path: root/drivers/parport
diff options
authorLinus Torvalds <torvalds@linux-foundation.org>2019-03-25 14:49:00 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-03-25 14:49:00 -0700
commita3ac7917b73070010c05b4485b8582a6c9cd69b6 (patch)
treeb53427da682c9004dce08e67d52a7984aaef5477 /drivers/parport
parent8c2ffd9174779014c3fe1f96d9dc3641d9175f00 (diff)
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>
Diffstat (limited to 'drivers/parport')
3 files changed, 3 insertions, 41 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));
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);
- dev = parport_register_dev_model(port, name, &par_cb, devnum);
+ dev = parport_register_device(port, name, NULL, NULL, NULL, 0, NULL);
if (!dev)
return NULL;
@@ -482,31 +480,3 @@ static int assign_addrs(struct parport *port)
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);
diff --git a/drivers/parport/probe.c b/drivers/parport/probe.c
index e5e6a463a941..e035174ba205 100644
--- a/drivers/parport/probe.c
+++ b/drivers/parport/probe.c
@@ -257,7 +257,7 @@ static ssize_t parport_read_device_id (struct parport *port, char *buffer,
ssize_t parport_device_id (int devnum, char *buffer, size_t count)
ssize_t retval = -ENXIO;
- struct pardevice *dev = parport_open(devnum, daisy_dev_name);
+ struct pardevice *dev = parport_open (devnum, "Device ID probe");
if (!dev)
return -ENXIO;
diff --git a/drivers/parport/share.c b/drivers/parport/share.c
index 0171b8dbcdcd..5dc53d420ca8 100644
--- a/drivers/parport/share.c
+++ b/drivers/parport/share.c
@@ -137,19 +137,11 @@ static struct bus_type parport_bus_type = {
int parport_bus_init(void)
- int retval;
- retval = bus_register(&parport_bus_type);
- if (retval)
- return retval;
- daisy_drv_init();
- return 0;
+ return bus_register(&parport_bus_type);
void parport_bus_exit(void)
- daisy_drv_exit();