apm-emulation: use wait_event_freezable() instead of freezer_[do_not_]count()
vfork is moving away from freezer_[do_not_]count() one way or the
other leaving apm_ioctl() as the only user. apm_ioctl() just wants to
wait for suspend/resume cycle to complete without hindering the
freezer. Use wait_event_freezable() instead.
The only annoyance is that wait_event_freezable() wakes up with
-ERESTART if there are pending signals while apm_ioctl() wants to
ignore all signals until suspend is complete. We can play with
@current->[real_]blocked but this is hardly a performance or latency
critical path - simply chill a bit on each iteration until
SUSPEND_DONE for unlikely cases where there are pending signals.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Oleg Nesterov <oleg@redhat.com>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>
diff --git a/drivers/char/apm-emulation.c b/drivers/char/apm-emulation.c
index 548708c..7e2709c 100644
--- a/drivers/char/apm-emulation.c
+++ b/drivers/char/apm-emulation.c
@@ -300,17 +300,13 @@
/*
* Wait for the suspend/resume to complete. If there
* are pending acknowledges, we wait here for them.
+ * wait_event_freezable() is interruptible and pending
+ * signal can cause busy looping. We aren't doing
+ * anything critical, chill a bit on each iteration.
*/
- freezer_do_not_count();
-
- wait_event(apm_suspend_waitqueue,
- as->suspend_state == SUSPEND_DONE);
-
- /*
- * Since we are waiting until the suspend is done, the
- * try_to_freeze() in freezer_count() will not trigger
- */
- freezer_count();
+ while (wait_event_freezable(apm_suspend_waitqueue,
+ as->suspend_state == SUSPEND_DONE))
+ msleep(10);
break;
case SUSPEND_ACKTO:
as->suspend_result = -ETIMEDOUT;