linux-kernel - Re: [PATCH v2] mei: Avoid the use of one-element arrays

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Message-ID: <5198b29f-2e62-4910-4a4d-52c7991915c5@embeddedor.com>
Date:   Wed, 22 Jul 2020 13:27:10 -0500
From:   "Gustavo A. R. Silva" <gustavo@...eddedor.com>
To:     "Gustavo A. R. Silva" <gustavoars@...nel.org>,
        Tomas Winkler <tomas.winkler@...el.com>,
        Arnd Bergmann <arnd@...db.de>,
        Greg Kroah-Hartman <gregkh@...uxfoundation.org>
Cc:     linux-kernel@...r.kernel.org
Subject: Re: [PATCH v2] mei: Avoid the use of one-element arrays

Hi all,

Friendly ping: who can take this? :)

Thanks
--
Gustavo

On 7/14/20 16:45, Gustavo A. R. Silva wrote:
> One-element arrays are being deprecated[1]. Replace the one-element
> arrays with a simple value type u8 reserved, once this is just a
> placeholder for alignment.
> 
> Also, while there, use the preferred form for passing a size of a struct.
> The alternative form where struct name is spelled out hurts readability
> and introduces an opportunity for a bug when the variable type is changed
> but the corresponding sizeof that is passed as argument is not.
> 
> [1] https://github.com/KSPP/linux/issues/79
> 
> Signed-off-by: Gustavo A. R. Silva <gustavoars@...nel.org>
> ---
> Changes in v2:
>  - Use a more concise changelog text.
> 
>  drivers/misc/mei/hbm.c | 4 ++--
>  drivers/misc/mei/hw.h  | 6 +++---
>  2 files changed, 5 insertions(+), 5 deletions(-)
> 
> diff --git a/drivers/misc/mei/hbm.c b/drivers/misc/mei/hbm.c
> index a44094cdbc36..f020d5594154 100644
> --- a/drivers/misc/mei/hbm.c
> +++ b/drivers/misc/mei/hbm.c
> @@ -408,14 +408,14 @@ static int mei_hbm_add_cl_resp(struct mei_device *dev, u8 addr, u8 status)
>  {
>  	struct mei_msg_hdr mei_hdr;
>  	struct hbm_add_client_response resp;
> -	const size_t len = sizeof(struct hbm_add_client_response);
> +	const size_t len = sizeof(resp);
>  	int ret;
>  
>  	dev_dbg(dev->dev, "adding client response\n");
>  
>  	mei_hbm_hdr(&mei_hdr, len);
>  
> -	memset(&resp, 0, sizeof(struct hbm_add_client_response));
> +	memset(&resp, 0, len);
>  	resp.hbm_cmd = MEI_HBM_ADD_CLIENT_RES_CMD;
>  	resp.me_addr = addr;
>  	resp.status  = status;
> diff --git a/drivers/misc/mei/hw.h b/drivers/misc/mei/hw.h
> index b1a8d5ec88b3..8c0297f0e7f3 100644
> --- a/drivers/misc/mei/hw.h
> +++ b/drivers/misc/mei/hw.h
> @@ -346,13 +346,13 @@ struct hbm_add_client_request {
>   * @hbm_cmd: bus message command header
>   * @me_addr: address of the client in ME
>   * @status: if HBMS_SUCCESS then the client can now accept connections.
> - * @reserved: reserved
> + * @reserved: reserved for alignment.
>   */
>  struct hbm_add_client_response {
>  	u8 hbm_cmd;
>  	u8 me_addr;
>  	u8 status;
> -	u8 reserved[1];
> +	u8 reserved;
>  } __packed;
>  
>  /**
> @@ -461,7 +461,7 @@ struct hbm_notification {
>  	u8 hbm_cmd;
>  	u8 me_addr;
>  	u8 host_addr;
> -	u8 reserved[1];
> +	u8 reserved;
>  } __packed;
>  
>  /**
>