Re: [PATCH 1/3] scsi_dh_rdac: switch to scsi_execute_req_flags()

[Christoph Hellwig <hch@lst.de>]

On Mon, Oct 31, 2016 at 06:59:28PM +0100, Hannes Reinecke wrote:
> Switch to using scsi_execute_req_flags() instead of using the
> block primitives.

__scsi_execute adds RQF_QUIET and RQF_PREEMPT to the request flags, which
would be a change in behavior.  A little analysis on why that's safe or
even desireable would be nice.  (This also applies to the other two patches
I think).

>  
>  static void release_controller(struct kref *kref)
>  static int get_lun_info(struct scsi_device *sdev, struct rdac_dh_data *h,
>  			char *array_name, u8 *array_id)
>  {
> +	int err = SCSI_DH_IO, i;
>  	struct c8_inquiry *inqp;
>  
> +	if (!scsi_get_vpd_page(sdev, 0xC8, (unsigned char *)h,
> +			       sizeof(struct c8_inquiry))) {

This looks completely bogus to me - h is a struct rdac_dh_data pointer,
which is an in-kernel data structure that scsi_get_vpd_page would
scramble over.