Thread (29 messages) 29 messages, 6 authors, 2017-11-28

Re: [PATCH v4 4/4] tpm: use tpm_msleep() value as max delay

From: Jarkko Sakkinen <hidden>
Date: 2017-10-19 14:22:20
Also in: linux-security-module, lkml

On Tue, Oct 17, 2017 at 04:32:32PM -0400, Nayna Jain wrote:
quoted hunk ↗ jump to hunk
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.

Fixes: 3b9af007869("tpm: replace msleep() with usleep_range() in TPM 1.2/
2.0 generic drivers")

Signed-off-by: Nayna Jain <redacted>
Acked-by: Mimi Zohar <redacted>
Tested-by: Jarkko Sakkinen <redacted>
Reviewed-by: Jarkko Sakkinen <redacted>
---
 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 4fc83ac7abeb..644de70de2cc 100644
--- a/drivers/char/tpm/tpm.h
+++ b/drivers/char/tpm/tpm.h
@@ -528,8 +528,8 @@ int tpm_pm_resume(struct device *dev);
 
 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
Tested-by: Jarkko Sakkinen <redacted>

/Jarkko
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