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SubjectRe: [PATCH v2 2/4] tpm: define __wait_for_tpm_stat to specify variable polling sleep time
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.

/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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