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

From: Tomas Winkler
Date: Tue Oct 16 2018 - 09:41:30 EST


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@xxxxxxxxxxxxxxx
Fixes: 627448e85c76 ("tpm: separate cmd_ready/go_idle from runtime_pm")
Signed-off-by: Tomas Winkler <tomas.winkler@xxxxxxxxx>
---
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 129f640424b7..95db630dd722 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -477,13 +477,15 @@ 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)
@@ -547,14 +549,13 @@ 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);

--
2.14.4