tpm: Fix initialization of the cdev

commit ba0ef85479c46a2ab354c2220bdb6152f7f4baf3 upstream.

When a cdev is contained in a dynamic structure the cdev parent kobj
should be set to the kobj that controls the lifetime of the enclosing
structure. In TPM's case this is the embedded struct device.

Also, cdev_init 0's the whole structure, so all sets must be after,
not before. This fixes module ref counting and cdev.

Fixes: 313d21eeab92 ("tpm: device class for tpm")
Signed-off-by: Jason Gunthorpe <jgunthorpe@obsidianresearch.com>
Reviewed-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
Reviewed-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Tested-by: Jarkko Sakkinen <jarkko.sakkinen@linux.intel.com>
Signed-off-by: Peter Huewe <peterhuewe@gmx.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/drivers/char/tpm/tpm-chip.c b/drivers/char/tpm/tpm-chip.c
index 283f00a..1082d4b 100644 (file)
--- a/drivers/char/tpm/tpm-chip.c
+++ b/drivers/char/tpm/tpm-chip.c
@@ -129,8 +129,9 @@ struct tpm_chip *tpmm_chip_alloc(struct device *dev,
 
        device_initialize(&chip->dev);
 
-       chip->cdev.owner = chip->pdev->driver->owner;
        cdev_init(&chip->cdev, &tpm_fops);
+       chip->cdev.owner = chip->pdev->driver->owner;
+       chip->cdev.kobj.parent = &chip->dev.kobj;
 
        return chip;
 }