linux-kernel - Re: [PATCH v2 4/4] tpm: use tpm

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Message-Id: <54cc7899-28df-3630-3337-684b561f3760@linux.vnet.ibm.com>
Date:   Thu, 14 Sep 2017 14:55:34 +0530
From:   Nayna Jain <nayna@...ux.vnet.ibm.com>
To:     Jarkko Sakkinen <jarkko.sakkinen@...ux.intel.com>
Cc:     tpmdd-devel@...ts.sourceforge.net, peterhuewe@....de,
        tpmdd@...horst.net, jgunthorpe@...idianresearch.com,
        linux-security-module@...r.kernel.org,
        linux-kernel@...r.kernel.org,
        linux-ima-devel@...ts.sourceforge.net, patrickc@...ibm.com
Subject: Re: [PATCH v2 4/4] tpm: use tpm_msleep() value as max delay



On 09/13/2017 06:17 AM, Jarkko Sakkinen wrote:
> On Wed, Sep 06, 2017 at 08:56:39AM -0400, Nayna Jain wrote:
>> Currently, tpm_msleep() uses delay_msec as the minimum value in
>> usleep_range. However, that is the maximum time we want to wait.
>> The function is modified to use the delay_msec as the maximum
>> value, not the minimum value.
>>
>> After this change, performance on a TPM 1.2 with an 8 byte
>> burstcount for 1000 extends improved from ~9sec to ~8sec.
>>
>> Signed-off-by: Nayna Jain <nayna@...ux.vnet.ibm.com>
>> Acked-by: Mimi Zohar <zohar@...ux.vnet.ibm.com>
>> ---
>>   drivers/char/tpm/tpm.h | 4 ++--
>>   1 file changed, 2 insertions(+), 2 deletions(-)
>>
>> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
>> index eb2f8818eded..ff5a8b7b80b9 100644
>> --- a/drivers/char/tpm/tpm.h
>> +++ b/drivers/char/tpm/tpm.h
>> @@ -533,8 +533,8 @@ int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
>>   
>>   static inline void tpm_msleep(unsigned int delay_msec)
>>   {
>> -	usleep_range(delay_msec * 1000,
>> -		     (delay_msec * 1000) + TPM_TIMEOUT_RANGE_US);
>> +	usleep_range((delay_msec * 1000) - TPM_TIMEOUT_RANGE_US,
>> +		     delay_msec * 1000);
>>   };
>>   
>>   struct tpm_chip *tpm_chip_find_get(int chip_num);
>> -- 
>> 2.13.3
>>
> Doesn't this need a Fixes tag?
Yeah.. will add.

    - Nayna
> /Jarkko
>