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SubjectRe: [PATCH v2 2/4] tpm: define __wait_for_tpm_stat to specify variable polling sleep time
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On 09/13/2017 06:28 AM, Jarkko Sakkinen wrote:
> On Wed, Sep 06, 2017 at 08:56:37AM -0400, Nayna Jain wrote:
>> The existing wait_for_tpm_stat() checks the chip status before
>> sleeping for 5 msec in a polling loop. For some functions although
>> the status isn't ready immediately, the status returns extremely
>> quickly. Waiting for 5 msec causes an unnecessary delay. An
>> example is the send() call in the tpms_tis driver.
>>
>> This patch defines __wait_for_tpm_stat(), allowing the caller
>> to specify the polling sleep timeout value within the loop.
>> The existing wait_for_tpm_stat() becomes a wrapper for this
>> function.
>>
>> After this change, performance on a TPM 1.2 with an 8 byte
>> burstcount for 1000 extends improved from ~14sec to ~10sec.
>>
>> Signed-off-by: Nayna Jain <nayna@linux.vnet.ibm.com>
>> Acked-by: Mimi Zohar <zohar@linux.vnet.ibm.com>
> Please get rid of wait_for_tpm_stat() rather than further making it more
> complex. It's hardware specific stuff. This function should not exist in
> tpm-interface.c.

I think I didn't understand the meaning of "get rid of wait_for_tpm_stat()".
Do you mean to take care of it in driver specific file ?
Can you please elaborate it ?

Thanks & Regards,
    - Nayna

>
> /Jarkko
>
>> ---
>> drivers/char/tpm/tpm-interface.c | 15 ++++++++++++---
>> drivers/char/tpm/tpm.h | 3 +++
>> drivers/char/tpm/tpm_tis_core.c | 11 ++++++-----
>> 3 files changed, 21 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
>> index 1d6729be4cd6..b23d006243b7 100644
>> --- a/drivers/char/tpm/tpm-interface.c
>> +++ b/drivers/char/tpm/tpm-interface.c
>> @@ -1050,8 +1050,9 @@ static bool wait_for_tpm_stat_cond(struct tpm_chip *chip, u8 mask,
>> return false;
>> }
>>
>> -int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
>> - wait_queue_head_t *queue, bool check_cancel)
>> +int __wait_for_tpm_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
>> + unsigned int poll_sleep, wait_queue_head_t *queue,
>> + bool check_cancel)
>> {
>> unsigned long stop;
>> long rc;
>> @@ -1085,7 +1086,7 @@ int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
>> }
>> } else {
>> do {
>> - tpm_msleep(TPM_TIMEOUT);
>> + tpm_msleep(poll_sleep);
>> status = chip->ops->status(chip);
>> if ((status & mask) == mask)
>> return 0;
>> @@ -1093,6 +1094,14 @@ int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
>> }
>> return -ETIME;
>> }
>> +EXPORT_SYMBOL_GPL(__wait_for_tpm_stat);
>> +
>> +int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
>> + wait_queue_head_t *queue, bool check_cancel)
>> +{
>> + return __wait_for_tpm_stat(chip, mask, timeout, TPM_TIMEOUT,
>> + queue, check_cancel);
>> +}
>> EXPORT_SYMBOL_GPL(wait_for_tpm_stat);
>>
>> #define TPM_ORD_SAVESTATE 152
>> diff --git a/drivers/char/tpm/tpm.h b/drivers/char/tpm/tpm.h
>> index 2d5466a72e40..eb2f8818eded 100644
>> --- a/drivers/char/tpm/tpm.h
>> +++ b/drivers/char/tpm/tpm.h
>> @@ -525,6 +525,9 @@ int tpm_do_selftest(struct tpm_chip *chip);
>> unsigned long tpm_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal);
>> int tpm_pm_suspend(struct device *dev);
>> int tpm_pm_resume(struct device *dev);
>> +int __wait_for_tpm_stat(struct tpm_chip *chip, u8 mask,
>> + unsigned long timeout, unsigned int poll_sleep,
>> + wait_queue_head_t *queue, bool check_cancel);
>> int wait_for_tpm_stat(struct tpm_chip *chip, u8 mask, unsigned long timeout,
>> wait_queue_head_t *queue, bool check_cancel);
>>
>> diff --git a/drivers/char/tpm/tpm_tis_core.c b/drivers/char/tpm/tpm_tis_core.c
>> index 6b9bf4c4d434..d1eab29cb447 100644
>> --- a/drivers/char/tpm/tpm_tis_core.c
>> +++ b/drivers/char/tpm/tpm_tis_core.c
>> @@ -268,8 +268,8 @@ static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len)
>> status = tpm_tis_status(chip);
>> if ((status & TPM_STS_COMMAND_READY) == 0) {
>> tpm_tis_ready(chip);
>> - if (wait_for_tpm_stat
>> - (chip, TPM_STS_COMMAND_READY, chip->timeout_b,
>> + if (__wait_for_tpm_stat
>> + (chip, TPM_STS_COMMAND_READY, chip->timeout_b, 1,
>> &priv->int_queue, false) < 0) {
>> rc = -ETIME;
>> goto out_err;
>> @@ -303,7 +303,8 @@ static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len)
>> if (ignore_burst_count)
>> continue;
>>
>> - if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
>> + if (__wait_for_tpm_stat(chip, TPM_STS_VALID,
>> + chip->timeout_c, 1,
>> &priv->int_queue, false) < 0) {
>> rc = -ETIME;
>> goto out_err;
>> @@ -320,8 +321,8 @@ static int tpm_tis_send_data(struct tpm_chip *chip, u8 *buf, size_t len)
>> if (rc < 0)
>> goto out_err;
>>
>> - if (wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
>> - &priv->int_queue, false) < 0) {
>> + if (__wait_for_tpm_stat(chip, TPM_STS_VALID, chip->timeout_c,
>> + 1, &priv->int_queue, false) < 0) {
>> rc = -ETIME;
>> goto out_err;
>> }
>> --
>> 2.13.3
>>

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