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mlx4: style: replace zero-length array with flexible-array member.

Message ID 1609309731-70464-1-git-send-email-abaci-bugfix@linux.alibaba.com
State New
Headers show
Series mlx4: style: replace zero-length array with flexible-array member. | expand

Commit Message

Abaci Team Dec. 30, 2020, 6:28 a.m. UTC
There is a regular need in the kernel to provide a way to declare
having a dynamically sized set of trailing elements in a structure.
Kernel code should always use "flexible array members"[1] for these
cases. The older style of one-element or zero-length arrays should
no longer be used[2].

[1] https://en.wikipedia.org/wiki/Flexible_array_member
[2] https://www.kernel.org/doc/html/v5.9/process/
    deprecated.html#zero-length-and-one-element-arrays

Signed-off-by: YANG LI <abaci-bugfix@linux.alibaba.com>
Reported-by: Abaci <abaci@linux.alibaba.com>
---
 drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

Comments

Tariq Toukan Dec. 30, 2020, 9:37 a.m. UTC | #1
On 12/30/2020 8:28 AM, YANG LI wrote:
> There is a regular need in the kernel to provide a way to declare
> having a dynamically sized set of trailing elements in a structure.
> Kernel code should always use "flexible array members"[1] for these
> cases. The older style of one-element or zero-length arrays should
> no longer be used[2].
> 
> [1] https://en.wikipedia.org/wiki/Flexible_array_member
> [2] https://www.kernel.org/doc/html/v5.9/process/
>      deprecated.html#zero-length-and-one-element-arrays
> 
> Signed-off-by: YANG LI <abaci-bugfix@linux.alibaba.com>
> Reported-by: Abaci <abaci@linux.alibaba.com>
> ---
>   drivers/net/ethernet/mellanox/mlx4/mlx4_en.h | 2 +-
>   1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
> index e8ed2319..4029a8b 100644
> --- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
> +++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
> @@ -314,7 +314,7 @@ struct mlx4_en_tx_ring {
>   
>   struct mlx4_en_rx_desc {
>   	/* actual number of entries depends on rx ring stride */
> -	struct mlx4_wqe_data_seg data[0];
> +	struct mlx4_wqe_data_seg data[];
>   };
>   
>   struct mlx4_en_rx_ring {
> 

Reviewed-by: Tariq Toukan <tariqt@nvidia.com>

Thanks.
Jakub Kicinski Jan. 4, 2021, 8:40 p.m. UTC | #2
On Wed, 30 Dec 2020 14:28:51 +0800 YANG LI wrote:
> There is a regular need in the kernel to provide a way to declare

> having a dynamically sized set of trailing elements in a structure.

> Kernel code should always use "flexible array members"[1] for these

> cases. The older style of one-element or zero-length arrays should

> no longer be used[2].

> 

> [1] https://en.wikipedia.org/wiki/Flexible_array_member

> [2] https://www.kernel.org/doc/html/v5.9/process/

>     deprecated.html#zero-length-and-one-element-arrays

> 

> Signed-off-by: YANG LI <abaci-bugfix@linux.alibaba.com>

> Reported-by: Abaci <abaci@linux.alibaba.com>


This breaks the build with allmodconfig, could you double check?
Are there dependencies?

In file included from drivers/net/ethernet/mellanox/mlx4/en_netdev.c:50:
drivers/net/ethernet/mellanox/mlx4/mlx4_en.h:316:27: error: flexible array member in a struct with no named members
  316 |  struct mlx4_wqe_data_seg data[];
      |                           ^~~~
diff mbox series

Patch

diff --git a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
index e8ed2319..4029a8b 100644
--- a/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
+++ b/drivers/net/ethernet/mellanox/mlx4/mlx4_en.h
@@ -314,7 +314,7 @@  struct mlx4_en_tx_ring {
 
 struct mlx4_en_rx_desc {
 	/* actual number of entries depends on rx ring stride */
-	struct mlx4_wqe_data_seg data[0];
+	struct mlx4_wqe_data_seg data[];
 };
 
 struct mlx4_en_rx_ring {