[PATCH] scsi: core: configure runtime pm before calling device_add in scsi_add_host_with_dma

[PATCH] scsi: core: configure runtime pm before calling device_add in scsi_add_host_with_dma

[Heiner Kallweit]

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

diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
index ba9af4a..9ab94ad 100644
--- a/drivers/scsi/hosts.c
+++ b/drivers/scsi/hosts.c
@@ -246,10 +246,6 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
 
 	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_Host *shost, struct device *dev,
 	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_Host *shost, struct device *dev,
  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))
-- 
2.9.2

Re: [PATCH] scsi: core: configure runtime pm before calling device_add in scsi_add_host_with_dma

[Heiner Kallweit]

Am 03.08.2016 um 21:49 schrieb Heiner Kallweit:
> 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@gmail.com>
> ---
>  drivers/scsi/hosts.c | 12 ++++++++----
>  1 file changed, 8 insertions(+), 4 deletions(-)
> 
> diff --git a/drivers/scsi/hosts.c b/drivers/scsi/hosts.c
> index ba9af4a..9ab94ad 100644
> --- a/drivers/scsi/hosts.c
> +++ b/drivers/scsi/hosts.c
> @@ -246,10 +246,6 @@ int scsi_add_host_with_dma(struct Scsi_Host *shost, struct device *dev,
>  
>  	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_Host *shost, struct device *dev,
>  	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_Host *shost, struct device *dev,
>   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))
> 
Acked-by: Alan Stern <stern@rowland.harvard.edu>

Re: [PATCH] scsi: core: configure runtime pm before calling device_add in scsi_add_host_with_dma

[Martin K. Petersen]

>>>>> "Heiner" == Heiner Kallweit <hkallweit1@gmail.com> writes:

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

Applied to 4.9/scsi-queue.

-- 
Martin K. Petersen	Oracle Linux Engineering