Re: [PATCH] staging: wilc1000: replace redundant computations with 0

From: Joe Perches
Date: Wed Oct 18 2017 - 18:54:40 EST


On Tue, 2017-10-10 at 15:05 +0100, Colin King wrote:
> From: Colin Ian King <colin.king@xxxxxxxxxxxxx>
>
> Shifting and masking strHostIfSetMulti->enabled is redundant since
> enabled is a bool and so all the shifted and masked values will be
> zero. Replace them with zero to simplify the code.
>
> Detected by CoverityScan, CID#1339458 ("Bad shift operation") and
> CID#1339506 ("Operands don't affect result").
>
> Signed-off-by: Colin Ian King <colin.king@xxxxxxxxxxxxx>
> ---
> drivers/staging/wilc1000/host_interface.c | 6 +++---
> 1 file changed, 3 insertions(+), 3 deletions(-)
>
> diff --git a/drivers/staging/wilc1000/host_interface.c b/drivers/staging/wilc1000/host_interface.c
> index 7b620658ec38..94477dd08c85 100644
> --- a/drivers/staging/wilc1000/host_interface.c
> +++ b/drivers/staging/wilc1000/host_interface.c
> @@ -2417,9 +2417,9 @@ static void Handle_SetMulticastFilter(struct wilc_vif *vif,
>
> pu8CurrByte = wid.val;
> *pu8CurrByte++ = (strHostIfSetMulti->enabled & 0xFF);
> - *pu8CurrByte++ = ((strHostIfSetMulti->enabled >> 8) & 0xFF);
> - *pu8CurrByte++ = ((strHostIfSetMulti->enabled >> 16) & 0xFF);
> - *pu8CurrByte++ = ((strHostIfSetMulti->enabled >> 24) & 0xFF);
> + *pu8CurrByte++ = 0;
> + *pu8CurrByte++ = 0;
> + *pu8CurrByte++ = 0;

This might be more an indication of another defect

Perhaps this is just supposed to be

*pu8CurrByte++ = strHostIfSetMulti->enabled;

without the three byte sets to zero after that.

> *pu8CurrByte++ = (strHostIfSetMulti->cnt & 0xFF);
> *pu8CurrByte++ = ((strHostIfSetMulti->cnt >> 8) & 0xFF);