scsi: core: Rework scsi_single_lun_run()

Use __starget_for_each_device() instead of open-coding
starget_for_each_device(). Run the queues asynchronously instead of
synchronously.

This commit removes code that calls scsi_device_put() from atomic context.

Cc: Christoph Hellwig <hch@lst.de>
Cc: Ming Lei <ming.lei@redhat.com>
Cc: Hannes Reinecke <hare@suse.de>
Cc: John Garry <john.garry@huawei.com>
Cc: Mike Christie <michael.christie@oracle.com>
Cc: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Signed-off-by: Bart Van Assche <bvanassche@acm.org>
Link: https://lore.kernel.org/r/20221015002418.30955-6-bvanassche@acm.org
Signed-off-by: Martin K. Petersen <martin.petersen@oracle.com>

diff --git a/drivers/scsi/scsi_lib.c b/drivers/scsi/scsi_lib.c
index 8b89fab..fa96d3c 100644 (file)
--- a/drivers/scsi/scsi_lib.c
+++ b/drivers/scsi/scsi_lib.c
@@ -308,6 +308,18 @@ static void scsi_kick_queue(struct request_queue *q)
 }
 
 /*
+ * Kick the queue of SCSI device @sdev if @sdev != current_sdev. Called with
+ * interrupts disabled.
+ */
+static void scsi_kick_sdev_queue(struct scsi_device *sdev, void *data)
+{
+       struct scsi_device *current_sdev = data;
+
+       if (sdev != current_sdev)
+               blk_mq_run_hw_queues(sdev->request_queue, true);
+}
+
+/*
  * Called for single_lun devices on IO completion. Clear starget_sdev_user,
  * and call blk_run_queue for all the scsi_devices on the target -
  * including current_sdev first.
@@ -317,7 +329,6 @@ static void scsi_kick_queue(struct request_queue *q)
 static void scsi_single_lun_run(struct scsi_device *current_sdev)
 {
        struct Scsi_Host *shost = current_sdev->host;
-       struct scsi_device *sdev, *tmp;
        struct scsi_target *starget = scsi_target(current_sdev);
        unsigned long flags;
 
@@ -334,22 +345,9 @@ static void scsi_single_lun_run(struct scsi_device *current_sdev)
        scsi_kick_queue(current_sdev->request_queue);
 
        spin_lock_irqsave(shost->host_lock, flags);
-       if (starget->starget_sdev_user)
-               goto out;
-       list_for_each_entry_safe(sdev, tmp, &starget->devices,
-                       same_target_siblings) {
-               if (sdev == current_sdev)
-                       continue;
-               if (scsi_device_get(sdev))
-                       continue;
-
-               spin_unlock_irqrestore(shost->host_lock, flags);
-               scsi_kick_queue(sdev->request_queue);
-               spin_lock_irqsave(shost->host_lock, flags);
-
-               scsi_device_put(sdev);
-       }
- out:
+       if (!starget->starget_sdev_user)
+               __starget_for_each_device(starget, current_sdev,
+                                         scsi_kick_sdev_queue);
        spin_unlock_irqrestore(shost->host_lock, flags);
 }