USB: serial: rework usb_serial_register/deregister_drivers()

This reworks the usb_serial_register_drivers() and
usb_serial_deregister_drivers() to not need a pointer to a struct
usb_driver anymore.  The usb_driver structure is now created dynamically
and registered and unregistered as needed.

This saves lines of code in each usb-serial driver.  All in-kernel users
of these functions were also fixed up at this time.  The pl2303 driver
was tested that everything worked properly.

Thanks for the idea to do this from Alan Stern.

Cc: Adhir Ramjiawan <adhirramjiawan0@gmail.com>
Cc: Alan Stern <stern@rowland.harvard.edu>
Cc: Al Borchers <alborchers@steinerpoint.com>
Cc: Aleksey Babahin <tamerlan311@gmail.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Andrew Worsley <amworsley@gmail.com>
Cc: Bart Hartgers <bart.hartgers@gmail.com>
Cc: Bill Pemberton <wfp5p@virginia.edu>
Cc: Dan Carpenter <error27@gmail.com>
Cc: Dan Williams <dcbw@redhat.com>
Cc: Donald Lee <donald@asix.com.tw>
Cc: Eric Dumazet <eric.dumazet@gmail.com>
Cc: "Eric W. Biederman" <ebiederm@xmission.com>
Cc: Felipe Balbi <balbi@ti.com>
Cc: Gary Brubaker <xavyer@ix.netcom.com>
Cc: Jesper Juhl <jj@chaosbits.net>
Cc: Jiri Kosina <jkosina@suse.cz>
Cc: Johan Hovold <jhovold@gmail.com>
Cc: Julia Lawall <julia@diku.dk>
Cc: Kautuk Consul <consul.kautuk@gmail.com>
Cc: Kuninori Morimoto <kuninori.morimoto.gx@renesas.com>
Cc: Lonnie Mendez <dignome@gmail.com>
Cc: Matthias Bruestle and Harald Welte <support@reiner-sct.com>
Cc: Matthias Urlichs <smurf@smurf.noris.de>
Cc: Mauro Carvalho Chehab <mchehab@redhat.com>
Cc: Michal Sroczynski <msroczyn@gmail.com>
Cc: "Michał Wróbel" <michal.wrobel@flytronic.pl>
Cc: Oliver Neukum <oliver@neukum.name>
Cc: Paul Gortmaker <paul.gortmaker@windriver.com>
Cc: Peter Berger <pberger@brimson.com>
Cc: Preston Fick <preston.fick@silabs.com>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Cc: Rigbert Hamisch <rigbert@gmx.de>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Cc: Simon Arlott <simon@fire.lp0.eu>
Cc: Support Department <support@connecttech.com>
Cc: Thomas Tuttle <ttuttle@chromium.org>
Cc: Uwe Bonnes <bon@elektron.ikp.physik.tu-darmstadt.de>
Cc: Wang YanQing <Udknight@gmail.com>
Cc: William Greathouse <wgreathouse@smva.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 22 insertions, 16 deletions

diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index d1840aef0d53..62dd92270525 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -1364,18 +1364,19 @@ static void usb_serial_deregister(struct usb_serial_driver *device)
 
 /**
  * usb_serial_register_drivers - register drivers for a usb-serial module
- * @udriver: usb_driver used for matching devices/interfaces
  * @serial_drivers: NULL-terminated array of pointers to drivers to be registered
+ * @name: name of the usb_driver for this set of @serial_drivers
+ * @id_table: list of all devices this @serial_drivers set binds to
  *
- * Registers @udriver and all the drivers in the @serial_drivers array.
- * Automatically fills in the .no_dynamic_id and PM fields in @udriver and
- * the .usb_driver field in each serial driver.
+ * Registers all the drivers in the @serial_drivers array, and dynamically
+ * creates a struct usb_driver with the name @name and id_table of @id_table.
  */
-int usb_serial_register_drivers(struct usb_driver *udriver,
-		struct usb_serial_driver * const serial_drivers[])
+int usb_serial_register_drivers(struct usb_serial_driver *const serial_drivers[],
+				const char *name,
+				const struct usb_device_id *id_table)
 {
 	int rc;
-	const struct usb_device_id *saved_id_table;
+	struct usb_driver *udriver;
 	struct usb_serial_driver * const *sd;
 
 	/*
@@ -1386,14 +1387,16 @@ int usb_serial_register_drivers(struct usb_driver *udriver,
 	 * Performance hack: We don't want udriver to be probed until
 	 * the serial drivers are registered, because the probe would
 	 * simply fail for lack of a matching serial driver.
-	 * Therefore save off udriver's id_table until we are all set.
+	 * So we leave udriver's id_table set to NULL until we are all set.
 	 *
 	 * Suspend/resume support is implemented in the usb-serial core,
 	 * so fill in the PM-related fields in udriver.
 	 */
-	saved_id_table = udriver->id_table;
-	udriver->id_table = NULL;
+	udriver = kzalloc(sizeof(*udriver), GFP_KERNEL);
+	if (!udriver)
+		return -ENOMEM;
 
+	udriver->name = name;
 	udriver->no_dynamic_id = 1;
 	udriver->supports_autosuspend = 1;
 	udriver->suspend = usb_serial_suspend;
@@ -1411,8 +1414,8 @@ int usb_serial_register_drivers(struct usb_driver *udriver,
 			goto failed;
 	}
 
-	/* Now restore udriver's id_table and look for matches */
-	udriver->id_table = saved_id_table;
+	/* Now set udriver's id_table and look for matches */
+	udriver->id_table = id_table;
 	rc = driver_attach(&udriver->drvwrap.driver);
 	return 0;
 
@@ -1426,17 +1429,20 @@ EXPORT_SYMBOL_GPL(usb_serial_register_drivers);
 
 /**
  * usb_serial_deregister_drivers - deregister drivers for a usb-serial module
- * @udriver: usb_driver to unregister
  * @serial_drivers: NULL-terminated array of pointers to drivers to be deregistered
  *
- * Deregisters @udriver and all the drivers in the @serial_drivers array.
+ * Deregisters all the drivers in the @serial_drivers array and deregisters and
+ * frees the struct usb_driver that was created by the call to
+ * usb_serial_register_drivers().
  */
-void usb_serial_deregister_drivers(struct usb_driver *udriver,
-		struct usb_serial_driver * const serial_drivers[])
+void usb_serial_deregister_drivers(struct usb_serial_driver *const serial_drivers[])
 {
+	struct usb_driver *udriver = (*serial_drivers)->usb_driver;
+
 	for (; *serial_drivers; ++serial_drivers)
 		usb_serial_deregister(*serial_drivers);
 	usb_deregister(udriver);
+	kfree(udriver);
 }
 EXPORT_SYMBOL_GPL(usb_serial_deregister_drivers);