Re: [tpmdd-devel] [PATCH v5 7/7] tpm: replace or remove printk error messages

[Jarkko S. <jar...@li...>]

On Wed, Oct 26, 2016 at 07:52:53AM +0530, Nayna wrote:
> 
> 
> On 10/21/2016 08:32 PM, Jarkko Sakkinen wrote:
> > On Fri, Oct 21, 2016 at 08:52:14AM +0530, Nayna wrote:
> > > 
> > > 
> > > On 10/20/2016 04:54 PM, Jarkko Sakkinen wrote:
> > > > On Thu, Oct 20, 2016 at 07:34:37AM +0000, Winkler, Tomas wrote:
> > > > > > On Tue, Oct 18, 2016 at 08:49:45PM -0400, Nayna Jain wrote:
> > > > > > > This patch removes the unnecessary error messages on failing to
> > > > > > > allocate memory and replaces pr_err/printk with dev_dbg/dev_info as
> > > > > > > applicable.
> > > > > > > 
> > > > > > > Suggested-by: Jason Gunthorpe <jgu...@ob...>
> > > > > > > Signed-off-by: Nayna Jain <na...@li...>
> > > > > > 
> > > > > > Reviewed-by: Jarkko Sakkinen <jar...@li...>
> > > > > > 
> > > > > > /Jarkko
> > > > > > 
> > > > > > > ---
> > > > > > >    drivers/char/tpm/tpm_acpi.c | 17 +++++------------
> > > > > > >    drivers/char/tpm/tpm_of.c   | 30 ++++++++++--------------------
> > > > > > >    2 files changed, 15 insertions(+), 32 deletions(-)
> > > > > > > 
> > > > > > > diff --git a/drivers/char/tpm/tpm_acpi.c b/drivers/char/tpm/tpm_acpi.c
> > > > > > > index 859bdba..22e42da 100644
> > > > > > > --- a/drivers/char/tpm/tpm_acpi.c
> > > > > > > +++ b/drivers/char/tpm/tpm_acpi.c
> > > > > > > @@ -60,11 +60,8 @@ int read_log_acpi(struct tpm_chip *chip)
> > > > > > >    	status = acpi_get_table(ACPI_SIG_TCPA, 1,
> > > > > > >    				(struct acpi_table_header **)&buff);
> > > > > > > 
> > > > > > > -	if (ACPI_FAILURE(status)) {
> > > > > > > -		printk(KERN_ERR "%s: ERROR - Could not get TCPA table\n",
> > > > > > > -		       __func__);
> > > > > > > +	if (ACPI_FAILURE(status))
> > > > > > >    		return -EIO;
> > > > > > > -	}
> > > > > > > 
> > > > > > >    	switch(buff->platform_class) {
> > > > > > >    	case BIOS_SERVER:
> > > > > > > @@ -78,25 +75,21 @@ int read_log_acpi(struct tpm_chip *chip)
> > > > > > >    		break;
> > > > > > >    	}
> > > > > > >    	if (!len) {
> > > > > > > -		printk(KERN_ERR "%s: ERROR - TCPA log area empty\n",
> > > > > > __func__);
> > > > > > > +		dev_dbg(&chip->dev, "%s: ERROR - TCPA log area empty\n",
> > > > > > > +			__func__);
> > > > > 
> > > > > 
> > > > > Why to keep __func__ here, dev_dbg already does it for you.
> > > > 
> > > > Good catch. I would actually consider also changing this to
> > > > 
> > > > dev_err(dev, FW_BUG "TCPA log area empty\n");
> > > > 
> > > > If TCPA exists but it's empty, that's most likely a FW bug.
> > > 
> > > If it can be possibly a FW bug, should it fail the probe also just like
> > > -ENOMEM error ?
> > 
> > I think so but I hold for second opinion on this. I mean wouldn't
> > it seem like a bit broken situation where TCPA tabe would exist but
> > would also be empty?
> 
> Hmm, is it possible for this to be firmware implementation dependent ?

Let me put it this way. Why would anyone expose TCPA to the user space
that is empty? What would be the point?

/Jarkko