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Commit 1701f680 authored by Linus Torvalds's avatar Linus Torvalds
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Revert "ppdev: use new parport device model" 



This reverts commit e7223f18.

It causes problems when a ppdev tries to register before the parport
driver has been registered with the device model. That will trigger the

        BUG_ON(!drv->bus->p);

at drivers/base/driver.c:153. The call chain is

  kernel_init ->
    kernel_init_freeable ->
      do_one_initcall ->
        ppdev_init ->
          __parport_register_driver ->
            driver_register *BOOM*

Reported-by: default avatarkernel test robot <fengguang.wu@intel.com>
Reported-by: default avatarRoss Zwisler <zwisler@gmail.com>
Reported-by: default avatarPetr Mladek <pmladek@suse.com>
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 3b3b3bd9

drivers/char/ppdev.c

+5 −20
Original line number Diff line number Diff line
@@ -286,7 +286,7 @@ static int register_device(int minor, struct pp_struct *pp) 
	struct parport *port;

	struct pardevice *pdev = NULL;

	char *name;

	struct pardev_cb ppdev_cb;

	int fl;



	name = kasprintf(GFP_KERNEL, CHRDEV "%x", minor);

	if (name == NULL)
@@ -299,11 +299,9 @@ static int register_device(int minor, struct pp_struct *pp) 
		return -ENXIO;

	}



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

	ppdev_cb.irq_func = pp_irq;

	ppdev_cb.flags = (pp->flags & PP_EXCL) ? PARPORT_FLAG_EXCL : 0;

	ppdev_cb.private = pp;

	pdev = parport_register_dev_model(port, name, &ppdev_cb, minor);

	fl = (pp->flags & PP_EXCL) ? PARPORT_FLAG_EXCL : 0;

	pdev = parport_register_device(port, name, NULL,

				       NULL, pp_irq, fl, pp);

	parport_put_port(port);



	if (!pdev) {
@@ -801,23 +799,10 @@ static void pp_detach(struct parport *port) 
	device_destroy(ppdev_class, MKDEV(PP_MAJOR, port->number));

}



static int pp_probe(struct pardevice *par_dev)

{

	struct device_driver *drv = par_dev->dev.driver;

	int len = strlen(drv->name);



	if (strncmp(par_dev->name, drv->name, len))

		return -ENODEV;



	return 0;

}



static struct parport_driver pp_driver = {

	.name		= CHRDEV,

	.probe		= pp_probe,

	.match_port	= pp_attach,

	.attach		= pp_attach,

	.detach		= pp_detach,

	.devmodel	= true,

};



static int __init ppdev_init(void)