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From:   Greg Kroah-Hartman <gregkh@linuxfoundation.org>
To:     linux-kernel@vger.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
        stable@vger.kernel.org, Tomas Winkler <tomas.winkler@intel.com>,
        Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Subject: [PATCH 4.20 144/145] tpm: tpm_try_transmit() refactor error flow.
Date:   Mon,  7 Jan 2019 13:33:01 +0100
Message-Id: <20190107104455.979533733@linuxfoundation.org>
In-Reply-To: <20190107104437.308206189@linuxfoundation.org>
References: <20190107104437.308206189@linuxfoundation.org>
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4.20-stable review patch.  If anyone has any objections, please let me know.

------------------

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

commit 01f54664a4db0d612de0ece8e0022f21f9374e9b upstream.

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@vger.kernel.org
Fixes: 627448e85c76 ("tpm: separate cmd_ready/go_idle from runtime_pm")
Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
 drivers/char/tpm/tpm-interface.c |   15 ++++++++-------
 1 file changed, 8 insertions(+), 7 deletions(-)

--- 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 t
 
 	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 @@ out_recv:
 		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);