linux-kernel - [PATCH 4.8 2/4] scsi: configure runtime pm before calling device_add in scsi_add_host_with

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Date:   Wed, 19 Oct 2016 20:31:27 +0200
From:   Greg Kroah-Hartman <gregkh@...uxfoundation.org>
To:     linux-kernel@...r.kernel.org
Cc:     Greg Kroah-Hartman <gregkh@...uxfoundation.org>,
        stable@...r.kernel.org, Heiner Kallweit <hkallweit1@...il.com>,
        Alan Stern <stern@...land.harvard.edu>,
        "Martin K. Petersen" <martin.petersen@...cle.com>
Subject: [PATCH 4.8 2/4] scsi: configure runtime pm before calling device_add in scsi_add_host_with_dma

4.8-stable review patch.  If anyone has any objections, please let me know.

------------------

From: Heiner Kallweit <hkallweit1@...il.com>

commit 0d5644b7d8daa3c1d91acb4367731f568c9c9469 upstream.

Runtime PM should be configured already once we call device_add. See
also the description in this mail thread
https://lists.linuxfoundation.org/pipermail/linux-pm/2009-November/023198.html
or the order of calls e.g. in usb_new_device.

The changed order also helps to avoid scenarios where runtime pm for
&shost->shost_gendev is activated whilst the parent is suspended,
resulting in error message "runtime PM trying to activate child device
hostx but parent yyy is not active".

In addition properly reverse the runtime pm calls in the error path.

Signed-off-by: Heiner Kallweit <hkallweit1@...il.com>
Acked-by: Alan Stern <stern@...land.harvard.edu>
Signed-off-by: Martin K. Petersen <martin.petersen@...cle.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@...uxfoundation.org>

---
 drivers/scsi/hosts.c |   12 ++++++++----
 1 file changed, 8 insertions(+), 4 deletions(-)

--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -246,10 +246,6 @@ int scsi_add_host_with_dma(struct Scsi_H

 	shost->dma_dev = dma_dev;

-	error = device_add(&shost->shost_gendev);
-	if (error)
-		goto out_destroy_freelist;
-
 	/*
 	 * Increase usage count temporarily here so that calling
 	 * scsi_autopm_put_host() will trigger runtime idle if there is
@@ -260,6 +256,10 @@ int scsi_add_host_with_dma(struct Scsi_H
 	pm_runtime_enable(&shost->shost_gendev);
 	device_enable_async_suspend(&shost->shost_gendev);

+	error = device_add(&shost->shost_gendev);
+	if (error)
+		goto out_destroy_freelist;
+
 	scsi_host_set_state(shost, SHOST_RUNNING);
 	get_device(shost->shost_gendev.parent);

@@ -309,6 +309,10 @@ int scsi_add_host_with_dma(struct Scsi_H
  out_del_gendev:
 	device_del(&shost->shost_gendev);
  out_destroy_freelist:
+	device_disable_async_suspend(&shost->shost_gendev);
+	pm_runtime_disable(&shost->shost_gendev);
+	pm_runtime_set_suspended(&shost->shost_gendev);
+	pm_runtime_put_noidle(&shost->shost_gendev);
 	scsi_destroy_command_freelist(shost);
  out_destroy_tags:
 	if (shost_use_blk_mq(shost))