Re: [PATCH ethtool] ethtool: support combinations of FEC modes

["John W. Linville" <linville@tuxdriver.com>]

On Wed, Sep 05, 2018 at 06:54:57PM +0100, Edward Cree wrote:
> Of the three drivers that currently support FEC configuration, two (sfc
>  and cxgb4[vf]) accept configurations with more than one bit set in the
>  feccmd.fec bitmask.  (The precise semantics of these combinations vary.)
> Thus, this patch adds the ability to specify such combinations through a
>  comma-separated list of FEC modes in the 'encoding' argument on the
>  command line.
> 
> Also adds --set-fec tests to test-cmdline.c, and corrects the man page
>  (the encoding argument is not optional) while updating it.
> 
> Signed-off-by: Edward Cree <ecree@solarflare.com>
> ---
> I've CCed the maintainers of the other drivers (cxgb4, nfp) that support
>  --set-fec, in case they have opinions on this.
> I'm not totally happy with the man page changebar; it might be clearer
>  just to leave the comma-less version in the syntax synopsis and only
>  mention the commas in the running-text.

LGTM -- queued for next release...thanks!

John
 
>  ethtool.8.in   | 11 ++++++++---
>  ethtool.c      | 50 +++++++++++++++++++++++++++++++++++++++-----------
>  test-cmdline.c |  9 +++++++++
>  3 files changed, 56 insertions(+), 14 deletions(-)
> 
> diff --git a/ethtool.8.in b/ethtool.8.in
> index c8a902a..414eaa1 100644
> --- a/ethtool.8.in
> +++ b/ethtool.8.in
> @@ -389,7 +389,8 @@ ethtool \- query or control network driver and hardware settings
>  .HP
>  .B ethtool \-\-set\-fec
>  .I devname
> -.B4 encoding auto off rs baser
> +.B encoding
> +.BR auto | off | rs | baser [ , ...]
>  .
>  .\" Adjust lines (i.e. full justification) and hyphenate.
>  .ad
> @@ -1119,8 +1120,12 @@ current FEC mode, the driver or firmware must take the link down
>  administratively and report the problem in the system logs for users to correct.
>  .RS 4
>  .TP
> -.A4 encoding auto off rs baser
> -Sets the FEC encoding for the device.
> +.BR encoding\ auto | off | rs | baser [ , ...]
> +
> +Sets the FEC encoding for the device.  Combinations of options are specified as
> +e.g.
> +.B auto,rs
> +; the semantics of such combinations vary between drivers.
>  .TS
>  nokeep;
>  lB	l.
> diff --git a/ethtool.c b/ethtool.c
> index e8b7703..9997930 100644
> --- a/ethtool.c
> +++ b/ethtool.c
> @@ -4967,20 +4967,48 @@ static int do_set_phy_tunable(struct cmd_context *ctx)
>  
>  static int fecmode_str_to_type(const char *str)
>  {
> +	if (!strcasecmp(str, "auto"))
> +		return ETHTOOL_FEC_AUTO;
> +	if (!strcasecmp(str, "off"))
> +		return ETHTOOL_FEC_OFF;
> +	if (!strcasecmp(str, "rs"))
> +		return ETHTOOL_FEC_RS;
> +	if (!strcasecmp(str, "baser"))
> +		return ETHTOOL_FEC_BASER;
> +
> +	return 0;
> +}
> +
> +/* Takes a comma-separated list of FEC modes, returns the bitwise OR of their
> + * corresponding ETHTOOL_FEC_* constants.
> + * Accepts repetitions (e.g. 'auto,auto') and trailing comma (e.g. 'off,').
> + */
> +static int parse_fecmode(const char *str)
> +{
>  	int fecmode = 0;
> +	char buf[6];
>  
>  	if (!str)
> -		return fecmode;
> -
> -	if (!strcasecmp(str, "auto"))
> -		fecmode |= ETHTOOL_FEC_AUTO;
> -	else if (!strcasecmp(str, "off"))
> -		fecmode |= ETHTOOL_FEC_OFF;
> -	else if (!strcasecmp(str, "rs"))
> -		fecmode |= ETHTOOL_FEC_RS;
> -	else if (!strcasecmp(str, "baser"))
> -		fecmode |= ETHTOOL_FEC_BASER;
> +		return 0;
> +	while (*str) {
> +		size_t next;
> +		int mode;
>  
> +		next = strcspn(str, ",");
> +		if (next >= 6) /* Bad mode, longest name is 5 chars */
> +			return 0;
> +		/* Copy into temp buffer and nul-terminate */
> +		memcpy(buf, str, next);
> +		buf[next] = 0;
> +		mode = fecmode_str_to_type(buf);
> +		if (!mode) /* Bad mode encountered */
> +			return 0;
> +		fecmode |= mode;
> +		str += next;
> +		/* Skip over ',' (but not nul) */
> +		if (*str)
> +			str++;
> +	}
>  	return fecmode;
>  }
>  
> @@ -5028,7 +5056,7 @@ static int do_sfec(struct cmd_context *ctx)
>  	if (!fecmode_str)
>  		exit_bad_args();
>  
> -	fecmode = fecmode_str_to_type(fecmode_str);
> +	fecmode = parse_fecmode(fecmode_str);
>  	if (!fecmode)
>  		exit_bad_args();
>  
> diff --git a/test-cmdline.c b/test-cmdline.c
> index a94edea..9c51cca 100644
> --- a/test-cmdline.c
> +++ b/test-cmdline.c
> @@ -266,6 +266,15 @@ static struct test_case {
>  	{ 0, "--set-eee devname tx-timer 42 advertise 0x4321" },
>  	{ 1, "--set-eee devname tx-timer foo" },
>  	{ 1, "--set-eee devname advertise foo" },
> +	{ 1, "--set-fec devname" },
> +	{ 0, "--set-fec devname encoding auto" },
> +	{ 0, "--set-fec devname encoding off," },
> +	{ 0, "--set-fec devname encoding baser,rs" },
> +	{ 0, "--set-fec devname encoding auto,auto," },
> +	{ 1, "--set-fec devname encoding foo" },
> +	{ 1, "--set-fec devname encoding auto,foo" },
> +	{ 1, "--set-fec devname encoding auto,," },
> +	{ 1, "--set-fec devname auto" },
>  	/* can't test --set-priv-flags yet */
>  	{ 0, "-h" },
>  	{ 0, "--help" },
> 

-- 
John W. Linville		Someday the world will need a hero, and you
linville@tuxdriver.com			might be all we have.  Be ready.