scsi: core: Rework scsi_host_block()

Make scsi_host_block() easier to read by converting it to the widely used
early-return style. See also commit f983622ae605 ("scsi: core: Avoid
calling synchronize_rcu() for each device in scsi_host_block()").

Reviewed-by: Mike Christie <[email protected]>
Reviewed-by: Ming Lei <[email protected]>
Cc: Ye Bin <[email protected]>
Cc: Hannes Reinecke <[email protected]>
Signed-off-by: Bart Van Assche <[email protected]>
Link: https://lore.kernel.org/r/[email protected]
Signed-off-by: Martin K. Petersen <[email protected]>

1 files changed, 13 insertions, 5 deletions

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index b7c569a42aa4..758a57616dd3 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2939,11 +2939,20 @@ scsi_target_unblock(struct device *dev, enum scsi_device_state new_state)
 }
 EXPORT_SYMBOL_GPL(scsi_target_unblock);
 
+/**
+ * scsi_host_block - Try to transition all logical units to the SDEV_BLOCK state
+ * @shost: device to block
+ *
+ * Pause SCSI command processing for all logical units associated with the SCSI
+ * host and wait until pending scsi_queue_rq() calls have finished.
+ *
+ * Returns zero if successful or a negative error code upon failure.
+ */
 int
 scsi_host_block(struct Scsi_Host *shost)
 {
 	struct scsi_device *sdev;
-	int ret = 0;
+	int ret;
 
 	/*
 	 * Call scsi_internal_device_block_nowait so we can avoid
@@ -2955,7 +2964,7 @@ scsi_host_block(struct Scsi_Host *shost)
 		mutex_unlock(&sdev->state_mutex);
 		if (ret) {
 			scsi_device_put(sdev);
-			break;
+			return ret;
 		}
 	}
 
@@ -2965,10 +2974,9 @@ scsi_host_block(struct Scsi_Host *shost)
 	 */
 	WARN_ON_ONCE(shost->tag_set.flags & BLK_MQ_F_BLOCKING);
 
-	if (!ret)
-		synchronize_rcu();
+	synchronize_rcu();
 
-	return ret;
+	return 0;
 }
 EXPORT_SYMBOL_GPL(scsi_host_block);