linux-kernel - Re: [PATCH] staging: most: replace multiple if..else with table lookup

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Date:	Wed, 30 Dec 2015 10:44:45 +0000
From:	"Gujulan Elango, Hari Prasath (H.)" <hgujulan@...teon.com>
To:	Joe Perches <joe@...ches.com>
CC:	"gregkh@...uxfoundation.org" <gregkh@...uxfoundation.org>,
	"christian.gromm@...rochip.com" <christian.gromm@...rochip.com>,
	"andrey.shvetsov@....de" <andrey.shvetsov@....de>,
	"adrianremonda@...il.com" <adrianremonda@...il.com>,
	"sudipm.mukherjee@...il.com" <sudipm.mukherjee@...il.com>,
	"devel@...verdev.osuosl.org" <devel@...verdev.osuosl.org>,
	"linux-kernel@...r.kernel.org" <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH] staging: most: replace multiple if..else with table
 lookup

On Thu, Dec 24, 2015 at 08:06:26AM -0800, Joe Perches wrote:
> On Thu, 2015-12-24 at 10:49 +0000, Gujulan Elango, Hari Prasath (H.) wrote:
> > From: Hari Prasath Gujulan Elango <hgujulan@...teon.com>
> > 
> > Replace multiple if..else if..statements with simple table lookup in two
> > functions.
> > 
> > Signed-off-by: Hari Prasath Gujulan Elango <hgujulan@...teon.com>
> > ---
> >  drivers/staging/most/mostcore/core.c | 39 ++++++++++++++++++++----------------
> >  1 file changed, 22 insertions(+), 17 deletions(-)
> > 
> > diff --git a/drivers/staging/most/mostcore/core.c b/drivers/staging/most/mostcore/core.c
> > index ed1ed25..7b4636b 100644
> > --- a/drivers/staging/most/mostcore/core.c
> > +++ b/drivers/staging/most/mostcore/core.c
> > @@ -82,6 +82,14 @@ struct most_inst_obj {
> >  	struct list_head list;
> >  };
> >  
> > +static const struct {
> > +	int most_ch_data_type;
> > +	char *name;
> > +} ch_data_type[] = { { MOST_CH_CONTROL, "control\n" },
> > +	{ MOST_CH_ASYNC, "async\n" },
> > +	{ MOST_CH_SYNC, "sync\n" },
> > +	{ MOST_CH_ISOC_AVP, "isoc_avp\n"} };
> > +
> >  #define to_inst_obj(d) container_of(d, struct most_inst_obj, kobj)
> >  
> >  /**
> > @@ -414,14 +422,12 @@ static ssize_t show_set_datatype(struct most_c_obj *c,
> >  				 struct most_c_attr *attr,
> >  				 char *buf)
> >  {
> > -	if (c->cfg.data_type & MOST_CH_CONTROL)
> > -		return snprintf(buf, PAGE_SIZE, "control\n");
> > -	else if (c->cfg.data_type & MOST_CH_ASYNC)
> > -		return snprintf(buf, PAGE_SIZE, "async\n");
> > -	else if (c->cfg.data_type & MOST_CH_SYNC)
> > -		return snprintf(buf, PAGE_SIZE, "sync\n");
> > -	else if (c->cfg.data_type & MOST_CH_ISOC_AVP)
> > -		return snprintf(buf, PAGE_SIZE, "isoc_avp\n");
> > +	int i;
> > +
> > +	for (i = 0; i < ARRAY_SIZE(ch_data_type); i++) {
> > +		if (c->cfg.data_type & ch_data_type[i].most_ch_data_type)
> > +			return snprintf(buf, PAGE_SIZE, ch_data_type[i].name);
> > +	}
> >  	return snprintf(buf, PAGE_SIZE, "unconfigured\n");
> >  }
> >  
> > @@ -430,15 +436,14 @@ static ssize_t store_set_datatype(struct most_c_obj *c,
> >  				  const char *buf,
> >  				  size_t count)
> >  {
> > -	if (!strcmp(buf, "control\n")) {
> > -		c->cfg.data_type = MOST_CH_CONTROL;
> > -	} else if (!strcmp(buf, "async\n")) {
> > -		c->cfg.data_type = MOST_CH_ASYNC;
> > -	} else if (!strcmp(buf, "sync\n")) {
> > -		c->cfg.data_type = MOST_CH_SYNC;
> > -	} else if (!strcmp(buf, "isoc_avp\n")) {
> > -		c->cfg.data_type = MOST_CH_ISOC_AVP;
> > -	} else {
> > +	int i;
> > +
> > +	for (i = 0; i < ARRAY_SIZE(ch_data_type); i++) {
> > +		if (!strcmp(buf, ch_data_type[i].name))
> > +			c->cfg.data_type = ch_data_type[i].most_ch_data_type;
> 
> Missing braces and break;
> 
> > +	}
> > +
> > +	if (i == ARRAY_SIZE(ch_data_type)) {
> >  		pr_info("WARN: invalid attribute settings\n");
> >  		return -EINVAL;
> >  	}
> 
> This seems like a lot of code for a simple test.
> 
Hello Joe,
I have sent a v2 for this patch with corrections made.

Regards,
Hari Prasath--
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