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Re: [PATCH v5 13/17] tpm: use tpm_try_get_ops() in tpm-sysfs.c.




On 11/8/18 9:15 AM, Jarkko Sakkinen wrote:
Use tpm_try_get_ops() in tpm-sysfs.c so that we can consider moving
other decorations (locking, localities, power management for example)
inside it. This direction can be of course taken only after other call
sites for tpm_transmit() have been treated in the same way.

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

Reviewed-by: Stefan Berger <stefanb@xxxxxxxxxxxxx>

---
  drivers/char/tpm/tpm-sysfs.c | 123 ++++++++++++++++++++++-------------
  1 file changed, 78 insertions(+), 45 deletions(-)

diff --git a/drivers/char/tpm/tpm-sysfs.c b/drivers/char/tpm/tpm-sysfs.c
index 03e704f99ed6..3733491671ca 100644
--- a/drivers/char/tpm/tpm-sysfs.c
+++ b/drivers/char/tpm/tpm-sysfs.c
@@ -39,7 +39,6 @@ static ssize_t pubek_show(struct device *dev, struct device_attribute *attr,
  {
  	struct tpm_buf tpm_buf;
  	struct tpm_readpubek_out *out;
-	ssize_t rc;
  	int i;
  	char *str = buf;
  	struct tpm_chip *chip = to_tpm_chip(dev);
@@ -47,17 +46,17 @@ static ssize_t pubek_show(struct device *dev, struct device_attribute *attr,

  	memset(&anti_replay, 0, sizeof(anti_replay));

-	if (tpm_buf_init(&tpm_buf, TPM_TAG_RQU_COMMAND, TPM_ORD_READPUBEK))
+	if (tpm_try_get_ops(chip))
  		return 0;

+	if (tpm_buf_init(&tpm_buf, TPM_TAG_RQU_COMMAND, TPM_ORD_READPUBEK))
+		goto out_ops;
+
  	tpm_buf_append(&tpm_buf, anti_replay, sizeof(anti_replay));

-	rc = tpm_transmit_cmd(chip, &tpm_buf, READ_PUBEK_RESULT_MIN_BODY_SIZE,
-			      0, "attempting to read the PUBEK");
-	if (rc) {
-		tpm_buf_destroy(&tpm_buf);
-		return 0;
-	}
+	if (tpm_transmit_cmd(chip, &tpm_buf, READ_PUBEK_RESULT_MIN_BODY_SIZE,
+			      0, "attempting to read the PUBEK"))
+		goto out_buf;

  	out = (struct tpm_readpubek_out *)&tpm_buf.data[10];
  	str +=
@@ -88,9 +87,11 @@ static ssize_t pubek_show(struct device *dev, struct device_attribute *attr,
  			str += sprintf(str, "\n");
  	}

-	rc = str - buf;
+out_buf:
  	tpm_buf_destroy(&tpm_buf);
-	return rc;
+out_ops:
+	tpm_put_ops(chip);
+	return str - buf;
  }
  static DEVICE_ATTR_RO(pubek);

@@ -103,10 +104,15 @@ static ssize_t pcrs_show(struct device *dev, struct device_attribute *attr,
  	char *str = buf;
  	struct tpm_chip *chip = to_tpm_chip(dev);

+	if (tpm_try_get_ops(chip))
+		return 0;
+
  	if (tpm1_getcap(chip, TPM_CAP_PROP_PCR, &cap,
  			"attempting to determine the number of PCRS",
-			sizeof(cap.num_pcrs)))
+			sizeof(cap.num_pcrs))) {
+		tpm_put_ops(chip);
  		return 0;
+	}

  	num_pcrs = be32_to_cpu(cap.num_pcrs);
  	for (i = 0; i < num_pcrs; i++) {
@@ -119,6 +125,7 @@ static ssize_t pcrs_show(struct device *dev, struct device_attribute *attr,
  			str += sprintf(str, "%02X ", digest[j]);
  		str += sprintf(str, "\n");
  	}
+	tpm_put_ops(chip);
  	return str - buf;
  }
  static DEVICE_ATTR_RO(pcrs);
@@ -126,16 +133,21 @@ static DEVICE_ATTR_RO(pcrs);
  static ssize_t enabled_show(struct device *dev, struct device_attribute *attr,
  		     char *buf)
  {
+	struct tpm_chip *chip = to_tpm_chip(dev);
+	ssize_t rc = 0;
  	cap_t cap;
-	ssize_t rc;

-	rc = tpm1_getcap(to_tpm_chip(dev), TPM_CAP_FLAG_PERM, &cap,
-			 "attempting to determine the permanent enabled state",
-			 sizeof(cap.perm_flags));
-	if (rc)
+	if (tpm_try_get_ops(chip))
  		return 0;

+	if (tpm1_getcap(chip, TPM_CAP_FLAG_PERM, &cap,
+			"attempting to determine the permanent enabled state",
+			sizeof(cap.perm_flags)))
+		goto out_ops;
+
  	rc = sprintf(buf, "%d\n", !cap.perm_flags.disable);
+out_ops:
+	tpm_put_ops(chip);
  	return rc;
  }
  static DEVICE_ATTR_RO(enabled);
@@ -143,16 +155,21 @@ static DEVICE_ATTR_RO(enabled);
  static ssize_t active_show(struct device *dev, struct device_attribute *attr,
  		    char *buf)
  {
+	struct tpm_chip *chip = to_tpm_chip(dev);
+	ssize_t rc = 0;
  	cap_t cap;
-	ssize_t rc;

-	rc = tpm1_getcap(to_tpm_chip(dev), TPM_CAP_FLAG_PERM, &cap,
-			 "attempting to determine the permanent active state",
-			 sizeof(cap.perm_flags));
-	if (rc)
+	if (tpm_try_get_ops(chip))
  		return 0;

+	if (tpm1_getcap(chip, TPM_CAP_FLAG_PERM, &cap,
+			"attempting to determine the permanent active state",
+			sizeof(cap.perm_flags)))
+		goto out_ops;
+
  	rc = sprintf(buf, "%d\n", !cap.perm_flags.deactivated);
+out_ops:
+	tpm_put_ops(chip);
  	return rc;
  }
  static DEVICE_ATTR_RO(active);
@@ -160,16 +177,21 @@ static DEVICE_ATTR_RO(active);
  static ssize_t owned_show(struct device *dev, struct device_attribute *attr,
  			  char *buf)
  {
+	struct tpm_chip *chip = to_tpm_chip(dev);
+	ssize_t rc = 0;
  	cap_t cap;
-	ssize_t rc;

-	rc = tpm1_getcap(to_tpm_chip(dev), TPM_CAP_PROP_OWNER, &cap,
-			 "attempting to determine the owner state",
-			 sizeof(cap.owned));
-	if (rc)
+	if (tpm_try_get_ops(chip))
  		return 0;

+	if (tpm1_getcap(to_tpm_chip(dev), TPM_CAP_PROP_OWNER, &cap,
+			"attempting to determine the owner state",
+			sizeof(cap.owned)))
+		goto out_ops;
+
  	rc = sprintf(buf, "%d\n", cap.owned);
+out_ops:
+	tpm_put_ops(chip);
  	return rc;
  }
  static DEVICE_ATTR_RO(owned);
@@ -177,16 +199,21 @@ static DEVICE_ATTR_RO(owned);
  static ssize_t temp_deactivated_show(struct device *dev,
  				     struct device_attribute *attr, char *buf)
  {
+	struct tpm_chip *chip = to_tpm_chip(dev);
+	ssize_t rc = 0;
  	cap_t cap;
-	ssize_t rc;

-	rc = tpm1_getcap(to_tpm_chip(dev), TPM_CAP_FLAG_VOL, &cap,
-			 "attempting to determine the temporary state",
-			 sizeof(cap.stclear_flags));
-	if (rc)
+	if (tpm_try_get_ops(chip))
  		return 0;

+	if (tpm1_getcap(to_tpm_chip(dev), TPM_CAP_FLAG_VOL, &cap,
+			"attempting to determine the temporary state",
+			sizeof(cap.stclear_flags)))
+		goto out_ops;
+
  	rc = sprintf(buf, "%d\n", cap.stclear_flags.deactivated);
+out_ops:
+	tpm_put_ops(chip);
  	return rc;
  }
  static DEVICE_ATTR_RO(temp_deactivated);
@@ -195,15 +222,18 @@ static ssize_t caps_show(struct device *dev, struct device_attribute *attr,
  			 char *buf)
  {
  	struct tpm_chip *chip = to_tpm_chip(dev);
-	cap_t cap;
-	ssize_t rc;
+	ssize_t rc = 0;
  	char *str = buf;
+	cap_t cap;

-	rc = tpm1_getcap(chip, TPM_CAP_PROP_MANUFACTURER, &cap,
-			 "attempting to determine the manufacturer",
-			 sizeof(cap.manufacturer_id));
-	if (rc)
+	if (tpm_try_get_ops(chip))
  		return 0;
+
+	if (tpm1_getcap(chip, TPM_CAP_PROP_MANUFACTURER, &cap,
+			"attempting to determine the manufacturer",
+			sizeof(cap.manufacturer_id)))
+		goto out_ops;
+
  	str += sprintf(str, "Manufacturer: 0x%x\n",
  		       be32_to_cpu(cap.manufacturer_id));

@@ -220,11 +250,10 @@ static ssize_t caps_show(struct device *dev, struct device_attribute *attr,
  			       cap.tpm_version_1_2.revMinor);
  	} else {
  		/* Otherwise just use TPM_STRUCT_VER */
-		rc = tpm1_getcap(chip, TPM_CAP_VERSION_1_1, &cap,
-				 "attempting to determine the 1.1 version",
-				 sizeof(cap.tpm_version));
-		if (rc)
-			return 0;
+		if (tpm1_getcap(chip, TPM_CAP_VERSION_1_1, &cap,
+				"attempting to determine the 1.1 version",
+				sizeof(cap.tpm_version)))
+			goto out_ops;
  		str += sprintf(str,
  			       "TCG version: %d.%d\nFirmware version: %d.%d\n",
  			       cap.tpm_version.Major,
@@ -232,8 +261,10 @@ static ssize_t caps_show(struct device *dev, struct device_attribute *attr,
  			       cap.tpm_version.revMajor,
  			       cap.tpm_version.revMinor);
  	}
-
-	return str - buf;
+	rc = str - buf;
+out_ops:
+	tpm_put_ops(chip);
+	return rc;
  }
  static DEVICE_ATTR_RO(caps);

@@ -241,10 +272,12 @@ static ssize_t cancel_store(struct device *dev, struct device_attribute *attr,
  			    const char *buf, size_t count)
  {
  	struct tpm_chip *chip = to_tpm_chip(dev);
-	if (chip == NULL)
+
+	if (tpm_try_get_ops(chip))
  		return 0;

  	chip->ops->cancel(chip);
+	tpm_put_ops(chip);
  	return count;
  }
  static DEVICE_ATTR_WO(cancel);