diff options
| author | Hugh Daschbach <hdasch@broadcom.com> | 2010-03-22 10:36:37 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2010-05-21 09:37:30 -0700 |
| commit | 6245838fe4d2ce4aab52f543224f7d1212d9155c (patch) | |
| tree | eabeb6ae52ae80f42ccb34bf479a60748989bf59 | |
| parent | e177123f0c2d77ed2fde724ca352166ca9464619 (diff) | |
| download | linux-6245838fe4d2ce4aab52f543224f7d1212d9155c.tar.bz2 | |
Driver core: Protect device shutdown from hot unplug events.
While device_shutdown() walks through devices_kset to shutdown all
devices, device unplug events may race to shutdown individual devices.
Specifically, sd_shutdown(), on behalf of fc_starget_delete(), has
been observed deleting devices during device_shutdown()'s list
traversal. So we factor out list_for_each_entry_safe_reverse(...) in
favor of while (!list_empty(...)).
Signed-off-by: Hugh Daschbach <hdasch@broadcom.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
| -rw-r--r-- | drivers/base/core.c | 25 |
1 files changed, 22 insertions, 3 deletions
diff --git a/drivers/base/core.c b/drivers/base/core.c index 4c5be85016b6..356dd011b8f9 100644 --- a/drivers/base/core.c +++ b/drivers/base/core.c @@ -1734,10 +1734,25 @@ EXPORT_SYMBOL_GPL(device_move); */ void device_shutdown(void) { - struct device *dev, *devn; + struct device *dev; + + spin_lock(&devices_kset->list_lock); + /* + * Walk the devices list backward, shutting down each in turn. + * Beware that device unplug events may also start pulling + * devices offline, even as the system is shutting down. + */ + while (!list_empty(&devices_kset->list)) { + dev = list_entry(devices_kset->list.prev, struct device, + kobj.entry); + get_device(dev); + /* + * Make sure the device is off the kset list, in the + * event that dev->*->shutdown() doesn't remove it. + */ + list_del_init(&dev->kobj.entry); + spin_unlock(&devices_kset->list_lock); - list_for_each_entry_safe_reverse(dev, devn, &devices_kset->list, - kobj.entry) { if (dev->bus && dev->bus->shutdown) { dev_dbg(dev, "shutdown\n"); dev->bus->shutdown(dev); @@ -1745,6 +1760,10 @@ void device_shutdown(void) dev_dbg(dev, "shutdown\n"); dev->driver->shutdown(dev); } + put_device(dev); + + spin_lock(&devices_kset->list_lock); } + spin_unlock(&devices_kset->list_lock); async_synchronize_full(); } |