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authorAndi Kleen <ak@linux.intel.com>2010-06-01 17:04:42 -0400
committerGreg Kroah-Hartman <gregkh@suse.de>2010-08-10 17:35:36 -0400
commit0daeed381c6a33fdbdc3b0e9f09d96f0a2a8a195 (patch)
tree01ec5ec82b3b08a20b64e5a16cbcd3a55aaf1002 /drivers
parentc532b29a6f6d31e84a7c88f995eebdc75ebd4248 (diff)
USB-BKL: Remove BKL use for usb serial driver probing
The usb serial driver initialization tried to use the BKL to stop driver modules from unloading, but that didn't work anyways. There was already some code to do proper try_module_get, but it was conditional on having a new probe interface. I checked all the low level drivers and they all have proper .owner = THIS_MODULE, so it's ok to always use. The other problem was the usb_serial_driver_list needing protection by a lock. This was broken anyways because unregister did not necessarily have the BKL. I extended the extending table_lock mutex to protect this case too. With these changes the BKL can be removed here. Signed-off-by: Andi Kleen <ak@linux.intel.com> Cc: Arnd Bergmann <arnd@arndb.de> Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/usb/serial/usb-serial.c30
1 files changed, 14 insertions, 16 deletions
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 941c2d409f85..443468e9d66e 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -653,6 +653,7 @@ exit:
653 return id; 653 return id;
654} 654}
655 655
656/* Caller must hold table_lock */
656static struct usb_serial_driver *search_serial_device( 657static struct usb_serial_driver *search_serial_device(
657 struct usb_interface *iface) 658 struct usb_interface *iface)
658{ 659{
@@ -718,17 +719,23 @@ int usb_serial_probe(struct usb_interface *interface,
718 int num_ports = 0; 719 int num_ports = 0;
719 int max_endpoints; 720 int max_endpoints;
720 721
721 lock_kernel(); /* guard against unloading a serial driver module */ 722 mutex_lock(&table_lock);
722 type = search_serial_device(interface); 723 type = search_serial_device(interface);
723 if (!type) { 724 if (!type) {
724 unlock_kernel(); 725 mutex_unlock(&table_lock);
725 dbg("none matched"); 726 dbg("none matched");
726 return -ENODEV; 727 return -ENODEV;
727 } 728 }
728 729
730 if (!try_module_get(type->driver.owner)) {
731 mutex_unlock(&table_lock);
732 dev_err(&interface->dev, "module get failed, exiting\n");
733 return -EIO;
734 }
735 mutex_unlock(&table_lock);
736
729 serial = create_serial(dev, interface, type); 737 serial = create_serial(dev, interface, type);
730 if (!serial) { 738 if (!serial) {
731 unlock_kernel();
732 dev_err(&interface->dev, "%s - out of memory\n", __func__); 739 dev_err(&interface->dev, "%s - out of memory\n", __func__);
733 return -ENOMEM; 740 return -ENOMEM;
734 } 741 }
@@ -737,20 +744,11 @@ int usb_serial_probe(struct usb_interface *interface,
737 if (type->probe) { 744 if (type->probe) {
738 const struct usb_device_id *id; 745 const struct usb_device_id *id;
739 746
740 if (!try_module_get(type->driver.owner)) {
741 unlock_kernel();
742 dev_err(&interface->dev,
743 "module get failed, exiting\n");
744 kfree(serial);
745 return -EIO;
746 }
747
748 id = get_iface_id(type, interface); 747 id = get_iface_id(type, interface);
749 retval = type->probe(serial, id); 748 retval = type->probe(serial, id);
750 module_put(type->driver.owner); 749 module_put(type->driver.owner);
751 750
752 if (retval) { 751 if (retval) {
753 unlock_kernel();
754 dbg("sub driver rejected device"); 752 dbg("sub driver rejected device");
755 kfree(serial); 753 kfree(serial);
756 return retval; 754 return retval;
@@ -822,7 +820,6 @@ int usb_serial_probe(struct usb_interface *interface,
822 * properly during a later invocation of usb_serial_probe 820 * properly during a later invocation of usb_serial_probe
823 */ 821 */
824 if (num_bulk_in == 0 || num_bulk_out == 0) { 822 if (num_bulk_in == 0 || num_bulk_out == 0) {
825 unlock_kernel();
826 dev_info(&interface->dev, "PL-2303 hack: descriptors matched but endpoints did not\n"); 823 dev_info(&interface->dev, "PL-2303 hack: descriptors matched but endpoints did not\n");
827 kfree(serial); 824 kfree(serial);
828 return -ENODEV; 825 return -ENODEV;
@@ -835,7 +832,6 @@ int usb_serial_probe(struct usb_interface *interface,
835 if (type == &usb_serial_generic_device) { 832 if (type == &usb_serial_generic_device) {
836 num_ports = num_bulk_out; 833 num_ports = num_bulk_out;
837 if (num_ports == 0) { 834 if (num_ports == 0) {
838 unlock_kernel();
839 dev_err(&interface->dev, 835 dev_err(&interface->dev,
840 "Generic device with no bulk out, not allowed.\n"); 836 "Generic device with no bulk out, not allowed.\n");
841 kfree(serial); 837 kfree(serial);
@@ -847,7 +843,6 @@ int usb_serial_probe(struct usb_interface *interface,
847 /* if this device type has a calc_num_ports function, call it */ 843 /* if this device type has a calc_num_ports function, call it */
848 if (type->calc_num_ports) { 844 if (type->calc_num_ports) {
849 if (!try_module_get(type->driver.owner)) { 845 if (!try_module_get(type->driver.owner)) {
850 unlock_kernel();
851 dev_err(&interface->dev, 846 dev_err(&interface->dev,
852 "module get failed, exiting\n"); 847 "module get failed, exiting\n");
853 kfree(serial); 848 kfree(serial);
@@ -878,7 +873,6 @@ int usb_serial_probe(struct usb_interface *interface,
878 max_endpoints = max(max_endpoints, num_interrupt_out); 873 max_endpoints = max(max_endpoints, num_interrupt_out);
879 max_endpoints = max(max_endpoints, (int)serial->num_ports); 874 max_endpoints = max(max_endpoints, (int)serial->num_ports);
880 serial->num_port_pointers = max_endpoints; 875 serial->num_port_pointers = max_endpoints;
881 unlock_kernel();
882 876
883 dbg("%s - setting up %d port structures for this device", 877 dbg("%s - setting up %d port structures for this device",
884 __func__, max_endpoints); 878 __func__, max_endpoints);
@@ -1349,6 +1343,7 @@ int usb_serial_register(struct usb_serial_driver *driver)
1349 driver->description = driver->driver.name; 1343 driver->description = driver->driver.name;
1350 1344
1351 /* Add this device to our list of devices */ 1345 /* Add this device to our list of devices */
1346 mutex_lock(&table_lock);
1352 list_add(&driver->driver_list, &usb_serial_driver_list); 1347 list_add(&driver->driver_list, &usb_serial_driver_list);
1353 1348
1354 retval = usb_serial_bus_register(driver); 1349 retval = usb_serial_bus_register(driver);
@@ -1360,6 +1355,7 @@ int usb_serial_register(struct usb_serial_driver *driver)
1360 printk(KERN_INFO "USB Serial support registered for %s\n", 1355 printk(KERN_INFO "USB Serial support registered for %s\n",
1361 driver->description); 1356 driver->description);
1362 1357
1358 mutex_unlock(&table_lock);
1363 return retval; 1359 return retval;
1364} 1360}
1365EXPORT_SYMBOL_GPL(usb_serial_register); 1361EXPORT_SYMBOL_GPL(usb_serial_register);
@@ -1370,8 +1366,10 @@ void usb_serial_deregister(struct usb_serial_driver *device)
1370 /* must be called with BKL held */ 1366 /* must be called with BKL held */
1371 printk(KERN_INFO "USB Serial deregistering driver %s\n", 1367 printk(KERN_INFO "USB Serial deregistering driver %s\n",
1372 device->description); 1368 device->description);
1369 mutex_lock(&table_lock);
1373 list_del(&device->driver_list); 1370 list_del(&device->driver_list);
1374 usb_serial_bus_deregister(device); 1371 usb_serial_bus_deregister(device);
1372 mutex_unlock(&table_lock);
1375} 1373}
1376EXPORT_SYMBOL_GPL(usb_serial_deregister); 1374EXPORT_SYMBOL_GPL(usb_serial_deregister);
1377 1375