freezer: introduce freezer-friendly waiting macros

Introduce freezer-friendly wrappers around wait_event_interruptible() and
wait_event_interruptible_timeout(), originally defined in <linux/wait.h>, to
be used in freezable kernel threads.  Make some of the freezable kernel
threads use them.

This is necessary for the freezer to stop sending signals to kernel threads,
which is implemented in the next patch.

Signed-off-by: Rafael J. Wysocki <rjw@sisk.pl>
Acked-by: Pavel Machek <pavel@ucw.cz>
Cc: Nigel Cunningham <nigel@nigel.suspend2.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

2 files changed, 2 insertions, 6 deletions

diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c
index 60a8f55a0cc7..036c3dea855e 100644
--- a/drivers/usb/core/hub.c
+++ b/drivers/usb/core/hub.c
@@ -2870,10 +2870,9 @@ static int hub_thread(void *__unused)
         set_freezable();
         do {
                 hub_events();
-                wait_event_interruptible(khubd_wait,
+                wait_event_freezable(khubd_wait,
                                 !list_empty(&hub_event_list) ||
                                 kthread_should_stop());
-                try_to_freeze();
         } while (!kthread_should_stop() || !list_empty(&hub_event_list));
 
         pr_debug("%s: khubd exiting\n", usbcore_name);
diff --git a/drivers/usb/storage/usb.c b/drivers/usb/storage/usb.c
index 3451e8d03ab0..ac6114eea0c3 100644
--- a/drivers/usb/storage/usb.c
+++ b/drivers/usb/storage/usb.c
@@ -907,12 +907,9 @@ static int usb_stor_scan_thread(void * __us)
         if (delay_use > 0) {
                 printk(KERN_DEBUG "usb-storage: waiting for device "
                                 "to settle before scanning\n");
-retry:
-                wait_event_interruptible_timeout(us->delay_wait,
+                wait_event_freezable_timeout(us->delay_wait,
                                 test_bit(US_FLIDX_DISCONNECTING, &us->flags),
                                 delay_use * HZ);
-                if (try_to_freeze())
-                        goto retry;
         }
 
         /* If the device is still connected, perform the scanning */