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authorJan Kara <jack@suse.cz>2011-09-02 17:04:09 -0600
committerJens Axboe <jaxboe@fusionio.com>2011-09-02 17:17:02 -0600
commit5a042aa4b8e994a15d2c2ee750219971f0ab3905 (patch)
treed7169fad55f66551fb8e8eb845cd1807bed25c47 /mm/backing-dev.c
parent56ebdaf2fa3c5276be201c5d1aff1490b682ecf2 (diff)
downloadlinux-5a042aa4b8e994a15d2c2ee750219971f0ab3905.tar.gz
mm: Cleanup clearing of BDI_pending bit in bdi_forker_thread()
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>
Diffstat (limited to 'mm/backing-dev.c')
-rw-r--r--mm/backing-dev.c23
1 files changed, 14 insertions, 9 deletions
diff --git a/mm/backing-dev.c b/mm/backing-dev.c
index d6edf8d14f9..94a047bb6c3 100644
--- a/mm/backing-dev.c
+++ b/mm/backing-dev.c
@@ -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;