Re: [dm-devel] [PATCH 1/3] scsi_dh: Allow NULL hardware handler name in scsi_dh_attach()

[Mike Snitzer <snitzer redhat com>]

On Tue, May 08 2012 at 10:18am -0400,
Hannes Reinecke <hare suse de> wrote:

> This patch allows to pass in a NULL hardware handler to
> scsi_dh_attach(), causing the reference count of the existing
> hardware handler to be increased.
> An error will be returned if no hardware handler is attached.
> 
> Signed-off-by: Hannes Reinecke <hare suse de>
> ---
>  drivers/scsi/device_handler/scsi_dh.c |    8 ++++++--
>  1 files changed, 6 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/scsi/device_handler/scsi_dh.c b/drivers/scsi/device_handler/scsi_dh.c
> index 48e46f5..9820f1f 100644
> --- a/drivers/scsi/device_handler/scsi_dh.c
> +++ b/drivers/scsi/device_handler/scsi_dh.c
> @@ -475,10 +475,14 @@ int scsi_dh_attach(struct request_queue *q, const char *name)
>  {
>  	unsigned long flags;
>  	struct scsi_device *sdev;
> -	struct scsi_device_handler *scsi_dh;
> +	struct scsi_device_handler *scsi_dh = NULL;
>  	int err = 0;
>  
> -	scsi_dh = get_device_handler(name);
> +	if (name) {
> +		scsi_dh = get_device_handler(name);
> +	} else if (sdev && sdev->scsi_dh_data) {
> +		scsi_dh = sdev->scsi_dh_data->scsi_dh;
> +	}

Like the first time you posted this, sdev is not initialized where
you're trying to use it (the sdev initialization happens later in
scsi_dh_attach).  And you have extraneous curly braces.