linux-kernel - [34-longterm 067/247] TPM: Long default timeout fix

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Message-Id: <1308850515-15242-8-git-send-email-paul.gortmaker@windriver.com>
Date:	Thu, 23 Jun 2011 13:32:15 -0400
From:	Paul Gortmaker <paul.gortmaker@...driver.com>
To:	stable@...nel.org, linux-kernel@...r.kernel.org
Cc:	stable-review@...nel.org,
	Rajiv Andrade <srajiv@...ux.vnet.ibm.com>,
	James Morris <jmorris@...ei.org>,
	Paul Gortmaker <paul.gortmaker@...driver.com>
Subject: [34-longterm 067/247] TPM: Long default timeout fix

From: Rajiv Andrade <srajiv@...ux.vnet.ibm.com>

                   -------------------
    This is a commit scheduled for the next v2.6.34 longterm release.
    If you see a problem with using this for longterm, please comment.
                   -------------------

commit c4ff4b829ef9e6353c0b133b7adb564a68054979 upstream.

If duration variable value is 0 at this point, it's because
chip->vendor.duration wasn't filled by tpm_get_timeouts() yet.
This patch sets then the lowest timeout just to give enough
time for tpm_get_timeouts() to further succeed.

This fix avoids long boot times in case another entity attempts
to send commands to the TPM when the TPM isn't accessible.

Signed-off-by: Rajiv Andrade <srajiv@...ux.vnet.ibm.com>
Signed-off-by: James Morris <jmorris@...ei.org>
Signed-off-by: Paul Gortmaker <paul.gortmaker@...driver.com>
---
 drivers/char/tpm/tpm.c |   10 ++++++----
 1 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/drivers/char/tpm/tpm.c b/drivers/char/tpm/tpm.c
index 068c816..6ab5381 100644
--- a/drivers/char/tpm/tpm.c
+++ b/drivers/char/tpm/tpm.c
@@ -354,12 +354,14 @@ unsigned long tpm_calc_ordinal_duration(struct tpm_chip *chip,
 		    tpm_protected_ordinal_duration[ordinal &
 						   TPM_PROTECTED_ORDINAL_MASK];
 
-	if (duration_idx != TPM_UNDEFINED)
+	if (duration_idx != TPM_UNDEFINED) {
 		duration = chip->vendor.duration[duration_idx];
-	if (duration <= 0)
+		/* if duration is 0, it's because chip->vendor.duration wasn't */
+		/* filled yet, so we set the lowest timeout just to give enough */
+		/* time for tpm_get_timeouts() to succeed */
+		return (duration <= 0 ? HZ : duration);
+	} else
 		return 2 * 60 * HZ;
-	else
-		return duration;
 }
 EXPORT_SYMBOL_GPL(tpm_calc_ordinal_duration);
 
-- 
1.7.4.4

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