Revert "parport: daisy: use new parport device model"

This reverts commit 1aec4211204d9463d1fd209eb50453de16254599.

Steven Rostedt reports that it causes a hang at bootup and bisected it
to this commit.

The troigger is apparently a module alias for "parport_lowlevel" that
points to "parport_pc", which causes a hang with

    modprobe -q -- parport_lowlevel

blocking forever with a backtrace like this:

    wait_for_completion_killable+0x1c/0x28
    call_usermodehelper_exec+0xa7/0x108
    __request_module+0x351/0x3d8
    get_lowlevel_driver+0x28/0x41 [parport]
    __parport_register_driver+0x39/0x1f4 [parport]
    daisy_drv_init+0x31/0x4f [parport]
    parport_bus_init+0x5d/0x7b [parport]
    parport_default_proc_register+0x26/0x1000 [parport]
    do_one_initcall+0xc2/0x1e0
    do_init_module+0x50/0x1d4
    load_module+0x1c2e/0x21b3
    sys_init_module+0xef/0x117

Supid says:
 "Due to the new device model daisy driver will now try to find the
  parallel ports while trying to register its driver so that it can bind
  with them. Now, since daisy driver is loaded while parport bus is
  initialising the list of parport is still empty and it tries to load
  the lowlevel driver, which has an alias set to parport_pc, now causes
  a deadlock"

But I don't think the daisy driver should be loaded by the parport
initialization in the first place, so let's revert the whole change.

If the daisy driver can just initialize separately on its own (like a
driver should), instead of hooking into the parport init sequence
directly, this issue probably would go away.

Reported-and-bisected-by: Steven Rostedt (VMware) <rostedt@goodmis.org>
Reported-by: Michal Kubecek <mkubecek@suse.cz>
Acked-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Sudip Mukherjee <sudipm.mukherjee@gmail.com>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 1 insertions, 31 deletions

diff --git a/drivers/parport/daisy.c b/drivers/parport/daisy.c
index 56dd83a45e55..5484a46dafda 100644
--- a/drivers/parport/daisy.c
+++ b/drivers/parport/daisy.c
@@ -213,12 +213,10 @@ void parport_daisy_fini(struct parport *port)
 struct pardevice *parport_open(int devnum, const char *name)
 {
 	struct daisydev *p = topology;
-	struct pardev_cb par_cb;
 	struct parport *port;
 	struct pardevice *dev;
 	int daisy;
 
-	memset(&par_cb, 0, sizeof(par_cb));
 	spin_lock(&topology_lock);
 	while (p && p->devnum != devnum)
 		p = p->next;
@@ -232,7 +230,7 @@ struct pardevice *parport_open(int devnum, const char *name)
 	port = parport_get_port(p->port);
 	spin_unlock(&topology_lock);
 
-	dev = parport_register_dev_model(port, name, &par_cb, devnum);
+	dev = parport_register_device(port, name, NULL, NULL, NULL, 0, NULL);
 	parport_put_port(port);
 	if (!dev)
 		return NULL;
@@ -482,31 +480,3 @@ static int assign_addrs(struct parport *port)
 	kfree(deviceid);
 	return detected;
 }
-
-static int daisy_drv_probe(struct pardevice *par_dev)
-{
-	struct device_driver *drv = par_dev->dev.driver;
-
-	if (strcmp(drv->name, "daisy_drv"))
-		return -ENODEV;
-	if (strcmp(par_dev->name, daisy_dev_name))
-		return -ENODEV;
-
-	return 0;
-}
-
-static struct parport_driver daisy_driver = {
-	.name = "daisy_drv",
-	.probe = daisy_drv_probe,
-	.devmodel = true,
-};
-
-int daisy_drv_init(void)
-{
-	return parport_register_driver(&daisy_driver);
-}
-
-void daisy_drv_exit(void)
-{
-	parport_unregister_driver(&daisy_driver);
-}