Subject: Re: [PATCH] ethtool: command line support for lro

From: Ben Hutchings <[email-masked]>
Date: Mon, 10 Mar 2008 18:07:07 +0000

Stephen Hemminger wrote:
> Add lro support to command in similar manner to TSO, GSO, etc.
> The file ethtool-copy.h is updated to be sanitised version of
> ethtool.h from 2.6.25-rc4 (ie make headers_install)

I already posted a patch to do this, though I didn't update
ethtool-copy.h.

> Not tested on actual LRO hardware.

Mine was, and this looks very similar.

> @@ -1559,12 +1566,20 @@ static int do_goffload(int fd, struct ifreq *ifr)
>  		allfail = 0;
>  	}
>  
> +	eval.cmd = ETHTOOL_GFLAGS;
> +	ifr->ifr_data = (caddr_t)&eval;
> +	err = ioctl(fd, SIOCETHTOOL, ifr);
> +	if (!err) {
> +		lro = eval.data & ETH_FLAG_LRO;
> +		allfail = 0;
> +	}
> +

To be consistent, this should print a specific error if the ioctl
fails.

> @@ -1641,6 +1656,30 @@ static int do_soffload(int fd, struct ifreq *ifr)
>  			return 90;
>  		}
>  	}
> +	if (off_lro_wanted >= 0) {
> +		changed = 1;
> +		eval.cmd = ETHTOOL_GFLAGS;
> +		eval.data = 0;
> +		ifr->ifr_data = (caddr_t)&eval;
> +		err = ioctl(fd, SIOCETHTOOL, ifr);
> +		if (err) {
> +			perror("Cannot get device flag settings");
> +			return 90;
> +		}

I didn't bother fetching the existing flags because only ETH_FLAG_LRO
is defined.  But this would be more future-proof.

> +
> +		eval.cmd = ETHTOOL_SFLAGS;
> +		if (off_lro_wanted == 1)
> +			eval.data |= ETH_FLAG_LRO;
> +		else
> +			eval.data &= ~ETH_FLAG_LRO;
> +			
> +		err = ioctl(fd, SIOCETHTOOL, ifr);
> +		if (err) {
> +			perror("Cannot set large receive offload settings");
> +			return 90;
> +		}

The error return codes are unique so far, so these error paths
should return 91 and 92, not 90.

Ben.

-- 
Ben Hutchings, Senior Software Engineer, Solarflare Communications
Not speaking for my employer; that's the marketing department's job.