[PATCH 2/2] tpm: tpm_try_transmit() refactor error flow.

[Aaron Ma]

From: Tomas Winkler <tomas.winkler at intel.com>

BugLink: https://bugs.launchpad.net/bugs/1836031

First, rename out_no_locality to out_locality for bailing out on
both tpm_cmd_ready() and tpm_request_locality() failure.
Second, ignore the return value of go_to_idle() as  it may override
the return value of the actual tpm operation, the go_to_idle() error
will be caught on any consequent command.
Last, fix the wrong 'goto out', that jumped back instead of forward.

Cc: stable at vger.kernel.org
Fixes: 627448e85c76 ("tpm: separate cmd_ready/go_idle from runtime_pm")
Signed-off-by: Tomas Winkler <tomas.winkler at intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen at linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen at linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen at linux.intel.com>
(cherry picked from commit 01f54664a4db0d612de0ece8e0022f21f9374e9b)
Signed-off-by: Aaron Ma <aaron.ma at canonical.com>
---
 drivers/char/tpm/tpm-interface.c | 15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index f89cb2eb083c..d328e13afda1 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -478,13 +478,15 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
 
 	if (need_locality) {
 		rc = tpm_request_locality(chip, flags);
-		if (rc < 0)
-			goto out_no_locality;
+		if (rc < 0) {
+			need_locality = false;
+			goto out_locality;
+		}
 	}
 
 	rc = tpm_cmd_ready(chip, flags);
 	if (rc)
-		goto out;
+		goto out_locality;
 
 	rc = tpm2_prepare_space(chip, space, ordinal, buf);
 	if (rc)
@@ -548,14 +550,13 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
 		dev_err(&chip->dev, "tpm2_commit_space: error %d\n", rc);
 
 out:
-	rc = tpm_go_idle(chip, flags);
-	if (rc)
-		goto out;
+	/* may fail but do not override previous error value in rc */
+	tpm_go_idle(chip, flags);
 
+out_locality:
 	if (need_locality)
 		tpm_relinquish_locality(chip, flags);
 
-out_no_locality:
 	if (chip->ops->clk_enable != NULL)
 		chip->ops->clk_enable(chip, false);
 
-- 
2.20.1