Subject: Re: [Intel-wired-lan] [PATCH] e1000e:Fix incorrect assumption that the function e1000e_up always runs successfully in e1000_change_mtu

From: Alexander Duyck <[email-masked]>
Date: Fri, 23 Oct 2015 23:01:02 -0700

On 10/23/2015 09:09 PM, Nicholas Krause wrote:
> This fixes the function e1000_change_mtu to properly check and run
> the error code by e1000e_up as this function can fail and the error
> code should be returned to the caller of the function e1000_change_mtu
> to signal a error has occurred when calling this particular function

The function e1000e_up always returns 0.  It should probably be switched 
to a void instead of an int.  You could probably go through and drop a 
bunch of dead code that is checking for the result of that function as well.

> Signed-off-by: Nicholas Krause <[email-masked]>
> ---
>   drivers/net/ethernet/intel/e1000e/netdev.c | 7 +++++--
>   1 file changed, 5 insertions(+), 2 deletions(-)
>
> diff --git a/drivers/net/ethernet/intel/e1000e/netdev.c b/drivers/net/ethernet/intel/e1000e/netdev.c
> index faf4b3f..aebccb1 100644
> --- a/drivers/net/ethernet/intel/e1000e/netdev.c
> +++ b/drivers/net/ethernet/intel/e1000e/netdev.c
> @@ -5931,6 +5931,7 @@ static int e1000_change_mtu(struct net_device *netdev, int new_mtu)
>   {
>   	struct e1000_adapter *adapter = netdev_priv(netdev);
>   	int max_frame = new_mtu + VLAN_ETH_HLEN + ETH_FCS_LEN;
> +	int err = 0;
>   
>   	/* Jumbo frame support */
>   	if ((max_frame > (VLAN_ETH_FRAME_LEN + ETH_FCS_LEN)) &&
> @@ -5984,7 +5985,9 @@ static int e1000_change_mtu(struct net_device *netdev, int new_mtu)
>   		adapter->rx_buffer_len = VLAN_ETH_FRAME_LEN + ETH_FCS_LEN;
>   
>   	if (netif_running(netdev))
> -		e1000e_up(adapter);
> +		err = e1000e_up(adapter);
> +		if (err)
> +			e_err("Failed to successfully bring up this adapter\n");
>   	else
>   		e1000e_reset(adapter);
>   
> @@ -5992,7 +5995,7 @@ static int e1000_change_mtu(struct net_device *netdev, int new_mtu)
>   
>   	clear_bit(__E1000_RESETTING, &adapter->state);
>   
> -	return 0;
> +	return err;
>   }
>   
>   static int e1000_mii_ioctl(struct net_device *netdev, struct ifreq *ifr,