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Re: [PATCH v5 06/17] tpm: clean up tpm_try_transmit() error handling flow




On 11/8/18 9:15 AM, Jarkko Sakkinen wrote:
Move locking, locality handling and power management to tpm_transmit()
in order to simplify the flow.

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@xxxxxxxxxxxxxxx>


Reviewed-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>


---
  drivers/char/tpm/tpm-interface.c | 71 ++++++++++++++++----------------
  1 file changed, 35 insertions(+), 36 deletions(-)

diff --git a/drivers/char/tpm/tpm-interface.c b/drivers/char/tpm/tpm-interface.c
index 7ffb16edab6f..28d48799b044 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)
@@ -201,30 +200,9 @@ 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_idle;
+		return rc;

  	rc = chip->ops->send(chip, buf, count);
  	if (rc < 0) {
@@ -273,19 +251,6 @@ static ssize_t tpm_try_transmit(struct tpm_chip *chip,
  	else
  		rc = tpm2_commit_space(chip, space, ordinal, buf, &len);

-out_idle:
-	/* 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 (!(flags & TPM_TRANSMIT_UNLOCKED) && !(flags & TPM_TRANSMIT_NESTED))
-		mutex_unlock(&chip->tpm_mutex);
  	return rc ? rc : len;
  }

@@ -315,6 +280,7 @@ 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,
@@ -330,7 +296,40 @@ 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);