linux-kernel - Re: [PATCH net-next 10/19] net: hns: bugfix about pfc pause frame statistics

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Message-ID: <1466588498.30123.235.camel@linux.intel.com>
Date:	Wed, 22 Jun 2016 12:41:38 +0300
From:	Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
To:	Yisen Zhuang <Yisen.zhuang@...wei.com>, davem@...emloft.net,
	salil.mehta@...wei.com, yankejian@...wei.com
Cc:	liguozhu@...wei.com, huangdaode@...ilicon.com, arnd@...db.de,
	andrew@...n.ch, geliangtang@....com, ivecera@...hat.com,
	fengguang.wu@...el.com, charles.chenxin@...wei.com,
	netdev@...r.kernel.org, linux-kernel@...r.kernel.org,
	linux-arm-kernel@...ts.infradead.org, linuxarm@...wei.com
Subject: Re: [PATCH net-next 10/19] net: hns: bugfix about pfc pause frame
 statistics

On Wed, 2016-06-22 at 09:43 +0800, Yisen Zhuang wrote:
> 
> 在 2016/6/21 18:32, Andy Shevchenko 写道:
> > On Tue, 2016-06-21 at 11:56 +0800, Yisen Zhuang wrote:
> > > From: Daode Huang <huangdaode@...ilicon.com>
> > > 
> > > For SoC hip06, PFC pause handled in dsaf, while hip05 in XGMAC,
> > > so change the statistics of pfc pause in dsaf and remove the old
> > > pfc pause frame statistics.
> > > 
> > 
> > 
> > > +static char *hns_dsaf_get_node_stats_strings(char *data, int
> > > node,
> > > +					     struct dsaf_device
> > > *dsaf_dev)
> > >  {
> > >  	char *buff = data;
> > > +	int i;
> > > +	bool is_ver1 = AE_IS_VER1(dsaf_dev->dsaf_ver);
> > >  
> > >  	snprintf(buff, ETH_GSTRING_LEN, "innod%d_pad_drop_pkts",
> > > node);
> > >  	buff = buff + ETH_GSTRING_LEN;
> > > @@ -2502,6 +2530,18 @@ static char
> > > *hns_dsaf_get_node_stats_strings(char *data, int node)
> > >  	buff = buff + ETH_GSTRING_LEN;
> > >  	snprintf(buff, ETH_GSTRING_LEN, "innod%d_stp_drop_pkts",
> > > node);
> > >  	buff = buff + ETH_GSTRING_LEN;
> > > +	if ((node < DSAF_SERVICE_NW_NUM) && (!is_ver1)) {
> > 
> > Redundant parens.
> > 
> > > +		for (i = 0; i < DSAF_PRIO_NR; i++) {
> > > +			snprintf(buff, ETH_GSTRING_LEN,
> > > +				 "inod%d_pfc_prio%d_pkts", node,
> > > i);
> > > +			buff = buff + ETH_GSTRING_LEN;
> > 
> > buff += ...
> > 
> > > +		}
> > > +		for (i = 0; i < DSAF_PRIO_NR; i++) {
> > > +			snprintf(buff, ETH_GSTRING_LEN,
> > > +				 "onod%d_pfc_prio%d_pkts", node,
> > > i);
> > > +			buff = buff + ETH_GSTRING_LEN;
> > 
> > Ditto.
> > 
> > >  {
> > >  	u64 *p = data;
> > > +	int i;
> > >  	struct dsaf_hw_stats *hw_stats = &ddev-
> > > >hw_stats[node_num];
> > > +	bool is_ver1 = AE_IS_VER1(ddev->dsaf_ver);
> > >  
> > >  	p[0] = hw_stats->pad_drop;
> > >  	p[1] = hw_stats->man_pkts;
> > > @@ -2527,8 +2569,16 @@ static u64 *hns_dsaf_get_node_stats(struct
> > > dsaf_device *ddev, u64 *data,
> > >  	p[10] = hw_stats->local_addr_false;
> > >  	p[11] = hw_stats->vlan_drop;
> > >  	p[12] = hw_stats->stp_drop;
> > > -	p[13] = hw_stats->tx_pkts;
> > > +	if ((node_num < DSAF_SERVICE_NW_NUM) && (!is_ver1)) {
> > > +		for (i = 0; i < DSAF_PRIO_NR; i++) {
> > > +			p[13 + i] = hw_stats->rx_pfc[i];
> > > +			p[13 + i + DSAF_PRIO_NR] = hw_stats-
> > > > tx_pfc[i];
> > > +		}
> > 
> > Two different approaches how to assign data. Above uses 2 for-loops,
> > here you put everything to one.
> 
> Above cann't be merged to 1 for-loop, because lenght of the string is
> unknowable.

It doesn't matter since you are incrementing start position by
constant. 

snprintf(buff, ETH_GSTRING_LEN, "inod%d_pfc_prio%d_pkts", node, i);
snprintf(buff, ETH_GSTRING_LEN, "onod%d_pfc_prio%d_pkts", node, i);

Same approach as below can be used

snprintf(buff + 0 * ETH_GSTRING_LEN * DSAF_PRIO_NR, ETH_GSTRING_LEN, ...
snprintf(buff + 1 * ETH_GSTRING_LEN * DSAF_PRIO_NR, ETH_GSTRING_LEN, ...

Of course to make it less verbose you may add new definition(s) and/ or
variable(s).

> 
> And here we put everything to one to reduce codes.
> 

I would suggest to use following pattern for such lines
p[13 + i + 0 * DSAF_PRIO_NR] = hw_stats->rx_pfc[i];
p[13 + i + 1 * DSAF_PRIO_NR] = hw_stats->tx_pfc[i];

That's allow reader to see what are you doing here.

P.S. This is for the future patches since current is already applied.

-- 

Andy Shevchenko <andriy.shevchenko@...ux.intel.com>
Intel Finland Oy