linux-kernel - Re: [PATCH 4.19 002/106] tpm: Fix TPM 1.2 Shutdown sequence to prevent future TPM operations

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Message-ID: <20191008234017.GA13437@linux.intel.com>
Date:   Wed, 9 Oct 2019 02:40:17 +0300
From:   Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
To:     Pavel Machek <pavel@...x.de>
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        linux-kernel@...r.kernel.org, stable@...r.kernel.org,
        Vadim Sukhomlinov <sukhomlinov@...gle.com>,
        Douglas Anderson <dianders@...omium.org>,
        Sasha Levin <sashal@...nel.org>
Subject: Re: [PATCH 4.19 002/106] tpm: Fix TPM 1.2 Shutdown sequence to
 prevent future TPM operations

> > --- a/drivers/char/tpm/tpm-chip.c
> > +++ b/drivers/char/tpm/tpm-chip.c
> > @@ -187,12 +187,13 @@ static int tpm_class_shutdown(struct device *dev)
> >  {
> >  	struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev);
> >  
> > +	down_write(&chip->ops_sem);
> >  	if (chip->flags & TPM_CHIP_FLAG_TPM2) {
> > -		down_write(&chip->ops_sem);
> >  		tpm2_shutdown(chip, TPM2_SU_CLEAR);
> >  		chip->ops = NULL;
> > -		up_write(&chip->ops_sem);
> >  	}
> > +	chip->ops = NULL;
> > +	up_write(&chip->ops_sem);
> >  
> >  	return 0;
> >  }
> 
> Still can be improved -- chip->ops = NULL; is done twice, copy inside
> the if {} is redundant...

Thanks. I can update this.

/Jarkko