Re: [PATCH 4/6] ibmvfc: add FC payload retrieval routines for versioned vfcFrames

[Brian King <brking@linux.vnet.ibm.com>]

On 11/11/20 7:04 PM, Tyrel Datwyler wrote:
> The FC iu and response payloads are located at different offsets
> depending on the ibmvfc_cmd version. This is a result of the version 2
> vfcFrame definition adding an extra 64bytes of reserved space to the
> structure prior to the payloads.
> 
> Add helper routines to determine the current vfcFrame version and
> returning pointers to the proper iu or response structures within that
> ibmvfc_cmd.
> 
> Signed-off-by: Tyrel Datwyler <tyreld@linux.ibm.com>
> ---
>  drivers/scsi/ibmvscsi/ibmvfc.c | 76 ++++++++++++++++++++++++----------
>  1 file changed, 53 insertions(+), 23 deletions(-)
> 
> diff --git a/drivers/scsi/ibmvscsi/ibmvfc.c b/drivers/scsi/ibmvscsi/ibmvfc.c
> index aa3445bec42c..5e666f7c9266 100644
> --- a/drivers/scsi/ibmvscsi/ibmvfc.c
> +++ b/drivers/scsi/ibmvscsi/ibmvfc.c
> @@ -138,6 +138,22 @@ static void ibmvfc_tgt_move_login(struct ibmvfc_target *);
>  
>  static const char *unknown_error = "unknown error";
>  
> +static struct ibmvfc_fcp_cmd_iu *ibmvfc_get_fcp_iu(struct ibmvfc_host *vhost, struct ibmvfc_cmd *vfc_cmd)
> +{
> +	if (be64_to_cpu(vhost->login_buf->resp.capabilities) & IBMVFC_HANDLE_VF_WWPN)

Suggest adding a flag to the vhost structure that you setup after login in order to
simplify this check and avoid chasing multiple pointers along with a byte swap.

Maybe something like:

vhost->is_v2

> +		return &vfc_cmd->v2.iu;
> +	else
> +		return &vfc_cmd->v1.iu;
> +}
> +
> +static struct ibmvfc_fcp_rsp *ibmvfc_get_fcp_rsp(struct ibmvfc_host *vhost, struct ibmvfc_cmd *vfc_cmd)
> +{
> +	if (be64_to_cpu(vhost->login_buf->resp.capabilities) & IBMVFC_HANDLE_VF_WWPN)

Same here

> +		return &vfc_cmd->v2.rsp;
> +	else
> +		return &vfc_cmd->v1.rsp;
> +}
> +
>  #ifdef CONFIG_SCSI_IBMVFC_TRACE
>  /**
>   * ibmvfc_trc_start - Log a start trace entry



-- 
Brian King
Power Linux I/O
IBM Linux Technology Center