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mm: Cleanup clearing of BDI_pending bit in bdi_forker_thread()

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bdi_forker_thread() clears BDI_pending bit at the end of the main loop.
However clearing of this bit must not be done in some cases which is
handled by calling 'continue' from switch statement. That's kind of
unusual construct and without a good reason so change the function into
more intuitive code flow.

CC: Wu Fengguang <fengguang.wu@intel.com>
CC: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Jan Kara <jack@suse.cz>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>
This commit is contained in:
Jan Kara 2011-09-02 17:04:09 -06:00 committed by Jens Axboe
parent 56ebdaf2fa
commit 5a042aa4b8
1 changed files with 14 additions and 9 deletions
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23
mm/backing-dev.c
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@ -359,6 +359,17 @@ static unsigned long bdi_longest_inactive(void)
return max(5UL * 60 * HZ, interval);
}
/*
* Clear pending bit and wakeup anybody waiting for flusher thread creation or
* shutdown
*/
static void bdi_clear_pending(struct backing_dev_info *bdi)
{
clear_bit(BDI_pending, &bdi->state);
smp_mb__after_clear_bit();
wake_up_bit(&bdi->state, BDI_pending);
}
static int bdi_forker_thread(void *ptr)
{
struct bdi_writeback *me = ptr;
@ -469,11 +480,13 @@ static int bdi_forker_thread(void *ptr)
spin_unlock_bh(&bdi->wb_lock);
wake_up_process(task);
}
bdi_clear_pending(bdi);
break;
case KILL_THREAD:
__set_current_state(TASK_RUNNING);
kthread_stop(task);
bdi_clear_pending(bdi);
break;
case NO_ACTION:
@ -489,16 +502,8 @@ static int bdi_forker_thread(void *ptr)
else
schedule_timeout(msecs_to_jiffies(dirty_writeback_interval * 10));
try_to_freeze();
/* Back to the main loop */
continue;
break;
}
/*
* Clear pending bit and wakeup anybody waiting to tear us down.
*/
clear_bit(BDI_pending, &bdi->state);
smp_mb__after_clear_bit();
wake_up_bit(&bdi->state, BDI_pending);
}
return 0;