From 1d927c3b5a4005a2ebc5356e7e1eec436e15fa22 Mon Sep 17 00:00:00 2001 From: Tejun Heo Date: Thu, 18 Aug 2011 10:06:53 +0200 Subject: [PATCH] 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 Cc: Oleg Nesterov Signed-off-by: Jiri Kosina --- drivers/char/apm-emulation.c | 16 ++++++---------- 1 file changed, 6 insertions(+), 10 deletions(-) diff --git a/drivers/char/apm-emulation.c b/drivers/char/apm-emulation.c index 548708c4b2b8..7e2709c35fcf 100644 --- a/drivers/char/apm-emulation.c +++ b/drivers/char/apm-emulation.c @@ -300,17 +300,13 @@ apm_ioctl(struct file *filp, u_int cmd, u_long arg) /* * 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;