Re: [PATCH] r8152: simplify loops in generic_ocp_{read,write}()

[Michal Pecio <michal.pecio@gmail.com>]

On Sat, 22 Aug 2026 23:21:54 +0300, Sergey Shtylyov wrote:
> In generic_ocp_{read,write}(), the *while* loops look very strange:
> the last iteration is executed differently to the prior ones, doing
> some useless assignments before *break*. Move the code for the last
> iteration out of the loop bodies, dropping the pointless statements
> as well...
> 
> Found by Linux Verification Center (linuxtesting.org) with the Svace
> static analysis tool.
> 
> Signed-off-by: Sergey Shtylyov <s.shtylyov@auroraos.dev>
> 
> ---
>  drivers/net/usb/r8152.c | 67 ++++++++++++++++-------------------------
>  1 file changed, 26 insertions(+), 41 deletions(-)
> 
> diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
> index f61686433031..de9738bdce85 100644
> --- a/drivers/net/usb/r8152.c
> +++ b/drivers/net/usb/r8152.c
> @@ -1431,27 +1431,19 @@ static int generic_ocp_read(struct r8152 *tp, u16 index, u16 size,
>  	if ((u32)index + (u32)size > 0xffff)
>  		return -EPERM;
>  
> -	while (size) {
> -		if (size > limit) {
> -			ret = get_registers(tp, index, type, limit, data);
> -			if (ret < 0)
> -				break;
> -
> -			index += limit;
> -			data += limit;
> -			size -= limit;
> -		} else {
> -			ret = get_registers(tp, index, type, size, data);
> -			if (ret < 0)
> -				break;
> +	while (size > limit) {
> +		ret = get_registers(tp, index, type, limit, data);
> +		if (ret < 0)
> +			goto error1;
>  
> -			index += size;
> -			data += size;
> -			size = 0;
> -			break;
> -		}
> +		index += limit;
> +		data += limit;
> +		size -= limit;
>  	}
>  
> +	ret = get_registers(tp, index, type, size, data);
> +
> +error1:
>  	if (ret == -ENODEV)
>  		rtl_set_unplug(tp);

Looks like it could be shorter still.

s/limit/chunk/

while (size) {
	if (size < chunk)
		chunk = size;
	ret = get_registers(tp, index, type, chunk, data);
	if (ret < 0)
		break;
	index += chunk;
	data += chunk;
	size -= chunk;
}

Then it could be do-while, because we know size > 0, though
I suppose compilers may figure it out themselves anyway.

Regards,
Michal