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tpm: fix call order in tpm-chip.c 

- 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().

Fixes: 313d21eeab ("tpm: device class for tpm")
Fixes: afb5abc262 ("tpm: two-phase chip management functions")

Signed-off-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Reviewed-by: Peter Huewe <peterhuewe@gmx.de>
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
This commit is contained in:
Jarkko Sakkinen 2015-03-01 23:55:47 +02:00 committed by Peter Huewe
parent 6da2517ddb
commit d972b0523f
1 changed files with 19 additions and 25 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

44
drivers/char/tpm/tpm-chip.c
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@ -140,16 +140,6 @@ static int tpm_dev_add_device(struct tpm_chip *chip)
{
int rc;
rc = device_add(&chip->dev);
if (rc) {
dev_err(&chip->dev,
"unable to device_register() %s, major %d, minor %d, err=%d\n",
chip->devname, MAJOR(chip->dev.devt),
MINOR(chip->dev.devt), rc);
return rc;
}
rc = cdev_add(&chip->cdev, chip->dev.devt, 1);
if (rc) {
dev_err(&chip->dev,
@ -161,6 +151,16 @@ static int tpm_dev_add_device(struct tpm_chip *chip)
return rc;
}
rc = device_add(&chip->dev);
if (rc) {
dev_err(&chip->dev,
"unable to device_register() %s, major %d, minor %d, err=%d\n",
chip->devname, MAJOR(chip->dev.devt),
MINOR(chip->dev.devt), rc);
return rc;
}
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);