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Subject: Re: [PATCH V2] sfc: ef10: Fix assigning negative value to unsigned
 variable
To:     Haowen Bai <baihaowen@meizu.com>,
        Martin Habets <habetsm.xilinx@gmail.com>,
        "David S. Miller" <davem@davemloft.net>,
        Jakub Kicinski <kuba@kernel.org>,
        Paolo Abeni <pabeni@redhat.com>
Cc:     netdev@vger.kernel.org, linux-kernel@vger.kernel.org
References: <1649640757-30041-1-git-send-email-baihaowen@meizu.com>
From:   Edward Cree <ecree.xilinx@gmail.com>
Message-ID: <1912936d-14b5-f6af-c927-c46fabc72da5@gmail.com>
Date:   Mon, 11 Apr 2022 17:27:01 +0100
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On 11/04/2022 02:32, Haowen Bai wrote:
> fix warning reported by smatch:
> 251 drivers/net/ethernet/sfc/ef10.c:2259 efx_ef10_tx_tso_desc()
> warn: assigning (-208) to unsigned variable 'ip_tot_len'
> 
> Signed-off-by: Haowen Bai <baihaowen@meizu.com>
> ---
Acked-by: Edward Cree <ecree.xilinx@gmail.com>

> V1->V2: to assign "0x10000 - EFX_TSO2_MAX_HDRLEN" is the actual 
> semantics of the value.
> 
>  drivers/net/ethernet/sfc/ef10.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
> 
> diff --git a/drivers/net/ethernet/sfc/ef10.c b/drivers/net/ethernet/sfc/ef10.c
> index 50d535981a35..c9ee5011803f 100644
> --- a/drivers/net/ethernet/sfc/ef10.c
> +++ b/drivers/net/ethernet/sfc/ef10.c
> @@ -2256,7 +2256,7 @@ int efx_ef10_tx_tso_desc(struct efx_tx_queue *tx_queue, struct sk_buff *skb,
>  	 * guaranteed to satisfy the second as we only attempt TSO if
>  	 * inner_network_header <= 208.
>  	 */
> -	ip_tot_len = -EFX_TSO2_MAX_HDRLEN;
> +	ip_tot_len = 0x10000 - EFX_TSO2_MAX_HDRLEN;
>  	EFX_WARN_ON_ONCE_PARANOID(mss + EFX_TSO2_MAX_HDRLEN +
>  				  (tcp->doff << 2u) > ip_tot_len);
>  
>