Re: [PATCH 3/3] bus: mhi: replace snprintf in show functions with sysfs_emit

[Hemant Kumar]

On 10/16/2021 9:15 AM, Manivannan Sadhasivam wrote:
> On Sat, Oct 16, 2021 at 05:07:06PM +0200, Greg KH wrote:
> > On Sat, Oct 16, 2021 at 03:24:17AM -0700, Joe Perches wrote:
> > > On Sat, 2021-10-16 at 09:37 +0200, Greg KH wrote:
> > > > On Sat, Oct 16, 2021 at 12:27:34PM +0530, Manivannan Sadhasivam wrote:
> > > > > From: Qing Wang <wangqing@xxxxxxxx>
> > > > > coccicheck complains about the use of snprintf() in sysfs show functions.
> > > []
> > > > > diff --git a/drivers/bus/mhi/core/init.c b/drivers/bus/mhi/core/init.c
> > > []
> > > > > @@ -94,7 +94,7 @@ static ssize_t serial_number_show(struct device *dev,
> > > > >   	struct mhi_device *mhi_dev = to_mhi_device(dev);
> > > > >   	struct mhi_controller *mhi_cntrl = mhi_dev->mhi_cntrl;
> > > > >   
> > > > > -	return snprintf(buf, PAGE_SIZE, "Serial Number: %u\n",
> > > > > +	return sysfs_emit(buf, "Serial Number: %u\n",
> > > > >   			mhi_cntrl->serial_number);
> > > >
> > > > The text "Serial Number: " should not be in here, right?  It's obvious
> > > > this is a serial number, that's what the documentation and file name
> > > > says.  Userspace should not have to parse sysfs files.
> > >
> > > sysfs is ABI right?  Parsing or not, it's what's already there.
> >
> > If no tools rely on this, and we can change it, we should at least try.
> >
> > We can not change ABI if something breaks.  If nothing relies on it,
> > then it is fine to do so.
>
> Hemant, Bhaumik, do you guys know if there are any possible users (scripts/apps)
> of this ABI? I'm not 100% inclined to change it but if we are _sure_ that there
> are no users yet, then I'm ok with it.

Mani, i dont know if any script being used by any user to parse "Serial 
Number".

Thanks,
Hemant
> Thanks,
> Mani
>
> > thanks,
> >
> > greg k-h

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