[PATCH] tpm: fix incorrect success returns from tpm_try_transmit()

[James Bottomley <James.Bottomley@HansenPartnership.com>]

Ever since 627448e85c766 "tpm: separate cmd_ready/go_idle from
runtime_pm" we have been returning success from tpm_try_transmit()
even if an error occurred.  The reason is that the introduction of rc
= tpm_go_idle() at the end of processing overwrites the value of rc if
it contains an error code (mostly with success).  Fix this by writing
the return to a new variable rc1 instead.

Fixes: 627448e85c766 "tpm: separate cmd_ready/go_idle from runtime_pm"
Cc: stable@vger.kernel.org
Signed-off-by: James Bottomley <James.Bottomley@HansenPartnership.com>

---

Note: the goto out looks fishy as well.  The only go_idle implementor
is tpm_crb and that can return a timeout as -ETIME, so it looks like it
would then loop forever

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 129f640424b7..ac7ebab6140c 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -432,7 +432,7 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
 				unsigned int flags)
 {
 	struct tpm_output_header *header = (void *)buf;
-	int rc;
+	int rc, rc1;
 	ssize_t len = 0;
 	u32 count, ordinal;
 	unsigned long stop;
@@ -547,8 +547,8 @@ 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)
+	rc1 = tpm_go_idle(chip, flags);
+	if (rc1)
 		goto out;
 
 	if (need_locality)