Re: [PATCH 18/25] Staging: hv: storvsc: Eliminate the usage of extfield in struct hv_device

[Greg KH]

On Thu, Sep 08, 2011 at 07:24:29AM -0700, K. Y. Srinivasan wrote:
> Now, eliminate the usage of ext field in struct  hv_device for storvsc driver.
> We do this by registering pointer to struct storvsc_device as the driver
> specific data and eliminating the current usage of driver specific data to
> save and retrieve the pointer to struct Scsi_Host.
> Additionally, all access to the driver specific data is through
> the vmbus wrapper functions.
> 
> Signed-off-by: K. Y. Srinivasan <kys@xxxxxxxxxxxxx>
> Signed-off-by: Haiyang Zhang <haiyangz@xxxxxxxxxxxxx>
> ---
>  drivers/staging/hv/storvsc_drv.c |   24 +++++++++++++++---------
>  1 files changed, 15 insertions(+), 9 deletions(-)
> 
> diff --git a/drivers/staging/hv/storvsc_drv.c b/drivers/staging/hv/storvsc_drv.c
> index 57c1035..98d47cd 100644
> --- a/drivers/staging/hv/storvsc_drv.c
> +++ b/drivers/staging/hv/storvsc_drv.c
> @@ -266,6 +266,7 @@ struct storvsc_device {
>  	bool	 destroy;
>  	bool	 drain_notify;
>  	atomic_t num_outstanding_req;
> +	struct Scsi_Host *host;

You are properly reference counting this pointer, right?

> @@ -306,7 +307,8 @@ static inline struct storvsc_device *get_out_stor_device(
>  {
>  	struct storvsc_device *stor_device;
>  
> -	stor_device = (struct storvsc_device *)device->ext;
> +	stor_device =
> +		(struct storvsc_device *)hv_get_drvdata(device);

Casting is not needed at all.

> @@ -1366,7 +1371,8 @@ static int storvsc_probe(struct hv_device *device,
>  	stor_device->destroy = false;
>  	init_waitqueue_head(&stor_device->waiting_to_drain);
>  	stor_device->device = device;
> -	device->ext = stor_device;
> +	stor_device->host = host;
> +	hv_set_drvdata(device, stor_device);

Lookie there, no reference count incremented, right?  Or did I miss it
somewhere else?

gotta love dynamic pointer lifetime rules...

greg k-h
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