linux-kernel - Re: [PATCH v10 04/14] tpm, tpm_tis: Do not skip reset of original interrupt vector

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Date:   Thu, 24 Nov 2022 14:25:05 +0100
From:   Lino Sanfilippo <LinoSanfilippo@....de>
To:     Jarkko Sakkinen <jarkko@...nel.org>
Cc:     peterhuewe@....de, jgg@...pe.ca, stefanb@...ux.vnet.ibm.com,
        linux@...ewoehner.de, linux-integrity@...r.kernel.org,
        linux-kernel@...r.kernel.org, jandryuk@...il.com,
        pmenzel@...gen.mpg.de, l.sanfilippo@...bus.com, lukas@...ner.de,
        p.rosenberger@...bus.com
Subject: Re: [PATCH v10 04/14] tpm, tpm_tis: Do not skip reset of original
 interrupt vector

On 24.11.22 at 07:58, Jarkko Sakkinen wrote:
> On Sun, Nov 20, 2022 at 02:31:24PM +0100, Lino Sanfilippo wrote:
>> From: Lino Sanfilippo <l.sanfilippo@...bus.com>
>>
>> If in tpm_tis_probe_irq_single() an error occurs after the original
>> interrupt vector has been read, restore the interrupts before the error is
>> returned.
>>
>> Since the caller does not check the error value, return -1 in any case that
>> the TPM_CHIP_FLAG_IRQ flag is not set. Since the return value of function
>> tpm_tis_gen_interrupt() is not longer used, make it a void function.
>>
>> Fixes: 1107d065fdf1 ("tpm_tis: Introduce intermediate layer for TPM access")
>> Signed-off-by: Lino Sanfilippo <l.sanfilippo@...bus.com>
>> ---
>>  drivers/char/tpm/tpm_tis_core.c | 33 +++++++++++++--------------------
>>  1 file changed, 13 insertions(+), 20 deletions(-)
>>
>> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
>> index 603b82ca56da..1eac1279594d 100644
>> --- a/drivers/char/tpm/tpm_tis_core.c
>> +++ b/drivers/char/tpm/tpm_tis_core.c
>> @@ -729,7 +729,7 @@ static irqreturn_t tis_int_handler(int dummy, void *dev_id)
>>  	return IRQ_HANDLED;
>>  }
>>
>> -static int tpm_tis_gen_interrupt(struct tpm_chip *chip)
>> +static void tpm_tis_gen_interrupt(struct tpm_chip *chip)
>>  {
>>  	const char *desc = "attempting to generate an interrupt";
>>  	u32 cap2;
>> @@ -738,16 +738,14 @@ static int tpm_tis_gen_interrupt(struct tpm_chip *chip)
>>
>>  	ret = request_locality(chip, 0);
>>  	if (ret < 0)
>> -		return ret;
>> +		return;
>>
>>  	if (chip->flags & TPM_CHIP_FLAG_TPM2)
>> -		ret = tpm2_get_tpm_pt(chip, 0x100, &cap2, desc);
>> +		tpm2_get_tpm_pt(chip, 0x100, &cap2, desc);
>
> In a successive patch:
>
> -               tpm2_get_tpm_pt(chip, 0x100, &cap2, desc);
> +               ret = tpm2_get_tpm_pt(chip, 0x100, &cap2, desc);
> `
>
> BR, Jarkko
>

If it was a single patch it would be IMHO correct to remove ret, since at this point it
is not needed any more. But as part of a series it is admittedly a bit odd to remove the value only
to re-add it in a later patch of the same series. I will fix this and send a v11.


Regards,
Lino