netdev - RE: [PATCH 2/4 ethtool] ethtool: Support for configurable RSS hash key.

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Message-ID: <BF3270C86E8B1349A26C34E4EC1C44CB2C84C261@CMEXMB1.ad.emulex.com>
Date:	Mon, 20 Jan 2014 11:15:10 +0000
From:	Venkata Duvvuru <VenkatKumar.Duvvuru@...lex.Com>
To:	Ben Hutchings <ben@...adent.org.uk>
CC:	"netdev@...r.kernel.org" <netdev@...r.kernel.org>
Subject: RE: [PATCH 2/4 ethtool] ethtool: Support for configurable RSS hash
 key.

Ben, Thanks for the feedback.

-----Original Message-----
From: Ben Hutchings [mailto:ben@...adent.org.uk] 
Sent: Monday, January 20, 2014 12:06 AM
To: Venkata Duvvuru
Cc: netdev@...r.kernel.org
Subject: Re: [PATCH 2/4 ethtool] ethtool: Support for configurable RSS hash key.

On Fri, 2014-01-17 at 13:02 +0000, Venkata Duvvuru wrote:
> This ethtool patch will primarily implement the parser for the options provided by the user for set and get hashkey before invoking the ioctl.
> This patch also has Ethtool man page changes which describes the Usage of set and get hashkey options.

I'd prefer to have this combined with the -x/-X options (and add new long options to reflect that they cover the key as well).

if we add hashkey options to the existing -x/-X (--show-rxfh-indir/ --set-rxfh-indir), I think it won't be appropriate going by the command name.
We could change the command name to something like --show-rssconfig /--rss-config but I'm afraid would that be backward compatible?

[...]
> diff --git a/ethtool.c b/ethtool.c
> index b06dfa3..4b05b0c 100644
> --- a/ethtool.c
> +++ b/ethtool.c
> @@ -471,6 +471,59 @@ static int rxflow_str_to_type(const char *str)
>  	return flow_type;
>  }
>  
> +static inline int is_hkey_char_valid(const char rss_hkey_string) {

A char is not a string.

> +	/* Are there any invalid characters in the string */
> +	return ((rss_hkey_string >= '0' && rss_hkey_string <= '9') ||
> +	       (rss_hkey_string >= 'a' && rss_hkey_string <= 'f') ||
> +	       (rss_hkey_string >= 'A' && rss_hkey_string <= 'F')); }

Braces are in the wrong places.  And the whole function is redundant with isxdigit() anyway.

> +static int convert_string_to_hashkey(struct ethtool_rss_hkey *rss_hkey,
> +				      const char *rss_hkey_string) {
> +	int i = 0;
> +	int hex_byte;
> +
> +	do {
> +		if (i > (RSS_HASH_KEY_LEN - 1)) {

Comparing with the wrong limit.

[...]
> +static int get_hashkey(struct cmd_context *ctx) {

Brace in the wrong place.

[...]
> +	for (i = 0; i < RSS_HASH_KEY_LEN; i++) {
> +		if (i == (RSS_HASH_KEY_LEN - 1))

Wrong length.

> +			printf("%02x\n", rss_hkey->data[i]);
> +		else
> +			printf("%02x:", rss_hkey->data[i]);
> +	}
> +
> +done:
> +	free(rss_hkey);
> +	return rc;
> +}
[...]

--
Ben Hutchings
friends: People who know you well, but like you anyway.