ChangeSet 1.2449.2.5, 2004/11/04 10:48:20-08:00, tj@home-tj.org [PATCH] driver-model: bus_recan_devices() locking fix df_02_bus_rescan_devcies_fix.patch bus_rescan_devices() eventually calls device_attach() and thus requires write locking the corresponding bus. The original code just called bus_for_each_dev() which only read locks the bus. This patch separates __bus_for_each_dev() and __bus_for_each_drv(), which don't do locking themselves, out from the original functions and call them with read lock in the original functions and with write lock in bus_rescan_devices(). Signed-off-by: Tejun Heo Signed-off-by: Greg Kroah-Hartman drivers/base/bus.c | 93 +++++++++++++++++++++++++++++++---------------------- 1 files changed, 56 insertions(+), 37 deletions(-) diff -Nru a/drivers/base/bus.c b/drivers/base/bus.c --- a/drivers/base/bus.c 2004-11-04 16:30:46 -08:00 +++ b/drivers/base/bus.c 2004-11-04 16:30:46 -08:00 @@ -135,6 +135,52 @@ decl_subsys(bus, &ktype_bus, NULL); +static int __bus_for_each_dev(struct bus_type *bus, struct device *start, + void *data, int (*fn)(struct device *, void *)) +{ + struct list_head *head; + struct device *dev; + int error = 0; + + if (!(bus = get_bus(bus))) + return -EINVAL; + + head = &bus->devices.list; + dev = list_prepare_entry(start, head, bus_list); + list_for_each_entry_continue(dev, head, bus_list) { + get_device(dev); + error = fn(dev, data); + put_device(dev); + if (error) + break; + } + put_bus(bus); + return error; +} + +static int __bus_for_each_drv(struct bus_type *bus, struct device_driver *start, + void * data, int (*fn)(struct device_driver *, void *)) +{ + struct list_head *head; + struct device_driver *drv; + int error = 0; + + if (!(bus = get_bus(bus))) + return -EINVAL; + + head = &bus->drivers.list; + drv = list_prepare_entry(start, head, kobj.entry); + list_for_each_entry_continue(drv, head, kobj.entry) { + get_driver(drv); + error = fn(drv, data); + put_driver(drv); + if (error) + break; + } + put_bus(bus); + return error; +} + /** * bus_for_each_dev - device iterator. * @bus: bus type. @@ -154,30 +200,16 @@ * to retain this data, it should do, and increment the reference * count in the supplied callback. */ + int bus_for_each_dev(struct bus_type * bus, struct device * start, void * data, int (*fn)(struct device *, void *)) { - struct device *dev; - struct list_head * head; - int error = 0; - - if (!(bus = get_bus(bus))) - return -EINVAL; - - head = &bus->devices.list; - dev = list_prepare_entry(start, head, bus_list); + int ret; down_read(&bus->subsys.rwsem); - list_for_each_entry_continue(dev, head, bus_list) { - get_device(dev); - error = fn(dev, data); - put_device(dev); - if (error) - break; - } + ret = __bus_for_each_dev(bus, start, data, fn); up_read(&bus->subsys.rwsem); - put_bus(bus); - return error; + return ret; } /** @@ -203,27 +235,12 @@ int bus_for_each_drv(struct bus_type * bus, struct device_driver * start, void * data, int (*fn)(struct device_driver *, void *)) { - struct list_head * head; - struct device_driver *drv; - int error = 0; - - if(!(bus = get_bus(bus))) - return -EINVAL; - - head = &bus->drivers.list; - drv = list_prepare_entry(start, head, kobj.entry); + int ret; down_read(&bus->subsys.rwsem); - list_for_each_entry_continue(drv, head, kobj.entry) { - get_driver(drv); - error = fn(drv, data); - put_driver(drv); - if(error) - break; - } + ret = __bus_for_each_drv(bus, start, data, fn); up_read(&bus->subsys.rwsem); - put_bus(bus); - return error; + return ret; } /** @@ -590,7 +607,9 @@ { int count = 0; - bus_for_each_dev(bus, NULL, &count, bus_rescan_devices_helper); + down_write(&bus->subsys.rwsem); + __bus_for_each_dev(bus, NULL, &count, bus_rescan_devices_helper); + up_write(&bus->subsys.rwsem); return count; }