- tpm_dev_add_device(): cdev_add() must be done before uevent is
propagated in order to avoid races.
- tpm_chip_register(): tpm_dev_add_device() must be done as the
last step before exposing device to the user space in order to
avoid races.
In addition clarified description in tpm_chip_register().
Signed-off-by: Jarkko Sakkinen <jarkko.sakki...@linux.intel.com>
---
drivers/char/tpm/tpm-chip.c | 34 ++++++++++++++--------------------
1 file changed, 14 insertions(+), 20 deletions(-)
diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 1d278cc..e096e9c 100644
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -140,24 +140,24 @@ static int tpm_dev_add_device(struct tpm_chip *chip)
{
int rc;
- rc = device_add(&chip->dev);
+ rc = cdev_add(&chip->cdev, chip->dev.devt, 1);
if (rc) {
dev_err(&chip->dev,
- "unable to device_register() %s, major %d, minor %d,
err=%d\n",
+ "unable to cdev_add() %s, major %d, minor %d, err=%d\n",
chip->devname, MAJOR(chip->dev.devt),
MINOR(chip->dev.devt), rc);
+ device_unregister(&chip->dev);
return rc;
}
- rc = cdev_add(&chip->cdev, chip->dev.devt, 1);
+ rc = device_add(&chip->dev);
if (rc) {
dev_err(&chip->dev,
- "unable to cdev_add() %s, major %d, minor %d, err=%d\n",
+ "unable to device_register() %s, major %d, minor %d,
err=%d\n",
chip->devname, MAJOR(chip->dev.devt),
MINOR(chip->dev.devt), rc);
- device_unregister(&chip->dev);
return rc;
}
@@ -174,27 +174,17 @@ static void tpm_dev_del_device(struct tpm_chip *chip)
* tpm_chip_register() - create a character device for the TPM chip
* @chip: TPM chip to use.
*
- * Creates a character device for the TPM chip and adds sysfs interfaces for
- * the device, PPI and TCPA. As the last step this function adds the
- * chip to the list of TPM chips available for use.
+ * Creates a character device for the TPM chip and adds sysfs attributes for
+ * the device. As the last step this function adds the chip to the list of TPM
+ * chips available for in-kernel use.
*
- * NOTE: This function should be only called after the chip initialization
- * is complete.
- *
- * Called from tpm_<specific>.c probe function only for devices
- * the driver has determined it should claim. Prior to calling
- * this function the specific probe function has called pci_enable_device
- * upon errant exit from this function specific probe function should call
- * pci_disable_device
+ * This function should be only called after the chip initialization is
+ * complete.
*/
int tpm_chip_register(struct tpm_chip *chip)
{
int rc;
- rc = tpm_dev_add_device(chip);
- if (rc)
- return rc;
-
/* Populate sysfs for TPM1 devices. */
if (!(chip->flags & TPM_CHIP_FLAG_TPM2)) {
rc = tpm_sysfs_add_device(chip);
@@ -208,6 +198,10 @@ int tpm_chip_register(struct tpm_chip *chip)
chip->bios_dir = tpm_bios_log_setup(chip->devname);
}
+ rc = tpm_dev_add_device(chip);
+ if (rc)
+ return rc;
+
/* Make the chip available. */
spin_lock(&driver_lock);
list_add_rcu(&chip->list, &tpm_chip_list);
--
2.1.4
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