Re: [PATCH] test_power: add missing newlines when printing parameters by sysfs

[Joe Perches]

On Sat, 2020-10-03 at 23:23 +0200, Sebastian Reichel wrote:
> Hi,
> 
> On Fri, Sep 04, 2020 at 02:09:58PM +0800, Xiongfeng Wang wrote:
> > When I cat some module parameters by sysfs, it displays as follows.
> > It's better to add a newline for easy reading.
[]
> > root@syzkaller:~# cd /sys/module/test_power/parameters/
> > root@syzkaller:/sys/module/test_power/parameters# cat ac_online
> > onroot@syzkaller:/sys/module/test_power/parameters# cat battery_present
> > trueroot@syzkaller:/sys/module/test_power/parameters# cat battery_health
> > goodroot@syzkaller:/sys/module/test_power/parameters# cat battery_status
> > dischargingroot@syzkaller:/sys/module/test_power/parameters# cat battery_technology
> > LIONroot@syzkaller:/sys/module/test_power/parameters# cat usb_online
> > onroot@syzkaller:/sys/module/test_power/parameters#
> > 
> > Signed-off-by: Xiongfeng Wang <wangxiongfeng2@xxxxxxxxxx>
> > ---
> 
> Thanks, queued.
[]
> > diff --git a/drivers/power/supply/test_power.c b/drivers/power/supply/test_power.c
[]
> > @@ -353,6 +353,7 @@ static int param_set_ac_online(const char *key, const struct kernel_param *kp)
> >  static int param_get_ac_online(char *buffer, const struct kernel_param *kp)
> >  {
> >  	strcpy(buffer, map_get_key(map_ac_online, ac_online, "unknown"));
> > +	strcat(buffer, "\n");
> >  	return strlen(buffer);
> >  }

All of these would be better as sprintf(buffer, "%s\n", <whatever>)
so the output is scanned just once instead of scanned three times.