# Re: \[PATCH v5 1/2\] tpm: add sysfs exports for all banks of PCR registers

- From: Joe Perches \<joe@perches.com\>
- Date: 2021-01-15 21:14:55 
- List: linux-api
- Page: https://ratatoskr.run/linux-api/2021/01/13330000
- Thread: https://ratatoskr.run/linux-integrity/2021/01/13329981/t.md

```text
On Fri, 2021-01-15 at 13:06 -0800, James Bottomley wrote:
> On Fri, 2021-01-15 at 12:48 -0800, Joe Perches wrote:
> > On Fri, 2021-01-15 at 10:07 -0800, James Bottomley wrote:
> > > On Fri, 2021-01-15 at 09:26 -0800, James Bottomley wrote:
> > > > On Fri, 2021-01-15 at 14:54 +0100, Greg KH wrote:
> > > > > On Thu, Jan 14, 2021 at 04:21:08PM -0800, James Bottomley
> > > > > wrote:
> > > > [...]
> > > > > > It looks like we already have a couple of bugs in the kernel
> > > > > > introduced by this confusion ...  return sysfs_emit() vs
> > > > > > return
> > > > > > sysfs_emit_at() being the most tricky ...
> > > > > 
> > > > > Hm, Joe, you did the conversion to these functions (and wrote
> > > > > the
> > > > > api), care to review this?
> > > > 
> > > > A cursory glance tells me that summary_show in 
> > > > drivers/infiniband/hw/usnic/usnic_ib_sysfs.c has a problem, I
> > > > think the last = should be +=
> > 
> > No, it's correct and overwriting what would otherwise be a trailing
> > space.
> 
> The last two lines of summary_show() are
> 
>    len = sysfs_emit_at(buf, len, "\n");
> 
>    return len;
> 
> So that always returns 2, the length of "\n",

1 rather than 2, but you are otherwise correct.

> rather than the length of
> everything you just put into buf, which is what sysfs attributes are
> supposed to return.

Ah, right.  My braino mistake.
This should not use the sysfs_emit_at return value at all.

Patch upcoming...

```