block: blk_cleanup_queue() should call blk_sync_queue()

When a driver calls blk_cleanup_queue(), the device should be fully idle.
However, the block layer may have pending plugging timers and the IO
schedulers may have pending work in the work queues. So quisce the device
by waiting for the timer and flushing the work queues.

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/block/blk-core.c b/block/blk-core.c
index d768a8ddc173a7ae5b0162c43218bd244e1aadb7..37fba001bdcf6b9a0174fdf40c6c8eb3eeda7fac 100644 (file)
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -436,6 +436,14 @@ void blk_put_queue(struct request_queue *q)
 
 void blk_cleanup_queue(struct request_queue *q)
 {
+       /*
+        * We know we have process context here, so we can be a little
+        * cautious and ensure that pending block actions on this device
+        * are done before moving on. Going into this function, we should
+        * not have processes doing IO to this device.
+        */
+       blk_sync_queue(q);
+
        mutex_lock(&q->sysfs_lock);
        queue_flag_set_unlocked(QUEUE_FLAG_DEAD, q);
        mutex_unlock(&q->sysfs_lock);