tpm: fix up the tpm_class shutdown_pre pointer when created

Do not wait until long after the struct class has been created to set
the shutdown_pre pointer for the tpm_class, assign it right away.

This is the only in-kernel offender that tries to modify the
device->class pointer contents after it has been assigned to a device,
so fix that up by doing the function pointer assignment before it is
matched with the device.  Because of this, the patch should go through
the driver core tree to allow later changes to struct device to be
possible.

Cc: Peter Huewe <peterhuewe@gmx.de>
Cc: Jarkko Sakkinen <jarkko@kernel.org>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: linux-integrity@vger.kernel.org
Reviewed-by: Jarkko Sakkinen <jarkko@kernel.org>
Link: https://lore.kernel.org/r/20230313181843.1207845-10-gregkh@linuxfoundation.orgSigned-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

drivers/char/tpm/tpm-chip.c

@@ -282,7 +282,7 @@ static void tpm_dev_release(struct device *dev)
  *
  * Return: always 0 (i.e. success)
  */
-static int tpm_class_shutdown(struct device *dev)
+int tpm_class_shutdown(struct device *dev)
 {
 	struct tpm_chip *chip = container_of(dev, struct tpm_chip, dev);
 
@@ -337,7 +337,6 @@ struct tpm_chip *tpm_chip_alloc(struct device *pdev,
 	device_initialize(&chip->dev);
 
 	chip->dev.class = tpm_class;
-	chip->dev.class->shutdown_pre = tpm_class_shutdown;
 	chip->dev.release = tpm_dev_release;
 	chip->dev.parent = pdev;
 	chip->dev.groups = chip->groups;

drivers/char/tpm/tpm-interface.c

@@ -467,6 +467,7 @@ static int __init tpm_init(void)
 	int rc;
 
 	tpm_class = class_create("tpm");
+	tpm_class->shutdown_pre = tpm_class_shutdown;
 	if (IS_ERR(tpm_class)) {
 		pr_err("couldn't create tpm class\n");
 		return PTR_ERR(tpm_class);

drivers/char/tpm/tpm.h

@@ -183,6 +183,7 @@ int tpm1_get_pcr_allocation(struct tpm_chip *chip);
 unsigned long tpm_calc_ordinal_duration(struct tpm_chip *chip, u32 ordinal);
 int tpm_pm_suspend(struct device *dev);
 int tpm_pm_resume(struct device *dev);
+int tpm_class_shutdown(struct device *dev);
 
 static inline void tpm_msleep(unsigned int delay_msec)
 {