Re: 回复: [PATCH] usb: replace snprintf in show functions with sysfs_emit

[Greg Kroah-Hartman <gregkh@linuxfoundation.org>]

On Wed, Oct 13, 2021 at 06:52:53AM +0000, 王擎 wrote:
>  
> >> On Tue, Oct 12, 2021 at 08:27:47PM -0700, Qing Wang wrote:
> >> coccicheck complains about the use of snprintf() in sysfs show functions.
> >> 
> >> Fix the following coccicheck warning:
> >> drivers/usb/core/sysfs.c:730:8-16: WARNING: use scnprintf or sprintf.
> >> drivers/usb/core/sysfs.c:921:8-16: WARNING: use scnprintf or sprintf.
> >> 
> >> Use sysfs_emit instead of scnprintf or sprintf makes more sense.
> >> 
> >> Signed-off-by: Qing Wang <wangqing@vivo.com>
> >> ---
> >>  drivers/usb/core/sysfs.c | 4 ++--
> >>  1 file changed, 2 insertions(+), 2 deletions(-)
> >> 
> >> diff --git a/drivers/usb/core/sysfs.c b/drivers/usb/core/sysfs.c
> >> index fa2e49d..6387c0d 100644
> >> --- a/drivers/usb/core/sysfs.c
> >> +++ b/drivers/usb/core/sysfs.c
> >> @@ -727,7 +727,7 @@ static ssize_t authorized_show(struct device *dev,
> >>                               struct device_attribute *attr, char *buf)
> >>  {
> >>        struct usb_device *usb_dev = to_usb_device(dev);
> >> -     return snprintf(buf, PAGE_SIZE, "%u\n", usb_dev->authorized);
> >> +     return sysfs_emit(buf, "%u\n", usb_dev->authorized);
> >>  }
> >>  
> >>  /*
> >> @@ -918,7 +918,7 @@ static ssize_t authorized_default_show(struct device *dev,
> >>        struct usb_hcd *hcd;
> >>  
> >>        hcd = bus_to_hcd(usb_bus);
> >> -     return snprintf(buf, PAGE_SIZE, "%u\n", hcd->dev_policy);
> >> +     return sysfs_emit(buf, "%u\n", hcd->dev_policy);
> >>  }
> >>  
> >>  static ssize_t authorized_default_store(struct device *dev,
> >> -- 
> >> 2.7.4
> >> 
> > 
> > If you are going to change this file, you should do this for all of the
> > sysfs show functions in this file, not just 2 of them, right?  Please
> > change this patch to do that.
> >
> > thanks,
> > 
> > greg k-h
> 
> Only these 2 snprintf need to be modified, other show functions
> used sprintf do not need to modify.

I do not think you understand the change you are trying to make here.

Either the whole file should use the same api, or just leave it as-is as
it obviously works properly today :)

thanks,

greg k-h