06:46

by Arkadi Sharshevsky

Subject: Re: [net-next PATCH 2/2] mlxsw: spectrum_kvdl: avoid uninitialized variable warning

On 02/23/2018 03:15 PM, Arnd Bergmann wrote:
> gcc warns that 'resource_id' is not initialized if we don't come though
> any of the three 'case' statements before:
>
> drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c: In function 'mlxsw_sp_kvdl_part_init':
> drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c:275:8: error: 'resource_id' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>
> In the current code, that won't happen, but it's more robust to explicitly
> handle this by returning a failure from mlxsw_sp_kvdl_part_init.
>
> Fixes: 887839e6960d ("mlxsw: spectrum_kvdl: Add support for dynamic partition set")
> Signed-off-by: Arnd Bergmann <[email protected]>
> ---
> drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c | 2 ++
> 1 file changed, 2 insertions(+)
>
> diff --git a/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c b/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c
> index 6fd701db90c9..059eb3214328 100644
> --- a/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c
> +++ b/drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c
> @@ -270,6 +270,8 @@ static int mlxsw_sp_kvdl_part_init(struct mlxsw_sp *mlxsw_sp,
> case MLXSW_SP_KVDL_PART_LARGE_CHUNKS:
> resource_id = MLXSW_SP_RESOURCE_KVD_LINEAR_LARGE_CHUNKS;
> break;
> + default:
> + return -EINVAL;
> }
>
> err = devlink_resource_size_get(devlink, resource_id, &resource_size);
>
Acked-by: Arkadi Sharshevsky <[email protected]>

2018-02-26 16:34:25

by David Miller

Subject: Re: [net-next PATCH 1/2] mlxsw: spectrum_kvdl: use div_u64() for 64-bit division

From: Arnd Bergmann <[email protected]>
Date: Fri, 23 Feb 2018 14:15:31 +0100

> Calculating the number of entries now uses 64-bit arithmetic that
> causes a link error on 32-bit architectures:
>
> drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.o: In function `mlxsw_sp_kvdl_init':
> spectrum_kvdl.c:(.text+0x51c): undefined reference to `__aeabi_uldivmod'
>
> We could probably use a 32-bit division here as before, but since this is
> not in a performance critical path, div_u64() seems cleaner here.
>
> Fixes: 887839e6960d ("mlxsw: spectrum_kvdl: Add support for dynamic partition set")
> Signed-off-by: Arnd Bergmann <[email protected]>

Applied.

2018-02-26 16:34:25

by David Miller

Subject: Re: [net-next PATCH 2/2] mlxsw: spectrum_kvdl: avoid uninitialized variable warning

From: Arnd Bergmann <[email protected]>
Date: Fri, 23 Feb 2018 14:15:32 +0100

> gcc warns that 'resource_id' is not initialized if we don't come though
> any of the three 'case' statements before:
>
> drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c: In function 'mlxsw_sp_kvdl_part_init':
> drivers/net/ethernet/mellanox/mlxsw/spectrum_kvdl.c:275:8: error: 'resource_id' may be used uninitialized in this function [-Werror=maybe-uninitialized]
>
> In the current code, that won't happen, but it's more robust to explicitly
> handle this by returning a failure from mlxsw_sp_kvdl_part_init.
>
> Fixes: 887839e6960d ("mlxsw: spectrum_kvdl: Add support for dynamic partition set")
> Signed-off-by: Arnd Bergmann <[email protected]>

Applied.