[PATCH RESEND v2 2/3] tpm2-cmd: Use dynamic delay to wait for self test result
flat view
STALE3318d
REVIEWED: 1 (0M)
From: Alexander Steffen <hidden>
Date: 2017-08-31 17:19:11
Also in:
lkml
Subsystem:
the rest, tpm device driver · Maintainers:
Linus Torvalds, Peter Huewe, Jarkko Sakkinen
1 review trailer.
In order to avoid delaying the code longer than necessary while still giving the TPM enough time to execute the self tests asynchronously, start with a small delay between two polls and increase it each round. Signed-off-by: Alexander Steffen <redacted> Reviewed-by: Jarkko Sakkinen <redacted> --- drivers/char/tpm/tpm2-cmd.c | 17 +++++++++-------- 1 file changed, 9 insertions(+), 8 deletions(-)
diff --git a/drivers/char/tpm/tpm2-cmd.c b/drivers/char/tpm/tpm2-cmd.c
index 8e940a5..2178437 100644
--- a/drivers/char/tpm/tpm2-cmd.c
+++ b/drivers/char/tpm/tpm2-cmd.c@@ -877,20 +877,17 @@ static int tpm2_start_selftest(struct tpm_chip *chip, bool full) static int tpm2_do_selftest(struct tpm_chip *chip) { int rc; - unsigned int loops; - unsigned int delay_msec = 100; - unsigned long duration; - int i; - - duration = tpm2_calc_ordinal_duration(chip, TPM2_CC_SELF_TEST); + unsigned int delay_msec = 20; + long duration; - loops = jiffies_to_msecs(duration) / delay_msec; + duration = jiffies_to_msecs( + tpm2_calc_ordinal_duration(chip, TPM2_CC_SELF_TEST)); rc = tpm2_start_selftest(chip, false); if (rc) return rc; - for (i = 0; i < loops; i++) { + while (duration > 0) { /* Attempt to read a PCR value */ rc = tpm2_pcr_read(chip, 0, NULL); if (rc < 0)
@@ -900,6 +897,10 @@ static int tpm2_do_selftest(struct tpm_chip *chip) break; tpm_msleep(delay_msec); + duration -= delay_msec; + + /* wait longer the next round */ + delay_msec *= 2; } return rc;
--
2.7.4
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