[PATCH V2 5/5] scsi: use blk-mq quiesce APIs to implement scsi_host_block

[Ming Lei]

scsi_host_block() calls synchronize_rcu() directly to wait for
quiesce done, this way is ugly since it exposes blk-mq quiesce's
implementation details.

Instead apply blk_mq_wait_quiesce_done() and
blk_mq_shared_quiesce_wait() for scsi_host_block().

Signed-off-by: Ming Lei <ming.lei at redhat.com>
---
 drivers/scsi/scsi_lib.c | 16 ++++++++--------
 1 file changed, 8 insertions(+), 8 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 5e8b5ecb3245..d93bfc08bc1a 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2952,15 +2952,15 @@ scsi_host_block(struct Scsi_Host *shost)
 		}
 	}
 
-	/*
-	 * SCSI never enables blk-mq's BLK_MQ_F_BLOCKING flag so
-	 * calling synchronize_rcu() once is enough.
-	 */
-	WARN_ON_ONCE(shost->tag_set.flags & BLK_MQ_F_BLOCKING);
-
-	if (!ret)
-		synchronize_rcu();
+	if (!ret) {
+		shost_for_each_device(sdev, shost) {
+			struct request_queue *q = sdev->request_queue;
 
+			blk_mq_wait_quiesce_done(q);
+			if (blk_mq_shared_quiesce_wait(q))
+				break;
+		}
+	}
 	return ret;
 }
 EXPORT_SYMBOL_GPL(scsi_host_block);
-- 
2.31.1