[PATCH] tpm: clean up tpm_try_transmit() error handling flow

[Jarkko Sakkinen]

Move locking, locality handling and power management to tpm_transmit()
in order to simplify the flow and fix the error message formatting in
tpm_try_transmit() to output correct function name by using the
'__func__' macro.

Cc: Peter Huewe <peterhuewe@xxxxxx>
Cc: Jason Gunthorpe <jgg@xxxxxxxx>
Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>
---
 drivers/char/tpm/tpm-interface.c | 103 ++++++++++++++-----------------
 1 file changed, 47 insertions(+), 56 deletions(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 64510ed81b46..967de254b156 100644
--- a/drivers/char/tpm/tpm-interface.c
+++ b/drivers/char/tpm/tpm-interface.c
@@ -171,7 +171,6 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
 	ssize_t len = 0;
 	u32 count, ordinal;
 	unsigned long stop;
-	bool need_locality;
 
 	rc = tpm_validate_command(chip, space, buf, bufsiz);
 	if (rc == -EINVAL)
@@ -201,37 +200,16 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
 		return -E2BIG;
 	}
 
-	if (!(flags & TPM_TRANSMIT_UNLOCKED) && !(flags & TPM_TRANSMIT_NESTED))
-		mutex_lock(&chip->tpm_mutex);
-
-	if (chip->ops->clk_enable != NULL)
-		chip->ops->clk_enable(chip, true);
-
-	/* Store the decision as chip->locality will be changed. */
-	need_locality = chip->locality == -1;
-
-	if (need_locality) {
-		rc = tpm_request_locality(chip, flags);
-		if (rc < 0) {
-			need_locality = false;
-			goto out_locality;
-		}
-	}
-
-	rc = tpm_cmd_ready(chip, flags);
-	if (rc)
-		goto out_locality;
-
 	rc = tpm2_prepare_space(chip, space, ordinal, buf);
 	if (rc)
-		goto out;
+		return rc;
 
 	rc = chip->ops->send(chip, buf, count);
 	if (rc < 0) {
 		if (rc != -EPIPE)
 			dev_err(&chip->dev,
 				"%s: tpm_send: error %d\n", __func__, rc);
-		goto out;
+		return rc;
 	}
 
 	if (chip->flags & TPM_CHIP_FLAG_IRQ)
@@ -246,8 +224,7 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
 
 		if (chip->ops->req_canceled(chip, status)) {
 			dev_err(&chip->dev, "Operation Canceled\n");
-			rc = -ECANCELED;
-			goto out;
+			return -ECANCELED;
 		}
 
 		tpm_msleep(TPM_TIMEOUT_POLL);
@@ -256,44 +233,24 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
 
 	chip->ops->cancel(chip);
 	dev_err(&chip->dev, "Operation Timed out\n");
-	rc = -ETIME;
-	goto out;
+	return -ETIME;
 
 out_recv:
 	len = chip->ops->recv(chip, buf, bufsiz);
 	if (len < 0) {
-		rc = len;
-		dev_err(&chip->dev,
-			"tpm_transmit: tpm_recv: error %d\n", rc);
-		goto out;
-	} else if (len < TPM_HEADER_SIZE) {
-		rc = -EFAULT;
-		goto out;
-	}
-
-	if (len != be32_to_cpu(header->length)) {
-		rc = -EFAULT;
-		goto out;
+		dev_err(&chip->dev, "%s: recv error %d\n", __func__, rc);
+		return len;
 	}
+	if (len < TPM_HEADER_SIZE || len != be32_to_cpu(header->length))
+		return -EFAULT;
 
 	rc = tpm2_commit_space(chip, space, ordinal, buf, &len);
-	if (rc)
-		dev_err(&chip->dev, "tpm2_commit_space: error %d\n", rc);
-
-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);
-
-	if (chip->ops->clk_enable != NULL)
-		chip->ops->clk_enable(chip, false);
+	if (rc) {
+		dev_err(&chip->dev, "%s: commit error %d\n", __func__, rc);
+		return rc;
+	}
 
-	if (!(flags & TPM_TRANSMIT_UNLOCKED) && !(flags & TPM_TRANSMIT_NESTED))
-		mutex_unlock(&chip->tpm_mutex);
-	return rc ? rc : len;
+	return len;
 }
 
 /**
@@ -322,6 +279,7 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
 	/* space for header and handles */
 	u8 save[TPM_HEADER_SIZE + 3*sizeof(u32)];
 	unsigned int delay_msec = TPM2_DURATION_SHORT;
+	bool has_locality = false;
 	u32 rc = 0;
 	ssize_t ret;
 	const size_t save_size = min(space ? sizeof(save) : TPM_HEADER_SIZE,
@@ -337,7 +295,40 @@ ssize_t tpm_transmit(struct tpm_chip *chip, struct tpm_space *space,
 	memcpy(save, buf, save_size);
 
 	for (;;) {
+		if (!(flags & TPM_TRANSMIT_UNLOCKED) &&
+		    !(flags & TPM_TRANSMIT_NESTED))
+			mutex_lock(&chip->tpm_mutex);
+
+		if (chip->ops->clk_enable != NULL)
+			chip->ops->clk_enable(chip, true);
+
+		if (chip->locality == -1) {
+			ret = tpm_request_locality(chip, flags);
+			if (ret)
+				goto out_locality;
+			has_locality = true;
+		}
+
+		ret = tpm_cmd_ready(chip, flags);
+		if (ret)
+			goto out_locality;
+
 		ret = tpm_try_transmit(chip, space, buf, bufsiz, flags);
+
+		/* This may fail but do not override ret. */
+		tpm_go_idle(chip, flags);
+
+out_locality:
+		if (has_locality)
+			tpm_relinquish_locality(chip, flags);
+
+		if (chip->ops->clk_enable != NULL)
+			chip->ops->clk_enable(chip, false);
+
+		if (!(flags & TPM_TRANSMIT_UNLOCKED) &&
+		    !(flags & TPM_TRANSMIT_NESTED))
+			mutex_unlock(&chip->tpm_mutex);
+
 		if (ret < 0)
 			break;
 		rc = be32_to_cpu(header->return_code);
-- 
2.19.1