[PATCH v4 1/5] scsi: core: Rework scsi_host_block()

Bart Van Assche
2023-05-29T20:26:50Z

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 <michael.christie@oracle.com>
Reviewed-by: Ming Lei <ming.lei@redhat.com>
Cc: Ye Bin <yebin10@huawei.com>
Cc: Hannes Reinecke <hare@suse.de>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
---
drivers/scsi/scsi_lib.c | 18 +++++++++++++-----
1 file changed, 13 insertions(+), 5 deletions(-)

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 25489fbd94c6..5f29faa0560f 100644
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -2940,11 +2940,20 @@ 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
@@ -2956,7 +2965,7 @@ scsi_host_block(struct Scsi_Host *shost)
mutex_unlock(&sdev->state_mutex);
if (ret) {
scsi_device_put(sdev);
- break;
+ return ret;
}
}

@@ -2966,10 +2975,9 @@ 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);