Subject: Re: [PATCH] net: stmmac: xgmac: add missing parentheses to fix precendence error

From: Dan Carpenter <[email-masked]>
Date: Wed, 2 Oct 2019 16:33:57 +0300

On Wed, Oct 02, 2019 at 12:08:49PM +0100, Colin King wrote:
> From: Colin Ian King <[email-masked]>
> 
> The expression !(hw_cap & XGMAC_HWFEAT_RAVSEL) >> 10 is always zero, so
> the masking operation is incorrect. Fix this by adding the missing
> parentheses to correctly bind the negate operator on the entire expression.
> 
> Addresses-Coverity: ("Operands don't affect result")
> Fixes: c2b69474d63b ("net: stmmac: xgmac: Correct RAVSEL field interpretation")
> Signed-off-by: Colin Ian King <[email-masked]>
> ---
>  drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c
> index 965cbe3e6f51..2e814aa64a5c 100644
> --- a/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c
> +++ b/drivers/net/ethernet/stmicro/stmmac/dwxgmac2_dma.c
> @@ -369,7 +369,7 @@ static void dwxgmac2_get_hw_feature(void __iomem *ioaddr,
>  	dma_cap->eee = (hw_cap & XGMAC_HWFEAT_EEESEL) >> 13;
>  	dma_cap->atime_stamp = (hw_cap & XGMAC_HWFEAT_TSSEL) >> 12;
>  	dma_cap->av = (hw_cap & XGMAC_HWFEAT_AVSEL) >> 11;
> -	dma_cap->av &= !(hw_cap & XGMAC_HWFEAT_RAVSEL) >> 10;
> +	dma_cap->av &= !((hw_cap & XGMAC_HWFEAT_RAVSEL) >> 10);

There is no point to the shift at all.

regards,
dan carpenter

_______________________________________________
linux-arm-kernel mailing list
[email-masked]
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel