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Date:   Fri, 30 Oct 2020 21:04:07 -0300
From:   Jason Gunthorpe <jgg@nvidia.com>
To:     Joe Perches <joe@perches.com>,
        Dennis Dalessandro <dennis.dalessandro@intel.com>
CC:     Doug Ledford <dledford@redhat.com>,
        Potnuri Bharat Teja <bharat@chelsio.com>,
        Mike Marciniszyn <mike.marciniszyn@intel.com>,
        "Yishai Hadas" <yishaih@nvidia.com>,
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        Jack Wang <jinpu.wang@cloud.ionos.com>,
        Bart Van Assche <bvanassche@acm.org>,
        <linux-rdma@vger.kernel.org>
Subject: Re: [PATCH 3/4] RDMA: manual changes for sysfs_emit and neatening
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On Thu, Oct 29, 2020 at 10:16:46AM -0700, Joe Perches wrote:
> On Wed, 2020-10-28 at 10:54 -0700, Joe Perches wrote:
> > On Wed, 2020-10-28 at 14:25 -0300, Jason Gunthorpe wrote:
> > > On Wed, Oct 07, 2020 at 07:36:26PM -0700, Joe Perches wrote:
> > >=20
> > > > @@ -653,10 +651,7 @@ static ssize_t serial_show(struct device *devi=
ce,
> > > > =C2=A0		rdma_device_to_drv_device(device, struct qib_ibdev, rdi.ibd=
ev);
> > > > =C2=A0	struct qib_devdata *dd =3D dd_from_dev(dev);
> > > > =C2=A0
> > > >=20
> > > > -	buf[sizeof(dd->serial)] =3D '\0';
> > > > -	memcpy(buf, dd->serial, sizeof(dd->serial));
> > > > -	strcat(buf, "\n");
> > > > -	return strlen(buf);
> > > > +	return sysfs_emit(buf, "%s\n", dd->serial);
> > > > =C2=A0}
> > >=20
> > > This is not the same thing? dd->serial does not look null terminated,
> > > eg it is filled like this:
> > >=20
> > > 		memcpy(dd->serial, ifp->if_serial, sizeof(ifp->if_serial));
> > >=20
> > > From data read off the flash
> >=20
> > It seems you are correct.
> >=20
> > Maybe instead:
> > static ssize_t serial_show(struct device *device,
> > 			   struct device_attribute *attr, char *buf)
> > {
> > 	struct qib_ibdev *dev =3D
> > 		rdma_device_to_drv_device(device, struct qib_ibdev, rdi.ibdev);
> > 	struct qib_devdata *dd =3D dd_from_dev(dev);
> > 	const u8 *end =3D memchr(dd->serial, 0, ARRAY_SIZE(dd->serial));
> > 	int size =3D end ? end - dd->serial : ARRAY_SIZE(dd->serial);
> >=20
> > 	return sysfs_emit(buf, "%*s\n", size, dd->serial);
>=20
> I believe for this to actually be correct, this should be:
>=20
> 	return sysfs_emit(buf, "%.*s\n", size, dd->serial);

Yes, I think so, I squished it in

Maybe Dennis can check it in the wip/jgg/for-next branch?

Thanks,
Jason