[PATCH v3 5/8] scsi: don't wait for quiesce in scsi_stop_queue()

mwilck
2023-06-07T18:24:14Z

From: Martin Wilck <mwilck@suse.com>

scsi_stop_queue() has just two callers, one with and one without
"nowait". As blk_mq_quiesce_queue() comes down to
blk_mq_quiesce_queue_nowait() followed by blk_mq_wait_quiesce_done(),
we might as well open-code this in scsi_device_block().

Signed-off-by: Martin Wilck <mwilck@suse.com>
---
drivers/scsi/scsi_lib.c | 24 +++++++++---------------
1 file changed, 9 insertions(+), 15 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 26e7ce25fa05..657d10c57205 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2726,24 +2726,16 @@ void scsi_start_queue(struct scsi_device *sdev)
blk_mq_unquiesce_queue(sdev->request_queue);
}

-static void scsi_stop_queue(struct scsi_device *sdev, bool nowait)
+static void scsi_stop_queue(struct scsi_device *sdev)
{
/*
* The atomic variable of ->queue_stopped covers that
* blk_mq_quiesce_queue* is balanced with blk_mq_unquiesce_queue.
*
- * However, we still need to wait until quiesce is done
- * in case that queue has been stopped.
+ * After return, we still need to wait until quiesce is done.
*/
- if (!cmpxchg(&sdev->queue_stopped, 0, 1)) {
- if (nowait)
- blk_mq_quiesce_queue_nowait(sdev->request_queue);
- else
- blk_mq_quiesce_queue(sdev->request_queue);
- } else {
- if (!nowait)
- blk_mq_wait_quiesce_done(sdev->request_queue->tag_set);
- }
+ if (!cmpxchg(&sdev->queue_stopped, 0, 1))
+ blk_mq_quiesce_queue_nowait(sdev->request_queue);
}

/**
@@ -2770,7 +2762,7 @@ int scsi_internal_device_block_nowait(struct scsi_device *sdev)
* request queue.
*/
if (!ret)
- scsi_stop_queue(sdev, true);
+ scsi_stop_queue(sdev);
return ret;
}
EXPORT_SYMBOL_GPL(scsi_internal_device_block_nowait);
@@ -2796,8 +2788,10 @@ static void scsi_device_block(struct scsi_device *sdev, void *data)
mutex_lock(&sdev->state_mutex);
err = __scsi_internal_device_block_nowait(sdev);
mutex_unlock(&sdev->state_mutex);
- if (err == 0)
- scsi_stop_queue(sdev, false);
+ if (err == 0) {
+ scsi_stop_queue(sdev);
+ blk_mq_wait_quiesce_done(sdev->request_queue->tag_set);
+ }

WARN_ONCE(err, "__scsi_internal_device_block_nowait(%s) failed: err = %d\n",
dev_name(&sdev->sdev_gendev), err);
--
2.40.1