Re: [PATCH] usb: host: replace zero-length array with flexible-array member

From: Greg KH <gregkh@linuxfoundation.org>
To: cgel.zte@gmail.com
Cc: mailhol.vincent@wanadoo.fr, lv.ruyi@zte.com.cn,
	cai.huoqing@linux.dev, linux-usb@vger.kernel.org,
	linux-kernel@vger.kernel.org, Zeal Robot <zealci@zte.com.cn>
Subject: Re: [PATCH] usb: host: replace zero-length array with flexible-array member
Date: Fri, 1 Apr 2022 11:10:42 +0200	[thread overview]
Message-ID: <YkbBktBbsWJakSZo@kroah.com> (raw)
In-Reply-To: <20220401080337.2407622-1-lv.ruyi@zte.com.cn>

On Fri, Apr 01, 2022 at 08:03:37AM +0000, cgel.zte@gmail.com wrote:
> From: Lv Ruyi <lv.ruyi@zte.com.cn>
> 
> 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/v5.16/process/deprecated.html#zero-length-and-one-element-arrays
> 
> Reported-by: Zeal Robot <zealci@zte.com.cn>
> Signed-off-by: Lv Ruyi <lv.ruyi@zte.com.cn>
> ---
>  drivers/usb/host/oxu210hp-hcd.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/usb/host/oxu210hp-hcd.c b/drivers/usb/host/oxu210hp-hcd.c
> index b741670525e3..86f92aadeb0e 100644
> --- a/drivers/usb/host/oxu210hp-hcd.c
> +++ b/drivers/usb/host/oxu210hp-hcd.c
> @@ -169,7 +169,7 @@ struct ehci_regs {
>  #define FLAG_CF		(1<<0)		/* true: we'll support "high speed" */
>  
>  	/* PORTSC: offset 0x44 */
> -	u32		port_status[0];	/* up to N_PORTS */
> +	u32		port_status[];	/* up to N_PORTS */
>  /* 31:23 reserved */
>  #define PORT_WKOC_E	(1<<22)		/* wake on overcurrent (enable) */
>  #define PORT_WKDISC_E	(1<<21)		/* wake on disconnect (enable) */
> -- 
> 2.25.1
> 

How did you test to verify that this change is correct?